diff options
Diffstat (limited to 'arch/x86/lib/getuser_32.S')
| -rw-r--r-- | arch/x86/lib/getuser_32.S | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/arch/x86/lib/getuser_32.S b/arch/x86/lib/getuser_32.S new file mode 100644 index 00000000000..6d84b53f12a --- /dev/null +++ b/arch/x86/lib/getuser_32.S @@ -0,0 +1,78 @@ +/* + * __get_user functions. + * + * (C) Copyright 1998 Linus Torvalds + * + * These functions have a non-standard call interface + * to make them more efficient, especially as they + * return an error value in addition to the "real" + * return value. + */ +#include <linux/linkage.h> +#include <asm/dwarf2.h> +#include <asm/thread_info.h> + + +/* + * __get_user_X + * + * Inputs: %eax contains the address + * + * Outputs: %eax is error code (0 or -EFAULT) + * %edx contains zero-extended value + * + * These functions should not modify any other registers, + * as they get called from within inline assembly. + */ + +.text +ENTRY(__get_user_1) + CFI_STARTPROC + GET_THREAD_INFO(%edx) + cmpl TI_addr_limit(%edx),%eax + jae bad_get_user +1: movzbl (%eax),%edx + xorl %eax,%eax + ret + CFI_ENDPROC +ENDPROC(__get_user_1) + +ENTRY(__get_user_2) + CFI_STARTPROC + addl $1,%eax + jc bad_get_user + GET_THREAD_INFO(%edx) + cmpl TI_addr_limit(%edx),%eax + jae bad_get_user +2: movzwl -1(%eax),%edx + xorl %eax,%eax + ret + CFI_ENDPROC +ENDPROC(__get_user_2) + +ENTRY(__get_user_4) + CFI_STARTPROC + addl $3,%eax + jc bad_get_user + GET_THREAD_INFO(%edx) + cmpl TI_addr_limit(%edx),%eax + jae bad_get_user +3: movl -3(%eax),%edx + xorl %eax,%eax + ret + CFI_ENDPROC +ENDPROC(__get_user_4) + +bad_get_user: + CFI_STARTPROC + xorl %edx,%edx + movl $-14,%eax + ret + CFI_ENDPROC +END(bad_get_user) + +.section __ex_table,"a" + .long 1b,bad_get_user + .long 2b,bad_get_user + .long 3b,bad_get_user +.previous |