[RFC PATCH v2 21/31] kvx: Add system call support
Yann Sionneau
ysionneau at kalray.eu
Fri Jan 20 06:09:52 PST 2023
Add system call support and related uaccess.h for kvx.
Co-developed-by: Clement Leger <clement at clement-leger.fr>
Signed-off-by: Clement Leger <clement at clement-leger.fr>
Co-developed-by: Guillaume Thouvenin <gthouvenin at kalray.eu>
Signed-off-by: Guillaume Thouvenin <gthouvenin at kalray.eu>
Co-developed-by: Julian Vetter <jvetter at kalray.eu>
Signed-off-by: Julian Vetter <jvetter at kalray.eu>
Co-developed-by: Julien Villette <jvillette at kalray.eu>
Signed-off-by: Julien Villette <jvillette at kalray.eu>
Co-developed-by: Marius Gligor <mgligor at kalray.eu>
Signed-off-by: Marius Gligor <mgligor at kalray.eu>
Co-developed-by: Yann Sionneau <ysionneau at kalray.eu>
Signed-off-by: Yann Sionneau <ysionneau at kalray.eu>
---
Notes:
V1 -> V2:
- typo fixes (clober* -> clobber*)
- use generic __access_ok
arch/kvx/include/asm/syscall.h | 73 ++
arch/kvx/include/asm/syscalls.h | 21 +
arch/kvx/include/asm/uaccess.h | 317 +++++
arch/kvx/include/asm/unistd.h | 11 +
arch/kvx/include/uapi/asm/cachectl.h | 25 +
arch/kvx/include/uapi/asm/unistd.h | 16 +
arch/kvx/kernel/entry.S | 1759 ++++++++++++++++++++++++++
arch/kvx/kernel/sys_kvx.c | 58 +
arch/kvx/kernel/syscall_table.c | 19 +
9 files changed, 2299 insertions(+)
create mode 100644 arch/kvx/include/asm/syscall.h
create mode 100644 arch/kvx/include/asm/syscalls.h
create mode 100644 arch/kvx/include/asm/uaccess.h
create mode 100644 arch/kvx/include/asm/unistd.h
create mode 100644 arch/kvx/include/uapi/asm/cachectl.h
create mode 100644 arch/kvx/include/uapi/asm/unistd.h
create mode 100644 arch/kvx/kernel/entry.S
create mode 100644 arch/kvx/kernel/sys_kvx.c
create mode 100644 arch/kvx/kernel/syscall_table.c
diff --git a/arch/kvx/include/asm/syscall.h b/arch/kvx/include/asm/syscall.h
new file mode 100644
index 000000000000..a3f6cef73e4a
--- /dev/null
+++ b/arch/kvx/include/asm/syscall.h
@@ -0,0 +1,73 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2017-2023 Kalray Inc.
+ * Author(s): Clement Leger
+ */
+
+#ifndef _ASM_KVX_SYSCALL_H
+#define _ASM_KVX_SYSCALL_H
+
+#include <linux/err.h>
+#include <linux/audit.h>
+
+#include <asm/ptrace.h>
+
+/* The array of function pointers for syscalls. */
+extern void *sys_call_table[];
+
+void scall_machine_exit(unsigned char value);
+
+/**
+ * syscall_get_nr - find which system call a task is executing
+ * @task: task of interest, must be blocked
+ * @regs: task_pt_regs() of @task
+ *
+ * If @task is executing a system call or is at system call
+ * tracing about to attempt one, returns the system call number.
+ * If @task is not executing a system call, i.e. it's blocked
+ * inside the kernel for a fault or signal, returns -1.
+ *
+ * Note this returns int even on 64-bit machines. Only 32 bits of
+ * system call number can be meaningful. If the actual arch value
+ * is 64 bits, this truncates to 32 bits so 0xffffffff means -1.
+ *
+ * It's only valid to call this when @task is known to be blocked.
+ */
+static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
+{
+ if (!in_syscall(regs))
+ return -1;
+
+ return es_sysno(regs);
+}
+
+static inline long syscall_get_error(struct task_struct *task,
+ struct pt_regs *regs)
+{
+ /* 0 if syscall succeeded, otherwise -Errorcode */
+ return IS_ERR_VALUE(regs->r0) ? regs->r0 : 0;
+}
+
+static inline long syscall_get_return_value(struct task_struct *task,
+ struct pt_regs *regs)
+{
+ return regs->r0;
+}
+
+static inline int syscall_get_arch(struct task_struct *task)
+{
+ return AUDIT_ARCH_KVX;
+}
+
+static inline void syscall_get_arguments(struct task_struct *task,
+ struct pt_regs *regs,
+ unsigned long *args)
+{
+ args[0] = regs->orig_r0;
+ args++;
+ memcpy(args, ®s->r1, 5 * sizeof(args[0]));
+}
+
+int __init setup_syscall_sigreturn_page(void *sigpage_addr);
+
+#endif
diff --git a/arch/kvx/include/asm/syscalls.h b/arch/kvx/include/asm/syscalls.h
new file mode 100644
index 000000000000..beec95ebb97a
--- /dev/null
+++ b/arch/kvx/include/asm/syscalls.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2017-2023 Kalray Inc.
+ * Author(s): Clement Leger
+ */
+
+#ifndef _ASM_KVX_SYSCALLS_H
+#define _ASM_KVX_SYSCALLS_H
+
+#include <asm-generic/syscalls.h>
+
+/* We redefine clone in assembly for special slowpath */
+asmlinkage long __sys_clone(unsigned long clone_flags, unsigned long newsp,
+ int __user *parent_tid, int __user *child_tid, int tls);
+
+#define sys_clone __sys_clone
+
+long sys_cachectl(unsigned long addr, unsigned long len, unsigned long cache,
+ unsigned long flags);
+
+#endif
diff --git a/arch/kvx/include/asm/uaccess.h b/arch/kvx/include/asm/uaccess.h
new file mode 100644
index 000000000000..24f91d75c1dd
--- /dev/null
+++ b/arch/kvx/include/asm/uaccess.h
@@ -0,0 +1,317 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * derived from arch/riscv/include/asm/uaccess.h
+ *
+ * Copyright (C) 2017-2023 Kalray Inc.
+ * Author(s): Clement Leger
+ * Guillaume Thouvenin
+ */
+
+#ifndef _ASM_KVX_UACCESS_H
+#define _ASM_KVX_UACCESS_H
+
+#include <linux/sched.h>
+#include <linux/types.h>
+
+/**
+ * access_ok: - Checks if a user space pointer is valid
+ * @addr: User space pointer to start of block to check
+ * @size: Size of block to check
+ *
+ * Context: User context only. This function may sleep.
+ *
+ * Checks if a pointer to a block of memory in user space is valid.
+ *
+ * Returns true (nonzero) if the memory block may be valid, false (zero)
+ * if it is definitely invalid.
+ *
+ * Note that, depending on architecture, this function probably just
+ * checks that the pointer is in the user space range - after calling
+ * this function, memory access functions may still return -EFAULT.
+ */
+#define access_ok(addr, size) ({ \
+ __chk_user_ptr(addr); \
+ likely(__access_ok((addr), (size))); \
+})
+
+#include <asm-generic/access_ok.h>
+
+/*
+ * The exception table consists of pairs of addresses: the first is the
+ * address of an instruction that is allowed to fault, and the second is
+ * the address at which the program should continue. No registers are
+ * modified, so it is entirely up to the continuation code to figure out
+ * what to do.
+ *
+ * All the routines below use bits of fixup code that are out of line
+ * with the main instruction path. This means when everything is well,
+ * we don't even have to jump over them. Further, they do not intrude
+ * on our cache or TLB entries.
+ */
+
+struct exception_table_entry {
+ unsigned long insn, fixup;
+};
+
+extern int fixup_exception(struct pt_regs *regs);
+
+/**
+ * Assembly defined function (usercopy.S)
+ */
+extern unsigned long
+raw_copy_from_user(void *to, const void __user *from, unsigned long n);
+
+extern unsigned long
+raw_copy_to_user(void __user *to, const void *from, unsigned long n);
+
+extern unsigned long
+asm_clear_user(void __user *to, unsigned long n);
+
+#define __clear_user asm_clear_user
+
+static inline __must_check unsigned long
+clear_user(void __user *to, unsigned long n)
+{
+ might_fault();
+ if (!access_ok(to, n))
+ return n;
+
+ return asm_clear_user(to, n);
+}
+
+extern __must_check long strnlen_user(const char __user *str, long n);
+extern long strncpy_from_user(char *dest, const char __user *src, long count);
+
+#define __enable_user_access()
+#define __disable_user_access()
+
+/**
+ * get_user: - Get a simple variable from user space.
+ * @x: Variable to store result.
+ * @ptr: Source address, in user space.
+ *
+ * Context: User context only. This function may sleep.
+ *
+ * This macro copies a single simple variable from user space to kernel
+ * space. It supports simple types like char and int, but not larger
+ * data types like structures or arrays.
+ *
+ * @ptr must have pointer-to-simple-variable type, and the result of
+ * dereferencing @ptr must be assignable to @x without a cast.
+ *
+ * Returns zero on success, or -EFAULT on error.
+ * On error, the variable @x is set to zero.
+ */
+#define get_user(x, ptr) \
+({ \
+ long __e = -EFAULT; \
+ const __typeof__(*(ptr)) __user *__p = (ptr); \
+ might_fault(); \
+ if (likely(access_ok(__p, sizeof(*__p)))) { \
+ __e = __get_user(x, __p); \
+ } else { \
+ x = 0; \
+ } \
+ __e; \
+})
+
+/**
+ * __get_user: - Get a simple variable from user space, with less checking.
+ * @x: Variable to store result.
+ * @ptr: Source address, in user space.
+ *
+ * Context: User context only. This function may sleep.
+ *
+ * This macro copies a single simple variable from user space to kernel
+ * space. It supports simple types like char and int, but not larger
+ * data types like structures or arrays.
+ *
+ * @ptr must have pointer-to-simple-variable type, and the result of
+ * dereferencing @ptr must be assignable to @x without a cast.
+ *
+ * Caller must check the pointer with access_ok() before calling this
+ * function.
+ *
+ * Returns zero on success, or -EFAULT on error.
+ * On error, the variable @x is set to zero.
+ */
+#define __get_user(x, ptr) \
+({ \
+ unsigned long __err = 0; \
+ __chk_user_ptr(ptr); \
+ \
+ __enable_user_access(); \
+ __get_user_nocheck(x, ptr, __err); \
+ __disable_user_access(); \
+ \
+ __err; \
+})
+
+#define __get_user_nocheck(x, ptr, err) \
+do { \
+ unsigned long __gu_addr = (unsigned long)(ptr); \
+ unsigned long __gu_val; \
+ switch (sizeof(*(ptr))) { \
+ case 1: \
+ __get_user_asm("lbz", __gu_val, __gu_addr, err); \
+ break; \
+ case 2: \
+ __get_user_asm("lhz", __gu_val, __gu_addr, err); \
+ break; \
+ case 4: \
+ __get_user_asm("lwz", __gu_val, __gu_addr, err); \
+ break; \
+ case 8: \
+ __get_user_asm("ld", __gu_val, __gu_addr, err); \
+ break; \
+ default: \
+ BUILD_BUG(); \
+ } \
+ (x) = (__typeof__(*(ptr)))__gu_val; \
+} while (0)
+
+#define __get_user_asm(op, x, addr, err) \
+({ \
+ __asm__ __volatile__( \
+ "1: "op" %1 = 0[%2]\n" \
+ " ;;\n" \
+ "2:\n" \
+ ".section .fixup,\"ax\"\n" \
+ "3: make %0 = 2b\n" \
+ " make %1 = 0\n" \
+ " ;;\n" \
+ " make %0 = %3\n" \
+ " igoto %0\n" \
+ " ;;\n" \
+ ".previous\n" \
+ ".section __ex_table,\"a\"\n" \
+ " .align 8\n" \
+ " .dword 1b,3b\n" \
+ ".previous" \
+ : "=r"(err), "=r"(x) \
+ : "r"(addr), "i"(-EFAULT), "0"(err)); \
+})
+
+/**
+ * put_user: - Write a simple value into user space.
