[PATCH v8] RISC-V: enable XIP
Alex Ghiti
alex at ghiti.fr
Sat Apr 24 12:30:17 BST 2021
Le 4/23/21 à 5:27 PM, Vitaly Wool a écrit :
> Hi Palmer,
>
> On Fri, Apr 23, 2021 at 6:22 AM Palmer Dabbelt <palmer at dabbelt.com> wrote:
>>
>> On Mon, 12 Apr 2021 23:35:14 PDT (-0700), alex at ghiti.fr wrote:
>>> From: Vitaly Wool <vitaly.wool at konsulko.com>
>>>
>>> Introduce XIP (eXecute In Place) support for RISC-V platforms.
>>> It allows code to be executed directly from non-volatile storage
>>> directly addressable by the CPU, such as QSPI NOR flash which can
>>> be found on many RISC-V platforms. This makes way for significant
>>> optimization of RAM footprint. The XIP kernel is not compressed
>>> since it has to run directly from flash, so it will occupy more
>>> space on the non-volatile storage. The physical flash address used
>>> to link the kernel object files and for storing it has to be known
>>> at compile time and is represented by a Kconfig option.
>>>
>>> XIP on RISC-V will for the time being only work on MMU-enabled
>>> kernels.
>>>
>>> Signed-off-by: Alexandre Ghiti <alex at ghiti.fr> [ Rebase on top of "Move
>>> kernel mapping outside the linear mapping" ]
>>> Signed-off-by: Vitaly Wool <vitaly.wool at konsulko.com>
>
> I'm currently looking at this patch in for-next
> [https://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux.git/commit/?h=for-next&id=2fd9503070f7e52cc8397845beb27ece2bcfe410]
> and see unresolved rejects, i. e. in '@@ -451,8 +547,13 @@ asmlinkage
> void __init setup_vm(uintptr_t dtb_pa)' chunk. Am I looking at the
> wrong place? I thought I'd flag it anyway just in case.
The patches I have done for fixing 32b kernel messed things up, so I'm
not surprised Palmer struggled to merge everything.
@Palmer: FWIW, I fixed all those things here, hope it helps!
https://github.com/AlexGhiti/riscv-linux/tree/int/alex%2Ffor_next_fix_5.13
>
> Best regards,
> Vitaly
>
>>> ---
>>> arch/riscv/Kconfig | 55 +++++++++++-
>>> arch/riscv/Makefile | 8 +-
>>> arch/riscv/boot/Makefile | 13 +++
>>> arch/riscv/include/asm/page.h | 21 +++++
>>> arch/riscv/include/asm/pgtable.h | 25 +++++-
>>> arch/riscv/kernel/head.S | 46 +++++++++-
>>> arch/riscv/kernel/head.h | 3 +
>>> arch/riscv/kernel/setup.c | 10 ++-
>>> arch/riscv/kernel/vmlinux-xip.lds.S | 133 ++++++++++++++++++++++++++++
>>> arch/riscv/kernel/vmlinux.lds.S | 6 ++
>>> arch/riscv/mm/init.c | 115 ++++++++++++++++++++++--
>>> 11 files changed, 418 insertions(+), 17 deletions(-)
>>> create mode 100644 arch/riscv/kernel/vmlinux-xip.lds.S
>>>
>>> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
>>> index 8ea60a0a19ae..7c7efdd67a10 100644
>>> --- a/arch/riscv/Kconfig
>>> +++ b/arch/riscv/Kconfig
>>> @@ -28,7 +28,7 @@ config RISCV
>>> select ARCH_HAS_PTE_SPECIAL
>>> select ARCH_HAS_SET_DIRECT_MAP
>>> select ARCH_HAS_SET_MEMORY
>>> - select ARCH_HAS_STRICT_KERNEL_RWX if MMU
>>> + select ARCH_HAS_STRICT_KERNEL_RWX if MMU && !XIP_KERNEL
>>
>> We now also have STRICT_MODULE_RWX, which causes a merge conflict. I've
>> added both as !XIP_KERNEL, though TBH I'm not even sure thot modules
>> make any sense with XIP.
>>
>>> select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
>>> select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX
>>> select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
>>> @@ -441,7 +441,7 @@ config EFI_STUB
>>>
>>> config EFI
>>> bool "UEFI runtime support"
>>> - depends on OF
>>> + depends on OF && !XIP_KERNEL
>>> select LIBFDT
>>> select UCS2_STRING
>>> select EFI_PARAMS_FROM_FDT
>>> @@ -465,11 +465,60 @@ config STACKPROTECTOR_PER_TASK
>>> def_bool y
>>> depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_TLS
>>>
>>> +config PHYS_RAM_BASE_FIXED
>>> + bool "Explicitly specified physical RAM address"
>>> + default n
>>> +
>>> +config PHYS_RAM_BASE
>>> + hex "Platform Physical RAM address"
>>> + depends on PHYS_RAM_BASE_FIXED
>>> + default "0x80000000"
>>> + help
>>> + This is the physical address of RAM in the system. It has to be
>>> + explicitly specified to run early relocations of read-write data
>>> + from flash to RAM.
