[PATCH 4.14 100/109] ARM: spectre-v1: add speculation barrier (csdb) macros

Greg Kroah-Hartman
2018-10-16T17:21:46Z

From: Russell King <rmk+kernel@armlinux.org.uk>

Commit a78d156587931a2c3b354534aa772febf6c9e855 upstream.

Add assembly and C macros for the new CSDB instruction.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Boot-tested-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: David A. Long <dave.long@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/arm/include/asm/assembler.h | 8 ++++++++
arch/arm/include/asm/barrier.h | 13 +++++++++++++
2 files changed, 21 insertions(+)

--- a/arch/arm/include/asm/assembler.h
+++ b/arch/arm/include/asm/assembler.h
@@ -447,6 +447,14 @@ THUMB( orr \reg , \reg , #PSR_T_BIT )
.size \name , . - \name
.endm

+ .macro csdb
+#ifdef CONFIG_THUMB2_KERNEL
+ .inst.w 0xf3af8014
+#else
+ .inst 0xe320f014
+#endif
+ .endm
+
.macro check_uaccess, addr:req, size:req, limit:req, tmp:req, bad:req
#ifndef CONFIG_CPU_USE_DOMAINS
adds \tmp, \addr, #\size - 1
--- a/arch/arm/include/asm/barrier.h
+++ b/arch/arm/include/asm/barrier.h
@@ -17,6 +17,12 @@
#define isb(option) __asm__ __volatile__ ("isb " #option : : : "memory")
#define dsb(option) __asm__ __volatile__ ("dsb " #option : : : "memory")
#define dmb(option) __asm__ __volatile__ ("dmb " #option : : : "memory")
+#ifdef CONFIG_THUMB2_KERNEL
+#define CSDB ".inst.w 0xf3af8014"
+#else
+#define CSDB ".inst 0xe320f014"
+#endif
+#define csdb() __asm__ __volatile__(CSDB : : : "memory")
#elif defined(CONFIG_CPU_XSC3) || __LINUX_ARM_ARCH__ == 6
#define isb(x) __asm__ __volatile__ ("mcr p15, 0, %0, c7, c5, 4" \
: : "r" (0) : "memory")
@@ -37,6 +43,13 @@
#define dmb(x) __asm__ __volatile__ ("" : : : "memory")
#endif

+#ifndef CSDB
+#define CSDB
+#endif
+#ifndef csdb
+#define csdb()
+#endif
+
#ifdef CONFIG_ARM_HEAVY_MB
extern void (*soc_mb)(void);
extern void arm_heavy_mb(void);