[PATCH v2] arm64: Get rid of struct cpu_table
Marc Zyngier
marc.zyngier at arm.com
Fri Mar 13 07:35:59 PDT 2015
struct cpu_table is an artifact left from the (very) early days of
the arm64 port, and its only real use is to allow the most beautiful
"AArch64 Processor" string to be displayed at boot time.
Really? Yes, really.
Let's get rid of it. In order to avoid another BogoMips-gate, the
aforementioned string is preserved.
Acked-by: Catalin Marinas <catalin.marinas at arm.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier at arm.com>
---
* From v1:
- Don't bother using adrp/add to compute the branch to __cpu_setup,
the kernel is small enough to be addressed with an imm26.
- Nuke some more unreachable code (__error_p and co).
arch/arm64/include/asm/cputable.h | 30 ----------------
arch/arm64/kernel/Makefile | 2 +-
arch/arm64/kernel/asm-offsets.c | 4 ---
arch/arm64/kernel/cputable.c | 33 -----------------
arch/arm64/kernel/head.S | 76 +++------------------------------------
arch/arm64/kernel/setup.c | 16 ++-------
6 files changed, 8 insertions(+), 153 deletions(-)
delete mode 100644 arch/arm64/include/asm/cputable.h
delete mode 100644 arch/arm64/kernel/cputable.c
diff --git a/arch/arm64/include/asm/cputable.h b/arch/arm64/include/asm/cputable.h
deleted file mode 100644
index e3bd983..0000000
--- a/arch/arm64/include/asm/cputable.h
+++ /dev/null
@@ -1,30 +0,0 @@
-/*
- * arch/arm64/include/asm/cputable.h
- *
- * Copyright (C) 2012 ARM Ltd.
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
- */
-#ifndef __ASM_CPUTABLE_H
-#define __ASM_CPUTABLE_H
-
-struct cpu_info {
- unsigned int cpu_id_val;
- unsigned int cpu_id_mask;
- const char *cpu_name;
- unsigned long (*cpu_setup)(void);
-};
-
-extern struct cpu_info *lookup_processor_type(unsigned int);
-
-#endif
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 5ee07ee..d5e7074 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -12,7 +12,7 @@ CFLAGS_REMOVE_insn.o = -pg
CFLAGS_REMOVE_return_address.o = -pg
# Object file lists.
-arm64-obj-y := cputable.o debug-monitors.o entry.o irq.o fpsimd.o \
+arm64-obj-y := debug-monitors.o entry.o irq.o fpsimd.o \
entry-fpsimd.o process.o ptrace.o setup.o signal.o \
sys.o stacktrace.o time.o traps.o io.o vdso.o \
hyp-stub.o psci.o psci-call.o cpu_ops.o insn.o \
diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
index f7fa65d..14dd3d1 100644
--- a/arch/arm64/kernel/asm-offsets.c
+++ b/arch/arm64/kernel/asm-offsets.c
@@ -24,7 +24,6 @@
#include <linux/kvm_host.h>
#include <asm/thread_info.h>
#include <asm/memory.h>
-#include <asm/cputable.h>
#include <asm/smp_plat.h>
#include <asm/suspend.h>
#include <asm/vdso_datapage.h>
@@ -71,9 +70,6 @@ int main(void)
BLANK();
DEFINE(PAGE_SZ, PAGE_SIZE);
BLANK();
- DEFINE(CPU_INFO_SZ, sizeof(struct cpu_info));
- DEFINE(CPU_INFO_SETUP, offsetof(struct cpu_info, cpu_setup));
- BLANK();
DEFINE(DMA_BIDIRECTIONAL, DMA_BIDIRECTIONAL);
DEFINE(DMA_TO_DEVICE, DMA_TO_DEVICE);
DEFINE(DMA_FROM_DEVICE, DMA_FROM_DEVICE);
diff --git a/arch/arm64/kernel/cputable.c b/arch/arm64/kernel/cputable.c
deleted file mode 100644
index fd3993c..0000000
--- a/arch/arm64/kernel/cputable.c
+++ /dev/null
@@ -1,33 +0,0 @@
-/*
- * arch/arm64/kernel/cputable.c
- *
- * Copyright (C) 2012 ARM Ltd.
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
- */
-
-#include <linux/init.h>
-
-#include <asm/cputable.h>
-
-extern unsigned long __cpu_setup(void);
-
-struct cpu_info cpu_table[] = {
- {
- .cpu_id_val = 0x000f0000,
- .cpu_id_mask = 0x000f0000,
- .cpu_name = "AArch64 Processor",
- .cpu_setup = __cpu_setup,
- },
- { /* Empty */ },
-};
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 8ce88e0..ee26aef 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -245,22 +245,12 @@ ENTRY(stext)
bl __calc_phys_offset // x24=PHYS_OFFSET, x28=PHYS_OFFSET-PAGE_OFFSET
bl set_cpu_boot_mode_flag
mrs x22, midr_el1 // x22=cpuid
- mov x0, x22
- bl lookup_processor_type
- mov x23, x0 // x23=current cpu_table
- /*
- * __error_p may end up out of range for cbz if text areas are
- * aligned up to section sizes.