+ * @x: Value to copy to user space.
+ * @ptr: Destination address, in user space.
+ *
+ * Context: User context only. This function may sleep.
+ *
+ * This macro copies a single simple value from kernel space to user
+ * space. It supports simple types like char and int, but not larger
+ * data types like structures or arrays.
+ *
+ * @ptr must have pointer-to-simple-variable type, and @x must be assignable
+ * to the result of dereferencing @ptr.
+ *
+ * Returns zero on success, or -EFAULT on error.
+ */
+#define put_user(x, ptr) \
+({ \
+ long __e = -EFAULT; \
+ __typeof__(*(ptr)) __user *__p = (ptr); \
+ might_fault(); \
+ if (likely(access_ok(__p, sizeof(*__p)))) { \
+ __e = __put_user(x, __p); \
+ } \
+ __e; \
+})
+
+/**
+ * __put_user: - Write a simple value into user space, with less checking.
+ * @x: Value to copy to user space.
+ * @ptr: Destination address, in user space.
+ *
+ * Context: User context only. This function may sleep.
+ *
+ * This macro copies a single simple value from kernel space to user
+ * space. It supports simple types like char and int, but not larger
+ * data types like structures or arrays.
+ *
+ * @ptr must have pointer-to-simple-variable type, and @x must be assignable
+ * to the result of dereferencing @ptr.
+ *
+ * Caller must check the pointer with access_ok() before calling this
+ * function.
+ *
+ * Returns zero on success, or -EFAULT on error.
+ */
+#define __put_user(x, ptr) \
+({ \
+ unsigned long __err = 0; \
+ __chk_user_ptr(ptr); \
+ \
+ __enable_user_access(); \
+ __put_user_nocheck(x, ptr, __err); \
+ __disable_user_access(); \
+ \
+ __err; \
+})
+
+#define __put_user_nocheck(x, ptr, err) \
+do { \
+ unsigned long __pu_addr = (unsigned long)(ptr); \
+ __typeof__(*(ptr)) __pu_val = (x); \
+ switch (sizeof(*(ptr))) { \
+ case 1: \
+ __put_user_asm("sb", __pu_val, __pu_addr, err); \
+ break; \
+ case 2: \
+ __put_user_asm("sh", __pu_val, __pu_addr, err); \
+ break; \
+ case 4: \
+ __put_user_asm("sw", __pu_val, __pu_addr, err); \
+ break; \
+ case 8: \
+ __put_user_asm("sd", __pu_val, __pu_addr, err); \
+ break; \
+ default: \
+ BUILD_BUG(); \
+ } \
+} while (0)
+
+#define __put_user_asm(op, x, addr, err) \
+({ \
+ __asm__ __volatile__( \
+ "1: "op" 0[%2], %1\n" \
+ " ;;\n" \
+ "2:\n" \
+ ".section .fixup,\"ax\"\n" \
+ "3: make %0 = 2b\n" \
+ " ;;\n" \
+ " make %0 = %3\n" \
+ " igoto %0\n" \
+ " ;;\n" \
+ ".previous\n" \
+ ".section __ex_table,\"a\"\n" \
+ " .align 8\n" \
+ " .dword 1b,3b\n" \
+ ".previous" \
+ : "=r"(err) \
+ : "r"(x), "r"(addr), "i"(-EFAULT), "0"(err)); \
+})
+
+#define HAVE_GET_KERNEL_NOFAULT
+
+#define __get_kernel_nofault(dst, src, type, err_label) \
+do { \
+ long __kr_err; \
+ \
+ __get_user_nocheck(*((type *)(dst)), (type *)(src), __kr_err); \
+ if (unlikely(__kr_err)) \
+ goto err_label; \
+} while (0)
+
+#define __put_kernel_nofault(dst, src, type, err_label) \
+do { \
+ long __kr_err; \
+ \
+ __put_user_nocheck(*((type *)(src)), (type *)(dst), __kr_err); \
+ if (unlikely(__kr_err)) \
+ goto err_label; \
+} while (0)
+
+
+#endif /* _ASM_KVX_UACCESS_H */
diff --git a/arch/kvx/include/asm/unistd.h b/arch/kvx/include/asm/unistd.h
new file mode 100644
index 000000000000..6cd093dbf2d8
--- /dev/null
+++ b/arch/kvx/include/asm/unistd.h
@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2017-2023 Kalray Inc.
+ * Author(s): Clement Leger
+ */
+
+#define __ARCH_WANT_SYS_CLONE
+
+#include <uapi/asm/unistd.h>
+
+#define NR_syscalls (__NR_syscalls)
diff --git a/arch/kvx/include/uapi/asm/cachectl.h b/arch/kvx/include/uapi/asm/cachectl.h
new file mode 100644
index 000000000000..be0a1aa23cf6
--- /dev/null
+++ b/arch/kvx/include/uapi/asm/cachectl.h
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0-only WITH Linux-syscall-note */
+/*
+ * Copyright (C) 2017-2023 Kalray Inc.
+ * Author(s): Clement Leger
+ */
+
+#ifndef _UAPI_ASM_KVX_CACHECTL_H
+#define _UAPI_ASM_KVX_CACHECTL_H
+
+/*
+ * Cache type for cachectl system call
+ */
+#define CACHECTL_CACHE_DCACHE (1 << 0)
+
+/*
+ * Flags for cachectl system call
+ */
+#define CACHECTL_FLAG_OP_INVAL (1 << 0)
+#define CACHECTL_FLAG_OP_WB (1 << 1)
+#define CACHECTL_FLAG_OP_MASK (CACHECTL_FLAG_OP_INVAL | \
+ CACHECTL_FLAG_OP_WB)
+
+#define CACHECTL_FLAG_ADDR_PHYS (1 << 2)
+
+#endif /* _UAPI_ASM_KVX_CACHECTL_H */
diff --git a/arch/kvx/include/uapi/asm/unistd.h b/arch/kvx/include/uapi/asm/unistd.h
new file mode 100644
index 000000000000..5f86d81dbb76
--- /dev/null
+++ b/arch/kvx/include/uapi/asm/unistd.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0-only WITH Linux-syscall-note */
+/*
+ * Copyright (C) 2017-2023 Kalray Inc.
+ * Author(s): Clement Leger
+ */
+
+#define __ARCH_WANT_RENAMEAT
+#define __ARCH_WANT_NEW_STAT
+#define __ARCH_WANT_SET_GET_RLIMIT
+#define __ARCH_WANT_SYS_CLONE3
+
+#include <asm-generic/unistd.h>
+
+/* Additional KVX specific syscalls */
+#define __NR_cachectl (__NR_arch_specific_syscall)
+__SYSCALL(__NR_cachectl, sys_cachectl)
diff --git a/arch/kvx/kernel/entry.S b/arch/kvx/kernel/entry.S
new file mode 100644
index 000000000000..e73dc2221c06
--- /dev/null
+++ b/arch/kvx/kernel/entry.S
@@ -0,0 +1,1759 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2017-2023 Kalray Inc.
+ * Author(s): Clement Leger
+ * Guillaume Thouvenin
+ * Marius Gligor
+ * Yann Sionneau
+ * Julien Villette
+ */
+
+#include <linux/linkage.h>
+
+#include <asm/thread_info.h>
+#include <asm/asm-offsets.h>
+#include <asm/cache.h>
+#include <asm/page.h>
+#include <asm/pgtable-bits.h>
+#include <asm/sys_arch.h>
+#include <asm/sfr_defs.h>
+#include <asm/tlb_defs.h>
+#include <asm/mem_map.h>
+#include <asm/traps.h>
+#include <asm/unistd.h>
+
+#define MMU_SET_MASK ((1 << KVX_SFR_MMC_SS_WIDTH) - 1)
+
+/* Mask to replicate data from 32bits LSB to MSBs */
+#define REPLICATE_32_MASK 0x0804020108040201
+
+#define PS_HWLOOP_ENABLE (KVX_SFR_PS_HLE_MASK << 32)
+#define PS_HWLOOP_DISABLE (KVX_SFR_PS_HLE_MASK)
+#define PS_HWLOOP_EN_ET_CLEAR_DAUS_DIS \
+ (PS_HWLOOP_ENABLE | KVX_SFR_PS_ET_MASK | SFR_SET_VAL_WFXL(PS, DAUS, 0))
+#define PS_ET_CLEAR KVX_SFR_PS_ET_MASK
+#define PS_HLE_EN_IT_EN_ET_CLEAR_DAUS_DIS \
+ (SFR_SET_VAL_WFXL(PS, HLE, 1) | \
+ SFR_SET_VAL_WFXL(PS, IE, 1) | \
+ SFR_SET_VAL_WFXL(PS, ET, 0) | \
+ SFR_SET_VAL_WFXL(PS, DAUS, 0))
+
+#define PS_IT_DIS KVX_SFR_PS_IE_MASK
+#define PS_IL_CLEAR KVX_SFR_PS_IL_WFXL_CLEAR
+
+#define MMC_CLEAR_TLB_CLEAR_WAY \
+ (SFR_CLEAR_WFXL(MMC, SB) | SFR_CLEAR_WFXL(MMC, SW))
+
+#define MMC_SEL_TLB_CLEAR_WAY(__tlb) \
+ (SFR_SET_WFXL(MMC, SB, __tlb) | MMC_CLEAR_TLB_CLEAR_WAY)
+#define MMC_SEL_JTLB_CLEAR_WAY MMC_SEL_TLB_CLEAR_WAY(MMC_SB_JTLB)
+#define MMC_SEL_LTLB_CLEAR_WAY MMC_SEL_TLB_CLEAR_WAY(MMC_SB_LTLB)
+
+#define MME_WFXL(_enable) SFR_SET_VAL_WFXL(PS, MME, _enable)
+
+/* Temporary scract system register for trap handling */
+#define TMP_SCRATCH_SR $sr_pl3
+
+.altmacro
+
+#define TEL_DEFAULT_VALUE (TLB_ES_A_MODIFIED << KVX_SFR_TEL_ES_SHIFT)
+
+#define TASK_THREAD_SAVE_AREA_QUAD(__q) \
+ (TASK_THREAD_SAVE_AREA + (__q) * QUAD_REG_SIZE)
+
+#ifdef CONFIG_DEBUG_EXCEPTION_STACK
+.section .rodata
+stack_error_panic_str_label:
+ .string "Stack has been messed up !"
+#endif
+
+#ifdef CONFIG_KVX_DEBUG_TLB_WRITE
+.section .rodata
+mmc_error_panic_str_label:
+ .string "Failed to write entry to the JTLB (in assembly refill)"
+#endif
+
+#ifdef CONFIG_KVX_DEBUG_ASN
+.section .rodata
+asn_error_panic_str_label:
+ .string "ASN mismatch !"
