diff options
Diffstat (limited to 'arch/x86/lib/copy_user_64.S')
| -rw-r--r-- | arch/x86/lib/copy_user_64.S | 23 |
1 files changed, 22 insertions, 1 deletions
diff --git a/arch/x86/lib/copy_user_64.S b/arch/x86/lib/copy_user_64.S index 0a81aafed7f8..06296eb69fd4 100644 --- a/arch/x86/lib/copy_user_64.S +++ b/arch/x86/lib/copy_user_64.S @@ -6,11 +6,13 @@ * Functions to copy from and to user space. */ +#include <linux/export.h> #include <linux/linkage.h> +#include <linux/cfi_types.h> +#include <linux/objtool.h> #include <asm/cpufeatures.h> #include <asm/alternative.h> #include <asm/asm.h> -#include <asm/export.h> /* * rep_movs_alternative - memory copy with exception handling. @@ -30,6 +32,7 @@ * it simpler for us, we can clobber rsi/rdi and rax freely. */ SYM_FUNC_START(rep_movs_alternative) + ANNOTATE_NOENDBR cmpq $64,%rcx jae .Llarge @@ -74,6 +77,24 @@ SYM_FUNC_START(rep_movs_alternative) _ASM_EXTABLE_UA( 0b, 1b) .Llarge_movsq: + /* Do the first possibly unaligned word */ +0: movq (%rsi),%rax +1: movq %rax,(%rdi) + + _ASM_EXTABLE_UA( 0b, .Lcopy_user_tail) + _ASM_EXTABLE_UA( 1b, .Lcopy_user_tail) + + /* What would be the offset to the aligned destination? */ + leaq 8(%rdi),%rax + andq $-8,%rax + subq %rdi,%rax + + /* .. and update pointers and count to match */ + addq %rax,%rdi + addq %rax,%rsi + subq %rax,%rcx + + /* make %rcx contain the number of words, %rax the remainder */ movq %rcx,%rax shrq $3,%rcx andl $7,%eax |