- */
- cbnz x23, 1f // invalid processor (x23=0)?
- b __error_p
-1:
+
bl __vet_fdt
bl __create_page_tables // x25=TTBR0, x26=TTBR1
/*
- * The following calls CPU specific code in a position independent
- * manner. See arch/arm64/mm/proc.S for details. x23 = base of
- * cpu_info structure selected by lookup_processor_type above.
+ * The following calls CPU setup code, see arch/arm64/mm/proc.S for
+ * details.
* On return, the CPU will be ready for the MMU to be turned on and
* the TCR will have been set.
*/
@@ -268,9 +258,7 @@ ENTRY(stext)
// MMU has been enabled
adrp lr, __enable_mmu // return (PIC) address
add lr, lr, #:lo12:__enable_mmu
- ldr x12, [x23, #CPU_INFO_SETUP]
- add x12, x12, x28 // __virt_to_phys
- br x12 // initialise processor
+ b __cpu_setup // initialise processor
ENDPROC(stext)
/*
@@ -634,15 +622,9 @@ ENTRY(secondary_startup)
* Common entry point for secondary CPUs.
*/
mrs x22, midr_el1 // x22=cpuid
- mov x0, x22
- bl lookup_processor_type
- mov x23, x0 // x23=current cpu_table
- cbz x23, __error_p // invalid processor (x23=0)?
pgtbl x25, x26, x28 // x25=TTBR0, x26=TTBR1
- ldr x12, [x23, #CPU_INFO_SETUP]
- add x12, x12, x28 // __virt_to_phys
- blr x12 // initialise processor
+ bl __cpu_setup // initialise processor
ldr x21, =secondary_data
ldr x27, =__secondary_switched // address to jump to after enabling the MMU
@@ -708,51 +690,3 @@ ENDPROC(__calc_phys_offset)
.align 3
1: .quad .
.quad PAGE_OFFSET
-
-/*
- * Exception handling. Something went wrong and we can't proceed. We ought to
- * tell the user, but since we don't have any guarantee that we're even
- * running on the right architecture, we do virtually nothing.
- */
-__error_p:
-ENDPROC(__error_p)
-
-__error:
-1: nop
- b 1b
-ENDPROC(__error)
-
-/*
- * This function gets the processor ID in w0 and searches the cpu_table[] for
- * a match. It returns a pointer to the struct cpu_info it found. The
- * cpu_table[] must end with an empty (all zeros) structure.
- *
- * This routine can be called via C code and it needs to work with the MMU
- * both disabled and enabled (the offset is calculated automatically).
- */
-ENTRY(lookup_processor_type)
- adr x1, __lookup_processor_type_data
- ldp x2, x3, [x1]
- sub x1, x1, x2 // get offset between VA and PA
- add x3, x3, x1 // convert VA to PA
-1:
- ldp w5, w6, [x3] // load cpu_id_val and cpu_id_mask
- cbz w5, 2f // end of list?
- and w6, w6, w0
- cmp w5, w6
- b.eq 3f
- add x3, x3, #CPU_INFO_SZ
- b 1b
-2:
- mov x3, #0 // unknown processor
-3:
- mov x0, x3
- ret
-ENDPROC(lookup_processor_type)
-
- .align 3
- .type __lookup_processor_type_data, %object
-__lookup_processor_type_data:
- .quad .
- .quad cpu_table
- .size __lookup_processor_type_data, . - __lookup_processor_type_data
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index e8420f6..a19eae2 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -50,7 +50,6 @@
#include <asm/cpu.h>
#include <asm/cputype.h>
#include <asm/elf.h>
-#include <asm/cputable.h>
#include <asm/cpufeature.h>
#include <asm/cpu_ops.h>
#include <asm/sections.h>
@@ -83,7 +82,6 @@ unsigned int compat_elf_hwcap2 __read_mostly;
DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS);
-static const char *cpu_name;
phys_addr_t __fdt_pointer __initdata;
/*
@@ -209,22 +207,12 @@ static void __init smp_build_mpidr_hash(void)
static void __init setup_processor(void)
{
- struct cpu_info *cpu_info;
u64 features, block;
u32 cwg;
int cls;
- cpu_info = lookup_processor_type(read_cpuid_id());
- if (!cpu_info) {
- printk("CPU configuration botched (ID %08x), unable to continue.\n",
- read_cpuid_id());
- while (1);
- }
-
- cpu_name = cpu_info->cpu_name;
-
- printk("CPU: %s [%08x] revision %d\n",
- cpu_name, read_cpuid_id(), read_cpuid_id() & 15);
+ printk("CPU: AArch64 Processor [%08x] revision %d\n",
+ read_cpuid_id(), read_cpuid_id() & 15);
sprintf(init_utsname()->machine, ELF_PLATFORM);
elf_hwcap = 0;
--
2.1.4
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