>>> +
>>> +config XIP_KERNEL
>>> + bool "Kernel Execute-In-Place from ROM"
>>> + depends on MMU && SPARSEMEM
>>> + select PHYS_RAM_BASE_FIXED
>>> + help
>>> + Execute-In-Place allows the kernel to run from non-volatile storage
>>> + directly addressable by the CPU, such as NOR flash. This saves RAM
>>> + space since the text section of the kernel is not loaded from flash
>>> + to RAM. Read-write sections, such as the data section and stack,
>>> + are still copied to RAM. The XIP kernel is not compressed since
>>> + it has to run directly from flash, so it will take more space to
>>> + store it. The flash address used to link the kernel object files,
>>> + and for storing it, is configuration dependent. Therefore, if you
>>> + say Y here, you must know the proper physical address where to
>>> + store the kernel image depending on your own flash memory usage.
>>> +
>>> + Also note that the make target becomes "make xipImage" rather than
>>> + "make zImage" or "make Image". The final kernel binary to put in
>>> + ROM memory will be arch/riscv/boot/xipImage.
>>> +
>>> + SPARSEMEM is required because the kernel text and rodata that are
>>> + flash resident are not backed by memmap, then any attempt to get
>>> + a struct page on those regions will trigger a fault.
>>> +
>>> + If unsure, say N.
>>> +
>>> +config XIP_PHYS_ADDR
>>> + hex "XIP Kernel Physical Location"
>>> + depends on XIP_KERNEL
>>> + default "0x21000000"
>>> + help
>>> + This is the physical address in your flash memory the kernel will
>>> + be linked for and stored to. This address is dependent on your
>>> + own flash usage.
>>> +
>>> endmenu
>>>
>>> config BUILTIN_DTB
>>> - def_bool n
>>> + bool
>>> depends on OF
>>> + default y if XIP_KERNEL
>>>
>>> menu "Power management options"
>>>
>>> diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
>>> index 1368d943f1f3..8fcbec03974d 100644
>>> --- a/arch/riscv/Makefile
>>> +++ b/arch/riscv/Makefile
>>> @@ -82,7 +82,11 @@ CHECKFLAGS += -D__riscv -D__riscv_xlen=$(BITS)
>>>
>>> # Default target when executing plain make
>>> boot := arch/riscv/boot
>>> +ifeq ($(CONFIG_XIP_KERNEL),y)
>>> +KBUILD_IMAGE := $(boot)/xipImage
>>> +else
>>> KBUILD_IMAGE := $(boot)/Image.gz
>>> +endif
>>>
>>> head-y := arch/riscv/kernel/head.o
>>>
>>> @@ -95,12 +99,14 @@ PHONY += vdso_install
>>> vdso_install:
>>> $(Q)$(MAKE) $(build)=arch/riscv/kernel/vdso $@
>>>
>>> +ifneq ($(CONFIG_XIP_KERNEL),y)
>>> ifeq ($(CONFIG_RISCV_M_MODE)$(CONFIG_SOC_CANAAN),yy)
>>> KBUILD_IMAGE := $(boot)/loader.bin
>>> else
>>> KBUILD_IMAGE := $(boot)/Image.gz
>>> endif
>>> -BOOT_TARGETS := Image Image.gz loader loader.bin
>>> +endif
>>> +BOOT_TARGETS := Image Image.gz loader loader.bin xipImage
>>>
>>> all: $(notdir $(KBUILD_IMAGE))
>>>
>>> diff --git a/arch/riscv/boot/Makefile b/arch/riscv/boot/Makefile
>>> index 03404c84f971..6bf299f70c27 100644
>>> --- a/arch/riscv/boot/Makefile
>>> +++ b/arch/riscv/boot/Makefile
>>> @@ -17,8 +17,21 @@
>>> KCOV_INSTRUMENT := n
>>>
>>> OBJCOPYFLAGS_Image :=-O binary -R .note -R .note.gnu.build-id -R .comment -S
>>> +OBJCOPYFLAGS_xipImage :=-O binary -R .note -R .note.gnu.build-id -R .comment -S
>>>
>>> targets := Image Image.* loader loader.o loader.lds loader.bin
>>> +targets := Image Image.* loader loader.o loader.lds loader.bin xipImage
>>> +
>>> +ifeq ($(CONFIG_XIP_KERNEL),y)
>>> +
>>> +quiet_cmd_mkxip = $(quiet_cmd_objcopy)
>>> +cmd_mkxip = $(cmd_objcopy)
>>> +
>>> +$(obj)/xipImage: vmlinux FORCE
>>> + $(call if_changed,mkxip)
>>> + @$(kecho) ' Physical Address of xipImage: $(CONFIG_XIP_PHYS_ADDR)'
>>> +
>>> +endif
>>>
>>> $(obj)/Image: vmlinux FORCE
>>> $(call if_changed,objcopy)
>>> diff --git a/arch/riscv/include/asm/page.h b/arch/riscv/include/asm/page.h
>>> index 22cfb2be60dc..635c6b486806 100644
>>> --- a/arch/riscv/include/asm/page.h
>>> +++ b/arch/riscv/include/asm/page.h
>>> @@ -91,6 +91,9 @@ typedef struct page *pgtable_t;
>>> #ifdef CONFIG_MMU
>>> extern unsigned long va_pa_offset;
