[ARM64,v4.4,V3,01/44] arm64: barrier: Add CSDB macros to control data-value prediction

Message ID 4ba4e0d015f2e044e3eaf57e1239ae3e12d5a80e.1567077734.git.viresh.kumar@linaro.org
State New
Headers show
Series
  • V4.4 backport of arm64 Spectre patches
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Commit Message

Viresh Kumar Aug. 29, 2019, 11:33 a.m.
From: Will Deacon <will.deacon@arm.com>


commit 669474e772b952b14f4de4845a1558fd4c0414a4 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: Viresh Kumar <viresh.kumar@linaro.org>

---
 arch/arm64/include/asm/assembler.h | 7 +++++++
 arch/arm64/include/asm/barrier.h   | 2 ++
 2 files changed, 9 insertions(+)

-- 
2.21.0.rc0.269.g1a574e7a288b

Comments

Mark Rutland Aug. 30, 2019, 9:39 a.m. | #1
On Thu, Aug 29, 2019 at 05:03:46PM +0530, Viresh Kumar wrote:
> From: Will Deacon <will.deacon@arm.com>

> 

> commit 669474e772b952b14f4de4845a1558fd4c0414a4 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: Viresh Kumar <viresh.kumar@linaro.org>


Reviewed-by: Mark Rutland <mark.rutland@arm.com> [v4.4 backport]


Mark.

> ---

>  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 f68abb17aa4b..683c2875278f 100644

> --- a/arch/arm64/include/asm/assembler.h

> +++ b/arch/arm64/include/asm/assembler.h

> @@ -95,6 +95,13 @@

>  	dmb	\opt

>  	.endm

>  

> +/*

> + * Value prediction barrier

> + */

> +	.macro	csdb

> +	hint	#20

> +	.endm

> +

>  #define USER(l, x...)				\

>  9999:	x;					\

>  	.section __ex_table,"a";		\

> diff --git a/arch/arm64/include/asm/barrier.h b/arch/arm64/include/asm/barrier.h

> index f2d2c0bbe21b..574486634c62 100644

> --- a/arch/arm64/include/asm/barrier.h

> +++ b/arch/arm64/include/asm/barrier.h

> @@ -28,6 +28,8 @@

>  #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)

> -- 

> 2.21.0.rc0.269.g1a574e7a288b

>

Patch

diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index f68abb17aa4b..683c2875278f 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -95,6 +95,13 @@ 
 	dmb	\opt
 	.endm
 
+/*
+ * Value prediction barrier
+ */
+	.macro	csdb
+	hint	#20
+	.endm
+
 #define USER(l, x...)				\
 9999:	x;					\
 	.section __ex_table,"a";		\
diff --git a/arch/arm64/include/asm/barrier.h b/arch/arm64/include/asm/barrier.h
index f2d2c0bbe21b..574486634c62 100644
--- a/arch/arm64/include/asm/barrier.h
+++ b/arch/arm64/include/asm/barrier.h
@@ -28,6 +28,8 @@ 
 #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)