sparc64: Convert copy_in_user to accurate exception reporting.

Report the exact number of bytes which have not been successfully
copied when an exception occurs, using the running remaining length.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 25 insertions, 10 deletions

diff --git a/arch/sparc/lib/copy_in_user.S b/arch/sparc/lib/copy_in_user.S
index 86e6663dd4e0..0252b218de45 100644
--- a/arch/sparc/lib/copy_in_user.S
+++ b/arch/sparc/lib/copy_in_user.S
@@ -9,18 +9,33 @@
 
 #define XCC xcc
 
-#define EX(x,y)                 \
+#define EX(x,y,z)               \
 98:     x,y;                    \
         .section __ex_table,"a";\
         .align 4;               \
-        .word 98b, __retl_mone; \
+        .word 98b, z;           \
         .text;                  \
         .align 4;
 
+#define EX_O4(x,y) EX(x,y,__retl_o4_plus_8)
+#define EX_O2_4(x,y) EX(x,y,__retl_o2_plus_4)
+#define EX_O2_1(x,y) EX(x,y,__retl_o2_plus_1)
+
         .register       %g2,#scratch
         .register       %g3,#scratch
 
         .text
+__retl_o4_plus_8:
+        add     %o4, %o2, %o4
+        retl
+         add    %o4, 8, %o0
+__retl_o2_plus_4:
+        retl
+         add    %o2, 4, %o0
+__retl_o2_plus_1:
+        retl
+         add    %o2, 1, %o0
+
         .align  32
 
         /* Don't try to get too fancy here, just nice and
@@ -45,8 +60,8 @@ ENTRY(___copy_in_user)	/* %o0=dst, %o1=src, %o2=len */
         andn            %o2, 0x7, %o4
         and             %o2, 0x7, %o2
 1:      subcc           %o4, 0x8, %o4
-        EX(ldxa [%o1] %asi, %o5)
-        EX(stxa %o5, [%o0] %asi)
+        EX_O4(ldxa [%o1] %asi, %o5)
+        EX_O4(stxa %o5, [%o0] %asi)
         add             %o1, 0x8, %o1
         bgu,pt          %XCC, 1b
          add            %o0, 0x8, %o0
@@ -54,8 +69,8 @@ ENTRY(___copy_in_user)	/* %o0=dst, %o1=src, %o2=len */
         be,pt           %XCC, 1f
          nop
         sub             %o2, 0x4, %o2
-        EX(lduwa [%o1] %asi, %o5)
-        EX(stwa %o5, [%o0] %asi)
+        EX_O2_4(lduwa [%o1] %asi, %o5)
+        EX_O2_4(stwa %o5, [%o0] %asi)
         add             %o1, 0x4, %o1
         add             %o0, 0x4, %o0
 1:      cmp             %o2, 0
@@ -71,8 +86,8 @@ ENTRY(___copy_in_user)	/* %o0=dst, %o1=src, %o2=len */
 
 82:
         subcc           %o2, 4, %o2
-        EX(lduwa [%o1] %asi, %g1)
-        EX(stwa %g1, [%o0] %asi)
+        EX_O2_4(lduwa [%o1] %asi, %g1)
+        EX_O2_4(stwa %g1, [%o0] %asi)
         add             %o1, 4, %o1
         bgu,pt          %XCC, 82b
          add            %o0, 4, %o0
@@ -83,8 +98,8 @@ ENTRY(___copy_in_user)	/* %o0=dst, %o1=src, %o2=len */
         .align  32
 90:
         subcc           %o2, 1, %o2
-        EX(lduba [%o1] %asi, %g1)
-        EX(stba %g1, [%o0] %asi)
+        EX_O2_1(lduba [%o1] %asi, %g1)
+        EX_O2_1(stba %g1, [%o0] %asi)
         add             %o1, 1, %o1
         bgu,pt          %XCC, 90b
          add            %o0, 1, %o0