ARM: spectre-v1: add speculation barrier (csdb) macros

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>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h
index 4a275fb..307901f 100644 (file)
--- a/arch/arm/include/asm/assembler.h
+++ b/arch/arm/include/asm/assembler.h
@@ -441,6 +441,14 @@ 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

diff --git a/arch/arm/include/asm/barrier.h b/arch/arm/include/asm/barrier.h
index 27c1d26..edd9e63 100644 (file)
--- a/arch/arm/include/asm/barrier.h
+++ b/arch/arm/include/asm/barrier.h
@@ -18,6 +18,12 @@
 #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")
@@ -38,6 +44,13 @@
 #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);