From: Aurelien Jarno <aurelien@xxxxxxxxxxx> commit 79b4a9cf0e2ea8203ce777c8d5cfa86c71eae86e upstream. Commit 4c21b8fd8f14 (MIPS: seccomp: Handle indirect system calls (o32)) added indirect syscall detection for O32 processes running on MIPS64, but it did not work correctly for big endian kernel/processes. The reason is that the syscall number is loaded from ARG1 using the lw instruction while this is a 64-bit value, so zero is loaded instead of the syscall number. Fix the code by using the ld instruction instead. When running a 32-bit processes on a 64 bit CPU, the values are properly sign-extended, so it ensures the value passed to syscall_trace_enter is correct. Recent systemd versions with seccomp enabled whitelist the getpid syscall for their internal processes (e.g. systemd-journald), but call it through syscall(SYS_getpid). This fix therefore allows O32 big endian systems with a 64-bit kernel to run recent systemd versions. Signed-off-by: Aurelien Jarno <aurelien@xxxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> # v3.15+ Reviewed-by: Philippe Mathieu-Daudé <f4bug@xxxxxxxxx> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx> Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx> Cc: James Hogan <jhogan@xxxxxxxxxx> Cc: linux-mips@xxxxxxxxxxxxxxx Cc: linux-kernel@xxxxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/mips/kernel/scall64-o32.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/mips/kernel/scall64-o32.S +++ b/arch/mips/kernel/scall64-o32.S @@ -125,7 +125,7 @@ trace_a_syscall: subu t1, v0, __NR_O32_Linux move a1, v0 bnez t1, 1f /* __NR_syscall at offset 0 */ - lw a1, PT_R4(sp) /* Arg1 for __NR_syscall case */ + ld a1, PT_R4(sp) /* Arg1 for __NR_syscall case */ .set pop 1: jal syscall_trace_enter