>>> extern unsigned long va_kernel_pa_offset;
>>> +#ifdef CONFIG_XIP_KERNEL
>>> +extern unsigned long va_kernel_xip_pa_offset;
>>> +#endif
>>> extern unsigned long pfn_base;
>>> #define ARCH_PFN_OFFSET (pfn_base)
>>> #else
>>> @@ -102,11 +105,29 @@ extern unsigned long pfn_base;
>>> extern unsigned long kernel_virt_addr;
>>>
>>> #define linear_mapping_pa_to_va(x) ((void *)((unsigned long)(x) + va_pa_offset))
>>> +#ifdef CONFIG_XIP_KERNEL
>>> +#define kernel_mapping_pa_to_va(y) ({ \
>>> + unsigned long _y = y; \
>>> + (_y >= CONFIG_PHYS_RAM_BASE) ? \
>>> + (void *)((unsigned long)(_y) + va_kernel_pa_offset + XIP_OFFSET) : \
>>> + (void *)((unsigned long)(_y) + va_kernel_xip_pa_offset); \
>>> + })
>>> +#else
>>> #define kernel_mapping_pa_to_va(x) ((void *)((unsigned long)(x) + va_kernel_pa_offset))
>>> +#endif
>>> #define __pa_to_va_nodebug(x) linear_mapping_pa_to_va(x)
>>>
>>> #define linear_mapping_va_to_pa(x) ((unsigned long)(x) - va_pa_offset)
>>> +#ifdef CONFIG_XIP_KERNEL
>>> +#define kernel_mapping_va_to_pa(y) ({ \
>>> + unsigned long _y = y; \
>>> + (_y < kernel_virt_addr + XIP_OFFSET) ? \
>>> + ((unsigned long)(_y) - va_kernel_xip_pa_offset) : \
>>> + ((unsigned long)(_y) - va_kernel_pa_offset - XIP_OFFSET); \
>>> + })
>>> +#else
>>> #define kernel_mapping_va_to_pa(x) ((unsigned long)(x) - va_kernel_pa_offset)
>>> +#endif
>>> #define __va_to_pa_nodebug(x) ({ \
>>> unsigned long _x = x; \
>>> (_x < kernel_virt_addr) ? \
>>> diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
>>> index 80e63a93e903..c2dc4f83eed8 100644
>>> --- a/arch/riscv/include/asm/pgtable.h
>>> +++ b/arch/riscv/include/asm/pgtable.h
>>> @@ -64,6 +64,19 @@
>>> #define FIXADDR_SIZE PGDIR_SIZE
>>> #endif
>>> #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
>>> +
>>> +#ifdef CONFIG_XIP_KERNEL
>>> +#define XIP_OFFSET SZ_8M
>>> +#define XIP_FIXUP(addr) ({ \
>>> + uintptr_t __a = (uintptr_t)(addr); \
>>> + (__a >= CONFIG_XIP_PHYS_ADDR && __a < CONFIG_XIP_PHYS_ADDR + SZ_16M) ? \
>>> + __a - CONFIG_XIP_PHYS_ADDR + CONFIG_PHYS_RAM_BASE - XIP_OFFSET :\
>>> + __a; \
>>> + })
>>> +#else
>>> +#define XIP_FIXUP(addr) (addr)
>>> +#endif /* CONFIG_XIP_KERNEL */
>>> +
>>> #endif
>>>
>>> #ifndef __ASSEMBLY__
>>> @@ -499,8 +512,16 @@ static inline int ptep_clear_flush_young(struct vm_area_struct *vma,
>>> #define kern_addr_valid(addr) (1) /* FIXME */
>>>
>>> extern char _start[];
>>> -extern void *dtb_early_va;
>>> -extern uintptr_t dtb_early_pa;
>>> +extern void *_dtb_early_va;
>>> +extern uintptr_t _dtb_early_pa;
>>> +#if defined(CONFIG_XIP_KERNEL) && defined(CONFIG_MMU)
>>> +#define dtb_early_va (*(void **)XIP_FIXUP(&_dtb_early_va))
>>> +#define dtb_early_pa (*(uintptr_t *)XIP_FIXUP(&_dtb_early_pa))
>>> +#else
>>> +#define dtb_early_va _dtb_early_va
>>> +#define dtb_early_pa _dtb_early_pa
>>> +#endif /* CONFIG_XIP_KERNEL */
>>> +
>>> void setup_bootmem(void);
>>> void paging_init(void);
>>> void misc_mem_init(void);
>>> diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S
>>> index 6cb05f22e52a..89cc58ab52b4 100644
>>> --- a/arch/riscv/kernel/head.S
>>> +++ b/arch/riscv/kernel/head.S
>>> @@ -9,11 +9,23 @@
>>> #include <linux/linkage.h>
>>> #include <asm/thread_info.h>
>>> #include <asm/page.h>
>>> +#include <asm/pgtable.h>
>>> #include <asm/csr.h>
>>> #include <asm/hwcap.h>
>>> #include <asm/image.h>
>>> #include "efi-header.S"
>>>
>>> +#ifdef CONFIG_XIP_KERNEL
>>> +.macro XIP_FIXUP_OFFSET reg
>>> + REG_L t0, _xip_fixup
>>> + add \reg, \reg, t0
>>> +.endm
>>> +_xip_fixup: .dword CONFIG_PHYS_RAM_BASE - CONFIG_XIP_PHYS_ADDR - XIP_OFFSET
>>> +#else
>>> +.macro XIP_FIXUP_OFFSET reg
>>> +.endm
>>> +#endif /* CONFIG_XIP_KERNEL */
>>> +
>>> __HEAD
>>> ENTRY(_start)
>>> /*
>>> @@ -70,6 +82,7 @@ pe_head_start:
>>> relocate:
>>> /* Relocate return address */
>>> la a1, kernel_virt_addr
>>> + XIP_FIXUP_OFFSET a1
>>> REG_L a1, 0(a1)
>>> la a2, _start
>>> sub a1, a1, a2
>>> @@ -92,6 +105,7 @@ relocate:
>>> * to ensure the new translations are in use.
