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Message-ID: <7b647da1-b3aa-287f-7ca8-3b44c5661cb8@ghiti.fr>
Date: Sun, 18 Apr 2021 07:38:09 -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,
Guenter Roeck <linux@...ck-us.net>
Subject: Re: [PATCH v5 1/3] riscv: Move kernel mapping outside of linear
mapping
Hi Palmer,
Le 4/15/21 à 2:00 PM, Alex Ghiti a écrit :
> 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 ownvirtual 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 inthe 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 onPMD_SIZE since we will
>>>> + * map the kernel in the linear mapping as read-only: we do not
>>>> want
>>>> + * any allocation to happen between _end andthe 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 spacewith
>>>> 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/
Guenter reported that this patchset broke 32b kernel build: I had
neglected it. So I pushed 2 other fixes for this where I added Fixes tag
and that can be squashed in case you want to squash them.
To sum up, there are 3 patches that fix this series:
https://patchwork.kernel.org/project/linux-riscv/patch/20210415110426.2238-1-alex@ghiti.fr/
https://patchwork.kernel.org/project/linux-riscv/patch/20210417172159.32085-1-alex@ghiti.fr/
https://patchwork.kernel.org/project/linux-riscv/patch/20210418112856.15078-1-alex@ghiti.fr/
Sorry for that,
Thanks,
Alex
>
>
> Thanks,
>
> Alex
>
>>
>> Thanks,
>>
>> Alex
>>
>> _______________________________________________
>> linux-riscv mailing list
>> linux-riscv@...ts.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-riscv
>
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