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Message-ID: <a58c4616-572f-4a0b-2ce9-fd00735843be@ghiti.fr>
Date: Thu, 15 Apr 2021 14:00:21 -0400
From: Alex Ghiti <alex@...ti.fr>
To: Palmer Dabbelt <palmer@...belt.com>
Cc: corbet@....net, Paul Walmsley <paul.walmsley@...ive.com>,
aou@...s.berkeley.edu, Arnd Bergmann <arnd@...db.de>,
aryabinin@...tuozzo.com, glider@...gle.com, dvyukov@...gle.com,
linux-doc@...r.kernel.org, linux-riscv@...ts.infradead.org,
linux-kernel@...r.kernel.org, kasan-dev@...glegroups.com,
linux-arch@...r.kernel.org, linux-mm@...ck.org
Subject: Re: [PATCH v5 1/3] riscv: Move kernel mapping outside of linear
mapping
Le 4/15/21 à 12:54 AM, Alex Ghiti a écrit :
> Le 4/15/21 à 12:20 AM, Palmer Dabbelt a écrit :
>> On Sun, 11 Apr 2021 09:41:44 PDT (-0700), alex@...ti.fr wrote:
>>> This is a preparatory patch for relocatable kernel and sv48 support.
>>>
>>> The kernel used to be linked at PAGE_OFFSET address therefore we
>>> could use
>>> the linear mapping for the kernel mapping. But the relocated kernel base
>>> address will be different from PAGE_OFFSET and since in the linear
>>> mapping,
>>> two different virtual addresses cannot point to the same physical
>>> address,
>>> the kernel mapping needs to lie outside the linear mapping so that we
>>> don't
>>> have to copy it at the same physical offset.
>>>
>>> The kernel mapping is moved to the last 2GB of the address space, BPF
>>> is now always after the kernel and modules use the 2GB memory range
>>> right
>>> before the kernel, so BPF and modules regions do not overlap. KASLR
>>> implementation will simply have to move the kernel in the last 2GB range
>>> and just take care of leaving enough space for BPF.
>>>
>>> In addition, by moving the kernel to the end of the address space, both
>>> sv39 and sv48 kernels will be exactly the same without needing to be
>>> relocated at runtime.
>>>
>>> Suggested-by: Arnd Bergmann <arnd@...db.de>
>>> Signed-off-by: Alexandre Ghiti <alex@...ti.fr>
>>> ---
>>> arch/riscv/boot/loader.lds.S | 3 +-
>>> arch/riscv/include/asm/page.h | 17 +++++-
>>> arch/riscv/include/asm/pgtable.h | 37 ++++++++----
>>> arch/riscv/include/asm/set_memory.h | 1 +
>>> arch/riscv/kernel/head.S | 3 +-
>>> arch/riscv/kernel/module.c | 6 +-
>>> arch/riscv/kernel/setup.c | 5 ++
>>> arch/riscv/kernel/vmlinux.lds.S | 3 +-
>>> arch/riscv/mm/fault.c | 13 +++++
>>> arch/riscv/mm/init.c | 87 ++++++++++++++++++++++-------
>>> arch/riscv/mm/kasan_init.c | 9 +++
>>> arch/riscv/mm/physaddr.c | 2 +-
>>> 12 files changed, 146 insertions(+), 40 deletions(-)
>>>
>>> diff --git a/arch/riscv/boot/loader.lds.S b/arch/riscv/boot/loader.lds.S
>>> index 47a5003c2e28..62d94696a19c 100644
>>> --- a/arch/riscv/boot/loader.lds.S
>>> +++ b/arch/riscv/boot/loader.lds.S
>>> @@ -1,13 +1,14 @@
>>> /* SPDX-License-Identifier: GPL-2.0 */
>>>
>>> #include <asm/page.h>
>>> +#include <asm/pgtable.h>
>>>
>>> OUTPUT_ARCH(riscv)
>>> ENTRY(_start)
