From 685e2564daa1493053fcd7f1dbed38b35ee2f3cb Mon Sep 17 00:00:00 2001 From: Reiji Watanabe Date: Sun, 5 Dec 2021 16:47:36 -0800 Subject: arm64: mte: DC {GVA,GZVA} shouldn't be used when DCZID_EL0.DZP == 1 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 Link: https://lore.kernel.org/r/20211206004736.1520989-3-reijiw@google.com Signed-off-by: Catalin Marinas --- arch/arm64/lib/mte.S | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'arch/arm64/lib') diff --git a/arch/arm64/lib/mte.S b/arch/arm64/lib/mte.S index e83643b3995f..f531dcb95174 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) /* -- cgit v1.2.3