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author | Russell King (Oracle) <rmk+kernel@armlinux.org.uk> | 2022-02-10 16:05:45 +0000 |
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committer | Russell King (Oracle) <rmk+kernel@armlinux.org.uk> | 2022-03-05 10:42:07 +0000 |
commit | b9baf5c8c5c356757f4f9d8180b5e9d234065bc3 (patch) | |
tree | d5a219c88d8888508c947a84a86df32a941887a3 /arch/arm/kernel/traps.c | |
parent | ARM: use LOADADDR() to get load address of sections (diff) | |
download | linux-dev-b9baf5c8c5c356757f4f9d8180b5e9d234065bc3.tar.xz linux-dev-b9baf5c8c5c356757f4f9d8180b5e9d234065bc3.zip |
ARM: Spectre-BHB workaround
Workaround the Spectre BHB issues for Cortex-A15, Cortex-A57,
Cortex-A72, Cortex-A73 and Cortex-A75. We also include Brahma B15 as
well to be safe, which is affected by Spectre V2 in the same ways as
Cortex-A15.
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Diffstat (limited to 'arch/arm/kernel/traps.c')
-rw-r--r-- | arch/arm/kernel/traps.c | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c index abc82dfeab51..90c887aa67a4 100644 --- a/arch/arm/kernel/traps.c +++ b/arch/arm/kernel/traps.c @@ -30,6 +30,7 @@ #include <linux/atomic.h> #include <asm/cacheflush.h> #include <asm/exception.h> +#include <asm/spectre.h> #include <asm/unistd.h> #include <asm/traps.h> #include <asm/ptrace.h> @@ -801,6 +802,43 @@ static void flush_vectors(void *vma, size_t offset, size_t size) flush_icache_range(start, end); } +#ifdef CONFIG_HARDEN_BRANCH_HISTORY +int spectre_bhb_update_vectors(unsigned int method) +{ + extern char __vectors_bhb_bpiall_start[], __vectors_bhb_bpiall_end[]; + extern char __vectors_bhb_loop8_start[], __vectors_bhb_loop8_end[]; + void *vec_start, *vec_end; + + if (system_state >= SYSTEM_FREEING_INITMEM) { + pr_err("CPU%u: Spectre BHB workaround too late - system vulnerable\n", + smp_processor_id()); + return SPECTRE_VULNERABLE; + } + + switch (method) { + case SPECTRE_V2_METHOD_LOOP8: + vec_start = __vectors_bhb_loop8_start; + vec_end = __vectors_bhb_loop8_end; + break; + + case SPECTRE_V2_METHOD_BPIALL: + vec_start = __vectors_bhb_bpiall_start; + vec_end = __vectors_bhb_bpiall_end; + break; + + default: + pr_err("CPU%u: unknown Spectre BHB state %d\n", + smp_processor_id(), method); + return SPECTRE_VULNERABLE; + } + + copy_from_lma(vectors_page, vec_start, vec_end); + flush_vectors(vectors_page, 0, vec_end - vec_start); + + return SPECTRE_MITIGATED; +} +#endif + void __init early_trap_init(void *vectors_base) { extern char __stubs_start[], __stubs_end[]; |