On Wed, Jul 07, 2021, Brijesh Singh wrote:
> Bit 31 in the page fault-error bit will be set when processor encounters
> an RMP violation.
>
> While at it, use the BIT() macro.
>
> Signed-off-by: Brijesh Singh <brijesh.singh@xxxxxxx>
> ---
> arch/x86/include/asm/trap_pf.h | 18 +++++++++++-------
> arch/x86/mm/fault.c | 1 +
> 2 files changed, 12 insertions(+), 7 deletions(-)
>
> diff --git a/arch/x86/include/asm/trap_pf.h b/arch/x86/include/asm/trap_pf.h
> index 10b1de500ab1..29f678701753 100644
> --- a/arch/x86/include/asm/trap_pf.h
> +++ b/arch/x86/include/asm/trap_pf.h
> @@ -2,6 +2,8 @@
> #ifndef _ASM_X86_TRAP_PF_H
> #define _ASM_X86_TRAP_PF_H
>
> +#include <vdso/bits.h> /* BIT() macro */
What are people's thoughts on using linux/bits.h instead of vdso.bits.h, even
though the vDSO version is technically sufficient? Seeing the "vdso" reference
definitely made me blink slowly a few times.
> +
> /*
> * Page fault error code bits:
> *
> @@ -12,15 +14,17 @@
> * bit 4 == 1: fault was an instruction fetch
> * bit 5 == 1: protection keys block access
> * bit 15 == 1: SGX MMU page-fault
> + * bit 31 == 1: fault was an RMP violation
> */
> enum x86_pf_error_code {
> - X86_PF_PROT = 1 << 0,
> - X86_PF_WRITE = 1 << 1,
> - X86_PF_USER = 1 << 2,
> - X86_PF_RSVD = 1 << 3,
> - X86_PF_INSTR = 1 << 4,
> - X86_PF_PK = 1 << 5,
> - X86_PF_SGX = 1 << 15,
> + X86_PF_PROT = BIT(0),
> + X86_PF_WRITE = BIT(1),
> + X86_PF_USER = BIT(2),
> + X86_PF_RSVD = BIT(3),
> + X86_PF_INSTR = BIT(4),
> + X86_PF_PK = BIT(5),
> + X86_PF_SGX = BIT(15),
> + X86_PF_RMP = BIT(31),
> };
>
> #endif /* _ASM_X86_TRAP_PF_H */
> diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
> index 1c548ad00752..2715240c757e 100644
> --- a/arch/x86/mm/fault.c
> +++ b/arch/x86/mm/fault.c
> @@ -545,6 +545,7 @@ show_fault_oops(struct pt_regs *regs, unsigned long error_code, unsigned long ad
> !(error_code & X86_PF_PROT) ? "not-present page" :
> (error_code & X86_PF_RSVD) ? "reserved bit violation" :
> (error_code & X86_PF_PK) ? "protection keys violation" :
> + (error_code & X86_PF_RMP) ? "rmp violation" :
> "permissions violation");
>
> if (!(error_code & X86_PF_USER) && user_mode(regs)) {
> --
> 2.17.1
>
