[PATCH] sparc64: don't treat 64-bit syscall return codes as 32-bit

[PATCH] sparc64: don't treat 64-bit syscall return codes as 32-bit

[Dave Kleikamp]

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
---
 arch/sparc/kernel/syscalls.S | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/sparc/kernel/syscalls.S b/arch/sparc/kernel/syscalls.S
index 87729ff..33a17e7 100644
--- a/arch/sparc/kernel/syscalls.S
+++ b/arch/sparc/kernel/syscalls.S
@@ -189,7 +189,8 @@ 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
@@ -217,7 +218,6 @@ 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
 
-- 
1.9.0

Re: [PATCH] sparc64: don't treat 64-bit syscall return codes as 32-bit

[David Miller]

From: Dave Kleikamp <dave.kleikamp@oracle.com>
Date: Fri, 14 Mar 2014 10:42:01 -0500

> 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>

Looks good, applied and queued up for -stable, thanks!