>>>
>>> SECTIONS
>>> {
>>> - . = PAGE_OFFSET;
>>> + . = KERNEL_LINK_ADDR;
>>>
>>> .payload : {
>>> *(.payload)
>>> diff --git a/arch/riscv/include/asm/page.h
>>> b/arch/riscv/include/asm/page.h
>>> index adc9d26f3d75..22cfb2be60dc 100644
>>> --- a/arch/riscv/include/asm/page.h
>>> +++ b/arch/riscv/include/asm/page.h
>>> @@ -90,15 +90,28 @@ typedef struct page *pgtable_t;
>>>
>>> #ifdef CONFIG_MMU
>>> extern unsigned long va_pa_offset;
>>> +extern unsigned long va_kernel_pa_offset;
>>> extern unsigned long pfn_base;
>>> #define ARCH_PFN_OFFSET (pfn_base)
>>> #else
>>> #define va_pa_offset 0
>>> +#define va_kernel_pa_offset 0
>>> #define ARCH_PFN_OFFSET (PAGE_OFFSET >> PAGE_SHIFT)
>>> #endif /* CONFIG_MMU */
>>>
>>> -#define __pa_to_va_nodebug(x) ((void *)((unsigned long) (x) +
>>> va_pa_offset))
>>> -#define __va_to_pa_nodebug(x) ((unsigned long)(x) - va_pa_offset)
>>> +extern unsigned long kernel_virt_addr;
>>> +
>>> +#define linear_mapping_pa_to_va(x) ((void *)((unsigned long)(x) +
>>> va_pa_offset))
>>> +#define kernel_mapping_pa_to_va(x) ((void *)((unsigned long)(x) +
>>> va_kernel_pa_offset))
>>> +#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)
>>> +#define kernel_mapping_va_to_pa(x) ((unsigned long)(x) -
>>> va_kernel_pa_offset)
>>> +#define __va_to_pa_nodebug(x) ({ \
>>> + unsigned long _x = x; \
>>> + (_x < kernel_virt_addr) ? \
>>> + linear_mapping_va_to_pa(_x) : kernel_mapping_va_to_pa(_x); \
>>> + })
>>>
>>> #ifdef CONFIG_DEBUG_VIRTUAL
>>> extern phys_addr_t __virt_to_phys(unsigned long x);
>>> diff --git a/arch/riscv/include/asm/pgtable.h
>>> b/arch/riscv/include/asm/pgtable.h
>>> index ebf817c1bdf4..80e63a93e903 100644
>>> --- a/arch/riscv/include/asm/pgtable.h
>>> +++ b/arch/riscv/include/asm/pgtable.h
>>> @@ -11,23 +11,30 @@
>>>
>>> #include <asm/pgtable-bits.h>
>>>
>>> -#ifndef __ASSEMBLY__
>>> -
>>> -/* Page Upper Directory not used in RISC-V */
>>> -#include <asm-generic/pgtable-nopud.h>
>>> -#include <asm/page.h>
>>> -#include <asm/tlbflush.h>
>>> -#include <linux/mm_types.h>
>>> +#ifndef CONFIG_MMU
>>> +#define KERNEL_LINK_ADDR PAGE_OFFSET
>>> +#else
>>>
>>> -#ifdef CONFIG_MMU
>>> +#define ADDRESS_SPACE_END (UL(-1))
>>> +/*
>>> + * Leave 2GB for kernel and BPF at the end of the address space
>>> + */
>>> +#define KERNEL_LINK_ADDR (ADDRESS_SPACE_END - SZ_2G + 1)
>>>
>>> #define VMALLOC_SIZE (KERN_VIRT_SIZE >> 1)
>>> #define VMALLOC_END (PAGE_OFFSET - 1)
>>> #define VMALLOC_START (PAGE_OFFSET - VMALLOC_SIZE)
>>>
>>> +/* KASLR should leave at least 128MB for BPF after the kernel */
>>> #define BPF_JIT_REGION_SIZE (SZ_128M)
>>> -#define BPF_JIT_REGION_START (PAGE_OFFSET - BPF_JIT_REGION_SIZE)
>>> -#define BPF_JIT_REGION_END (VMALLOC_END)
>>> +#define BPF_JIT_REGION_START PFN_ALIGN((unsigned long)&_end)
>>> +#define BPF_JIT_REGION_END (BPF_JIT_REGION_START +
>>> BPF_JIT_REGION_SIZE)
>>> +
>>> +/* Modules always live before the kernel */
>>> +#ifdef CONFIG_64BIT
