From d0f38f9130b7683e39611c5a661349e301ee43c8 Mon Sep 17 00:00:00 2001 From: Robin Murphy Date: Mon, 7 Oct 2013 18:30:34 +0100 Subject: [PATCH] arm64: update 32-bit kuser helpers to ARMv8 This patch updates the barrier semantics in the kuser helper functions to take advantage of the ARMv8 additions to AArch32, which are guaranteed to be available in situations where these functions will be called. Note that this slightly changes the cmpxchg functions in that they are no longer necessarily full barriers if they return 1. However, the documentation only states they include their own barriers "as needed", not that they are obligated to act as a full barrier for the caller. Signed-off-by: Robin Murphy Acked-by: Will Deacon CC: Matthew Leach CC: Dave Martin CC: Mark Rutland Signed-off-by: Catalin Marinas --- arch/arm64/kernel/kuser32.S | 15 ++++++--------- 1 file changed, 6 insertions(+), 9 deletions(-) diff --git a/arch/arm64/kernel/kuser32.S b/arch/arm64/kernel/kuser32.S index 1e4905d52d30..63c48ffdf230 100644 --- a/arch/arm64/kernel/kuser32.S +++ b/arch/arm64/kernel/kuser32.S @@ -38,33 +38,30 @@ __kuser_cmpxchg64: // 0xffff0f60 .inst 0xe92d00f0 // push {r4, r5, r6, r7} .inst 0xe1c040d0 // ldrd r4, r5, [r0] .inst 0xe1c160d0 // ldrd r6, r7, [r1] - .inst 0xf57ff05f // dmb sy - .inst 0xe1b20f9f // 1: ldrexd r0, r1, [r2] + .inst 0xe1b20e9f // 1: ldaexd r0, r1, [r2] .inst 0xe0303004 // eors r3, r0, r4 .inst 0x00313005 // eoreqs r3, r1, r5 - .inst 0x01a23f96 // strexdeq r3, r6, [r2] + .inst 0x01a23e96 // stlexdeq r3, r6, [r2] .inst 0x03330001 // teqeq r3, #1 .inst 0x0afffff9 // beq 1b - .inst 0xf57ff05f // dmb sy .inst 0xe2730000 // rsbs r0, r3, #0 .inst 0xe8bd00f0 // pop {r4, r5, r6, r7} .inst 0xe12fff1e // bx lr .align 5 __kuser_memory_barrier: // 0xffff0fa0 - .inst 0xf57ff05f // dmb sy + .inst 0xf57ff05b // dmb ish .inst 0xe12fff1e // bx lr .align 5 __kuser_cmpxchg: // 0xffff0fc0 - .inst 0xf57ff05f // dmb sy - .inst 0xe1923f9f // 1: ldrex r3, [r2] + .inst 0xe1923e9f // 1: ldaex r3, [r2] .inst 0xe0533000 // subs r3, r3, r0 - .inst 0x01823f91 // strexeq r3, r1, [r2] + .inst 0x01823e91 // stlexeq r3, r1, [r2] .inst 0x03330001 // teqeq r3, #1 .inst 0x0afffffa // beq 1b .inst 0xe2730000 // rsbs r0, r3, #0 - .inst 0xeaffffef // b <__kuser_memory_barrier> + .inst 0xe12fff1e // bx lr .align 5 __kuser_get_tls: // 0xffff0fe0 -- 2.20.1