提交 9be34be8 编写于 作者: M Mark Brown 提交者: Catalin Marinas

arm64: Add macro version of the BTI instruction

BTI is only available from v8.5 so we need to encode it using HINT in
generic code and for older toolchains. Add an assembler macro based on
one written by Mark Rutland which lets us use the mnemonic and update
the existing users.
Suggested-by: NMark Rutland <mark.rutland@arm.com>
Acked-by: NArd Biesheuvel <ardb@kernel.org>
Acked-by: NWill Deacon <will@kernel.org>
Signed-off-by: NMark Brown <broonie@kernel.org>
Acked-by: NMark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20211214152714.2380849-2-broonie@kernel.orgSigned-off-by: NCatalin Marinas <catalin.marinas@arm.com>
上级 580b536b
......@@ -363,15 +363,15 @@ ST5( mov v4.16b, vctr.16b )
adr x16, 1f
sub x16, x16, x12, lsl #3
br x16
hint 34 // bti c
bti c
mov v0.d[0], vctr.d[0]
hint 34 // bti c
bti c
mov v1.d[0], vctr.d[0]
hint 34 // bti c
bti c
mov v2.d[0], vctr.d[0]
hint 34 // bti c
bti c
mov v3.d[0], vctr.d[0]
ST5( hint 34 )
ST5( bti c )
ST5( mov v4.d[0], vctr.d[0] )
1: b 2f
.previous
......
......@@ -790,6 +790,16 @@ alternative_endif
.Lnoyield_\@:
.endm
/*
* Branch Target Identifier (BTI)
*/
.macro bti, targets
.equ .L__bti_targets_c, 34
.equ .L__bti_targets_j, 36
.equ .L__bti_targets_jc,38
hint #.L__bti_targets_\targets
.endm
/*
* This macro emits a program property note section identifying
* architecture features which require special handling, mainly for
......
......@@ -6,12 +6,7 @@
#if defined(CONFIG_ARM64_BTI_KERNEL) && defined(__aarch64__)
/*
* Since current versions of gas reject the BTI instruction unless we
* set the architecture version to v8.5 we use the hint instruction
* instead.
*/
#define BTI_C hint 34 ;
#define BTI_C bti c ;
/*
* When using in-kernel BTI we need to ensure that PCS-conformant assembly
......
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