diff options
| author | Christopher M. Riedl <cmr@informatik.wtf> | 2019-05-23 21:46:48 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-11-28 18:26:28 +0100 |
| commit | 1efaf619f4220ab9f223063f485739607b468984 (patch) | |
| tree | 7b532d58563b7d257b33bf8e7cd1a8ed32ee55a1 /arch/powerpc | |
| parent | 4e23e97241b70f56c0d4478ef92e6cc290944214 (diff) | |
powerpc/64s: support nospectre_v2 cmdline option
commit d8f0e0b073e1ec52a05f0c2a56318b47387d2f10 upstream.
Add support for disabling the kernel implemented spectre v2 mitigation
(count cache flush on context switch) via the nospectre_v2 and
mitigations=off cmdline options.
Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Christopher M. Riedl <cmr@informatik.wtf>
Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190524024647.381-1-cmr@informatik.wtf
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/powerpc')
| -rw-r--r-- | arch/powerpc/kernel/security.c | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/arch/powerpc/kernel/security.c b/arch/powerpc/kernel/security.c index fe30ddfd51ee..32b3a44ee723 100644 --- a/arch/powerpc/kernel/security.c +++ b/arch/powerpc/kernel/security.c @@ -29,7 +29,7 @@ static enum count_cache_flush_type count_cache_flush_type = COUNT_CACHE_FLUSH_NO bool barrier_nospec_enabled; static bool no_nospec; static bool btb_flush_enabled; -#ifdef CONFIG_PPC_FSL_BOOK3E +#if defined(CONFIG_PPC_FSL_BOOK3E) || defined(CONFIG_PPC_BOOK3S_64) static bool no_spectrev2; #endif @@ -107,7 +107,7 @@ static __init int barrier_nospec_debugfs_init(void) device_initcall(barrier_nospec_debugfs_init); #endif /* CONFIG_DEBUG_FS */ -#ifdef CONFIG_PPC_FSL_BOOK3E +#if defined(CONFIG_PPC_FSL_BOOK3E) || defined(CONFIG_PPC_BOOK3S_64) static int __init handle_nospectre_v2(char *p) { no_spectrev2 = true; @@ -115,6 +115,9 @@ static int __init handle_nospectre_v2(char *p) return 0; } early_param("nospectre_v2", handle_nospectre_v2); +#endif /* CONFIG_PPC_FSL_BOOK3E || CONFIG_PPC_BOOK3S_64 */ + +#ifdef CONFIG_PPC_FSL_BOOK3E void setup_spectre_v2(void) { if (no_spectrev2) @@ -390,7 +393,17 @@ static void toggle_count_cache_flush(bool enable) void setup_count_cache_flush(void) { - toggle_count_cache_flush(true); + bool enable = true; + + if (no_spectrev2 || cpu_mitigations_off()) { + if (security_ftr_enabled(SEC_FTR_BCCTRL_SERIALISED) || + security_ftr_enabled(SEC_FTR_COUNT_CACHE_DISABLED)) + pr_warn("Spectre v2 mitigations not under software control, can't disable\n"); + + enable = false; + } + + toggle_count_cache_flush(enable); } #ifdef CONFIG_DEBUG_FS |