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

From: Ashish Kalra
Date: Mon Jun 20 2022 - 19:04:13 EST


From: Brijesh Singh <brijesh.singh@xxxxxxx>

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 <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..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)) {
--
2.25.1