>>> +#define MODULES_VADDR (PFN_ALIGN((unsigned long)&_end) - SZ_2G)
>>> +#define MODULES_END (PFN_ALIGN((unsigned long)&_start))
>>> +#endif
>>>
>>> /*
>>> * Roughly size the vmemmap space to be large enough to fit enough
>>> @@ -57,9 +64,16 @@
>>> #define FIXADDR_SIZE PGDIR_SIZE
>>> #endif
>>> #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
>>> -
>>> #endif
>>>
>>> +#ifndef __ASSEMBLY__
>>> +
>>> +/* Page Upper Directory not used in RISC-V */
>>> +#include <asm-generic/pgtable-nopud.h>
>>> +#include <asm/page.h>
>>> +#include <asm/tlbflush.h>
>>> +#include <linux/mm_types.h>
>>> +
>>> #ifdef CONFIG_64BIT
>>> #include <asm/pgtable-64.h>
>>> #else
>>> @@ -484,6 +498,7 @@ 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;
>>> void setup_bootmem(void);
>>> diff --git a/arch/riscv/include/asm/set_memory.h
>>> b/arch/riscv/include/asm/set_memory.h
>>> index 6887b3d9f371..a9c56776fa0e 100644
>>> --- a/arch/riscv/include/asm/set_memory.h
>>> +++ b/arch/riscv/include/asm/set_memory.h
>>> @@ -17,6 +17,7 @@ int set_memory_x(unsigned long addr, int numpages);
>>> int set_memory_nx(unsigned long addr, int numpages);
>>> int set_memory_rw_nx(unsigned long addr, int numpages);
>>> void protect_kernel_text_data(void);
>>> +void protect_kernel_linear_mapping_text_rodata(void);
>>> #else
>>> static inline int set_memory_ro(unsigned long addr, int numpages) {
>>> return 0; }
>>> static inline int set_memory_rw(unsigned long addr, int numpages) {
>>> return 0; }
>>> diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S
>>> index f5a9bad86e58..6cb05f22e52a 100644
>>> --- a/arch/riscv/kernel/head.S
>>> +++ b/arch/riscv/kernel/head.S
>>> @@ -69,7 +69,8 @@ pe_head_start:
>>> #ifdef CONFIG_MMU
>>> relocate:
>>> /* Relocate return address */
>>> - li a1, PAGE_OFFSET
>>> + la a1, kernel_virt_addr
>>> + REG_L a1, 0(a1)
>>> la a2, _start
>>> sub a1, a1, a2
>>> add ra, ra, a1
>>> diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c
>>> index 104fba889cf7..ce153771e5e9 100644
>>> --- a/arch/riscv/kernel/module.c
>>> +++ b/arch/riscv/kernel/module.c
>>> @@ -408,12 +408,10 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const
>>> char *strtab,
>>> }
>>>
>>> #if defined(CONFIG_MMU) && defined(CONFIG_64BIT)
>>> -#define VMALLOC_MODULE_START \
>>> - max(PFN_ALIGN((unsigned long)&_end - SZ_2G), VMALLOC_START)
>>> void *module_alloc(unsigned long size)
>>> {
>>> - return __vmalloc_node_range(size, 1, VMALLOC_MODULE_START,
>>> - VMALLOC_END, GFP_KERNEL,
>>> + return __vmalloc_node_range(size, 1, MODULES_VADDR,
>>> + MODULES_END, GFP_KERNEL,
>>> PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE,
>>> __builtin_return_address(0));
>>> }
>>> diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
>>> index e85bacff1b50..30e4af0fd50c 100644
>>> --- a/arch/riscv/kernel/setup.c
>>> +++ b/arch/riscv/kernel/setup.c
>>> @@ -265,6 +265,11 @@ 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)
