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| author | Russell King <rmk+kernel@armlinux.org.uk> | 2018-05-14 16:20:21 +0300 |
|---|---|---|
| committer | Russell King <rmk+kernel@armlinux.org.uk> | 2018-05-31 12:40:32 +0300 |
| commit | f5fe12b1eaee220ce62ff9afb8b90929c396595f (patch) | |
| tree | c1a1264964eb0d9e6e4ed77ee2788139553108d6 /arch/arm/include | |
| parent | e388b80288aade31135aca23d32eee93dd106795 (diff) | |
| download | linux-f5fe12b1eaee220ce62ff9afb8b90929c396595f.tar.xz | |
ARM: spectre-v2: harden user aborts in kernel space
In order to prevent aliasing attacks on the branch predictor,
invalidate the BTB or instruction cache on CPUs that are known to be
affected when taking an abort on a address that is outside of a user
task limit:
Cortex A8, A9, A12, A17, A73, A75: flush BTB.
Cortex A15, Brahma B15: invalidate icache.
If the IBE bit is not set, then there is little point to enabling the
workaround.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Boot-tested-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Diffstat (limited to 'arch/arm/include')
| -rw-r--r-- | arch/arm/include/asm/cp15.h | 3 | ||||
| -rw-r--r-- | arch/arm/include/asm/system_misc.h | 15 |
2 files changed, 18 insertions, 0 deletions
diff --git a/arch/arm/include/asm/cp15.h b/arch/arm/include/asm/cp15.h index 4c9fa72b59f5..07e27f212dc7 100644 --- a/arch/arm/include/asm/cp15.h +++ b/arch/arm/include/asm/cp15.h @@ -65,6 +65,9 @@ #define __write_sysreg(v, r, w, c, t) asm volatile(w " " c : : "r" ((t)(v))) #define write_sysreg(v, ...) __write_sysreg(v, __VA_ARGS__) +#define BPIALL __ACCESS_CP15(c7, 0, c5, 6) +#define ICIALLU __ACCESS_CP15(c7, 0, c5, 0) + extern unsigned long cr_alignment; /* defined in entry-armv.S */ static inline unsigned long get_cr(void) diff --git a/arch/arm/include/asm/system_misc.h b/arch/arm/include/asm/system_misc.h index 78f6db114faf..8e76db83c498 100644 --- a/arch/arm/include/asm/system_misc.h +++ b/arch/arm/include/asm/system_misc.h @@ -8,6 +8,7 @@ #include <linux/linkage.h> #include <linux/irqflags.h> #include <linux/reboot.h> +#include <linux/percpu.h> extern void cpu_init(void); @@ -15,6 +16,20 @@ void soft_restart(unsigned long); extern void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd); extern void (*arm_pm_idle)(void); +#ifdef CONFIG_HARDEN_BRANCH_PREDICTOR +typedef void (*harden_branch_predictor_fn_t)(void); +DECLARE_PER_CPU(harden_branch_predictor_fn_t, harden_branch_predictor_fn); +static inline void harden_branch_predictor(void) +{ + harden_branch_predictor_fn_t fn = per_cpu(harden_branch_predictor_fn, + smp_processor_id()); + if (fn) + fn(); +} +#else +#define harden_branch_predictor() do { } while (0) +#endif + #define UDBG_UNDEFINED (1 << 0) #define UDBG_SYSCALL (1 << 1) #define UDBG_BADABORT (1 << 2) |