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| author | Alexandre Ghiti <alex@ghiti.fr> | 2021-04-11 19:41:44 +0300 |
|---|---|---|
| committer | Palmer Dabbelt <palmerdabbelt@google.com> | 2021-04-26 18:25:04 +0300 |
| commit | 2bfc6cd81bd17e4306e24ee47b9554c967bcb499 (patch) | |
| tree | c06ff6ac90cb7735bb0871aa357c5d2b8049a6dc /arch/riscv/mm/kasan_init.c | |
| parent | 8a07ac39f87d6c762006398029762c40e4d9d075 (diff) | |
| download | linux-2bfc6cd81bd17e4306e24ee47b9554c967bcb499.tar.xz | |
riscv: Move kernel mapping outside of linear mapping
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@arndb.de>
Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
[Palmer: Squash the STRICT_RWX fix, and a !MMU fix]
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Diffstat (limited to 'arch/riscv/mm/kasan_init.c')
| -rw-r--r-- | arch/riscv/mm/kasan_init.c | 9 |
1 files changed, 9 insertions, 0 deletions
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), |