[PATCH 4.8 39/49] sparc64: Convert copy_in_user to accurate exception reporting.

From: Greg Kroah-Hartman
Date: Sat Nov 19 2016 - 04:25:22 EST


4.8-stable review patch. If anyone has any objections, please let me know.

------------------

From: "David S. Miller" <davem@xxxxxxxxxxxxx>


[ Upstream commit 0096ac9f47b1a2e851b3165d44065d18e5f13d58 ]

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@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/sparc/lib/copy_in_user.S | 35 +++++++++++++++++++++++++----------
1 file changed, 25 insertions(+), 10 deletions(-)

--- a/arch/sparc/lib/copy_in_user.S
+++ b/arch/sparc/lib/copy_in_user.S
@@ -8,18 +8,33 @@

#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
@@ -44,8 +59,8 @@ ENTRY(___copy_in_user) /* %o0=dst, %o1=s
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
@@ -53,8 +68,8 @@ ENTRY(___copy_in_user) /* %o0=dst, %o1=s
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
@@ -70,8 +85,8 @@ ENTRY(___copy_in_user) /* %o0=dst, %o1=s

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
@@ -82,8 +97,8 @@ ENTRY(___copy_in_user) /* %o0=dst, %o1=s
.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