From: Markos Chandras <[email protected]>

This patch has been added to the 3.18 stable tree. If you have any
objections, please let us know.

===============

[ Upstream commit 9f161439e4104b641a7bfb9b89581d801159fec8 ]

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: <[email protected]> # 3.15+
Reviewed-by: James Hogan <[email protected]>
Signed-off-by: Markos Chandras <[email protected]>
Cc: [email protected]
Patchwork: https://patchwork.linux-mips.org/patch/10951/
Signed-off-by: Ralf Baechle <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
---
 arch/mips/kernel/scall64-64.S  | 2 +-
 arch/mips/kernel/scall64-n32.S | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/mips/kernel/scall64-64.S b/arch/mips/kernel/scall64-64.S
index 5251565..a6576cf1 100644
--- 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 77e7439..a8eb657 100644
--- 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
-- 
2.1.4

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