>>> */
>>> la a0, trampoline_pg_dir
>>> + XIP_FIXUP_OFFSET a0
>>> srl a0, a0, PAGE_SHIFT
>>> or a0, a0, a1
>>> sfence.vma
>>> @@ -145,7 +159,9 @@ secondary_start_sbi:
>>>
>>> slli a3, a0, LGREG
>>> la a4, __cpu_up_stack_pointer
>>> + XIP_FIXUP_OFFSET a4
>>> la a5, __cpu_up_task_pointer
>>> + XIP_FIXUP_OFFSET a5
>>> add a4, a3, a4
>>> add a5, a3, a5
>>> REG_L sp, (a4)
>>> @@ -157,6 +173,7 @@ secondary_start_common:
>>> #ifdef CONFIG_MMU
>>> /* Enable virtual memory and relocate to virtual address */
>>> la a0, swapper_pg_dir
>>> + XIP_FIXUP_OFFSET a0
>>> call relocate
>>> #endif
>>> call setup_trap_vector
>>> @@ -237,12 +254,33 @@ pmp_done:
>>> .Lgood_cores:
>>> #endif
>>>
>>> +#ifndef CONFIG_XIP_KERNEL
>>> /* Pick one hart to run the main boot sequence */
>>> la a3, hart_lottery
>>> li a2, 1
>>> amoadd.w a3, a2, (a3)
>>> bnez a3, .Lsecondary_start
>>>
>>> +#else
>>> + /* hart_lottery in flash contains a magic number */
>>> + la a3, hart_lottery
>>> + mv a2, a3
>>> + XIP_FIXUP_OFFSET a2
>>> + lw t1, (a3)
>>> + amoswap.w t0, t1, (a2)
>>> + /* first time here if hart_lottery in RAM is not set */
>>> + beq t0, t1, .Lsecondary_start
>>> +
>>> + la sp, _end + THREAD_SIZE
>>> + XIP_FIXUP_OFFSET sp
>>> + mv s0, a0
>>> + call __copy_data
>>> +
>>> + /* Restore a0 copy */
>>> + mv a0, s0
>>> +#endif
>>> +
>>> +#ifndef CONFIG_XIP_KERNEL
>>> /* Clear BSS for flat non-ELF images */
>>> la a3, __bss_start
>>> la a4, __bss_stop
>>> @@ -252,15 +290,18 @@ clear_bss:
>>> add a3, a3, RISCV_SZPTR
>>> blt a3, a4, clear_bss
>>> clear_bss_done:
>>> -
>>> +#endif
>>> /* Save hart ID and DTB physical address */
>>> mv s0, a0
>>> mv s1, a1
>>> +
>>> la a2, boot_cpu_hartid
>>> + XIP_FIXUP_OFFSET a2
>>> REG_S a0, (a2)
>>>
>>> /* Initialize page tables and relocate to virtual addresses */
>>> la sp, init_thread_union + THREAD_SIZE
>>> + XIP_FIXUP_OFFSET sp
>>> #ifdef CONFIG_BUILTIN_DTB
>>> la a0, __dtb_start
>>> #else
>>> @@ -269,6 +310,7 @@ clear_bss_done:
>>> call setup_vm
>>> #ifdef CONFIG_MMU
>>> la a0, early_pg_dir
>>> + XIP_FIXUP_OFFSET a0
>>> call relocate
>>> #endif /* CONFIG_MMU */
>>>
>>> @@ -293,7 +335,9 @@ clear_bss_done:
>>>
>>> slli a3, a0, LGREG
>>> la a1, __cpu_up_stack_pointer
>>> + XIP_FIXUP_OFFSET a1
>>> la a2, __cpu_up_task_pointer
>>> + XIP_FIXUP_OFFSET a2
>>> add a1, a3, a1
>>> add a2, a3, a2
>>>
>>> diff --git a/arch/riscv/kernel/head.h b/arch/riscv/kernel/head.h
>>> index b48dda3d04f6..aabbc3ac3e48 100644
>>> --- a/arch/riscv/kernel/head.h
>>> +++ b/arch/riscv/kernel/head.h
>>> @@ -12,6 +12,9 @@ extern atomic_t hart_lottery;
>>>
>>> asmlinkage void do_page_fault(struct pt_regs *regs);
>>> asmlinkage void __init setup_vm(uintptr_t dtb_pa);
>>> +#ifdef CONFIG_XIP_KERNEL
>>> +asmlinkage void __init __copy_data(void);
>>> +#endif
>>>
>>> extern void *__cpu_up_stack_pointer[];
>>> extern void *__cpu_up_task_pointer[];
>>> diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
>>> index 30e4af0fd50c..2ddf654c72bb 100644
>>> --- a/arch/riscv/kernel/setup.c
>>> +++ b/arch/riscv/kernel/setup.c
>>> @@ -50,7 +50,11 @@ struct screen_info screen_info __section(".data") = {
>>> * This is used before the kernel initializes the BSS so it can't be in the
>>> * BSS.
