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Message-ID: <mhng-08bcf932-3a06-43cf-b0b0-9614d09aa17d@palmerdabbelt-glaptop>
Date: Mon, 26 Apr 2021 08:32:48 -0700 (PDT)
From: Palmer Dabbelt <palmer@...belt.com>
To: vitaly.wool@...sulko.com
CC: alex@...ti.fr, Paul Walmsley <paul.walmsley@...ive.com>,
aou@...s.berkeley.edu, linux-riscv@...ts.infradead.org,
linux-kernel@...r.kernel.org, linux-arch@...r.kernel.org,
linux-mm@...ck.org
Subject: Re: [PATCH v8] RISC-V: enable XIP
On Fri, 23 Apr 2021 14:27:26 PDT (-0700), vitaly.wool@...sulko.com wrote:
> Hi Palmer,
>
> On Fri, Apr 23, 2021 at 6:22 AM Palmer Dabbelt <palmer@...belt.com> wrote:
>>
>> On Mon, 12 Apr 2021 23:35:14 PDT (-0700), alex@...ti.fr wrote:
>> > From: Vitaly Wool <vitaly.wool@...sulko.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@...ti.fr> [ Rebase on top of "Move
>> > kernel mapping outside the linear mapping" ]
>> > Signed-off-by: Vitaly Wool <vitaly.wool@...sulko.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.
Sorry about that, they should be fixed now.
>
> 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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