lkml.org 
[lkml]   [2018]   [Mar]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 03/45] arm64: barrier: Add CSDB macros to control data-value prediction
Date
From: Will Deacon <will.deacon@arm.com>

commit 669474e772b9 upstream.

For CPUs capable of data value prediction, CSDB waits for any outstanding
predictions to architecturally resolve before allowing speculative execution
to continue. Provide macros to expose it to the arch code.

Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Alex Shi <alex.shi@linaro.org>
---
arch/arm64/include/asm/assembler.h | 7 +++++++
arch/arm64/include/asm/barrier.h | 2 ++
2 files changed, 9 insertions(+)

diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index 851290d..8760300 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -87,6 +87,13 @@
.endm

/*
+ * Value prediction barrier
+ */
+ .macro csdb
+ hint #20
+ .endm
+
+/*
* NOP sequence
*/
.macro nops, num
diff --git a/arch/arm64/include/asm/barrier.h b/arch/arm64/include/asm/barrier.h
index 0fe7e43..c68fdc5 100644
--- a/arch/arm64/include/asm/barrier.h
+++ b/arch/arm64/include/asm/barrier.h
@@ -31,6 +31,8 @@
#define dmb(opt) asm volatile("dmb " #opt : : : "memory")
#define dsb(opt) asm volatile("dsb " #opt : : : "memory")

+#define csdb() asm volatile("hint #20" : : : "memory")
+
#define mb() dsb(sy)
#define rmb() dsb(ld)
#define wmb() dsb(st)
--
2.7.4
\
 
 \ /
  Last update: 2018-03-01 14:32    [W:0.346 / U:0.044 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site