>>> */
>>> -atomic_t hart_lottery __section(".sdata");
>>> +atomic_t hart_lottery __section(".sdata")
>>> +#ifdef CONFIG_XIP_KERNEL
>>> += ATOMIC_INIT(0xC001BEEF)
>>> +#endif
>>> +;
>>> unsigned long boot_cpu_hartid;
>>> static DEFINE_PER_CPU(struct cpu, cpu_devices);
>>>
>>> @@ -254,7 +258,7 @@ void __init setup_arch(char **cmdline_p)
>>> #if IS_ENABLED(CONFIG_BUILTIN_DTB)
>>> unflatten_and_copy_device_tree();
>>> #else
>>> - if (early_init_dt_verify(__va(dtb_early_pa)))
>>> + if (early_init_dt_verify(__va(XIP_FIXUP(dtb_early_pa))))
>>> unflatten_device_tree();
>>> else
>>> pr_err("No DTB found in kernel mappings\n");
>>> @@ -266,7 +270,7 @@ void __init setup_arch(char **cmdline_p)
>>> if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX))
>>> protect_kernel_text_data();
>>>
>>> -#if defined(CONFIG_64BIT) && defined(CONFIG_MMU)
>>> +#if defined(CONFIG_64BIT) && defined(CONFIG_MMU) && !defined(CONFIG_XIP_KERNEL)
>>> protect_kernel_linear_mapping_text_rodata();
>>> #endif
>>
>> My tree doesn't look quite like this. Not sure if I just got the wrong
>> version of something, but I didn't have the CONFIG_MMU check. It turns
>> out that, as I was merging this in, I saw that failing allnoconfig
>> (which is !MMU). I went ahead and squashed in
>>
>> diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
>> index ab394d173cd4..3e7930869ee7 100644
>> --- a/arch/riscv/kernel/setup.c
>> +++ b/arch/riscv/kernel/setup.c
>> @@ -266,7 +266,7 @@ void __init setup_arch(char **cmdline_p)
>>
>> if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX)) {
>> protect_kernel_text_data();
>> -#ifdef CONFIG_64BIT
>> +#if defined(CONFIG_64BIT) && defined(CONFIG_MMU)
>> protect_kernel_linear_mapping_text_rodata();
>> #endif
>> }
>>
>> to your memory map rearrangement patch, but I'm a bit worried that I managed to
>> miss something in the process.
>>
>>>
>>> diff --git a/arch/riscv/kernel/vmlinux-xip.lds.S b/arch/riscv/kernel/vmlinux-xip.lds.S
>>> new file mode 100644
>>> index 000000000000..4b29b9917f99
>>> --- /dev/null
>>> +++ b/arch/riscv/kernel/vmlinux-xip.lds.S
>>> @@ -0,0 +1,133 @@
>>> +/* SPDX-License-Identifier: GPL-2.0-only */
>>> +/*
>>> + * Copyright (C) 2012 Regents of the University of California
>>> + * Copyright (C) 2017 SiFive
>>> + * Copyright (C) 2020 Vitaly Wool, Konsulko AB
>>> + */
>>> +
>>> +#include <asm/pgtable.h>
>>> +#define LOAD_OFFSET KERNEL_LINK_ADDR
>>> +/* No __ro_after_init data in the .rodata section - which will always be ro */
>>> +#define RO_AFTER_INIT_DATA
>>> +
>>> +#include <asm/vmlinux.lds.h>
>>> +#include <asm/page.h>
>>> +#include <asm/pgtable.h>
>>> +#include <asm/cache.h>
>>> +#include <asm/thread_info.h>
>>> +
>>> +OUTPUT_ARCH(riscv)
>>> +ENTRY(_start)
>>> +
>>> +jiffies = jiffies_64;
>>> +
>>> +SECTIONS
>>> +{
>>> + /* Beginning of code and text segment */
>>> + . = LOAD_OFFSET;
>>> + _xiprom = .;
>>> + _start = .;
>>> + HEAD_TEXT_SECTION
>>> + INIT_TEXT_SECTION(PAGE_SIZE)
>>> + /* we have to discard exit text and such at runtime, not link time */
>>> + .exit.text :
>>> + {
>>> + EXIT_TEXT
>>> + }
>>> +
>>> + .text : {
>>> + _text = .;
>>> + _stext = .;
>>> + TEXT_TEXT
>>> + SCHED_TEXT
>>> + CPUIDLE_TEXT
>>> + LOCK_TEXT
>>> + KPROBES_TEXT
>>> + ENTRY_TEXT
>>> + IRQENTRY_TEXT
>>> + SOFTIRQENTRY_TEXT
>>> + *(.fixup)
>>> + _etext = .;
>>> + }
>>> + RO_DATA(L1_CACHE_BYTES)
>>> + .srodata : {
>>> + *(.srodata*)
>>> + }
