From: Will Deacon <will.deacon@arm.com>
Date: Mon, 5 Feb 2018 15:34:16 +0000 (+0000)
Subject: arm64: barrier: Add CSDB macros to control data-value prediction
X-Git-Tag: rel_imx_4.19.35_1.1.0~10711^2~27
X-Git-Url: https://git.somdevices.com/?a=commitdiff_plain;h=669474e772b952b14f4de4845a1558fd4c0414a4;p=linux.git

arm64: barrier: Add CSDB macros to control data-value prediction

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>
---

diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index 544878a9f29e..1f44b4255a28 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -115,6 +115,13 @@
 	hint    #16
 	.endm
 
+/*
+ * Value prediction barrier
+ */
+	.macro	csdb
+	hint	#20
+	.endm
+
 /*
  * NOP sequence
  */
diff --git a/arch/arm64/include/asm/barrier.h b/arch/arm64/include/asm/barrier.h
index 77651c49ef44..c0a846d2c602 100644
--- a/arch/arm64/include/asm/barrier.h
+++ b/arch/arm64/include/asm/barrier.h
@@ -32,6 +32,7 @@
 #define dsb(opt)	asm volatile("dsb " #opt : : : "memory")
 
 #define psb_csync()	asm volatile("hint #17" : : : "memory")
+#define csdb()		asm volatile("hint #20" : : : "memory")
 
 #define mb()		dsb(sy)
 #define rmb()		dsb(ld)