>>> + protect_kernel_linear_mapping_text_rodata();
>>> +#endif
>>> +
>>> #ifdef CONFIG_SWIOTLB
>>> swiotlb_init(1);
>>> #endif
>>> diff --git a/arch/riscv/kernel/vmlinux.lds.S
>>> b/arch/riscv/kernel/vmlinux.lds.S
>>> index de03cb22d0e9..0726c05e0336 100644
>>> --- a/arch/riscv/kernel/vmlinux.lds.S
>>> +++ b/arch/riscv/kernel/vmlinux.lds.S
>>> @@ -4,7 +4,8 @@
>>> * Copyright (C) 2017 SiFive
>>> */
>>>
>>> -#define LOAD_OFFSET PAGE_OFFSET
>>> +#include <asm/pgtable.h>
>>> +#define LOAD_OFFSET KERNEL_LINK_ADDR
>>> #include <asm/vmlinux.lds.h>
>>> #include <asm/page.h>
>>> #include <asm/cache.h>
>>> diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c
>>> index 8f17519208c7..1b14d523a95c 100644
>>> --- a/arch/riscv/mm/fault.c
>>> +++ b/arch/riscv/mm/fault.c
>>> @@ -231,6 +231,19 @@ asmlinkage void do_page_fault(struct pt_regs *regs)
>>> return;
>>> }
>>>
>>> +#ifdef CONFIG_64BIT
>>> + /*
>>> + * Modules in 64bit kernels lie in their own virtual region
>>> which is not
>>> + * in the vmalloc region, but dealing with page faults in this
>>> region
>>> + * or the vmalloc region amounts to doing the same thing:
>>> checking that
>>> + * the mapping exists in init_mm.pgd and updating user page
>>> table, so
>>> + * just use vmalloc_fault.
>>> + */
>>> + if (unlikely(addr >= MODULES_VADDR && addr < MODULES_END)) {
>>> + vmalloc_fault(regs, code, addr);
>>> + return;
>>> + }
>>> +#endif
>>> /* Enable interrupts if they were enabled in the parent context. */
>>> if (likely(regs->status & SR_PIE))
>>> local_irq_enable();
>>> diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
>>> index 7f5036fbee8c..093f3a96ecfc 100644
>>> --- a/arch/riscv/mm/init.c
>>> +++ b/arch/riscv/mm/init.c
>>> @@ -25,6 +25,9 @@
>>>
>>> #include "../kernel/head.h"
>>>
>>> +unsigned long kernel_virt_addr = KERNEL_LINK_ADDR;
>>> +EXPORT_SYMBOL(kernel_virt_addr);
>>> +
>>> unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)]
>>> __page_aligned_bss;
>>> EXPORT_SYMBOL(empty_zero_page);
>>> @@ -88,6 +91,8 @@ static void print_vm_layout(void)
>>> (unsigned long)VMALLOC_END);
>>> print_mlm("lowmem", (unsigned long)PAGE_OFFSET,
>>> (unsigned long)high_memory);
>>> + print_mlm("kernel", (unsigned long)KERNEL_LINK_ADDR,
>>> + (unsigned long)ADDRESS_SPACE_END);
>>> }
>>> #else
>>> static void print_vm_layout(void) { }
>>> @@ -116,8 +121,13 @@ void __init setup_bootmem(void)
>>> /* The maximal physical memory size is -PAGE_OFFSET. */
>>> memblock_enforce_memory_limit(-PAGE_OFFSET);
>>>
>>> - /* Reserve from the start of the kernel to the end of the kernel */
>>> - memblock_reserve(vmlinux_start, vmlinux_end - vmlinux_start);
>>> + /*
>>> + * Reserve from the start of the kernel to the end of the kernel
>>> + * and make sure we align the reservation on PMD_SIZE since we will
>>> + * map the kernel in the linear mapping as read-only: we do not
>>> want
>>> + * any allocation to happen between _end and the next pmd
>>> aligned page.
