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author | Alexandre Ghiti <alexghiti@rivosinc.com> | 2023-06-06 15:04:44 +0200 |
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committer | Palmer Dabbelt <palmer@rivosinc.com> | 2023-06-07 07:13:53 -0700 |
commit | 25abe0db92437fde463204c3e4eb5a71b62d6e5d (patch) | |
tree | f68b8318d1220f37771d6994e28e2fd19f48902d /arch/riscv/mm/init.c | |
parent | 6569fc12e442ea973d96db39e542aa19a7bc3a79 (diff) | |
download | linux-stable-25abe0db92437fde463204c3e4eb5a71b62d6e5d.tar.gz linux-stable-25abe0db92437fde463204c3e4eb5a71b62d6e5d.tar.bz2 linux-stable-25abe0db92437fde463204c3e4eb5a71b62d6e5d.zip |
riscv: Fix kfence now that the linear mapping can be backed by PUD/P4D/PGD
RISC-V Kfence implementation used to rely on the fact the linear mapping
was backed by at most PMD hugepages, which is not true anymore since
commit 3335068f8721 ("riscv: Use PUD/P4D/PGD pages for the linear
mapping").
Instead of splitting PUD/P4D/PGD mappings afterwards, directly map the
kfence pool region using PTE mappings by allocating this region before
setup_vm_final().
Reported-by: syzbot+a74d57bddabbedd75135@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=a74d57bddabbedd75135
Fixes: 3335068f8721 ("riscv: Use PUD/P4D/PGD pages for the linear mapping")
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20230606130444.25090-1-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Diffstat (limited to 'arch/riscv/mm/init.c')
-rw-r--r-- | arch/riscv/mm/init.c | 35 |
1 files changed, 30 insertions, 5 deletions
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c index 0fe75c9713f8..38c4b4d6b64f 100644 --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -23,6 +23,7 @@ #ifdef CONFIG_RELOCATABLE #include <linux/elf.h> #endif +#include <linux/kfence.h> #include <asm/fixmap.h> #include <asm/tlbflush.h> @@ -1167,14 +1168,16 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa) } static void __init create_linear_mapping_range(phys_addr_t start, - phys_addr_t end) + phys_addr_t end, + uintptr_t fixed_map_size) { phys_addr_t pa; uintptr_t va, map_size; for (pa = start; pa < end; pa += map_size) { va = (uintptr_t)__va(pa); - map_size = best_map_size(pa, end - pa); + map_size = fixed_map_size ? fixed_map_size : + best_map_size(pa, end - pa); create_pgd_mapping(swapper_pg_dir, va, pa, map_size, pgprot_from_va(va)); @@ -1184,6 +1187,7 @@ static void __init create_linear_mapping_range(phys_addr_t start, static void __init create_linear_mapping_page_table(void) { phys_addr_t start, end; + phys_addr_t kfence_pool __maybe_unused; u64 i; #ifdef CONFIG_STRICT_KERNEL_RWX @@ -1197,6 +1201,19 @@ static void __init create_linear_mapping_page_table(void) memblock_mark_nomap(krodata_start, krodata_size); #endif +#ifdef CONFIG_KFENCE + /* + * kfence pool must be backed by PAGE_SIZE mappings, so allocate it + * before we setup the linear mapping so that we avoid using hugepages + * for this region. + */ + kfence_pool = memblock_phys_alloc(KFENCE_POOL_SIZE, PAGE_SIZE); + BUG_ON(!kfence_pool); + + memblock_mark_nomap(kfence_pool, KFENCE_POOL_SIZE); + __kfence_pool = __va(kfence_pool); +#endif + /* Map all memory banks in the linear mapping */ for_each_mem_range(i, &start, &end) { if (start >= end) @@ -1207,17 +1224,25 @@ static void __init create_linear_mapping_page_table(void) if (end >= __pa(PAGE_OFFSET) + memory_limit) end = __pa(PAGE_OFFSET) + memory_limit; - create_linear_mapping_range(start, end); + create_linear_mapping_range(start, end, 0); } #ifdef CONFIG_STRICT_KERNEL_RWX - create_linear_mapping_range(ktext_start, ktext_start + ktext_size); + create_linear_mapping_range(ktext_start, ktext_start + ktext_size, 0); create_linear_mapping_range(krodata_start, - krodata_start + krodata_size); + krodata_start + krodata_size, 0); memblock_clear_nomap(ktext_start, ktext_size); memblock_clear_nomap(krodata_start, krodata_size); #endif + +#ifdef CONFIG_KFENCE + create_linear_mapping_range(kfence_pool, + kfence_pool + KFENCE_POOL_SIZE, + PAGE_SIZE); + + memblock_clear_nomap(kfence_pool, KFENCE_POOL_SIZE); +#endif } static void __init setup_vm_final(void) |