MIPS: Octeon: Implement Octeon specific __copy_user_inatomic
The generic version seems to prefetch past the end of memory.
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/3929/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/cavium-octeon/octeon-memcpy.S b/arch/mips/cavium-octeon/octeon-memcpy.S
index 88e0cdd..db478db 100644
--- a/arch/mips/cavium-octeon/octeon-memcpy.S
+++ b/arch/mips/cavium-octeon/octeon-memcpy.S
@@ -164,6 +164,14 @@
.set noat
/*
+ * t7 is used as a flag to note inatomic mode.
+ */
+LEAF(__copy_user_inatomic)
+ b __copy_user_common
+ li t7, 1
+ END(__copy_user_inatomic)
+
+/*
* A combined memcpy/__copy_user
* __copy_user sets len to 0 for success; else to an upper bound of
* the number of uncopied bytes.
@@ -174,6 +182,8 @@
move v0, dst /* return value */
__memcpy:
FEXPORT(__copy_user)
+ li t7, 0 /* not inatomic */
+__copy_user_common:
/*
* Note: dst & src may be unaligned, len may be 0
* Temps
@@ -412,7 +422,6 @@
* Assumes src < THREAD_BUADDR($28)
*/
LOAD t0, TI_TASK($28)
- nop
LOAD t0, THREAD_BUADDR(t0)
1:
EXC( lb t1, 0(src), l_exc)
@@ -422,10 +431,9 @@
ADD dst, dst, 1
l_exc:
LOAD t0, TI_TASK($28)
- nop
LOAD t0, THREAD_BUADDR(t0) # t0 is just past last good address
- nop
SUB len, AT, t0 # len number of uncopied bytes
+ bnez t7, 2f /* Skip the zeroing out part if inatomic */
/*
* Here's where we rely on src and dst being incremented in tandem,
* See (3) above.
@@ -443,7 +451,7 @@
ADD dst, dst, 1
bnez src, 1b
SUB src, src, 1
- jr ra
+2: jr ra
nop