From: Greg Kroah-Hartman Date: Sat, 18 Apr 2026 08:02:01 +0000 (+0200) Subject: 6.6-stable patches X-Git-Tag: v5.10.253~5 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b63612a14aee1dc6890cd50066887e00c1db01ea;p=thirdparty%2Fkernel%2Fstable-queue.git 6.6-stable patches added patches: x86-cpu-fix-fpdss-on-zen1.patch --- diff --git a/queue-6.6/series b/queue-6.6/series index 387eae5fe8..464607de36 100644 --- a/queue-6.6/series +++ b/queue-6.6/series @@ -1,3 +1,4 @@ +x86-cpu-fix-fpdss-on-zen1.patch lib-crypto-chacha-zeroize-permuted_state-before-it-leaves-scope.patch wifi-rt2x00usb-fix-devres-lifetime.patch xfrm_user-fix-info-leak-in-build_report.patch diff --git a/queue-6.6/x86-cpu-fix-fpdss-on-zen1.patch b/queue-6.6/x86-cpu-fix-fpdss-on-zen1.patch new file mode 100644 index 0000000000..02a33af18d --- /dev/null +++ b/queue-6.6/x86-cpu-fix-fpdss-on-zen1.patch @@ -0,0 +1,47 @@ +From e55d98e7756135f32150b9b8f75d580d0d4b2dd3 Mon Sep 17 00:00:00 2001 +From: "Borislav Petkov (AMD)" +Date: Tue, 7 Apr 2026 11:40:03 +0200 +Subject: x86/CPU: Fix FPDSS on Zen1 + +From: Borislav Petkov (AMD) + +commit e55d98e7756135f32150b9b8f75d580d0d4b2dd3 upstream. + +Zen1's hardware divider can leave, under certain circumstances, partial +results from previous operations. Those results can be leaked by +another, attacker thread. + +Fix that with a chicken bit. + +Signed-off-by: Borislav Petkov (AMD) +Signed-off-by: Linus Torvalds +Signed-off-by: Greg Kroah-Hartman +--- + arch/x86/include/asm/msr-index.h | 3 +++ + arch/x86/kernel/cpu/amd.c | 3 +++ + 2 files changed, 6 insertions(+) + +--- a/arch/x86/include/asm/msr-index.h ++++ b/arch/x86/include/asm/msr-index.h +@@ -582,6 +582,9 @@ + #define MSR_AMD64_DC_CFG 0xc0011022 + #define MSR_AMD64_TW_CFG 0xc0011023 + ++#define MSR_AMD64_FP_CFG 0xc0011028 ++#define MSR_AMD64_FP_CFG_ZEN1_DENORM_FIX_BIT 9 ++ + #define MSR_AMD64_DE_CFG 0xc0011029 + #define MSR_AMD64_DE_CFG_LFENCE_SERIALIZE_BIT 1 + #define MSR_AMD64_DE_CFG_LFENCE_SERIALIZE BIT_ULL(MSR_AMD64_DE_CFG_LFENCE_SERIALIZE_BIT) +--- a/arch/x86/kernel/cpu/amd.c ++++ b/arch/x86/kernel/cpu/amd.c +@@ -1112,6 +1112,9 @@ static void init_amd_zen1(struct cpuinfo + msr_clear_bit(MSR_K7_HWCR, MSR_K7_HWCR_IRPERF_EN_BIT); + clear_cpu_cap(c, X86_FEATURE_IRPERF); + } ++ ++ pr_notice_once("AMD Zen1 FPDSS bug detected, enabling mitigation.\n"); ++ msr_set_bit(MSR_AMD64_FP_CFG, MSR_AMD64_FP_CFG_ZEN1_DENORM_FIX_BIT); + } + + static bool cpu_has_zenbleed_microcode(void)