x86-64: Fix "bytes left to copy" return value for copy_from_user()

[pandora-kernel.git] / arch / x86 / lib / copy_user_64.S

diff --git a/arch/x86/lib/copy_user_64.S b/arch/x86/lib/copy_user_64.S
index 70bebd3..ee1c3f6 100644 (file)
--- a/arch/x86/lib/copy_user_64.S
+++ b/arch/x86/lib/copy_user_64.S
@@ -217,19 +217,19 @@ ENTRY(copy_user_generic_unrolled)
        /* table sorted by exception address */
        .section __ex_table,"a"
        .align 8
-       .quad .Ls1,.Ls1e
-       .quad .Ls2,.Ls2e
-       .quad .Ls3,.Ls3e
-       .quad .Ls4,.Ls4e
-       .quad .Ld1,.Ls1e
+       .quad .Ls1,.Ls1e        /* Ls1-Ls4 have copied zero bytes */
+       .quad .Ls2,.Ls1e
+       .quad .Ls3,.Ls1e
+       .quad .Ls4,.Ls1e
+       .quad .Ld1,.Ls1e        /* Ld1-Ld4 have copied 0-24 bytes */
        .quad .Ld2,.Ls2e
        .quad .Ld3,.Ls3e
        .quad .Ld4,.Ls4e
-       .quad .Ls5,.Ls5e
-       .quad .Ls6,.Ls6e
-       .quad .Ls7,.Ls7e
-       .quad .Ls8,.Ls8e
-       .quad .Ld5,.Ls5e
+       .quad .Ls5,.Ls5e        /* Ls5-Ls8 have copied 32 bytes */
+       .quad .Ls6,.Ls5e
+       .quad .Ls7,.Ls5e
+       .quad .Ls8,.Ls5e
+       .quad .Ld5,.Ls5e        /* Ld5-Ld8 have copied 32-56 bytes */
        .quad .Ld6,.Ls6e
        .quad .Ld7,.Ls7e
        .quad .Ld8,.Ls8e
@@ -244,11 +244,8 @@ ENTRY(copy_user_generic_unrolled)
        .quad .Le5,.Le_zero
        .previous
 
-       /* compute 64-offset for main loop. 8 bytes accuracy with error on the
-          pessimistic side. this is gross. it would be better to fix the
-          interface. */
        /* eax: zero, ebx: 64 */
-.Ls1e:         addl $8,%eax
+.Ls1e:         addl $8,%eax            /* eax is bytes left uncopied within the loop (Ls1e: 64 .. Ls8e: 8) */
 .Ls2e:         addl $8,%eax
 .Ls3e:         addl $8,%eax
 .Ls4e:         addl $8,%eax