[Part2,v6,08/49] x86/traps: Define RMP violation #PF error code

Commit Message

Kalra, Ashish June 20, 2022, 11:03 p.m. UTC

From: Brijesh Singh <[e-mail]>

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 Aug. 8, 2022, 1:13 p.m. UTC | #1

On Mon, Jun 20, 2022 at 11:03:27PM +0000, Ashish Kalra wrote:
> @@ -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),

Yeah, I remember dhansen asked for those to use the BIT() macro but the
_ULL is an overkill. Those PF flags are 32 and they fit in an unsigned
int.

But we don't have BUT_UI() so I guess the next best thing - BIT() -
which uses UL internally, should be good enough.

So pls use BIT() here - not BIT_ULL().

Thx.

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 fad8faa29d04..a4c270e99f7f 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -546,6 +546,7 @@  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)) {