[PATCH] x86/asm: Remove CR4 read fault handler
From: Brian Gerst
Date: Sat Sep 05 2026 - 18:57:18 EST
Remove the fault handler from native_read_cr4() since 486 support has
been removed.
Signed-off-by: Brian Gerst <brgerst@xxxxxxxxx>
---
arch/x86/include/asm/special_insns.h | 13 -------------
1 file changed, 13 deletions(-)
diff --git a/arch/x86/include/asm/special_insns.h b/arch/x86/include/asm/special_insns.h
index 46aa2c9c1bda..6c80f69cf62b 100644
--- a/arch/x86/include/asm/special_insns.h
+++ b/arch/x86/include/asm/special_insns.h
@@ -46,20 +46,7 @@ static __always_inline void native_write_cr3(unsigned long val)
static inline unsigned long native_read_cr4(void)
{
unsigned long val;
-#ifdef CONFIG_X86_32
- /*
- * This could fault if CR4 does not exist. Non-existent CR4
- * is functionally equivalent to CR4 == 0. Keep it simple and pretend
- * that CR4 == 0 on CPUs that don't have CR4.
- */
- asm volatile("1: mov %%cr4, %0\n"
- "2:\n"
- _ASM_EXTABLE(1b, 2b)
- : "=r" (val) : "0" (0));
-#else
- /* CR4 always exists on x86_64. */
asm volatile("mov %%cr4,%0" : "=r" (val));
-#endif
return val;
}
base-commit: ea789738cbf82b72f5495cd1e2b231a917e0e6d5
--
2.55.0