MIPS: Fix seccomp syscall argument for MIPS64

Commit 4c21b8fd8f14 ("MIPS: seccomp: Handle indirect system calls (o32)")
fixed indirect system calls on O32 but it also introduced a bug for MIPS64
where it erroneously modified the v0 (syscall) register with the assumption
that the sycall offset hasn't been taken into consideration. This breaks
seccomp on MIPS64 n64 and n32 ABIs. We fix this by replacing the addition
with a move instruction.

Fixes: 4c21b8fd8f14 ("MIPS: seccomp: Handle indirect system calls (o32)")
Cc: <stable@vger.kernel.org> # 3.15+
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10951/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --git a/arch/mips/kernel/scall64-64.S b/arch/mips/kernel/scall64-64.S
index ad4d446..a6f6b76 100644 (file)
--- a/arch/mips/kernel/scall64-64.S
+++ b/arch/mips/kernel/scall64-64.S
@@ -80,7 +80,7 @@ syscall_trace_entry:
        SAVE_STATIC
        move    s0, t2
        move    a0, sp
-       daddiu  a1, v0, __NR_64_Linux
+       move    a1, v0
        jal     syscall_trace_enter
 
        bltz    v0, 2f                  # seccomp failed? Skip syscall

diff --git a/arch/mips/kernel/scall64-n32.S b/arch/mips/kernel/scall64-n32.S
index 446cc65..4b20106 100644 (file)
--- a/arch/mips/kernel/scall64-n32.S
+++ b/arch/mips/kernel/scall64-n32.S
@@ -72,7 +72,7 @@ n32_syscall_trace_entry:
        SAVE_STATIC
        move    s0, t2
        move    a0, sp
-       daddiu  a1, v0, __NR_N32_Linux
+       move    a1, v0
        jal     syscall_trace_enter
 
        bltz    v0, 2f                  # seccomp failed? Skip syscall