>>> + .init.rodata : {
>>> + INIT_SETUP(16)
>>> + INIT_CALLS
>>> + CON_INITCALL
>>> + INIT_RAM_FS
>>> + }
>>> + _exiprom = .; /* End of XIP ROM area */
>>> +
>>> +
>>> +/*
>>> + * From this point, stuff is considered writable and will be copied to RAM
>>> + */
>>> + __data_loc = ALIGN(16); /* location in file */
>>> + . = LOAD_OFFSET + XIP_OFFSET; /* location in memory */
>>> +
>>> + _sdata = .; /* Start of data section */
>>> + _data = .;
>>> + RW_DATA(L1_CACHE_BYTES, PAGE_SIZE, THREAD_SIZE)
>>> + _edata = .;
>>> + __start_ro_after_init = .;
>>> + .data.ro_after_init : AT(ADDR(.data.ro_after_init) - LOAD_OFFSET) {
>>> + *(.data..ro_after_init)
>>> + }
>>> + __end_ro_after_init = .;
>>> +
>>> + . = ALIGN(PAGE_SIZE);
>>> + __init_begin = .;
>>> + .init.data : {
>>> + INIT_DATA
>>> + }
>>> + .exit.data : {
>>> + EXIT_DATA
>>> + }
>>> + . = ALIGN(8);
>>> + __soc_early_init_table : {
>>> + __soc_early_init_table_start = .;
>>> + KEEP(*(__soc_early_init_table))
>>> + __soc_early_init_table_end = .;
>>> + }
>>> + __soc_builtin_dtb_table : {
>>> + __soc_builtin_dtb_table_start = .;
>>> + KEEP(*(__soc_builtin_dtb_table))
>>> + __soc_builtin_dtb_table_end = .;
>>> + }
>>> + PERCPU_SECTION(L1_CACHE_BYTES)
>>> +
>>> + . = ALIGN(PAGE_SIZE);
>>> + __init_end = .;
>>> +
>>> + .sdata : {
>>> + __global_pointer$ = . + 0x800;
>>> + *(.sdata*)
>>> + *(.sbss*)
>>> + }
>>> +
>>> + BSS_SECTION(PAGE_SIZE, PAGE_SIZE, 0)
>>> + EXCEPTION_TABLE(0x10)
>>> +
>>> + .rel.dyn : AT(ADDR(.rel.dyn) - LOAD_OFFSET) {
>>> + *(.rel.dyn*)
>>> + }
>>> +
>>> + /*
>>> + * End of copied data. We need a dummy section to get its LMA.
>>> + * Also located before final ALIGN() as trailing padding is not stored
>>> + * in the resulting binary file and useless to copy.
>>> + */
>>> + .data.endmark : AT(ADDR(.data.endmark) - LOAD_OFFSET) { }
>>> + _edata_loc = LOADADDR(.data.endmark);
>>> +
>>> + . = ALIGN(PAGE_SIZE);
>>> + _end = .;
>>> +
>>> + STABS_DEBUG
>>> + DWARF_DEBUG
>>> +
>>> + DISCARDS
>>> +}
>>> diff --git a/arch/riscv/kernel/vmlinux.lds.S b/arch/riscv/kernel/vmlinux.lds.S
>>> index 0726c05e0336..0a59b65cf789 100644
>>> --- a/arch/riscv/kernel/vmlinux.lds.S
>>> +++ b/arch/riscv/kernel/vmlinux.lds.S
>>> @@ -4,8 +4,13 @@
>>> * Copyright (C) 2017 SiFive
>>> */
>>>
>>> +#ifdef CONFIG_XIP_KERNEL
>>> +#include "vmlinux-xip.lds.S"
>>> +#else
>>> +
>>> #include <asm/pgtable.h>
>>> #define LOAD_OFFSET KERNEL_LINK_ADDR
>>> +
>>> #include <asm/vmlinux.lds.h>
>>> #include <asm/page.h>
>>> #include <asm/cache.h>
>>> @@ -133,3 +138,4 @@ SECTIONS
>>>
>>> DISCARDS
>>> }
>>> +#endif /* CONFIG_XIP_KERNEL */
>>> diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
>>> index 093f3a96ecfc..d03e5e43d2d0 100644
>>> --- a/arch/riscv/mm/init.c
>>> +++ b/arch/riscv/mm/init.c
>>> @@ -27,6 +27,9 @@
>>>
>>> unsigned long kernel_virt_addr = KERNEL_LINK_ADDR;
>>> EXPORT_SYMBOL(kernel_virt_addr);
>>> +#ifdef CONFIG_XIP_KERNEL
>>> +#define kernel_virt_addr (*((unsigned long *)XIP_FIXUP(&kernel_virt_addr)))
>>> +#endif
>>>
>>> unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)]
>>> __page_aligned_bss;
>>> @@ -34,8 +37,8 @@ EXPORT_SYMBOL(empty_zero_page);
>>>
>>> extern char _start[];
>>> #define DTB_EARLY_BASE_VA PGDIR_SIZE
>>> -void *dtb_early_va __initdata;
>>> -uintptr_t dtb_early_pa __initdata;
>>> +void *_dtb_early_va __initdata;
>>> +uintptr_t _dtb_early_pa __initdata;
>>>
>>> struct pt_alloc_ops {