>>> + */
>>> + memblock_reserve(vmlinux_start, (vmlinux_end - vmlinux_start +
>>> PMD_SIZE - 1) & PMD_MASK);
>>>
>>> /*
>>> * memblock allocator is not aware of the fact that last 4K
>>> bytes of
>>> @@ -152,8 +162,12 @@ void __init setup_bootmem(void)
>>> #ifdef CONFIG_MMU
>>> static struct pt_alloc_ops pt_ops;
>>>
>>> +/* Offset between linear mapping virtual address and kernel load
>>> address */
>>> unsigned long va_pa_offset;
>>> EXPORT_SYMBOL(va_pa_offset);
>>> +/* Offset between kernel mapping virtual address and kernel load
>>> address */
>>> +unsigned long va_kernel_pa_offset;
>>> +EXPORT_SYMBOL(va_kernel_pa_offset);
>>> unsigned long pfn_base;
>>> EXPORT_SYMBOL(pfn_base);
>>>
>>> @@ -257,7 +271,7 @@ static pmd_t *get_pmd_virt_late(phys_addr_t pa)
>>>
>>> static phys_addr_t __init alloc_pmd_early(uintptr_t va)
>>> {
>>> - BUG_ON((va - PAGE_OFFSET) >> PGDIR_SHIFT);
>>> + BUG_ON((va - kernel_virt_addr) >> PGDIR_SHIFT);
>>>
>>> return (uintptr_t)early_pmd;
>>> }
>>> @@ -372,17 +386,32 @@ static uintptr_t __init
>>> best_map_size(phys_addr_t base, phys_addr_t size)
>>> #error "setup_vm() is called from head.S before relocate so it
>>> should not use absolute addressing."
>>> #endif
>>>
>>> +uintptr_t load_pa, load_sz;
>>> +
>>> +static void __init create_kernel_page_table(pgd_t *pgdir, uintptr_t
>>> map_size)
>>> +{
>>> + uintptr_t va, end_va;
>>> +
>>> + end_va = kernel_virt_addr + load_sz;
>>> + for (va = kernel_virt_addr; va < end_va; va += map_size)
>>> + create_pgd_mapping(pgdir, va,
>>> + load_pa + (va - kernel_virt_addr),
>>> + map_size, PAGE_KERNEL_EXEC);
>>> +}
>>> +
>>> asmlinkage void __init setup_vm(uintptr_t dtb_pa)
>>> {
>>> - uintptr_t va, pa, end_va;
>>> - uintptr_t load_pa = (uintptr_t)(&_start);
>>> - uintptr_t load_sz = (uintptr_t)(&_end) - load_pa;
>>> + uintptr_t pa;
>>> uintptr_t map_size;
>>> #ifndef __PAGETABLE_PMD_FOLDED
>>> pmd_t fix_bmap_spmd, fix_bmap_epmd;
>>> #endif
>>> + load_pa = (uintptr_t)(&_start);
>>> + load_sz = (uintptr_t)(&_end) - load_pa;
>>>
>>> va_pa_offset = PAGE_OFFSET - load_pa;
>>> + va_kernel_pa_offset = kernel_virt_addr - load_pa;
>>> +
>>> pfn_base = PFN_DOWN(load_pa);
>>>
>>> /*
>>> @@ -410,26 +439,22 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
>>> create_pmd_mapping(fixmap_pmd, FIXADDR_START,
>>> (uintptr_t)fixmap_pte, PMD_SIZE, PAGE_TABLE);
>>> /* Setup trampoline PGD and PMD */
>>> - create_pgd_mapping(trampoline_pg_dir, PAGE_OFFSET,
>>> + create_pgd_mapping(trampoline_pg_dir, kernel_virt_addr,
>>> (uintptr_t)trampoline_pmd, PGDIR_SIZE, PAGE_TABLE);
>>> - create_pmd_mapping(trampoline_pmd, PAGE_OFFSET,
>>> + create_pmd_mapping(trampoline_pmd, kernel_virt_addr,
>>> load_pa, PMD_SIZE, PAGE_KERNEL_EXEC);
>>> #else
>>> /* Setup trampoline PGD */
>>> - create_pgd_mapping(trampoline_pg_dir, PAGE_OFFSET,
>>> + create_pgd_mapping(trampoline_pg_dir, kernel_virt_addr,
>>> load_pa, PGDIR_SIZE, PAGE_KERNEL_EXEC);
>>> #endif
>>>
>>> /*
>>> - * Setup early PGD covering entire kernel which will allows
>>> + * Setup early PGD covering entire kernel which will allow
>>> * us to reach paging_init(). We map all memory banks later
>>> * in setup_vm_final() below.
