It has been reported some configuration where the kernel doesn't boot with KASAN enabled.

This is due to wrong BAT allocation for the KASAN area:

---[ Data Block Address Translation ]--- 0: 0xc0000000-0xcfffffff 0x00000000 256M Kernel rw m 1: 0xd0000000-0xdfffffff 0x10000000 256M Kernel rw m 2: 0xe0000000-0xefffffff 0x20000000 256M Kernel rw m 3: 0xf8000000-0xf9ffffff 0x2a000000 32M Kernel rw m 4: 0xfa000000-0xfdffffff 0x2c000000 64M Kernel rw m

A BAT must have both virtual and physical addresses alignment matching the size of the BAT. This is not the case for BAT 4 above.

Fix kasan_init_region() by using block_size() function that is in book3s32/mmu.c. To be able to reuse it here, make it non static and change its name to bat_block_size() in order to avoid name conflict with block_size() defined in <linux/blkdev.h>

Also reuse find_free_bat() to avoid an error message from setbat() when no BAT is available.

With this change we get correct alignment for BATs:

---[ Data Block Address Translation ]--- 0: 0xc0000000-0xcfffffff 0x00000000 256M Kernel rw 1: 0xd0000000-0xdfffffff 0x10000000 256M Kernel rw 2: 0xe0000000-0xefffffff 0x20000000 256M Kernel rw 3: 0xf8000000-0xfbffffff 0x2c000000 64M Kernel rw 4: 0xfc000000-0xfdffffff 0x2a000000 32M Kernel rw

Reported-by: Maxime Bizon mbizon@freebox.fr Fixes: 7974c4732642 ("powerpc/32s: Implement dedicated kasan_init_region()") Cc: stable@vger.kernel.org Signed-off-by: Christophe Leroy christophe.leroy@csgroup.eu --- arch/powerpc/include/asm/book3s/32/mmu-hash.h | 2 + arch/powerpc/mm/book3s32/mmu.c | 10 ++--- arch/powerpc/mm/kasan/book3s_32.c | 43 ++++++++++--------- 3 files changed, 29 insertions(+), 26 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/32/mmu-hash.h b/arch/powerpc/include/asm/book3s/32/mmu-hash.h index f5be185cbdf8..5b45c648a8d9 100644 --- a/arch/powerpc/include/asm/book3s/32/mmu-hash.h +++ b/arch/powerpc/include/asm/book3s/32/mmu-hash.h @@ -143,6 +143,8 @@ static __always_inline void update_user_segments(u32 val) update_user_segment(15, val); }

+int find_free_bat(void); +unsigned int bat_block_size(unsigned long base, unsigned long top); #endif /* !__ASSEMBLY__ */

/* We happily ignore the smaller BATs on 601, we don't actually use diff --git a/arch/powerpc/mm/book3s32/mmu.c b/arch/powerpc/mm/book3s32/mmu.c index cb48e4a5106d..9e7714a861bf 100644 --- a/arch/powerpc/mm/book3s32/mmu.c +++ b/arch/powerpc/mm/book3s32/mmu.c @@ -76,7 +76,7 @@ unsigned long p_block_mapped(phys_addr_t pa) return 0; }

-static int find_free_bat(void) +int find_free_bat(void) { int b; int n = mmu_has_feature(MMU_FTR_USE_HIGH_BATS) ? 8 : 4; @@ -100,7 +100,7 @@ static int find_free_bat(void) * - block size has to be a power of two. This is calculated by finding the * highest bit set to 1. */ -static unsigned int block_size(unsigned long base, unsigned long top) +unsigned int bat_block_size(unsigned long base, unsigned long top) { unsigned int max_size = SZ_256M; unsigned int base_shift = (ffs(base) - 1) & 31; @@ -145,7 +145,7 @@ static unsigned long __init __mmu_mapin_ram(unsigned long base, unsigned long to int idx;

while ((idx = find_free_bat()) != -1 && base != top) { - unsigned int size = block_size(base, top); + unsigned int size = bat_block_size(base, top);

if (size < 128 << 10) break; @@ -204,12 +204,12 @@ void mmu_mark_initmem_nx(void) unsigned long size;

for (i = 0; i < nb - 1 && base < top && top - base > (128 << 10);) { - size = block_size(base, top); + size = bat_block_size(base, top); setibat(i++, PAGE_OFFSET + base, base, size, PAGE_KERNEL_TEXT); base += size; } if (base < top) { - size = block_size(base, top); + size = bat_block_size(base, top); size = max(size, 128UL << 10); if ((top - base) > size) { size <<= 1; diff --git a/arch/powerpc/mm/kasan/book3s_32.c b/arch/powerpc/mm/kasan/book3s_32.c index 202bd260a009..c2ff93c63dfa 100644 --- a/arch/powerpc/mm/kasan/book3s_32.c +++ b/arch/powerpc/mm/kasan/book3s_32.c @@ -11,32 +11,33 @@ int __init kasan_init_region(void *start, size_t size) unsigned long k_start = (unsigned long)kasan_mem_to_shadow(start); unsigned long k_end = (unsigned long)kasan_mem_to_shadow(start + size); unsigned long k_cur = k_start; - int k_size = k_end - k_start; - int k_size_base = 1 << (ffs(k_size) - 1); int ret; void *block;

- block = memblock_alloc(k_size, k_size_base); - - if (block && k_size_base >= SZ_128K && k_start == ALIGN(k_start, k_size_base)) { - int k_size_more = 1 << (ffs(k_size - k_size_base) - 1); - - setbat(-1, k_start, __pa(block), k_size_base, PAGE_KERNEL); - if (k_size_more >= SZ_128K) - setbat(-1, k_start + k_size_base, __pa(block) + k_size_base, - k_size_more, PAGE_KERNEL); - if (v_block_mapped(k_start)) - k_cur = k_start + k_size_base; - if (v_block_mapped(k_start + k_size_base)) - k_cur = k_start + k_size_base + k_size_more; - - update_bats(); + while (k_cur < k_end) { + unsigned int k_size = bat_block_size(k_cur, k_end); + phys_addr_t phys; + int idx = find_free_bat(); + + if (idx == -1) + break; + if (k_size < SZ_128K) + break; + phys = memblock_phys_alloc(k_size, k_size); + if (!phys) + break; + + setbat(idx, k_cur, phys, k_size, PAGE_KERNEL); + k_cur += k_size; } + if (k_cur != k_start) + update_bats();

- if (!block) - block = memblock_alloc(k_size, PAGE_SIZE); - if (!block) - return -ENOMEM; + if (k_cur < k_end) { + block = memblock_alloc(k_end - k_cur, PAGE_SIZE); + if (!block) + return -ENOMEM; + }

ret = kasan_init_shadow_page_tables(k_start, k_end); if (ret)