>>> pte_t *(*get_pte_virt)(phys_addr_t pa);
>>> @@ -118,6 +121,10 @@ void __init setup_bootmem(void)
>>> phys_addr_t dram_end = memblock_end_of_DRAM();
>>> phys_addr_t max_mapped_addr = __pa(~(ulong)0);
>>>
>>> +#ifdef CONFIG_XIP_KERNEL
>>> + vmlinux_start = __pa_symbol(&_sdata);
>>> +#endif
>>> +
>>> /* The maximal physical memory size is -PAGE_OFFSET. */
>>> memblock_enforce_memory_limit(-PAGE_OFFSET);
>>>
>>> @@ -159,15 +166,39 @@ void __init setup_bootmem(void)
>>> memblock_allow_resize();
>>> }
>>>
>>> +#ifdef CONFIG_XIP_KERNEL
>>> +
>>> +extern char _xiprom[], _exiprom[];
>>> +extern char _sdata[], _edata[];
>>> +
>>> +#endif /* CONFIG_XIP_KERNEL */
>>> +
>>> #ifdef CONFIG_MMU
>>> -static struct pt_alloc_ops pt_ops;
>>> +static struct pt_alloc_ops _pt_ops;
>>> +
>>> +#ifdef CONFIG_XIP_KERNEL
>>> +#define pt_ops (*(struct pt_alloc_ops *)XIP_FIXUP(&_pt_ops))
>>> +#else
>>> +#define pt_ops _pt_ops
>>> +#endif
>>>
>>> /* Offset between linear mapping virtual address and kernel load address */
>>> unsigned long va_pa_offset;
>>> EXPORT_SYMBOL(va_pa_offset);
>>> +#ifdef CONFIG_XIP_KERNEL
>>> +#define va_pa_offset (*((unsigned long *)XIP_FIXUP(&va_pa_offset)))
>>> +#endif
>>> /* Offset between kernel mapping virtual address and kernel load address */
>>> unsigned long va_kernel_pa_offset;
>>> EXPORT_SYMBOL(va_kernel_pa_offset);
>>> +#ifdef CONFIG_XIP_KERNEL
>>> +#define va_kernel_pa_offset (*((unsigned long *)XIP_FIXUP(&va_kernel_pa_offset)))
>>> +#endif
>>> +unsigned long va_kernel_xip_pa_offset;
>>> +EXPORT_SYMBOL(va_kernel_xip_pa_offset);
>>> +#ifdef CONFIG_XIP_KERNEL
>>> +#define va_kernel_xip_pa_offset (*((unsigned long *)XIP_FIXUP(&va_kernel_xip_pa_offset)))
>>> +#endif
>>> unsigned long pfn_base;
>>> EXPORT_SYMBOL(pfn_base);
>>>
>>> @@ -177,6 +208,12 @@ pte_t fixmap_pte[PTRS_PER_PTE] __page_aligned_bss;
>>>
>>> pgd_t early_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE);
>>>
>>> +#ifdef CONFIG_XIP_KERNEL
>>> +#define trampoline_pg_dir ((pgd_t *)XIP_FIXUP(trampoline_pg_dir))
>>> +#define fixmap_pte ((pte_t *)XIP_FIXUP(fixmap_pte))
>>> +#define early_pg_dir ((pgd_t *)XIP_FIXUP(early_pg_dir))
>>> +#endif /* CONFIG_XIP_KERNEL */
>>> +
>>> void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot)
>>> {
>>> unsigned long addr = __fix_to_virt(idx);
>>> @@ -252,6 +289,12 @@ pmd_t fixmap_pmd[PTRS_PER_PMD] __page_aligned_bss;
>>> pmd_t early_pmd[PTRS_PER_PMD] __initdata __aligned(PAGE_SIZE);
>>> pmd_t early_dtb_pmd[PTRS_PER_PMD] __initdata __aligned(PAGE_SIZE);
>>>
>>> +#ifdef CONFIG_XIP_KERNEL
>>> +#define trampoline_pmd ((pmd_t *)XIP_FIXUP(trampoline_pmd))
>>> +#define fixmap_pmd ((pmd_t *)XIP_FIXUP(fixmap_pmd))
>>> +#define early_pmd ((pmd_t *)XIP_FIXUP(early_pmd))
>>> +#endif /* CONFIG_XIP_KERNEL */
>>> +
>>> static pmd_t *__init get_pmd_virt_early(phys_addr_t pa)
>>> {
>>> /* Before MMU is enabled */
>>> @@ -368,6 +411,19 @@ static uintptr_t __init best_map_size(phys_addr_t base, phys_addr_t size)
>>> return PMD_SIZE;
>>> }
>>>
>>> +#ifdef CONFIG_XIP_KERNEL
>>> +/* called from head.S with MMU off */
>>> +asmlinkage void __init __copy_data(void)
>>> +{
>>> + void *from = (void *)(&_sdata);
>>> + void *end = (void *)(&_end);
>>> + void *to = (void *)CONFIG_PHYS_RAM_BASE;
>>> + size_t sz = (size_t)(end - from + 1);
>>> +
>>> + memcpy(to, from, sz);
>>> +}
>>> +#endif
>>> +
>>> /*
>>> * setup_vm() is called from head.S with MMU-off.
