[Part2,v5,07/45] x86/traps: Define RMP violation #PF error code

Commit Message

Brijesh Singh Aug. 20, 2021, 3:58 p.m. UTC

Bit 31 in the page fault-error bit will be set when processor encounters
an RMP violation.

While at it, use the BIT_ULL() macro.

Signed-off-by: Brijesh Singh <[e-mail]>
---
 arch/x86/include/asm/trap_pf.h | 18 +++++++++++-------
 arch/x86/mm/fault.c            |  1 +
 2 files changed, 12 insertions(+), 7 deletions(-)

Comments

Borislav Petkov Sept. 29, 2021, 5:25 p.m. UTC | #1

On Fri, Aug 20, 2021 at 10:58:40AM -0500, Brijesh Singh wrote:
>  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_ULL(0),
> +	X86_PF_WRITE	=		BIT_ULL(1),
> +	X86_PF_USER	=		BIT_ULL(2),
> +	X86_PF_RSVD	=		BIT_ULL(3),
> +	X86_PF_INSTR	=		BIT_ULL(4),
> +	X86_PF_PK	=		BIT_ULL(5),
> +	X86_PF_SGX	=		BIT_ULL(15),
> +	X86_PF_RMP	=		BIT_ULL(31),

Those are tested against error_code mostly, which is unsigned long so it
looks like you wanna use _BITUL() here. Not that it matters on x86-64
but if we want to be precise...

Patch

diff --git a/arch/x86/include/asm/trap_pf.h b/arch/x86/include/asm/trap_pf.h
index 10b1de500ab1..89b705114b3f 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 <linux/bits.h>  /* BIT() macro */
+
 /*
  * 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 due to 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_ULL(0),
+	X86_PF_WRITE	=		BIT_ULL(1),
+	X86_PF_USER	=		BIT_ULL(2),
+	X86_PF_RSVD	=		BIT_ULL(3),
+	X86_PF_INSTR	=		BIT_ULL(4),
+	X86_PF_PK	=		BIT_ULL(5),
+	X86_PF_SGX	=		BIT_ULL(15),
+	X86_PF_RMP	=		BIT_ULL(31),
 };
 
 #endif /* _ASM_X86_TRAP_PF_H */
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index b2eefdefc108..8b7a5757440e 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)) {