From 690658471b5f28d306e6492c4585d748cb5304e8 Mon Sep 17 00:00:00 2001 From: Tony Luck Date: Tue, 17 Aug 2021 17:29:42 -0700 Subject: [PATCH] x86/mce: Drop copyin special case for #MC 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. For a full list of those fixes, see the output of: git log --oneline v5.14 ^v5.13 -- lib/iov_iter.c Signed-off-by: Tony Luck Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/20210818002942.1607544-4-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 57b79c5..2797e63 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) -- 2.7.4