+#endif
+
+/**
+ * call_trace_hardirqs: hardirqs tracing call
+ * state: State of hardirqs to be reported (on/off)
+ */
+.macro call_trace_hardirqs state
+#ifdef CONFIG_TRACE_IRQFLAGS
+ call trace_hardirqs_\state
+ ;;
+#endif
+.endm
+
+/**
+ * disable_interrupts: Disable interrupts
+ * tmp_reg: Temporary register to use for interrupt disabling
+ */
+.macro disable_interrupt tmp_reg
+ make \tmp_reg = KVX_SFR_PS_IE_MASK
+ ;;
+ wfxl $ps, \tmp_reg
+ ;;
+.endm
+
+/**
+ * call_do_work_pending: Call do_work_pending and set stack argument ($r0)
+ * NOTE: Since do_work_pending requires thread_flags in $r1, they must
+ * be provided in $r1 before calling this macro.
+ * Moreover, do_work_pending expects interrupts to be disabled.
+ */
+.macro call_do_work_pending
+ copyd $r0 = $sp
+ call do_work_pending
+ ;;
+.endm
+
+/**
+ * save_quad_regs: Save quad registers in temporary thread area
+ * After call, the quad is saved in task_struct.thread.save_area.
+ * sr_swap_reg is only used as a temporary value and will be
+ * restored after returning from this macro
+ *
+ * quad: Quad to saved
+ * sr_swap_reg: Register used for sr swap and quad saving.
+ */
+.macro save_quad_regs quad sr_swap_reg
+ rswap \sr_swap_reg = $sr
+ ;;
+ /* Save registers in save_area */
+ so __PA(TASK_THREAD_SAVE_AREA_QUAD(0))[\sr_swap_reg] = \quad
+ /* Restore register */
+ rswap \sr_swap_reg = $sr
+ ;;
+.endm
+
+/**
+ * Switch task when entering kernel if needed.
+ * sp_reg: register which will be used to store original stack pointer when
+ * entering the kernel
+ * task_reg: is a register containing the current task pointer
+ * save_regs_label: label to jump to save register immediately. This label is
+ * used when we are already in kernel execution context.
+ * NOTE: when returning from this macro, we consider that the assembly following
+ * it will be executed only when coming from user space
+ */
+.macro switch_stack sp_reg task_reg save_regs_label
+ get \sp_reg = $sps
+ ;;
+ /* Check if $sps.pl bit is 0 (ie in kernel mode)
+ * if so, then we dont have to switch stack */
+ cb.even \sp_reg? \save_regs_label
+ /* Copy original $sp in a scratch reg */
+ copyd \sp_reg = $sp
+ ;;
+ /* restore sp from kernel stack pointer */
+ ld $sp = __PA(TASK_THREAD_KERNEL_SP)[\task_reg]
+ ;;
+.endm
+
+/**
+ * Disable MMU using a specified register
+ * scratch_reg: Scratch register to be used for $ps modification (clobbered)
+ * ps_val: Additionnal $ps modifications after returning disabling MMU
+ */
+.macro disable_mmu scratch_reg ps_val=0
+ /* Disable MME in $sps */
+ make \scratch_reg = MME_WFXL(0)
+ ;;
+ wfxl $sps = \scratch_reg
+ ;;
+ /* Enable DAUS in $ps */
+ make \scratch_reg = SFR_SET_VAL_WFXL(PS, DAUS, 1) | \ps_val
+ ;;
+ wfxl $ps = \scratch_reg
+ /* We are now accessing data with MMU disabled */
+ ;;
+.endm
+
+/**
+ * Disable MMU when entering exception path
+ * This macro does not require any register since used register will be
+ * restored after use. This can safely be used directly after entering
+ * exceptions.
+ */
+.macro exception_entry_disable_mmu
+ set TMP_SCRATCH_SR = $r0
+ disable_mmu $r0
+ ;;
+ get $r0 = TMP_SCRATCH_SR
+ ;;
+.endm
+
+/* Save callee registers on stack */
+.macro save_callee
+ sq PT_R18R19[$sp] = $r18r19
+ ;;
+ so PT_Q20[$sp] = $r20r21r22r23
+ ;;
+ so PT_Q24[$sp] = $r24r25r26r27
+ ;;
+ so PT_Q28[$sp] = $r28r29r30r31
+ ;;
+.endm
+
+/**
+ * Save registers for entry in kernel space.
+ * sp_reg should point to the original stack pointer when entering kernel space
+ * task_reg is a register containing the current task pointer
+ * both task_reg and sp_reg must be in saved_quad since they have been
+ * clobberred and will be restored when restoring saved_quad.
+ * pt_regs_sp is a single register which will be filled by pt_regs addr.
+ * When "returning" from this macro, hardware loop are enabled and exception
+ * is cleared, allowing to call kernel function without any risk.
+ */
+.macro save_regs_for_exception sp_reg task_reg saved_quad pt_regs_sp
+.if (\saved_quad==$r4r5r6r7 || \saved_quad==$r60r61r62r63)
+.error "saved_quad must not be $r4r5r6r7 or $r60r61r62r63 !"
+.endif
+ /* make some room on stack to save registers */
+ addd $sp = $sp, -(PT_SIZE_ON_STACK)
+ so __PA(PT_Q4-PT_SIZE_ON_STACK)[$sp] = $r4r5r6r7
+ /* Compute physical address of stack to avoid using 64bits immediate */
+ addd $r6 = $sp, VA_TO_PA_OFFSET - (PT_SIZE_ON_STACK)
+ ;;
+ so PT_Q60[$r6] = $r60r61r62r63
+ /* Now that $r60r61r62r63 is saved, we can use it for saving
+ * original stack stored in scratch_reg. Note that we can not
+ * use the r12r13r14r15 quad to do that because it would
+ * modify the current $r12/sp ! This is if course not what we
+ * want and hence we use the freshly saved quad $r60r61r62r63.
+ *
+ * Note that we must use scratch_reg before reloading the saved
+ * quad since the scratch reg is contained in it, so reloading
+ * it before copying it would overwrite it.
+ */
+ copyd $r60 = \sp_reg
+ ;;
+ /* Reload the saved quad registers to save correct values
+ * Since we use the scratch reg before that */
+ lo \saved_quad = __PA(TASK_THREAD_SAVE_AREA_QUAD(0))[\task_reg]
+ ;;
+ so PT_Q8[$r6] = $r8r9r10r11
+ ;;
+ so PT_Q0[$r6] = $r0r1r2r3
+ copyd $r61 = $r13
+ get $r5 = $le
+ ;;
+ sq PT_R16R17[$r6] = $r16r17
+ make $r10 = 0x0
+ copyd $r62 = $r14
+ ;;
+ so PT_Q32[$r6] = $r32r33r34r35
+ /* Since we are going to enable hardware loop, we must be careful
+ * and reset le (loop exit) to avoid any exploit and return to
+ * user with kernel mode */
+ set $le = $r10
+ copyd $r63 = $r15
+ ;;
+ so PT_Q36[$r6] = $r36r37r38r39
+ get $r0 = $cs
+ ;;
+ so PT_Q40[$r6] = $r40r41r42r43
+ get $r1 = $spc
+ ;;
+ so PT_Q44[$r6] = $r44r45r46r47
+ get $r2 = $sps
+ ;;
+ so PT_Q48[$r6] = $r48r49r50r51
+ get $r3 = $es
+ ;;
+ so PT_Q52[$r6] = $r52r53r54r55
+ get $r7 = $ra
+ ;;
+ so PT_Q56[$r6] = $r56r57r58r59
+ get $r4 = $lc
+ ;;
+ so PT_Q12[$r6] = $r60r61r62r63
+ copyd $r63 = $r6
+ get $r6 = $ls
+ ;;
+ so PT_CS_SPC_SPS_ES[$r63] = $r0r1r2r3
+ ;;
+ so PT_LC_LE_LS_RA[$r63] = $r4r5r6r7
+ /* Clear frame pointer */
+ make $fp = 0
+ ;;
+ /* Copy regs stack pointer for macro caller */
+ copyd \pt_regs_sp = $sp
+#ifdef CONFIG_DEBUG_EXCEPTION_STACK
+ addd $sp = $sp, -STACK_REG_SIZE
+ ;;
+ sd VA_TO_PA_OFFSET[$sp] = $sp
+ ;;
+#endif
+ /* Reenable hwloop, MMU and clear exception taken */
+ make $r8 = PS_HWLOOP_EN_ET_CLEAR_DAUS_DIS
+ ;;
+ wfxl $ps, $r8
+ ;;
+.endm
+
+/***********************************************************************
+* Exception vectors trampolines
+***********************************************************************/
+#define exception_trampoline(__type) \
+.section .exception.## __type, "ax", @progbits ;\
+ENTRY(kvx_##__type ##_handler_trampoline): ;\
+ goto kvx_## __type ##_handler ;\
+ ;; ;\
+ENDPROC(kvx_ ## __type ## _handler_trampoline) ;\
+.section .early_exception.## __type, "ax", @progbits ;\
+ENTRY(kvx_## __type ##_early_handler): ;\
+1: nop ;\
+ ;; ;\
+ goto 1b ;\
+ ;; ;\
+ENDPROC(kvx_ ## __type ## _early_handler)
+
+exception_trampoline(debug)
+exception_trampoline(trap)
+exception_trampoline(interrupt)
+exception_trampoline(syscall)
+
+#define EXCEPTION_ENTRY(__name) \
+.section .exception.text, "ax", @progbits ;\
+ENTRY(__name)
+
+
+/***********************************************************************
+* Common exception return path
+***********************************************************************/
+/**
+ * Restore registers after exception
+ * When entering this macro, $sp must be located right before regs
+ * storage.
+ */
+EXCEPTION_ENTRY(return_from_exception)
+#ifdef CONFIG_DEBUG_EXCEPTION_STACK
+ ld $r1 = 0[$sp]
+ ;;
+ sbfd $r1 = $r1, $sp
+ ;;
+ cb.deqz $r1, _check_ok
+ ;;
+ make $r2 = panic
+ make $r0 = stack_error_panic_str_label
+ ;;
+ icall $r2
+ ;;
+_check_ok:
+ addd $sp = $sp, STACK_REG_SIZE
+ ;;
+#endif
+ get $r11 = $sr
+ /* Load sps value from saved registers */
+ ld $r6 = PT_SPS[$sp]
+ ;;
+ /* Disable interrupt to check task flags atomically */
+ disable_interrupt $r60
+ ;;
+ /* Check PL bit of sps, if set, then it means we are returning
+ * to a lower privilege level (ie to user), if so, we need to
+ * check work pending. If coming from kernel, directly go to
+ * register restoration */
+ cb.even $r6? _restore_regs
+ ld $r1 = TASK_TI_FLAGS[$r11]
+ ;;
+ /* Do we have work pending ? */
+ andd $r5 = $r1, _TIF_WORK_MASK
+ ;;
+ /**
+ * If we do not have work pending (ie $r5 == 0) then we can
+ * directly jump to _restore_regs without calling do_work_pending
+ */
+ cb.deqz $r5? _restore_regs
+ ;;
+ /*
+ * Work pending can potentially call a signal handler and then return
+ * via rt_sigreturn. Return path will be different (restore all regs)
+ * and hence all registers are needed to be saved.