>>> *
>>> @@ -387,7 +443,35 @@ static uintptr_t __init best_map_size(phys_addr_t base, phys_addr_t size)
>>> #endif
>>>
>>> uintptr_t load_pa, load_sz;
>>> +#ifdef CONFIG_XIP_KERNEL
>>> +#define load_pa (*((uintptr_t *)XIP_FIXUP(&load_pa)))
>>> +#define load_sz (*((uintptr_t *)XIP_FIXUP(&load_sz)))
>>> +#endif
>>> +
>>> +#ifdef CONFIG_XIP_KERNEL
>>> +uintptr_t xiprom, xiprom_sz;
>>> +#define xiprom_sz (*((uintptr_t *)XIP_FIXUP(&xiprom_sz)))
>>> +#define xiprom (*((uintptr_t *)XIP_FIXUP(&xiprom)))
>>>
>>> +static void __init create_kernel_page_table(pgd_t *pgdir, uintptr_t map_size)
>>> +{
>>> + uintptr_t va, end_va;
>>> +
>>> + /* Map the flash resident part */
>>> + end_va = kernel_virt_addr + xiprom_sz;
>>> + for (va = kernel_virt_addr; va < end_va; va += map_size)
>>> + create_pgd_mapping(pgdir, va,
>>> + xiprom + (va - kernel_virt_addr),
>>> + map_size, PAGE_KERNEL_EXEC);
>>> +
>>> + /* Map the data in RAM */
>>> + end_va = kernel_virt_addr + XIP_OFFSET + load_sz;
>>> + for (va = kernel_virt_addr + XIP_OFFSET; va < end_va; va += map_size)
>>> + create_pgd_mapping(pgdir, va,
>>> + load_pa + (va - (kernel_virt_addr + XIP_OFFSET)),
>>> + map_size, PAGE_KERNEL);
>>> +}
>>> +#else
>>> static void __init create_kernel_page_table(pgd_t *pgdir, uintptr_t map_size)
>>> {
>>> uintptr_t va, end_va;
>>> @@ -398,16 +482,28 @@ static void __init create_kernel_page_table(pgd_t *pgdir, uintptr_t map_size)
>>> load_pa + (va - kernel_virt_addr),
>>> map_size, PAGE_KERNEL_EXEC);
>>> }
>>> +#endif
>>>
>>> asmlinkage void __init setup_vm(uintptr_t dtb_pa)
>>> {
>>> - uintptr_t pa;
>>> + uintptr_t __maybe_unused pa;
>>> uintptr_t map_size;
>>> #ifndef __PAGETABLE_PMD_FOLDED
>>> pmd_t fix_bmap_spmd, fix_bmap_epmd;
>>> #endif
>>> +
>>> +#ifdef CONFIG_XIP_KERNEL
>>> + xiprom = (uintptr_t)CONFIG_XIP_PHYS_ADDR;
>>> + xiprom_sz = (uintptr_t)(&_exiprom) - (uintptr_t)(&_xiprom);
>>> +
>>> + load_pa = (uintptr_t)CONFIG_PHYS_RAM_BASE;
>>> + load_sz = (uintptr_t)(&_end) - (uintptr_t)(&_sdata);
>>> +
>>> + va_kernel_xip_pa_offset = kernel_virt_addr - xiprom;
>>> +#else
>>> load_pa = (uintptr_t)(&_start);
>>> load_sz = (uintptr_t)(&_end) - load_pa;
>>> +#endif
>>>
>>> va_pa_offset = PAGE_OFFSET - load_pa;
>>> va_kernel_pa_offset = kernel_virt_addr - load_pa;
>>> @@ -441,8 +537,13 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
>>> /* Setup trampoline PGD and PMD */
>>> create_pgd_mapping(trampoline_pg_dir, kernel_virt_addr,
>>> (uintptr_t)trampoline_pmd, PGDIR_SIZE, PAGE_TABLE);
>>> +#ifdef CONFIG_XIP_KERNEL
>>> + create_pmd_mapping(trampoline_pmd, kernel_virt_addr,
>>> + xiprom, PMD_SIZE, PAGE_KERNEL_EXEC);
>>> +#else
>>> create_pmd_mapping(trampoline_pmd, kernel_virt_addr,
>>> load_pa, PMD_SIZE, PAGE_KERNEL_EXEC);
>>> +#endif
>>> #else
>>> /* Setup trampoline PGD */
>>> create_pgd_mapping(trampoline_pg_dir, kernel_virt_addr,
>>> @@ -474,7 +575,7 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
>>> * whereas dtb_early_va will be used before setup_vm_final installs
>>> * the linear mapping.
>>> */
>>> - dtb_early_va = kernel_mapping_pa_to_va(dtb_pa);
>>> + dtb_early_va = kernel_mapping_pa_to_va(XIP_FIXUP(dtb_pa));
>>> #endif /* CONFIG_BUILTIN_DTB */
>>> #else
>>> #ifndef CONFIG_BUILTIN_DTB
>>> @@ -486,7 +587,7 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
>>> pa + PGDIR_SIZE, PGDIR_SIZE, PAGE_KERNEL);
>>> dtb_early_va = (void *)DTB_EARLY_BASE_VA + (dtb_pa & (PGDIR_SIZE - 1));
>>> #else /* CONFIG_BUILTIN_DTB */
>>> - dtb_early_va = kernel_mapping_pa_to_va(dtb_pa);
>>> + dtb_early_va = kernel_mapping_pa_to_va(XIP_FIXUP(dtb_pa));
>>> #endif /* CONFIG_BUILTIN_DTB */
>>> #endif
>>> dtb_early_pa = dtb_pa;
>>> @@ -522,7 +623,7 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
>>> #endif
>>> }
>>>
>>> -#ifdef CONFIG_64BIT
>>> +#if defined(CONFIG_64BIT) && !defined(CONFIG_XIP_KERNEL)
>>> void protect_kernel_linear_mapping_text_rodata(void)
>>> {
>>> unsigned long text_start = (unsigned long)lm_alias(_start);
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