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| author | Josh Poimboeuf <jpoimboe@kernel.org> | 2022-06-14 15:07:19 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-07-25 11:26:45 +0200 |
| commit | fbab1c94eb1a3139d7ac0620dc6d7d6a33f3b255 (patch) | |
| tree | 6de717e981337e50b0b734b90a1dc924722ad3ba | |
| parent | c8845b875437b8ea9cd023f15b44c436c9c5b62d (diff) | |
| download | linux-fbab1c94eb1a3139d7ac0620dc6d7d6a33f3b255.tar.gz linux-fbab1c94eb1a3139d7ac0620dc6d7d6a33f3b255.tar.bz2 linux-fbab1c94eb1a3139d7ac0620dc6d7d6a33f3b255.zip | |
x86/bugs: Do IBPB fallback check only once
commit 0fe4aeea9c01baabecc8c3afc7889c809d939bc2 upstream.
When booting with retbleed=auto, if the kernel wasn't built with
CONFIG_CC_HAS_RETURN_THUNK, the mitigation falls back to IBPB. Make
sure a warning is printed in that case. The IBPB fallback check is done
twice, but it really only needs to be done once.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/x86/kernel/cpu/bugs.c | 15 |
1 files changed, 5 insertions, 10 deletions
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 0e25b0a66621..8205834dd11e 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -847,18 +847,13 @@ static void __init retbleed_select_mitigation(void) case RETBLEED_CMD_AUTO: default: if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD || - boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) { - - if (IS_ENABLED(CONFIG_RETPOLINE) && - IS_ENABLED(CONFIG_CC_HAS_RETURN_THUNK)) - retbleed_mitigation = RETBLEED_MITIGATION_UNRET; - else - retbleed_mitigation = RETBLEED_MITIGATION_IBPB; - } + boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) + retbleed_mitigation = RETBLEED_MITIGATION_UNRET; /* - * The Intel mitigation (IBRS) was already selected in - * spectre_v2_select_mitigation(). + * The Intel mitigation (IBRS or eIBRS) was already selected in + * spectre_v2_select_mitigation(). 'retbleed_mitigation' will + * be set accordingly below. */ break; |