+ */
+ save_callee
+ ;;
+ call_do_work_pending
+ ;;
+#ifdef CONFIG_TRACE_IRQFLAGS
+ /* reload sps value from saved registers */
+ ld $r6 = PT_SPS[$sp]
+ ;;
+#endif
+_restore_regs:
+#ifdef CONFIG_TRACE_IRQFLAGS
+ /* Check if IRQs are going to be reenable in next context */
+ andd $r6 = $r6, KVX_SFR_SPS_IE_MASK
+ ;;
+ cb.deqz $r6? 1f
+ ;;
+ call trace_hardirqs_on
+ ;;
+1:
+#endif
+ disable_mmu $r0, PS_HWLOOP_DISABLE
+ ;;
+ lo $r0r1r2r3 = __PA(PT_CS_SPC_SPS_ES)[$sp]
+ /* Compute physical address of stack to avoid using 64bits immediate */
+ addd $r11 = $sp, VA_TO_PA_OFFSET
+ ;;
+ lo $r4r5r6r7 = PT_LC_LE_LS_RA[$r11]
+ ;;
+ lo $r60r61r62r63 = PT_Q60[$r11]
+ ;;
+ lo $r56r57r58r59 = PT_Q56[$r11]
+ ;;
+ lo $r52r53r54r55 = PT_Q52[$r11]
+ get $r14 = $sps
+ ;;
+ lo $r48r49r50r51 = PT_Q48[$r11]
+ /* Generate a mask of ones at each bit where the current $sps
+ * differs from the $sps to be restored
+ */
+ xord $r14 = $r2, $r14
+ /* prepare wfxl clear mask on LSBs */
+ notd $r15 = $r2
+ /* prepare wfxl set mask on MSBs */
+ slld $r13 = $r2, 32
+ ;;
+ lo $r44r45r46r47 = PT_Q44[$r11]
+ /* Replicate mask of ones on the 32 MSBs */
+ sbmm8 $r14 = $r14, REPLICATE_32_MASK
+ /* Combine the set and clear mask for wfxl */
+ insf $r13 = $r15, 31, 0
+ ;;
+ lo $r40r41r42r43 = PT_Q40[$r11]
+ set $lc = $r4
+ /* Mask to drop identical bits in order to avoid useless
+ * privilege traps
+ */
+ andd $r13 = $r13, $r14
+ ;;
+ lq $r16r17 = PT_R16R17[$r11]
+ set $le = $r5
+ ;;
+ lo $r32r33r34r35 = PT_Q32[$r11]
+ set $ls = $r6
+ ;;
+ lo $r36r37r38r39 = PT_Q36[$r11]
+ copyd $r14 = $r11
+ set $ra = $r7
+ ;;
+ lo $r8r9r10r11 = PT_Q8[$r14]
+ set $cs = $r0
+ /* MME was disabled by disable_mmu, reenable it before leaving */
+ ord $r13 = $r13, SFR_SET_VAL_WFXL(SPS, MME, 1)
+ ;;
+ lo $r4r5r6r7 = PT_Q4[$r14]
+ set $spc = $r1
+ ;;
+ lo $r0r1r2r3 = PT_Q0[$r14]
+ /* Store $sps wfxl value in scratch system register */
+ set TMP_SCRATCH_SR = $r13
+ ;;
+ lo $r12r13r14r15 = PT_Q12[$r14]
+ rswap $r0 = TMP_SCRATCH_SR
+ ;;
+ wfxl $sps = $r0
+ ;;
+ /* Finally, restore $r0 value */
+ rswap $r0 = TMP_SCRATCH_SR
+ ;;
+ rfe
+ ;;
+ENDPROC(return_from_exception)
+
+/***********************************************************************
+* Debug handling
+***********************************************************************/
+EXCEPTION_ENTRY(kvx_debug_handler):
+ exception_entry_disable_mmu
+ ;;
+ save_quad_regs $r0r1r2r3 $r4
+ ;;
+ get $r2 = $sr
+ ;;
+ switch_stack $r1 $r2 debug_save_regs
+ ;;
+debug_save_regs:
+ save_regs_for_exception $r1 $r2 $r0r1r2r3 $r1
+ ;;
+ get $r0 = $ea
+ /* tail-call for return_from_exception */
+ make $r3 = return_from_exception
+ ;;
+ set $ra = $r3
+ ;;
+ goto debug_handler
+ ;;
+ENDPROC(kvx_debug_handler)
+
+/***********************************************************************
+* Traps handling
+***********************************************************************/
+/* These labels will be used for instruction patching */
+.global kvx_perf_tlb_refill, kvx_std_tlb_refill
+EXCEPTION_ENTRY(kvx_trap_handler):
+ /* Enable DAUS for physical data access */
+ exception_entry_disable_mmu
+ ;;
+ /* Save r3 in a temporary system register to check if the trap is a
+ * nomapping or not */
+ set TMP_SCRATCH_SR = $r3
+ ;;
+ get $r3 = $es
+ ;;
+ /* Hardware trap cause */
+ extfz $r3 = $r3, KVX_SFR_END(ES_HTC), KVX_SFR_START(ES_HTC)
+ ;;
+ /* Is this a nomapping trap ? */
+ compd.eq $r3 = $r3, KVX_TRAP_NOMAPPING
+ ;;
+ /* if nomapping trap, try fast_refill */
+ cb.even $r3? trap_slow_path
+ ;;
+ /*
+ * Fast TLB refill routine
+ *
+ * On kvx, we do not have hardware page walking, hence, TLB refill is
+ * done using the core on no-mapping traps.
+ * This routine must be as fast as possible to avoid wasting CPU time.
+ * For that purpose, it is called directly from trap_handle after saving
+ * only 8 registers ($r0 -> $r7) in a dedicated buffer.
+ * To avoid taking nomapping while accessing page tables inside this
+ * refill handler we switch to physical accesses using DAUS.
+ * Once the switch is done, we save up to 8 registers to compute
+ * the refill data.
+ * This allows to avoid computing a complete task switching in order
+ * to greatly reduce the refill time.
+ *
+ * We refill the JTLB which contains 128 sets with 4 way each.
+ * Currently, the way selection is done using a round robin algorithm.
+ *
+ * The refill is using the basic flow:
+ * 1 - Enable physical access using DAUS.
+ * 2 - Save necessary registers
+ * 3 - Walk the page table to find the TLB entry to add (virtual to
+ * physical)
+ * 4 - Compute the TLB entry to be written (convert PTE to TLB entry)
+ * 5 - Compute the target set (0 -> 127) for the new TLB entry
+ * This is done by extracting the 6 lsb of page number
+ * 6 - Get the current way to be used which is selected using a
+ simple round robin
+ * 7 - Mark PTE entry as _PAGE_ACCESSED (and optionally PAGE_DIRTY)
+ * 8 - Commit the new tlb entry
+ * 9 - Restore the virtual memory by disabling DAUS.
+ *
+ */
+ /* Get current task */
+ rswap $r63 = $sr
+ ;;
+#ifdef CONFIG_KVX_MMU_STATS
+ get $r3 = $pm0
+ ;;
+ sd __PA(TASK_THREAD_ENTRY_TS)[$r63] = $r3
+ ;;
+#endif
+ /* Restore $r3 from temporary system scratch register */
+ get $r3 = TMP_SCRATCH_SR
+ /* Save registers to save $tel, $teh and $mmc */
+ so __PA(TASK_THREAD_SAVE_AREA_QUAD(2))[$r63] = $r8r9r10r11
+ ;;
+ get $r8 = $tel
+ /* Save register for refill handler */
+ so __PA(TASK_THREAD_SAVE_AREA_QUAD(1))[$r63] = $r4r5r6r7
+ ;;
+ /* Get exception address */
+ get $r0 = $ea
+ /* Save more registers to be comfy */
+ so __PA(TASK_THREAD_SAVE_AREA_QUAD(0))[$r63] = $r0r1r2r3
+ ;;
+ get $r9 = $teh
+ ;;
+ get $r10 = $mmc
+ ;;
+ /* Restore $r63 value */
+ rswap $r63 = $sr
+ /* Check kernel address range */
+ addd $r4 = $r0, -KERNEL_DIRECT_MEMORY_MAP_BASE
+ /* Load task active mm for pgd loading in macro_tlb_refill */
+ ld $r1 = __PA(TASK_ACTIVE_MM)[$r63]
+ ;;
+kvx_perf_tlb_refill:
+ /* Check if the address is in the kernel direct memory mapping */
+ compd.ltu $r3 = $r4, KERNEL_DIRECT_MEMORY_MAP_SIZE
+ /* Clear low bits of virtual address to align on page size */
+ andd $r5 = $r0, ~(REFILL_PERF_PAGE_SIZE - 1)
+ /* Create corresponding physical address */
+ addd $r2 = $r4, PHYS_OFFSET
+ ;;
+ /* If address is not a kernel one, take the standard path */
+ cb.deqz $r3? kvx_std_tlb_refill
+ /* Prepare $teh value with virtual address and kernel value */
+ ord $r7 = $r5, REFILL_PERF_TEH_VAL
+ ;;
+ /* Get $pm0 value as a pseudo random value for LTLB way to use */
+ get $r4 = $pm0
+ /* Clear low bits of physical address to align on page size */
+ andd $r2 = $r2, ~(REFILL_PERF_PAGE_SIZE - 1)
+ /* Prepare value for $mmc wfxl to select LTLB and correct way */
+ make $r5 = MMC_SEL_LTLB_CLEAR_WAY
+ ;;
+ /* Keep low bits of timer value */
+ andw $r4 = $r4, (REFILL_PERF_ENTRIES - 1)
+ /* Get current task pointer for register restoration */
+ get $r11 = $sr
+ ;;
+ /* Add LTLB base way number for kernel refill way */
+ addw $r4 = $r4, LTLB_KERNEL_RESERVED
+ /* Prepare $tel value with physical address and kernel value */
+ ord $r6 = $r2, REFILL_PERF_TEL_VAL
+ set $teh = $r7
+ ;;
+ /* insert way in $mmc wfxl value */
+ insf $r5 = $r4, KVX_SFR_END(MMC_SW) + 32, KVX_SFR_START(MMC_SW) + 32
+ set $tel = $r6
+ ;;
+ wfxl $mmc = $r5
+ ;;
+ goto do_tlb_write
+ ;;
+kvx_std_tlb_refill:
+ /* extract PGD offset */
+ extfz $r3 = $r0, (ASM_PGDIR_SHIFT + ASM_PGDIR_BITS - 1), ASM_PGDIR_SHIFT
+ /* is mm NULL ? if so, use init_mm */
+ cmoved.deqz $r1? $r1 = init_mm
+ ;;
+ get $r7 = $pcr
+ /* Load pgd base address into $r1 */
+ ld $r1 = __PA(MM_PGD)[$r1]
+ ;;
+ /* Add offset for physical address */
+ addd $r1 = $r1, VA_TO_PA_OFFSET
+ /* Extract processor ID to compute cpu_offset*/
+ extfz $r7 = $r7, KVX_SFR_END(PCR_PID), KVX_SFR_START(PCR_PID)
+ ;;
+ /* Load PGD entry offset */
+ ld.xs $r1 = $r3[$r1]
+ /* Load per_cpu_offset */
+#if defined(CONFIG_SMP)
+ make $r5 = __PA(__per_cpu_offset)
+#endif
+ ;;
+ /* extract PMD offset*/
+ extfz $r3 = $r0, (ASM_PMD_SHIFT + ASM_PMD_BITS - 1), ASM_PMD_SHIFT
+ /* If pgd entry is null -> out */
+ cb.deqz $r1? refill_err_out
+#if defined(CONFIG_SMP)
+ /* Load cpu offset */
+ ld.xs $r7 = $r7[$r5]
+#else
+ /* Force cpu offset to 0 */
+ make $r7 = 0
+#endif
+ ;;
+ /* Load PMD entry offset and keep pointer to the entry for huge page */
+ addx8d $r2 = $r3, $r1
+ ld.xs $r1 = $r3[$r1]
+ ;;
+ /* Check if it is a huge page (2Mb or 512Mb in PMD table)*/
+ andd $r6 = $r1, _PAGE_HUGE
+ /* If pmd entry is null -> out */
+ cb.deqz $r1? refill_err_out
+ /* extract PTE offset */
+ extfz $r3 = $r0, (PAGE_SHIFT + 8), PAGE_SHIFT
+ ;;
+ /*
+ * If the page is a huge one we already have set the PTE and the
+ * pointer to the PTE.