>>> */
>>> - end_va = PAGE_OFFSET + load_sz;
>>> - for (va = PAGE_OFFSET; va < end_va; va += map_size)
>>> - create_pgd_mapping(early_pg_dir, va,
>>> - load_pa + (va - PAGE_OFFSET),
>>> - map_size, PAGE_KERNEL_EXEC);
>>> + create_kernel_page_table(early_pg_dir, map_size);
>>>
>>> #ifndef __PAGETABLE_PMD_FOLDED
>>> /* Setup early PMD for DTB */
>>> @@ -444,7 +469,12 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
>>> pa + PMD_SIZE, PMD_SIZE, PAGE_KERNEL);
>>> dtb_early_va = (void *)DTB_EARLY_BASE_VA + (dtb_pa & (PMD_SIZE -
>>> 1));
>>> #else /* CONFIG_BUILTIN_DTB */
>>> - dtb_early_va = __va(dtb_pa);
>>> + /*
>>> + * __va can't be used since it would return a linear mapping
>>> address
>>> + * 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);
>>> #endif /* CONFIG_BUILTIN_DTB */
>>> #else
>>> #ifndef CONFIG_BUILTIN_DTB
>>> @@ -456,7 +486,7 @@ 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 = __va(dtb_pa);
>>> + dtb_early_va = kernel_mapping_pa_to_va(dtb_pa);
>>> #endif /* CONFIG_BUILTIN_DTB */
>>> #endif
>>> dtb_early_pa = dtb_pa;
>>> @@ -492,6 +522,22 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
>>> #endif
>>> }
>>>
>>> +#ifdef CONFIG_64BIT
>>> +void protect_kernel_linear_mapping_text_rodata(void)
>>> +{
>>> + unsigned long text_start = (unsigned long)lm_alias(_start);
>>> + unsigned long init_text_start = (unsigned
>>> long)lm_alias(__init_text_begin);
>>> + unsigned long rodata_start = (unsigned
>>> long)lm_alias(__start_rodata);
>>> + unsigned long data_start = (unsigned long)lm_alias(_data);
>>> +
>>> + set_memory_ro(text_start, (init_text_start - text_start) >>
>>> PAGE_SHIFT);
>>> + set_memory_nx(text_start, (init_text_start - text_start) >>
>>> PAGE_SHIFT);
>>> +
>>> + set_memory_ro(rodata_start, (data_start - rodata_start) >>
>>> PAGE_SHIFT);
>>> + set_memory_nx(rodata_start, (data_start - rodata_start) >>
>>> PAGE_SHIFT);
>>> +}
>>> +#endif
>>> +
>>> static void __init setup_vm_final(void)
>>> {
>>> uintptr_t va, map_size;
>>> @@ -513,7 +559,7 @@ static void __init setup_vm_final(void)
>>> __pa_symbol(fixmap_pgd_next),
>>> PGDIR_SIZE, PAGE_TABLE);
>>>
>>> - /* Map all memory banks */
>>> + /* Map all memory banks in the linear mapping */
>>> for_each_mem_range(i, &start, &end) {
>>> if (start >= end)
>>> break;
>>> @@ -525,10 +571,13 @@ static void __init setup_vm_final(void)
>>> for (pa = start; pa < end; pa += map_size) {
>>> va = (uintptr_t)__va(pa);
>>> create_pgd_mapping(swapper_pg_dir, va, pa,
>>> - map_size, PAGE_KERNEL_EXEC);
>>> + map_size, PAGE_KERNEL);
>>> }
>>> }
>>>
>>> + /* Map the kernel */
>>> + create_kernel_page_table(swapper_pg_dir, PMD_SIZE);
