diff options
| -rw-r--r-- | arch/x86/lib/copy_mc.c | 32 | ||||
| -rw-r--r-- | arch/x86/lib/copy_mc_64.S | 36 | ||||
| -rw-r--r-- | tools/objtool/check.c | 1 |
3 files changed, 9 insertions, 60 deletions
diff --git a/arch/x86/lib/copy_mc.c b/arch/x86/lib/copy_mc.c index c13e8c9ee926..2633635530b7 100644 --- a/arch/x86/lib/copy_mc.c +++ b/arch/x86/lib/copy_mc.c @@ -45,8 +45,6 @@ void enable_copy_mc_fragile(void) #define copy_mc_fragile_enabled (0) #endif -unsigned long copy_mc_enhanced_fast_string(void *dst, const void *src, unsigned len); - /** * copy_mc_to_kernel - memory copy that handles source exceptions * @@ -54,11 +52,9 @@ unsigned long copy_mc_enhanced_fast_string(void *dst, const void *src, unsigned * @src: source address * @len: number of bytes to copy * - * Call into the 'fragile' version on systems that benefit from avoiding - * corner case poison consumption scenarios, For example, accessing - * poison across 2 cachelines with a single instruction. Almost all - * other uses case can use copy_mc_enhanced_fast_string() for a fast - * recoverable copy, or fallback to plain memcpy. + * Call into the 'fragile' version on systems that have trouble + * actually do machine check recovery. Everyone else can just + * use memcpy(). * * Return 0 for success, or number of bytes not copied if there was an * exception. @@ -67,8 +63,6 @@ unsigned long __must_check copy_mc_to_kernel(void *dst, const void *src, unsigne { if (copy_mc_fragile_enabled) return copy_mc_fragile(dst, src, len); - if (static_cpu_has(X86_FEATURE_ERMS)) - return copy_mc_enhanced_fast_string(dst, src, len); memcpy(dst, src, len); return 0; } @@ -78,19 +72,11 @@ unsigned long __must_check copy_mc_to_user(void *dst, const void *src, unsigned { unsigned long ret; - if (copy_mc_fragile_enabled) { - __uaccess_begin(); - ret = copy_mc_fragile(dst, src, len); - __uaccess_end(); - return ret; - } - - if (static_cpu_has(X86_FEATURE_ERMS)) { - __uaccess_begin(); - ret = copy_mc_enhanced_fast_string(dst, src, len); - __uaccess_end(); - return ret; - } + if (!copy_mc_fragile_enabled) + return copy_user_generic(dst, src, len); - return copy_user_generic(dst, src, len); + __uaccess_begin(); + ret = copy_mc_fragile(dst, src, len); + __uaccess_end(); + return ret; } diff --git a/arch/x86/lib/copy_mc_64.S b/arch/x86/lib/copy_mc_64.S index 892d8915f609..c3b613c4544a 100644 --- a/arch/x86/lib/copy_mc_64.S +++ b/arch/x86/lib/copy_mc_64.S @@ -124,40 +124,4 @@ EXPORT_SYMBOL_GPL(copy_mc_fragile) _ASM_EXTABLE(.L_write_words, .E_write_words) _ASM_EXTABLE(.L_write_trailing_bytes, .E_trailing_bytes) #endif /* CONFIG_X86_MCE */ - -/* - * copy_mc_enhanced_fast_string - memory copy with exception handling - * - * Fast string copy + fault / exception handling. If the CPU does - * support machine check exception recovery, but does not support - * recovering from fast-string exceptions then this CPU needs to be - * added to the copy_mc_fragile_key set of quirks. Otherwise, absent any - * machine check recovery support this version should be no slower than - * standard memcpy. - */ -SYM_FUNC_START(copy_mc_enhanced_fast_string) - movq %rdi, %rax - movq %rdx, %rcx -.L_copy: - rep movsb - /* Copy successful. Return zero */ - xorl %eax, %eax - ret -SYM_FUNC_END(copy_mc_enhanced_fast_string) - - .section .fixup, "ax" -.E_copy: - /* - * On fault %rcx is updated such that the copy instruction could - * optionally be restarted at the fault position, i.e. it - * contains 'bytes remaining'. A non-zero return indicates error - * to copy_mc_generic() users, or indicate short transfers to - * user-copy routines. - */ - movq %rcx, %rax - ret - - .previous - - _ASM_EXTABLE_FAULT(.L_copy, .E_copy) #endif /* !CONFIG_UML */ diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 42ac19e0299c..cf2d076f6ba5 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -550,7 +550,6 @@ static const char *uaccess_safe_builtin[] = { "csum_partial_copy_generic", "copy_mc_fragile", "copy_mc_fragile_handle_tail", - "copy_mc_enhanced_fast_string", "ftrace_likely_update", /* CONFIG_TRACE_BRANCH_PROFILING */ NULL }; |