+ */
+ cb.dnez $r6? is_huge_page
+ ;;
+ /* Load PTE entry */
+ ld.xs $r1 = $r3[$r1]
+ addx8d $r2 = $r3, $r1
+ ;;
+ /* Check if it is a huge page (64Kb in PTE table) */
+ andd $r6 = $r1, _PAGE_HUGE
+ ;;
+ /* Check if PTE entry is for a huge page */
+ cb.dnez $r6? is_huge_page
+ ;;
+ /* 4K: Extract set value */
+ extfz $r0 = $r1, (PAGE_SHIFT + KVX_SFR_MMC_SS_WIDTH - 1), PAGE_SHIFT
+ /* 4K: Extract virt page from ea */
+ andd $r4 = $r0, PAGE_MASK
+ ;;
+/*
+ * This path expects the following:
+ * - $r0 = set index
+ * - $r1 = pte entry
+ * - $r2 = pte entry address
+ * - $r4 = virtual page address
+ */
+pte_prepared:
+ /* Compute per_cpu_offset + current way of set address */
+ addd $r5 = $r0, $r7
+ /* Get exception cause for access type handling (page dirtying) */
+ get $r7 = $es
+ /* Clear way and select JTLB */
+ make $r6 = MMC_SEL_JTLB_CLEAR_WAY
+ ;;
+ /* Load current way to use for current set */
+ lbz $r0 = __PA(jtlb_current_set_way)[$r5]
+ /* Check if the access was a "write" access */
+ andd $r7 = $r7, (KVX_TRAP_RWX_WRITE << KVX_SFR_ES_RWX_SHIFT)
+ ;;
+ /* If bit PRESENT of pte entry is 0, then entry is not present */
+ cb.even $r1? refill_err_out
+ /*
+ * Set the JTLB way in $mmc value, add 32 bits to be in the set part.
+ * Since we are refilling JTLB, we must make sure we insert only
+ * relevant bits (ie 2 bits for ways) to avoid using nonexistent ways.
+ */
+ insf $r6 = $r0, KVX_SFR_START(MMC_SW) + 32 + (MMU_JTLB_WAYS_SHIFT - 1),\
+ KVX_SFR_START(MMC_SW) + 32
+ /* Extract page global bit */
+ extfz $r3 = $r1, _PAGE_GLOBAL_SHIFT, _PAGE_GLOBAL_SHIFT
+ /* Increment way value, note that we do not care about overflow since
+ * we only use the two lower byte */
+ addd $r0 = $r0, 1
+ ;;
+ /* Prepare MMC */
+ wfxl $mmc, $r6
+ ;;
+ /* Insert global bit (if any) to its position into $teh value */
+ insf $r4 = $r3, KVX_SFR_TEH_G_SHIFT, KVX_SFR_TEH_G_SHIFT
+ /* If "write" access ($r7 != 0), then set it as dirty */
+ cmoved.dnez $r7? $r7 = _PAGE_DIRTY
+ /* Clear bits not related to FN in the pte entry for TEL writing */
+ andd $r6 = $r1, KVX_PFN_MASK
+ /* Store new way */
+ sb __PA(jtlb_current_set_way)[$r5] = $r0
+ ;;
+ /* Extract access perms from pte entry (discard PAGE_READ bit +1) */
+ extfz $r3 = $r1, KVX_ACCESS_PERM_STOP_BIT, KVX_ACCESS_PERM_START_BIT + 1
+ /* Move FN bits to their place */
+ srld $r6 = $r6, KVX_PFN_SHIFT - PAGE_SHIFT
+ /* Extract the page size + cache policy */
+ andd $r0 = $r1, (KVX_PAGE_SZ_MASK | KVX_PAGE_CP_MASK)
+ /* Prepare SBMM value */
+ make $r5 = KVX_SBMM_BYTE_SEL
+ ;;
+ /* Add page size + cache policy to $tel value */
+ ord $r6 = $r6, $r0
+ /* Get $mmc to get current ASN */
+ get $r0 = $mmc
+ /* Add _PAGE_ACCESSED bit to PTE entry for writeback */
+ ord $r7 = $r7, _PAGE_ACCESSED
+ ;;
+ /* OR PTE value with accessed/dirty flags */
+ ord $r1 = $r1, $r7
+ /* Generate the byte selection for sbmm */
+ slld $r5 = $r5, $r3
+ /* Compute the mask to extract set and mask exception address */
+ make $r7 = KVX_PAGE_PA_MATRIX
+ ;;
+ ord $r0 = $r6, TEL_DEFAULT_VALUE
+ /* Add ASN from mmc into future $teh value */
+ insf $r4 = $r0, KVX_SFR_END(MMC_ASN), KVX_SFR_START(MMC_ASN)
+ /* Get the page permission value */
+ sbmm8 $r6 = $r7, $r5
+ /* Check PAGE_READ bit in PTE entry */
+ andd $r3 = $r1, _PAGE_READ
+ ;;
+ /* If PAGE_READ bit is not set, set policy as NA_NA */
+ cmoved.deqz $r3? $r6 = TLB_PA_NA_NA
+ ;;
+ /* Shift PA to correct position */
+ slld $r6 = $r6, KVX_SFR_TEL_PA_SHIFT
+ set $teh = $r4
+ ;;
+ /* Store updated pte entry */
+ sd 0[$r2] = $r1
+ /* Prepare tel */
+ ord $r6 = $r0, $r6
+ /* Get current task pointer for register restoration */
+ get $r11 = $sr
+ ;;
+ set $tel = $r6
+ ;;
+do_tlb_write:
+ tlbwrite
+ ;;
+#ifdef CONFIG_KVX_DEBUG_TLB_WRITE
+ goto mmc_error_check
+ ;;
+mmc_error_check_ok:
+#endif
+#ifdef CONFIG_KVX_DEBUG_ASN
+ goto asn_check
+ ;;
+asn_check_ok:
+#endif
+ set $tel = $r8
+ /* Restore registers */
+ lo $r4r5r6r7 = __PA(TASK_THREAD_SAVE_AREA_QUAD(1))[$r11]
+ ;;
+ set $teh = $r9
+ lo $r0r1r2r3 = __PA(TASK_THREAD_SAVE_AREA_QUAD(0))[$r11]
+ ;;
+ set $mmc = $r10
+ ;;
+ lo $r8r9r10r11 = __PA(TASK_THREAD_SAVE_AREA_QUAD(2))[$r11]
+ ;;
+#ifdef CONFIG_KVX_MMU_STATS
+ /*
+ * Fence to simulate a direct data dependency after returning from trap
+ * nomapping handling. This is the worst case that can happen and the
+ * processor will be stalled waiting for previous loads to complete.
+ */
+ fence
+ ;;
+ get $r4 = $pm0
+ ;;
+ get $r0 = $sr
+ ;;
+ /* Get cycles measured on trap entry */
+ ld $r1 = __PA(TASK_THREAD_ENTRY_TS)[$r0]
+ ;;
+ /* Compute refill time */
+ sbfd $r0 = $r1, $r4
+ ;;
+#ifdef CONFIG_SMP
+ get $r1 = $pcr
+ ;;
+ /* Extract processor ID to compute cpu_offset */
+ extfz $r1 = $r1, KVX_SFR_END(PCR_PID), KVX_SFR_START(PCR_PID)
+ make $r2 = __PA(__per_cpu_offset)
+ ;;
+ /* Load cpu offset */
+ ld.xs $r1 = $r1[$r2]
+ ;;
+ addd $r1 = $r1, __PA(mmu_stats)
+ ;;
+#else
+ make $r1 = __PA(mmu_stats)
+ ;;
+#endif
+ /* Load time between refill + last refill cycle */
+ lq $r2r3 = MMU_STATS_CYCLES_BETWEEN_REFILL_OFF[$r1]
+ ;;
+ /* Set last update time to current if 0 */
+ cmoved.deqz $r3? $r3 = $r4
+ /* remove current refill time to current cycle */
+ sbfd $r4 = $r0, $r4
+ ;;
+ /* Compute time between last refill and current refill */
+ sbfd $r5 = $r3, $r4
+ /* Update last cycle time */
+ copyd $r3 = $r4
+ ;;
+ /* Increment total time between refill */
+ addd $r2 = $r2, $r5
+ ;;
+ sq MMU_STATS_CYCLES_BETWEEN_REFILL_OFF[$r1] = $r2r3
+ /* Get exception address */
+ get $r4 = $ea
+ ;;
+ /* $r2 holds refill type (user/kernel/kernel_direct) */
+ make $r2 = MMU_STATS_REFILL_KERNEL_OFF
+ /* Check if address is a kernel direct mapping one */
+ compd.ltu $r3 = $r4, (KERNEL_DIRECT_MEMORY_MAP_BASE + \
+ KERNEL_DIRECT_MEMORY_MAP_SIZE)
+ ;;
+ cmoved.dnez $r3? $r2 = MMU_STATS_REFILL_KERNEL_DIRECT_OFF
+ /* Check if address is a user (ie below kernel) */
+ compd.ltu $r3 = $r4, KERNEL_DIRECT_MEMORY_MAP_BASE
+ ;;
+ cmoved.dnez $r3? $r2 = MMU_STATS_REFILL_USER_OFF
+ ;;
+ /* Compute refill struct addr into one reg */
+ addd $r1 = $r2, $r1
+ /* Load refill_struct values */
+ lo $r4r5r6r7 = $r2[$r1]
+ ;;
+ /* Increment count */
+ addd $r4 = $r4, 1
+ /* Increment total cycles count */
+ addd $r5 = $r5, $r0
+ ;;
+ /* Set min to ~0 if 0 */
+ cmoved.deqz $r6? $r6 = ~0
+ ;;
+ /* Compare min and max */
+ compd.ltu $r2 = $r0, $r6
+ compd.gtu $r3 = $r0, $r7
+ ;;
+ /* Update min and max*/
+ cmoved.dnez $r2? $r6 = $r0
+ cmoved.dnez $r3? $r7 = $r0
+ ;;
+ /* store back all values */
+ so 0[$r1] = $r4r5r6r7
+ ;;
+ get $r0 = $sr
+ ;;
+ /* Restore clobberred registers */
+ lo $r4r5r6r7 = __PA(TASK_THREAD_SAVE_AREA_QUAD(1))[$r0]
+ ;;
+ lo $r0r1r2r3 = __PA(TASK_THREAD_SAVE_AREA_QUAD(0))[$r0]
+ ;;
+#endif
+ /* Save $r4 for reenabling mmu and data cache in sps */
+ set TMP_SCRATCH_SR = $r4
+ /* Enable MME in $sps */
+ make $r4 = MME_WFXL(1)
+ ;;
+ /* Reenable $mme in $sps */
+ wfxl $sps = $r4
+ ;;
+ get $r4 = TMP_SCRATCH_SR
+ ;;
+ rfe
+ ;;
+
+is_huge_page:
+ /*
+ * When entering this path:
+ * - $r0 = $ea
+ * - $r1 = pte entry
+ * - $r7 = cpu offset for tlb_current_set_way
+ *
+ * From now on, we have the pte value in $r1 so we can extract the page
+ * size. This value is stored as it is expected by the MMU (ie between
+ * 0 and 3).
