[PATCH v2 3/3] x86/mce: Drop copyin special case for #MC
From: Tony Luck <tony.luck@intel.com>
Date: 2021-08-18 00:30:00
Also in:
linux-mm, lkml
Subsystem:
the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
Fixes to the iterator code to handle faults that are not on page boundaries mean that the special case for machine check during copy from user is no longer needed. Signed-off-by: Tony Luck <tony.luck@intel.com> --- arch/x86/lib/copy_user_64.S | 13 ------------- 1 file changed, 13 deletions(-)
diff --git a/arch/x86/lib/copy_user_64.S b/arch/x86/lib/copy_user_64.S
index 57b79c577496..2797e630b9b1 100644
--- a/arch/x86/lib/copy_user_64.S
+++ b/arch/x86/lib/copy_user_64.S@@ -234,24 +234,11 @@ EXPORT_SYMBOL(copy_user_enhanced_fast_string) */ SYM_CODE_START_LOCAL(.Lcopy_user_handle_tail) movl %edx,%ecx - cmp $X86_TRAP_MC,%eax /* check if X86_TRAP_MC */ - je 3f 1: rep movsb 2: mov %ecx,%eax ASM_CLAC ret - /* - * Return zero to pretend that this copy succeeded. This - * is counter-intuitive, but needed to prevent the code - * in lib/iov_iter.c from retrying and running back into - * the poison cache line again. The machine check handler - * will ensure that a SIGBUS is sent to the task. - */ -3: xorl %eax,%eax - ASM_CLAC - ret - _ASM_EXTABLE_CPY(1b, 2b) SYM_CODE_END(.Lcopy_user_handle_tail)
--
2.29.2