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authorAurelien Jarno <aurelien@aurel32.net>2019-04-09 16:53:55 +0200
committerPaul Burton <paul.burton@mips.com>2019-04-15 10:35:12 -0700
commit79b4a9cf0e2ea8203ce777c8d5cfa86c71eae86e (patch)
tree20d389f358cb71e9283186041acf53d92256c508 /arch/mips
parent1bfb97b9a51901103677a4d1a2386d223c15bc71 (diff)
MIPS: scall64-o32: Fix indirect syscall number load
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@aurel32.net> Cc: <stable@vger.kernel.org> # v3.15+ Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <jhogan@kernel.org> Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org
Diffstat (limited to 'arch/mips')
-rw-r--r--arch/mips/kernel/scall64-o32.S2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/mips/kernel/scall64-o32.S b/arch/mips/kernel/scall64-o32.S
index f158c5894a9a..feb2653490df 100644
--- 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