+ * Note that page size value is located at the same place as in $tel
+ * and this is checked at build time so we can use TEL_PS defines.
+ * In this codepath, we will extract the set and mask exception address
+ * and align virt and phys address with what the hardware expect.
+ * Indeed, MMU expect lsb of the virtual and physycal address to be 0
+ * according to page size.
+ * This means that for 4K pages, the 12 lsb must be 0, for 64K
+ * pages, the 16 lsb must be 0 and so on.
+ */
+ extfz $r5 = $r1, KVX_SFR_END(TEL_PS), KVX_SFR_START(TEL_PS)
+ /* Compute the mask to extract set and mask exception address */
+ make $r4 = KVX_PS_SHIFT_MATRIX
+ make $r6 = KVX_SBMM_BYTE_SEL
+ ;;
+ /* Generate the byte selection for sbmm */
+ slld $r6 = $r6, $r5
+ ;;
+ /* Get the shift value */
+ sbmm8 $r5 = $r4, $r6
+ make $r4 = 0xFFFFFFFFFFFFFFFF
+ ;;
+ /* extract TLB set from ea (6 lsb of virtual page) */
+ srld $r5 = $r0, $r5
+ /* Generate ea masking according to page shift */
+ slld $r4 = $r4, $r5
+ ;;
+ /* Mask to get the set value */
+ andd $r0 = $r5, MMU_SET_MASK
+ /* Extract virt page from ea */
+ andd $r4 = $r0, $r4
+ ;;
+ /* Returned to fast path */
+ goto pte_prepared
+ ;;
+
+#ifdef CONFIG_KVX_DEBUG_TLB_WRITE
+mmc_error_check:
+ get $r1 = $mmc
+ ;;
+ andd $r1 = $r1, KVX_SFR_MMC_E_MASK
+ ;;
+ cb.deqz $r1? mmc_error_check_ok
+ ;;
+ make $r0 = mmc_error_panic_str_label
+ goto asm_panic
+ ;;
+#endif
+#ifdef CONFIG_KVX_DEBUG_ASN
+/*
+ * When entering this path $r11 = $sr.
+ * WARNING: Do not clobber it here if you don't want to mess up with registers
+ * restoration above.
+ */
+asn_check:
+ get $r1 = $ea
+ ;;
+ /* Check if kernel address, if so, there is no ASN */
+ compd.geu $r2 = $r1, PAGE_OFFSET
+ ;;
+ cb.dnez $r2? asn_check_ok
+ ;;
+ get $r2 = $pcr
+ /* Load active mm addr */
+ ld $r3 = __PA(TASK_ACTIVE_MM)[$r11]
+ ;;
+ get $r5 = $mmc
+ /* Extract processor ID to compute cpu_offset*/
+ extfz $r2 = $r2, KVX_SFR_END(PCR_PID), KVX_SFR_START(PCR_PID)
+ addd $r3 = $r3, MM_CTXT_ASN
+ ;;
+ extfz $r4 = $r5, KVX_SFR_END(MMC_ASN), KVX_SFR_START(MMC_ASN)
+ addd $r3 = $r3, VA_TO_PA_OFFSET
+ ;;
+ /* Load current asn from active_mm */
+ ld.xs $r3 = $r2[$r3]
+ ;;
+ /* Error if ASN is not set */
+ cb.deqz $r3? asn_check_err
+ /* Mask $r3 asn cycle part */
+ andd $r5 = $r3, ((1 << KVX_SFR_MMC_ASN_WIDTH) - 1)
+ ;;
+ /* Compare asn in $mmc and asn in current task mm */
+ compd.eq $r3 = $r5, $r4
+ ;;
+ cb.dnez $r3? asn_check_ok
+ ;;
+asn_check_err:
+ /* We are fried, die peacefully */
+ make $r0 = asn_error_panic_str_label
+ goto asm_panic
+ ;;
+#endif
+
+#if defined(CONFIG_KVX_DEBUG_ASN) || defined(CONFIG_KVX_DEBUG_TLB_WRITE)
+
+/**
+ * This routine calls panic from assembly after setting appropriate things
+ * $r0 = panic string
+ */
+asm_panic:
+ /*
+ * Reenable hardware loop and traps (for nomapping) since some functions
+ * might need it. Moreover, disable DAUS to reenable MMU accesses.
+ */
+ make $r32 = PS_HWLOOP_EN_ET_CLEAR_DAUS_DIS
+ make $r33 = 0
+ get $r34 = $sr
+ ;;
+ /* Clear hw loop exit to disable current loop */
+ set $le = $r33
+ ;;
+ wfxl $ps = $r32
+ ;;
+ /* Restore kernel stack */
+ ld $r12 = TASK_THREAD_KERNEL_SP[$r34]
+ ;;
+ call panic
+ ;;
+#endif
+
+/* Error path for TLB refill */
+refill_err_out:
+ get $r2 = $sr
+ ;;
+ /* Restore clobbered registers */
+ lo $r8r9r10r11 = __PA(TASK_THREAD_SAVE_AREA_QUAD(2))[$r2]
+ ;;
+ lo $r4r5r6r7 = __PA(TASK_THREAD_SAVE_AREA_QUAD(1))[$r2]
+ goto trap_switch_stack
+ ;;
+
+/* This path is entered only when the trap is NOT a NOMAPPING */
+trap_slow_path:
+ /* Restore $r3 from temporary scratch system register */
+ get $r3 = TMP_SCRATCH_SR
+ ;;
+ save_quad_regs $r0r1r2r3 $r4
+ ;;
+ get $r2 = $sr
+ ;;
+trap_switch_stack:
+ switch_stack $r1 $r2 trap_save_regs
+ ;;
+trap_save_regs:
+ save_regs_for_exception $r1 $r2 $r0r1r2r3 $r2
+ ;;
+ get $r1 = $ea
+ /* tail-call for return_from_exception */
+ make $r3 = return_from_exception
+ ;;
+ set $ra = $r3
+ ;;
+ /* Handler call */
+ get $r0 = $es
+ ;;
+ goto trap_handler
+ ;;
+ENDPROC(kvx_trap_handler)
+
+/***********************************************************************
+* Interrupts handling
+***********************************************************************/
+EXCEPTION_ENTRY(kvx_interrupt_handler):
+ exception_entry_disable_mmu
+ ;;
+ save_quad_regs $r0r1r2r3 $r4
+ ;;
+ get $r0 = $sr
+ ;;
+ switch_stack $r1 $r0 it_save_regs
+ ;;
+#ifdef CONFIG_SECURE_DAME_HANDLING
+ /**
+ * In order to securely Handle Data Asynchronous Memory Error,
+ * we need to have a correct entry point. This means we do not
+ * want to handle a user induced DAME interrupt when entering
+ * kernel.
+ * In order to do that, we need to do a barrier, which will
+ * reflect the DAME status in $ilr (if any).
+ */
+ barrier
+ ;;
+#endif
+it_save_regs:
+ save_regs_for_exception $r1 $r0 $r0r1r2r3 $r1
+ ;;
+ get $r0 = $ilr
+ ;;
+ get $r2 = $ile
+ ;;
+ /**
+ * When an interrupt happens, the processor automatically clears the
+ * corresponding bit in $ilr. However, as we are using $ilr to get the
+ * list of irqs we want to handle, we need to add the automatically
+ * cleared interrupt bit. This is done by getting the interrupt number
+ * from $es.
+ */
+ get $r3 = $es
+ make $r4 = 1
+ ;;
+ /* Extract interrupt number from $es */
+ extfz $r3 = $r3, KVX_SFR_END(ES_ITN), KVX_SFR_START(ES_ITN)
+ /**
+ * Mask requests with enabled line since ILR will also contain disabled
+ * interrupt lines (ie not enabled in $ile) and we want to respect the
+ * current state of interrupt lines.
+ */
+ andd $r0 = $r0, $r2
+ ;;
+ /* Clear $ilr with bits we are going to handle */
+ wfxl $ilr = $r0
+ slld $r4 = $r4, $r3
+ ;;
+ /* OR the irq mask with the current pending irq */
+ ord $r0 = $r0, $r4
+ call do_IRQ
+ ;;
+ /* From now on, lower the interrupt level (IL) to allow IT nesting.
+ * If returning to user, we will call schedule which will reenable
+ * interrupts by itself when ready.
+ * If returning to kernel and with CONFIG_PREEMPT, we will call
+ * preempt_schedule_irq which will do the same.
+ */
+ make $r0 = PS_IL_CLEAR
+ ;;
+ wfxl $ps = $r0
+ ;;
+ goto return_from_exception
+ ;;
+ENDPROC(kvx_interrupt_handler)
+
+/***********************************************************************
+* Syscall handling
+***********************************************************************/
+EXCEPTION_ENTRY(kvx_syscall_handler):
+ /**
+ * Syscalls are seen as standard func call from ABI POV
+ * We may use all caller saved register whithout causing havoc
+ * in the userspace. We need to save callee registers because they
+ * will be restored when returning from fork.
+ * Note that r0 -> r11 MUST not be used since they are
+ * containing syscall parameters !
+ * During this function, $r38 is the syscall handler address. Hence,
+ * this register must not be clobberred during function calls (tracing
+ * for instance.
