The following commit has been merged into the x86/fred branch of tip: Commit-ID: ff45746fbf005f96e42bea466698e3fdbf926013 Gitweb: https://git.kernel.org/tip/ff45746fbf005f96e42bea466698e3fdbf926013 Author: H. Peter Anvin (Intel) <hpa@xxxxxxxxx> AuthorDate: Tue, 05 Dec 2023 02:50:00 -08:00 Committer: Borislav Petkov (AMD) <bp@xxxxxxxxx> CommitterDate: Wed, 31 Jan 2024 22:00:38 +01:00 x86/cpu: Add X86_CR4_FRED macro Add X86_CR4_FRED macro for the FRED bit in %cr4. This bit must not be changed after initialization, so add it to the pinned CR4 bits. Signed-off-by: H. Peter Anvin (Intel) <hpa@xxxxxxxxx> Signed-off-by: Xin Li <xin3.li@xxxxxxxxx> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx> Tested-by: Shan Kang <shan.kang@xxxxxxxxx> Link: https://lore.kernel.org/r/20231205105030.8698-12-xin3.li@xxxxxxxxx --- arch/x86/include/uapi/asm/processor-flags.h | 7 +++++++ arch/x86/kernel/cpu/common.c | 5 ++--- 2 files changed, 9 insertions(+), 3 deletions(-) diff --git a/arch/x86/include/uapi/asm/processor-flags.h b/arch/x86/include/uapi/asm/processor-flags.h index d898432..f1a4adc 100644 --- a/arch/x86/include/uapi/asm/processor-flags.h +++ b/arch/x86/include/uapi/asm/processor-flags.h @@ -139,6 +139,13 @@ #define X86_CR4_LAM_SUP_BIT 28 /* LAM for supervisor pointers */ #define X86_CR4_LAM_SUP _BITUL(X86_CR4_LAM_SUP_BIT) +#ifdef __x86_64__ +#define X86_CR4_FRED_BIT 32 /* enable FRED kernel entry */ +#define X86_CR4_FRED _BITUL(X86_CR4_FRED_BIT) +#else +#define X86_CR4_FRED (0) +#endif + /* * x86-64 Task Priority Register, CR8 */ diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 0b97bcd..c3a1757 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -382,9 +382,8 @@ out: } /* These bits should not change their value after CPU init is finished. */ -static const unsigned long cr4_pinned_mask = - X86_CR4_SMEP | X86_CR4_SMAP | X86_CR4_UMIP | - X86_CR4_FSGSBASE | X86_CR4_CET; +static const unsigned long cr4_pinned_mask = X86_CR4_SMEP | X86_CR4_SMAP | X86_CR4_UMIP | + X86_CR4_FSGSBASE | X86_CR4_CET | X86_CR4_FRED; static DEFINE_STATIC_KEY_FALSE_RO(cr_pinning); static unsigned long cr4_pinned_bits __ro_after_init;
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