[PATCH 3.4 20/27] sparc64: dont treat 64-bit syscall return codes as 32-bit

Greg Kroah-Hartman
2014-04-24T21:53:27Z

From: Dave Kleikamp <dave.kleikamp@oracle.com>

[ Upstream commit 1535bd8adbdedd60a0ee62e28fd5225d66434371 ]

When checking a system call return code for an error,
linux_sparc_syscall was sign-extending the lower 32-bit value and
comparing it to -ERESTART_RESTARTBLOCK. lseek can return valid return
codes whose lower 32-bits alone would indicate a failure (such as 4G-1).
Use the whole 64-bit value to check for errors. Only the 32-bit path
should sign extend the lower 32-bit value.

Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Acked-by: Bob Picco <bob.picco@oracle.com>
Acked-by: Allen Pais <allen.pais@oracle.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: sparclinux@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/sparc/kernel/syscalls.S | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/arch/sparc/kernel/syscalls.S
+++ b/arch/sparc/kernel/syscalls.S
@@ -184,7 +184,8 @@ linux_sparc_syscall32:
mov %i0, %l5 ! IEU1
5: call %l7 ! CTI Group brk forced
srl %i5, 0, %o5 ! IEU1
- ba,a,pt %xcc, 3f
+ ba,pt %xcc, 3f
+ sra %o0, 0, %o0

/* Linux native system calls enter here... */
.align 32
@@ -212,7 +213,6 @@ linux_sparc_syscall:
3: stx %o0, [%sp + PTREGS_OFF + PT_V9_I0]
ret_sys_call:
ldx [%sp + PTREGS_OFF + PT_V9_TSTATE], %g3
- sra %o0, 0, %o0
mov %ulo(TSTATE_XCARRY | TSTATE_ICARRY), %g2
sllx %g2, 32, %g2