+ */
+ disable_mmu $r43
+ ;;
+ get $r43 = $es
+ copyd $r52 = $sp
+ copyd $r53 = $tp
+ ;;
+ get $r36 = $sr
+ copyd $r54 = $fp
+ copyd $r55 = $r15
+ ;;
+ /* Extract syscall number */
+ extfz $r32 = $r43, KVX_SFR_END(ES_SN), KVX_SFR_START(ES_SN)
+ /* Get regs to save on stack */
+ get $r63 = $ra
+ addd $r36 = $r36, VA_TO_PA_OFFSET
+ ;;
+ ld $r39 = TASK_TI_FLAGS[$r36]
+ get $r41 = $spc
+ make $r42 = __PA(sys_call_table)
+ ;;
+ /* Check for out-of-bound syscall number */
+ sbfd $r50 = $r32, __NR_syscalls
+ /* Compute syscall func addr (ie sys_call_table[$r32])*/
+ ld.xs $r38 = $r32[$r42]
+ get $r42 = $sps
+ ;;
+ /* True if trace syscall enable */
+ andd $r37 = $r39, _TIF_SYSCALL_WORK
+ /* Restore kernel stack pointer */
+ ld $sp = TASK_THREAD_KERNEL_SP[$r36]
+ /* If the syscall number is invalid, set invalid handler */
+ cmoved.dlez $r50? $r38 = sys_ni_syscall
+ ;;
+ /* Prepare space on stack */
+ addd $sp = $sp, -PT_SIZE_ON_STACK
+ get $r40 = $cs
+ /* Save regs r0 -> r3 in pt_regs for restart & trace if needed */
+ so __PA(PT_Q0 - PT_SIZE_ON_STACK)[$sp] = $r0r1r2r3
+ ;;
+ /* Store user stack pointer, frame pointer, thread pointer and r15 */
+ so __PA(PT_Q12)[$sp] = $r52r53r54r55
+ addd $r36 = $sp, VA_TO_PA_OFFSET
+ get $r60 = $lc
+ ;;
+#ifdef CONFIG_SECURE_DAME_HANDLING
+ get $r44 = $ilr
+ make $r45 = SFR_CLEAR_WFXL(ILR, IT16);
+ ;;
+ /* Extract $ilr.dame bit */
+ extfz $r44 = $r44, KVX_SFR_END(ILR_IT16), KVX_SFR_START(ILR_IT16)
+ /* Save $ilr value */
+ sd PT_ILR[$r36] = $r44
+ /* Clear $ilr.dame */
+ wfxl $ilr = $r45
+ ;;
+#endif
+ so PT_CS_SPC_SPS_ES[$r36] = $r40r41r42r43
+ get $r61 = $le
+ make $r43 = 0x0
+ ;;
+ /* Reenable hardware loops, IT, exceptions and disable DAUS */
+ make $r44 = PS_HLE_EN_IT_EN_ET_CLEAR_DAUS_DIS
+ get $r62 = $ls
+ /* Save regs r4 -> r7 in pt_regs for restart & trace if needed */
+ so PT_Q4[$r36] = $r4r5r6r7
+ ;;
+ /* Clear $le on entry */
+ set $le = $r43
+ /* Save hw loop stuff */
+ so PT_LC_LE_LS_RA[$r36] = $r60r61r62r63
+ /* Clear frame pointer for kernel */
+ make $fp = 0
+ ;;
+ /* Enable hwloop and interrupts and MMU
+ * Note that we have to reenable interrupts after saving context
+ * to avoid losing registers content */
+ wfxl $ps, $r44
+ ;;
+ /* Do we have to trace the syscall ? */
+ cb.dnez $r37? trace_syscall_enter
+ /* Stroe original r0 value */
+ sd PT_ORIG_R0[$sp] = $r0
+ ;;
+do_syscall:
+ /* Call the syscall handler */
+ icall $r38
+ ;;
+ /*
+ * rt_sigreturn syscall will not take this exit path (see
+ * sys_rt_sigreturn for more information).
+ */
+ /* Reload task flags since the syscall might have generated a signal*/
+ get $r36 = $sr
+ ;;
+#ifdef CONFIG_SECURE_DAME_HANDLING
+ /* Barrier to force DAME interrupt to be generated if any pending */
+ barrier
+ ;;
+#endif
+ /* Disable interrupt to check task flags atomically */
+ disable_interrupt $r60
+ ;;
+ ld $r38 = TASK_TI_FLAGS[$r36]
+ ;;
+ andd $r37 = $r38, _TIF_SYSCALL_WORK
+ ;;
+ /* Save r0 which was returned from do_scall previously and will be
+ * clobberred by do_work_pending (and potentially do_syscall_trace_exit
+ * if tracing is enabled)
+ * If do_signal is called and that syscall is restarted,
+ * it will be modified by handle_restart to restore original
+ * r0 value
+ */
+ sd PT_Q0[$sp] = $r0
+ /* used to store if trace system */
+ cb.dnez $r37? trace_syscall_exit
+ ;;
+check_work_pending:
+ /* Do we have work pending ? */
+ andd $r1 = $r38, _TIF_WORK_MASK
+ ;;
+ /* If no work pending, directly continue to ret_to_user */
+ cb.dnez $r1? call_work_pending
+ ;;
+ret_to_user:
+ disable_mmu $r60, PS_HWLOOP_DISABLE
+ ;;
+ /* Compute $sp virtual address to avoid using 64 bits offset */
+ addd $r15 = $sp, VA_TO_PA_OFFSET
+ ;;
+ /* Restore registers */
+ lo $r60r61r62r63 = PT_LC_LE_LS_RA[$r15]
+ get $r33 = $sps
+ ;;
+ lo $r40r41r42r43 = PT_CS_SPC_SPS_ES[$r15];
+ set $ra = $r63
+ ;;
+ /* Restore syscall arguments since they might be needed for
+ * syscall restart
+ */
+ lo $r0r1r2r3 = PT_Q0[$r15]
+ set $cs = $r40
+ /* Generate a mask of ones at each bit where the current $sps
+ * differs from the $sps to be restored
+ */
+ xord $r33 = $r42, $r33
+ /* prepare wfxl clear mask on LSBs */
+ notd $r34 = $r42
+ /* prepare wfxl set mask on MSBs */
+ slld $r35 = $r42, 32
+ ;;
+ set $lc = $r60
+ /* Replicate mask of ones on the 32 MSBs */
+ sbmm8 $r33 = $r33, REPLICATE_32_MASK
+ /* Combine the set and clear mask for wfxl */
+ insf $r35 = $r34, 31, 0
+ ;;
+ lo $r4r5r6r7 = PT_Q4[$r15]
+ set $le = $r61
+ /* Mask to drop identical bits in order to avoid useless
+ * privilege traps
+ */
+ andd $r35 = $r35, $r33
+ ;;
+ /* Restore $ilr */
+ ld $r44 = PT_ILR[$r15]
+ set $ls = $r62
+ /* Reenable MMU in $sps */
+ ord $r35 = $r35, SFR_SET_VAL_WFXL(SPS, MME, 1)
+ ;;
+ /* Restore user pointer */
+ lo $r12r13r14r15 = PT_Q12[$r15]
+ /* Prepare $r44 as a set mask for $ilr wfxl */
+ slld $r44 = $r44, 32
+ ;;
+ /**
+ * wfxl on $ilr to avoid privilege traps when restoring with set
+ * Note that we do that after disabling interrupt since we explicitly
+ * want to serve DAME itnerrupt to the user (ie not in kernel mode).
+ */
+ wfxl $ilr = $r44
+ ;;
+ wfxl $sps = $r35
+ ;;
+ set $spc = $r41
+ ;;
+ /* TODO: we might have to clear some registers to avoid leaking
+ * information to user space ! callee saved regs have been
+ * restored by called function but caller saved regs might
+ * have been used without being cleared */
+ rfe
+ ;;
+
+/* Slow paths handling */
+call_work_pending:
+ /*
+ * Work pending can potentially call a signal handler and then return
+ * via rt_sigreturn. Return path will be different (restore all regs)
+ * and hence all registers are needed to be saved.
+ */
+ save_callee
+ ;;
+ call_do_work_pending
+ ;;
+ /* Since we are returning to user, interrupts will be reenabled */
+ call_trace_hardirqs on
+ ;;
+ goto ret_to_user
+ ;;
+
+trace_syscall_enter:
+ /* Save $r38 (syscall handler) which was computed above */
+ sd PT_R38[$sp] = $r38
+ ;;
+ /* do_syscall_trace_enter expect pt_regs and syscall number
+ * as argument */
+ copyd $r0 = $sp
+ copyd $r1 = $r32
+ ;;
+ call do_syscall_trace_enter
+ ;;
+ /* Restore r38 (syscall handler) which might has been clobbered by
+ * do_syscall_trace_enter */
+ ld $r38 = PT_R38[$sp]
+ ;;
+ /* if the trace system requested to abort syscall, set $r38 to
+ * non implemented syscall */
+ cmoved.dnez $r0? $r38 = sys_ni_syscall
+ ;;
+ /* Restore registers since the do_syscall_trace_enter call might
+ * have clobbered them and we need them for the actual syscall
+ * call */
+ lo $r0r1r2r3 = PT_Q0[$sp]
+ ;;
+ lo $r4r5r6r7 = PT_Q4[$sp]
+ ;;
+ goto do_syscall
+ ;;
+trace_syscall_exit:
+ copyd $r0 = $sp
+ call do_syscall_trace_exit
+ ;;
+ /* ptrace_notify might re-enable interrupts, disable them to be sure
+ * it will not mess up context restoration path */
+ disable_interrupt $r36
+ ;;
+ get $r36 = $sr
+ ;;
+ ld $r38 = TASK_TI_FLAGS[$r36]
+ goto check_work_pending
+ ;;
+ENDPROC(kvx_syscall_handler)
+
+.text
+/**
+ * sys_rt_sigreturn: Special handler for sigreturn
+ * rt_sigreturn is called after invoking a user signal handler (see
+ * user_scall_rt_sigreturn). Since this signal handler can be invoked after
+ * interrupts have been handled, this means we must restore absolutely all user
+ * registers. Normally, this has been done by setup_sigcontext which saved all
+ * user registers on the user stack.
+ * In restore sigcontext, they have been restored onto entry stack (stack to be
+ * restored). However, the standard syscall path do not restore it completely
+ * since only callee-saved registers are restored for fork and al.
+ * Here, we will restore all registers which might have been clobberred.
+ */
+ENTRY(sys_rt_sigreturn)
+ /*
+ * If syscall tracing is enable (stored in $r37 during syscall
+ * fastpath), tail-call to trace_exit. If not, tail-call to
+ * ret_from_kernel.
+ */
+ cmoved.dnez $r37? $r38 = scall_trace_exit
+ cmoved.deqz $r37? $r38 = ret_from_kernel
+ ;;
+ set $ra = $r38
+ ;;
+ goto _sys_rt_sigreturn
+ ;;
+scall_trace_exit:
+ copyd $r0 = $sp
+ call do_syscall_trace_exit
+ ;;
+ goto ret_from_kernel
+ ;;
+ENDPROC(sys_rt_sigreturn)
+
+/**
+ * __sys_clone: slow path handler for clone
+ *
+ * Save callee registers (from $r18 to $31) since they are needed for
+ * child process when restoring it.
+ * Indeed, when forking we want it to have the same registers contents
+ * as its parent. These registers will then be restored in
+ * ret_from_fork.
+ * This slow path saves them out of the fast path to avoid bloating all syscall
+ * just for one special case.
+ */
+ENTRY(__sys_clone)
+ save_callee
+ ;;
+ /*
+ * Use goto since we want sys_clone to "ret" to the previous caller.