>>> +
>>> /* Clear fixmap PTE and PMD mappings */
>>> clear_fixmap(FIX_PTE);
>>> clear_fixmap(FIX_PMD);
>>> diff --git a/arch/riscv/mm/kasan_init.c b/arch/riscv/mm/kasan_init.c
>>> index 2c39f0386673..28f4d52cf17e 100644
>>> --- a/arch/riscv/mm/kasan_init.c
>>> +++ b/arch/riscv/mm/kasan_init.c
>>> @@ -171,6 +171,10 @@ void __init kasan_init(void)
>>> phys_addr_t _start, _end;
>>> u64 i;
>>>
>>> + /*
>>> + * Populate all kernel virtual address space with
>>> kasan_early_shadow_page
>>> + * except for the linear mapping and the modules/kernel/BPF
>>> mapping.
>>> + */
>>> kasan_populate_early_shadow((void *)KASAN_SHADOW_START,
>>> (void *)kasan_mem_to_shadow((void *)
>>> VMEMMAP_END));
>>> @@ -183,6 +187,7 @@ void __init kasan_init(void)
>>> (void *)kasan_mem_to_shadow((void *)VMALLOC_START),
>>> (void *)kasan_mem_to_shadow((void *)VMALLOC_END));
>>>
>>> + /* Populate the linear mapping */
>>> for_each_mem_range(i, &_start, &_end) {
>>> void *start = (void *)__va(_start);
>>> void *end = (void *)__va(_end);
>>> @@ -193,6 +198,10 @@ void __init kasan_init(void)
>>> kasan_populate(kasan_mem_to_shadow(start),
>>> kasan_mem_to_shadow(end));
>>> };
>>>
>>> + /* Populate kernel, BPF, modules mapping */
>>> + kasan_populate(kasan_mem_to_shadow((const void *)MODULES_VADDR),
>>> + kasan_mem_to_shadow((const void *)BPF_JIT_REGION_END));
>>> +
>>> for (i = 0; i < PTRS_PER_PTE; i++)
>>> set_pte(&kasan_early_shadow_pte[i],
>>> mk_pte(virt_to_page(kasan_early_shadow_page),
>>> diff --git a/arch/riscv/mm/physaddr.c b/arch/riscv/mm/physaddr.c
>>> index e8e4dcd39fed..35703d5ef5fd 100644
>>> --- a/arch/riscv/mm/physaddr.c
>>> +++ b/arch/riscv/mm/physaddr.c
>>> @@ -23,7 +23,7 @@ EXPORT_SYMBOL(__virt_to_phys);
>>>
>>> phys_addr_t __phys_addr_symbol(unsigned long x)
>>> {
>>> - unsigned long kernel_start = (unsigned long)PAGE_OFFSET;
>>> + unsigned long kernel_start = (unsigned long)kernel_virt_addr;
>>> unsigned long kernel_end = (unsigned long)_end;
>>>
>>> /*
>>
>> This is breaking boot for me with CONFIG_STRICT_KERNEL_RWX=n. I'm not
>> even really convinced that's a useful config to support, but it's
>> currently optional and I'd prefer to avoid breaking it if possible.
>>
>> I can't quite figure out what's going on here and I'm pretty much
>> tired out for tonight. LMK if you don't have time to look at it and
>> I'll try to give it another shot.
>
> I'm taking a look at that.
Just to make sure you don't miss it, I fixed this issue in
https://patchwork.kernel.org/project/linux-riscv/patch/20210415110426.2238-1-alex@ghiti.fr/
Thanks,
Alex
>
> Thanks,
>
> Alex
>
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