From: Reiji Watanabe reijiw@google.com
[ Upstream commit 685e2564daa1493053fcd7f1dbed38b35ee2f3cb ]
Currently, mte_set_mem_tag_range() and mte_zero_clear_page_tags() use DC {GVA,GZVA} unconditionally. But, they should make sure that DCZID_EL0.DZP, which indicates whether or not use of those instructions is prohibited, is zero when using those instructions. Use ST{G,ZG,Z2G} instead when DCZID_EL0.DZP == 1.
Fixes: 013bb59dbb7c ("arm64: mte: handle tags zeroing at page allocation time") Fixes: 3d0cca0b02ac ("kasan: speed up mte_set_mem_tag_range") Signed-off-by: Reiji Watanabe reijiw@google.com Link: https://lore.kernel.org/r/20211206004736.1520989-3-reijiw@google.com Signed-off-by: Catalin Marinas catalin.marinas@arm.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/arm64/include/asm/mte-kasan.h | 8 +++++--- arch/arm64/lib/mte.S | 8 +++++++- 2 files changed, 12 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/include/asm/mte-kasan.h b/arch/arm64/include/asm/mte-kasan.h index 478b9bcf69ad1..e4704a403237e 100644 --- a/arch/arm64/include/asm/mte-kasan.h +++ b/arch/arm64/include/asm/mte-kasan.h @@ -84,10 +84,12 @@ static inline void __dc_gzva(u64 p) static inline void mte_set_mem_tag_range(void *addr, size_t size, u8 tag, bool init) { - u64 curr, mask, dczid_bs, end1, end2, end3; + u64 curr, mask, dczid, dczid_bs, dczid_dzp, end1, end2, end3;
/* Read DC G(Z)VA block size from the system register. */ - dczid_bs = 4ul << (read_cpuid(DCZID_EL0) & 0xf); + dczid = read_cpuid(DCZID_EL0); + dczid_bs = 4ul << (dczid & 0xf); + dczid_dzp = (dczid >> 4) & 1;
curr = (u64)__tag_set(addr, tag); mask = dczid_bs - 1; @@ -106,7 +108,7 @@ static inline void mte_set_mem_tag_range(void *addr, size_t size, u8 tag, */ #define SET_MEMTAG_RANGE(stg_post, dc_gva) \ do { \ - if (size >= 2 * dczid_bs) { \ + if (!dczid_dzp && size >= 2 * dczid_bs) {\ do { \ curr = stg_post(curr); \ } while (curr < end1); \ diff --git a/arch/arm64/lib/mte.S b/arch/arm64/lib/mte.S index e83643b3995f4..f531dcb95174a 100644 --- a/arch/arm64/lib/mte.S +++ b/arch/arm64/lib/mte.S @@ -43,17 +43,23 @@ SYM_FUNC_END(mte_clear_page_tags) * x0 - address to the beginning of the page */ SYM_FUNC_START(mte_zero_clear_page_tags) + and x0, x0, #(1 << MTE_TAG_SHIFT) - 1 // clear the tag mrs x1, dczid_el0 + tbnz x1, #4, 2f // Branch if DC GZVA is prohibited and w1, w1, #0xf mov x2, #4 lsl x1, x2, x1 - and x0, x0, #(1 << MTE_TAG_SHIFT) - 1 // clear the tag
1: dc gzva, x0 add x0, x0, x1 tst x0, #(PAGE_SIZE - 1) b.ne 1b ret + +2: stz2g x0, [x0], #(MTE_GRANULE_SIZE * 2) + tst x0, #(PAGE_SIZE - 1) + b.ne 2b + ret SYM_FUNC_END(mte_zero_clear_page_tags)
/*