+ * This allows to simply go back in the normal syscall fastpath
+ */
+ goto sys_clone
+ ;;
+ENDPROC(__sys_clone)
+/***********************************************************************
+* Context switch
+***********************************************************************/
+
+#define SAVE_TCA_REG(__reg_num, __task_reg, __zero_reg1, __zero_reg2) \
+ xso (CTX_SWITCH_TCA_REGS + (__reg_num * TCA_REG_SIZE))[__task_reg] = \
+ $a##__reg_num ;\
+ movetq $a##__reg_num##.lo = __zero_reg1, __zero_reg2 ;\
+ movetq $a##__reg_num##.hi = __zero_reg1, __zero_reg2 ;\
+ ;;
+
+.macro save_tca_regs task_reg zero_reg1 zero_reg2
+ SAVE_TCA_REG(0, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(1, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(2, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(3, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(4, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(5, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(6, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(7, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(8, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(9, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(10, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(11, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(12, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(13, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(14, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(15, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(16, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(17, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(18, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(19, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(20, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(21, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(22, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(23, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(24, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(25, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(26, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(27, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(28, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(29, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(30, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(31, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(32, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(33, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(34, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(35, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(36, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(37, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(38, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(39, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(40, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(41, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(42, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(43, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(44, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(45, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(46, \task_reg, \zero_reg1, \zero_reg2)
+ SAVE_TCA_REG(47, \task_reg, \zero_reg1, \zero_reg2)
+.endm
+
+#define RESTORE_TCA_REG(__reg_num, __task_reg) \
+ xlo.u $a##__reg_num = (CTX_SWITCH_TCA_REGS + (__reg_num * TCA_REG_SIZE)) \
+ [__task_reg] ;\
+ ;;
+
+.macro restore_tca_regs task_reg
+ RESTORE_TCA_REG(0, \task_reg)
+ RESTORE_TCA_REG(1, \task_reg)
+ RESTORE_TCA_REG(2, \task_reg)
+ RESTORE_TCA_REG(3, \task_reg)
+ RESTORE_TCA_REG(4, \task_reg)
+ RESTORE_TCA_REG(5, \task_reg)
+ RESTORE_TCA_REG(6, \task_reg)
+ RESTORE_TCA_REG(7, \task_reg)
+ RESTORE_TCA_REG(8, \task_reg)
+ RESTORE_TCA_REG(9, \task_reg)
+ RESTORE_TCA_REG(10, \task_reg)
+ RESTORE_TCA_REG(11, \task_reg)
+ RESTORE_TCA_REG(12, \task_reg)
+ RESTORE_TCA_REG(13, \task_reg)
+ RESTORE_TCA_REG(14, \task_reg)
+ RESTORE_TCA_REG(15, \task_reg)
+ RESTORE_TCA_REG(16, \task_reg)
+ RESTORE_TCA_REG(17, \task_reg)
+ RESTORE_TCA_REG(18, \task_reg)
+ RESTORE_TCA_REG(19, \task_reg)
+ RESTORE_TCA_REG(20, \task_reg)
+ RESTORE_TCA_REG(21, \task_reg)
+ RESTORE_TCA_REG(22, \task_reg)
+ RESTORE_TCA_REG(23, \task_reg)
+ RESTORE_TCA_REG(24, \task_reg)
+ RESTORE_TCA_REG(25, \task_reg)
+ RESTORE_TCA_REG(26, \task_reg)
+ RESTORE_TCA_REG(27, \task_reg)
+ RESTORE_TCA_REG(28, \task_reg)
+ RESTORE_TCA_REG(29, \task_reg)
+ RESTORE_TCA_REG(30, \task_reg)
+ RESTORE_TCA_REG(31, \task_reg)
+ RESTORE_TCA_REG(32, \task_reg)
+ RESTORE_TCA_REG(33, \task_reg)
+ RESTORE_TCA_REG(34, \task_reg)
+ RESTORE_TCA_REG(35, \task_reg)
+ RESTORE_TCA_REG(36, \task_reg)
+ RESTORE_TCA_REG(37, \task_reg)
+ RESTORE_TCA_REG(38, \task_reg)
+ RESTORE_TCA_REG(39, \task_reg)
+ RESTORE_TCA_REG(40, \task_reg)
+ RESTORE_TCA_REG(41, \task_reg)
+ RESTORE_TCA_REG(42, \task_reg)
+ RESTORE_TCA_REG(43, \task_reg)
+ RESTORE_TCA_REG(44, \task_reg)
+ RESTORE_TCA_REG(45, \task_reg)
+ RESTORE_TCA_REG(46, \task_reg)
+ RESTORE_TCA_REG(47, \task_reg)
+.endm
+
+.text
+/*
+ * When entering in ret_from_kernel_thread, r20 and r21 where set by
+ * copy_thread and have been restored in switch_to.
+ * These registers contains the values needed to call a function
+ * specified by the switch_to caller (or where set by copy_thread).
+ */
+ENTRY(ret_from_kernel_thread)
+ call schedule_tail
+ ;;
+ /* Call fn(arg) */
+ copyd $r0 = $r21
+ ;;
+ icall $r20
+ ;;
+ goto ret_from_kernel
+ ;;
+ENDPROC(ret_from_kernel_thread)
+
+/**
+ * Return from fork.
+ * start_thread will set return stack and pc. Then copy_thread will
+ * take care of the copying logic.
+ * $r20 will then contains 0 if tracing disabled (set by copy_thread)
+ * The mechanism is almost the same as for ret_from_kernel_thread.
+ */
+ENTRY(ret_from_fork)
+ call schedule_tail
+ ;;
+ /* $r20 contains 0 if tracing disable */
+ cb.deqz $r20? ret_from_kernel
+ ;;
+ copyd $r0 = $sp
+ call do_syscall_trace_exit
+ ;;
+ret_from_kernel:
+ /*
+ * When returning from a fork, the child will take this path.
+ * Since we did not restore callee in return_from_exception, we
+ * must do it before.
+ */
+ lo $r28r29r30r31 = PT_Q28[$sp]
+ ;;
+ lo $r24r25r26r27 = PT_Q24[$sp]
+ ;;
+ lo $r20r21r22r23 = PT_Q20[$sp]
+ ;;
+ lq $r18r19 = PT_R18R19[$sp]
+ ;;
+#ifdef CONFIG_DEBUG_EXCEPTION_STACK
+ /**
+ * Debug code expect entry stack to be stored at current $sp.
+ * Make some room and store current $sp to avoid triggering false alarm.
+ */
+ addd $sp = $sp, -STACK_REG_SIZE
+ ;;
+ sd 0[$sp] = $sp
+#endif
+ ;;
+ goto return_from_exception
+ ;;
+ENDPROC(ret_from_fork)
+
+/*
+ * The callee-saved registers must be saved and restored.
+ * When entering:
+ * - r0 = previous task struct
+ * - r1 = next task struct
+ * Moreover, the parameters for function call (given by copy_thread)
+ * are stored in:
+ * - r20 = Func to call
+ * - r21 = Argument for function
+ */
+ENTRY(__switch_to)
+ sd CTX_SWITCH_FP[$r0] = $fp
+ ;;
+ /* Save previous task context */
+ so CTX_SWITCH_Q20[$r0] = $r20r21r22r23
+ ;;
+ so CTX_SWITCH_Q24[$r0] = $r24r25r26r27
+ get $r16 = $ra
+ ;;
+ so CTX_SWITCH_Q28[$r0] = $r28r29r30r31
+ copyd $r17 = $sp
+ get $r2 = $cs
+ ;;
+ so CTX_SWITCH_RA_SP_R18_R19[$r0] = $r16r17r18r19
+ /* Extract XMF bit which means coprocessor was used by user */
+ andd $r3 = $r2, KVX_SFR_CS_XMF_MASK
+ ;;
+#ifdef CONFIG_ENABLE_TCA
+ make $r4 = 0
+ make $r5 = 0
+ make $r6 = 1
+ cb.dnez $r3? save_tca_registers
+ /* Check if next task needs TCA registers to be restored */
+ ld $r7 = CTX_SWITCH_TCA_REGS_SAVED[$r1]
+ ;;
+check_restore_tca:
+ cb.dnez $r7? restore_tca_registers
+ ;;
+restore_fast_path:
+#endif
+ /* Restore next task context */
+ lo $r16r17r18r19 = CTX_SWITCH_RA_SP_R18_R19[$r1]
+ ;;
+ lo $r20r21r22r23 = CTX_SWITCH_Q20[$r1]
+ ;;
+ lo $r24r25r26r27 = CTX_SWITCH_Q24[$r1]
+ copyd $sp = $r17
+ set $ra = $r16
+ ;;
+ lo $r28r29r30r31 = CTX_SWITCH_Q28[$r1]
+ set $sr = $r1
+ ;;
+ ld $fp = CTX_SWITCH_FP[$r1]
+ ;;
+ ret
+ ;;
+#ifdef CONFIG_ENABLE_TCA
+save_tca_registers:
+ save_tca_regs $r0 $r4 $r5
+ ;;
+ /* Indicates that we saved the TCA context */
+ sb CTX_SWITCH_TCA_REGS_SAVED[$r0] = $r6
+ goto check_restore_tca
+ ;;
+restore_tca_registers:
+ restore_tca_regs $r1
+ ;;
+ /* Clear TCA registers saved hint */
+ sb CTX_SWITCH_TCA_REGS_SAVED[$r1] = $r5
+ goto restore_fast_path
+ ;;
+#endif
+ENDPROC(__switch_to)
+
+/***********************************************************************
+* Misc functions
+***********************************************************************/
+
+/**
+ * Avoid hardcoding trampoline for rt_sigreturn by using this code and
+ * copying it on user trampoline
+ */
+.pushsection .text
+.global user_scall_rt_sigreturn_end
+ENTRY(user_scall_rt_sigreturn)
+ make $r6 = __NR_rt_sigreturn
+ ;;
+ scall $r6
+ ;;
+user_scall_rt_sigreturn_end:
+ENDPROC(user_scall_rt_sigreturn)
+.popsection
diff --git a/arch/kvx/kernel/sys_kvx.c b/arch/kvx/kernel/sys_kvx.c
new file mode 100644
index 000000000000..b32a821d76c9
--- /dev/null
+++ b/arch/kvx/kernel/sys_kvx.c
@@ -0,0 +1,58 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2017-2023 Kalray Inc.
+ * Author(s): Clement Leger
+ * Guillaume Thouvenin
+ */
+
+#include <linux/syscalls.h>
+
+#include <asm/cacheflush.h>
+#include <asm/cachectl.h>
+
+SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,
+ unsigned long, prot, unsigned long, flags,
+ unsigned long, fd, off_t, off)
+{
+ /* offset must be a multiple of the page size */
+ if (unlikely(offset_in_page(off) != 0))
+ return -EINVAL;
+
+ /* Unlike mmap2 where the offset is in PAGE_SIZE-byte units, here it
+ * is in bytes. So we need to use PAGE_SHIFT.
+ */
+ return ksys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT);
+}
+
+SYSCALL_DEFINE4(cachectl, unsigned long, addr, unsigned long, len,
+ unsigned long, cache, unsigned long, flags)
+{
+ bool wb = !!(flags & CACHECTL_FLAG_OP_WB);
+ bool inval = !!(flags & CACHECTL_FLAG_OP_INVAL);
+
+ if (len == 0)
+ return 0;
+
+ /* Check for overflow */
+ if (addr + len < addr)
+ return -EFAULT;
+
+ if (cache != CACHECTL_CACHE_DCACHE)
+ return -EINVAL;
+
+ if ((flags & CACHECTL_FLAG_OP_MASK) == 0)
+ return -EINVAL;
+
+ if (flags & CACHECTL_FLAG_ADDR_PHYS) {
+ if (!IS_ENABLED(CONFIG_CACHECTL_UNSAFE_PHYS_OPERATIONS))
+ return -EINVAL;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ dcache_wb_inval_phys_range(addr, len, wb, inval);
+ return 0;
+ }
+
+ return dcache_wb_inval_virt_range(addr, len, wb, inval);
+}
diff --git a/arch/kvx/kernel/syscall_table.c b/arch/kvx/kernel/syscall_table.c
new file mode 100644
index 000000000000..7859d25e728d
--- /dev/null
+++ b/arch/kvx/kernel/syscall_table.c
@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * derived from arch/riscv/kernel/syscall_table.c
+ *
+ * Copyright (C) 2017-2023 Kalray Inc.
+ * Author(s): Clement Leger
+ */
+
+#include <linux/syscalls.h>
+
+#include <asm/syscalls.h>
+
+#undef __SYSCALL
+#define __SYSCALL(nr, call) [nr] = (call),
+
+void *sys_call_table[__NR_syscalls] = {
+ [0 ... __NR_syscalls - 1] = sys_ni_syscall,
+#include <asm/unistd.h>
+};
--
2.37.2
More information about the linux-riscv
mailing list