diff options
Diffstat (limited to 'arch/cris/arch-v32/lib/csumcpfruser.S')
-rw-r--r-- | arch/cris/arch-v32/lib/csumcpfruser.S | 69 |
1 files changed, 69 insertions, 0 deletions
diff --git a/arch/cris/arch-v32/lib/csumcpfruser.S b/arch/cris/arch-v32/lib/csumcpfruser.S new file mode 100644 index 00000000000..600ec16b9f2 --- /dev/null +++ b/arch/cris/arch-v32/lib/csumcpfruser.S @@ -0,0 +1,69 @@ +/* + * Add-on to transform csum_partial_copy_nocheck in checksumcopy.S into + * csum_partial_copy_from_user by adding exception records. + * + * Copyright (C) 2001, 2003 Axis Communications AB. + * + * Author: Hans-Peter Nilsson. + */ + +#include <asm/errno.h> + +/* Same function body, but a different name. If we just added exception + records to _csum_partial_copy_nocheck and made it generic, we wouldn't + know a user fault from a kernel fault and we would have overhead in + each kernel caller for the error-pointer argument. + + unsigned int csum_partial_copy_from_user + (const char *src, char *dst, int len, unsigned int sum, int *errptr); + + Note that the errptr argument is only set if we encounter an error. + It is conveniently located on the stack, so the normal function body + does not have to handle it. */ + +#define csum_partial_copy_nocheck csum_partial_copy_from_user + +/* There are local labels numbered 1, 2 and 3 present to mark the + different from-user accesses. */ +#include "checksumcopy.S" + + .section .fixup,"ax" + +;; Here from the movem loop; restore stack. +4: + movem [$sp+],$r8 +;; r12 is already decremented. Add back chunk_size-2. + addq 40-2,$r12 + +;; Here from the word loop; r12 is off by 2; add it back. +5: + addq 2,$r12 + +;; Here from a failing single byte. +6: + +;; Signal in *errptr that we had a failing access. + move.d [$sp],$acr + moveq -EFAULT,$r9 + subq 4,$sp + move.d $r9,[$acr] + +;; Clear the rest of the destination area using memset. Preserve the +;; checksum for the readable bytes. + move.d $r13,[$sp] + subq 4,$sp + move.d $r11,$r10 + move $srp,[$sp] + jsr memset + clear.d $r11 + + move [$sp+],$srp + ret + move.d [$sp+],$r10 + + .previous + .section __ex_table,"a" + .dword 1b,4b + .dword 2b,5b + .dword 3b,6b + .previous |