[PATCHv8 13/17] x86/traps: Generalize #GP address decode and hint code

Kirill A. Shutemov
2025-07-01T09:59:22Z

Handlers for #GP and #SS will now share code to decode the exception
address and retrieve the exception hint string.

The helper, enum, and array should be renamed as they are no longer
specific to #GP.

No functional change intended.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
arch/x86/kernel/traps.c | 62 ++++++++++++++++++++---------------------
1 file changed, 31 insertions(+), 31 deletions(-)

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 5206eb0ab01a..ceb091f17a5b 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -633,28 +633,28 @@ DEFINE_IDTENTRY(exc_bounds)
cond_local_irq_disable(regs);
}

-enum kernel_gp_hint {
- GP_NO_HINT,
- GP_NON_CANONICAL,
- GP_CANONICAL,
- GP_LASS_VIOLATION,
- GP_NULL_POINTER,
+enum kernel_exc_hint {
+ EXC_NO_HINT,
+ EXC_NON_CANONICAL,
+ EXC_CANONICAL,
+ EXC_LASS_VIOLATION,
+ EXC_NULL_POINTER,
};

-static const char * const kernel_gp_hint_help[] = {
- [GP_NON_CANONICAL] = "probably for non-canonical address",
- [GP_CANONICAL] = "maybe for address",
- [GP_LASS_VIOLATION] = "LASS prevented access to address",
- [GP_NULL_POINTER] = "kernel NULL pointer dereference",
+static const char * const kernel_exc_hint_help[] = {
+ [EXC_NON_CANONICAL] = "probably for non-canonical address",
+ [EXC_CANONICAL] = "maybe for address",
+ [EXC_LASS_VIOLATION] = "LASS prevented access to address",
+ [EXC_NULL_POINTER] = "kernel NULL pointer dereference",
};

/*
- * When an uncaught #GP occurs, try to determine the memory address accessed by
- * the instruction and return that address to the caller. Also, try to figure
- * out whether any part of the access to that address was non-canonical.
+ * When an uncaught #GP/#SS occurs, try to determine the memory address accessed
+ * by the instruction and return that address to the caller. Also, try to
+ * figure out whether any part of the access to that address was non-canonical.
*/
-static enum kernel_gp_hint get_kernel_gp_address(struct pt_regs *regs,
- unsigned long *addr)
+static enum kernel_exc_hint get_kernel_exc_address(struct pt_regs *regs,
+ unsigned long *addr)
{
u8 insn_buf[MAX_INSN_SIZE];
struct insn insn;
@@ -662,15 +662,15 @@ static enum kernel_gp_hint get_kernel_gp_address(struct pt_regs *regs,

if (copy_from_kernel_nofault(insn_buf, (void *)regs->ip,
MAX_INSN_SIZE))
- return GP_NO_HINT;
+ return EXC_NO_HINT;

ret = insn_decode_kernel(&insn, insn_buf);
if (ret < 0)
- return GP_NO_HINT;
+ return EXC_NO_HINT;

*addr = (unsigned long)insn_get_addr_ref(&insn, regs);
if (*addr == -1UL)
- return GP_NO_HINT;
+ return EXC_NO_HINT;

#ifdef CONFIG_X86_64
/*
@@ -680,16 +680,16 @@ static enum kernel_gp_hint get_kernel_gp_address(struct pt_regs *regs,
*/
if (*addr < ~__VIRTUAL_MASK &&
*addr + insn.opnd_bytes - 1 > __VIRTUAL_MASK)
- return GP_NON_CANONICAL;
+ return EXC_NON_CANONICAL;
else if (*addr < ~__VIRTUAL_MASK &&
cpu_feature_enabled(X86_FEATURE_LASS)) {
if (*addr < PAGE_SIZE)
- return GP_NULL_POINTER;
- return GP_LASS_VIOLATION;
+ return EXC_NULL_POINTER;
+ return EXC_LASS_VIOLATION;
}
#endif

- return GP_CANONICAL;
+ return EXC_CANONICAL;
}

#define GPFSTR "general protection fault"
@@ -808,8 +808,8 @@ static void gp_user_force_sig_segv(struct pt_regs *regs, int trapnr,
DEFINE_IDTENTRY_ERRORCODE(exc_general_protection)
{
char desc[sizeof(GPFSTR) + 50 + 2*sizeof(unsigned long) + 1] = GPFSTR;
- enum kernel_gp_hint hint = GP_NO_HINT;
- unsigned long gp_addr;
+ enum kernel_exc_hint hint = EXC_NO_HINT;
+ unsigned long exc_addr;

if (user_mode(regs) && try_fixup_enqcmd_gp())
return;
@@ -846,21 +846,21 @@ DEFINE_IDTENTRY_ERRORCODE(exc_general_protection)
if (error_code)
snprintf(desc, sizeof(desc), "segment-related " GPFSTR);
else
- hint = get_kernel_gp_address(regs, &gp_addr);
+ hint = get_kernel_exc_address(regs, &exc_addr);

- if (hint != GP_NO_HINT) {
+ if (hint != EXC_NO_HINT) {
snprintf(desc, sizeof(desc), GPFSTR ", %s 0x%lx",
- kernel_gp_hint_help[hint], gp_addr);
+ kernel_exc_hint_help[hint], exc_addr);
}

/*
* KASAN is interested only in the non-canonical case, clear it
* otherwise.
*/
- if (hint != GP_NON_CANONICAL)
- gp_addr = 0;
+ if (hint != EXC_NON_CANONICAL)
+ exc_addr = 0;

- die_addr(desc, regs, error_code, gp_addr);
+ die_addr(desc, regs, error_code, exc_addr);

exit:
cond_local_irq_disable(regs);
--
2.47.2