diff options
authorPavel Tatashin <>2017-12-13 01:10:12 +0000
committerJohannes Weiner <>2017-12-13 01:10:12 +0000
commit79b618146c99e1e71486978ba806fc58fa6bc6d4 (patch)
parentebab467c6abdfcbe4aed90856225fcf0c775d529 (diff)
sparc64: NG4 memset 32 bits overflow
Early in boot Linux patches memset and memcpy to branch to platform optimized versions of these routines. The NG4 (Niagra 4) versions are currently used on all platforms starting from T4. Recently, there were M7 optimized routines added into UEK4 but not into mainline yet. So, even with M7 optimized routines NG4 are still going to be used on T4, T5, M5, and M6 processors. While investigating how to improve initialization time of dentry_hashtable which is 8G long on M6 ldom with 7T of main memory, I noticed that memset() does not reset all the memory in this array, after studying the code, I realized that NG4memset() branches use %icc register instead of %xcc to check compare, so if value of length is over 32-bit long, which is true for 8G array, these routines fail to work properly. The fix is to replace all %icc with %xcc in these routines. (Alternative is to use %ncc, but this is misleading, as the code already has sparcv9 only instructions, and cannot be compiled on 32-bit). This is important to fix this bug, because even older T4-4 can have 2T of memory, and there are large memory proportional data structures in kernel which can be larger than 4G in size. The failing of memset() is silent and corruption is hard to detect. Link: Signed-off-by: Pavel Tatashin <> Reviewed-by: Babu Moger <> Cc: David Miller <> Cc: Al Viro <> Signed-off-by: Andrew Morton <>
1 files changed, 13 insertions, 13 deletions
diff --git a/arch/sparc/lib/NG4memset.S b/arch/sparc/lib/NG4memset.S
index f81ee5419e2c..d0c4d195fd40 100644
--- a/arch/sparc/lib/NG4memset.S
+++ b/arch/sparc/lib/NG4memset.S
@@ -14,14 +14,14 @@
.globl NG4memset
andcc %o1, 0xff, %o4
- be,pt %icc, 1f
+ be,pt %xcc, 1f
mov %o2, %o1
sllx %o4, 8, %g1
or %g1, %o4, %o2
sllx %o2, 16, %g1
or %g1, %o2, %o2
sllx %o2, 32, %g1
- ba,pt %icc, 1f
+ ba,pt %xcc, 1f
or %g1, %o2, %o4
.size NG4memset,.-NG4memset
@@ -30,7 +30,7 @@ NG4memset:
clr %o4
1: cmp %o1, 16
- ble %icc, .Ltiny
+ ble %xcc, .Ltiny
mov %o0, %o3
sub %g0, %o0, %g1
and %g1, 0x7, %g1
@@ -38,7 +38,7 @@ NG4bzero:
sub %o1, %g1, %o1
1: stb %o4, [%o0 + 0x00]
subcc %g1, 1, %g1
- bne,pt %icc, 1b
+ bne,pt %xcc, 1b
add %o0, 1, %o0
cmp %o1, 64 + (64 - 8)
@@ -49,7 +49,7 @@ NG4bzero:
sub %o1, %g1, %o1
1: stx %o4, [%o0 + 0x00]
subcc %g1, 8, %g1
- bne,pt %icc, 1b
+ bne,pt %xcc, 1b
add %o0, 0x8, %o0
andn %o1, 64 - 1, %g1
@@ -59,30 +59,30 @@ NG4bzero:
1: stxa %o4, [%o0 + %g0] ASI_BLK_INIT_QUAD_LDD_P
subcc %g1, 0x40, %g1
stxa %o4, [%o0 + %g2] ASI_BLK_INIT_QUAD_LDD_P
- bne,pt %icc, 1b
+ bne,pt %xcc, 1b
add %o0, 0x40, %o0
cmp %o1, 8
- bl,pn %icc, .Ltiny
+ bl,pn %xcc, .Ltiny
membar #StoreStore|#StoreLoad
andn %o1, 0x7, %g1
sub %o1, %g1, %o1
1: stx %o4, [%o0 + 0x00]
subcc %g1, 0x8, %g1
- bne,pt %icc, 1b
+ bne,pt %xcc, 1b
add %o0, 0x08, %o0
andcc %o1, 0x4, %g1
- be,pt %icc, .Ltiny
+ be,pt %xcc, .Ltiny
sub %o1, %g1, %o1
stw %o4, [%o0 + 0x00]
add %o0, 0x4, %o0
cmp %o1, 0
- be,pn %icc, .Lexit
+ be,pn %xcc, .Lexit
1: subcc %o1, 1, %o1
stb %o4, [%o0 + 0x00]
- bne,pt %icc, 1b
+ bne,pt %xcc, 1b
add %o0, 1, %o0
@@ -100,8 +100,8 @@ NG4bzero:
stxa %o4, [%o0 + %g2] ASI_BLK_INIT_QUAD_LDD_P
stxa %o4, [%o0 + %g3] ASI_BLK_INIT_QUAD_LDD_P
stxa %o4, [%o0 + %o5] ASI_BLK_INIT_QUAD_LDD_P
- bne,pt %icc, 1b
+ bne,pt %xcc, 1b
add %o0, 0x30, %o0
- ba,a,pt %icc, .Lpostloop
+ ba,a,pt %xcc, .Lpostloop
.size NG4bzero,.-NG4bzero