diff options
| author | Kees Cook <keescook@chromium.org> | 2012-11-15 22:12:17 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2012-11-19 15:14:18 +0100 |
| commit | ad75b51459ae076a0d406391496f81b897bf6992 (patch) | |
| tree | c34449b78cd833c2506237eb09d8cd291a2b63c3 | |
| parent | ARM: 7578/1: arch/move secure_computing into trace (diff) | |
| download | linux-ad75b51459ae076a0d406391496f81b897bf6992.tar.xz linux-ad75b51459ae076a0d406391496f81b897bf6992.zip | |
ARM: 7579/1: arch/allow a scno of -1 to not cause a SIGILL
On tracehook-friendly platforms, a system call number of -1 falls
through without running much code or taking much action.
ARM is different. This adds a short-circuit check in the trace path to
avoid any additional work, as suggested by Russell King, to make sure
that ARM behaves the same way as other platforms.
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Will Drewry <wad@chromium.org>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
| -rw-r--r-- | arch/arm/kernel/entry-common.S | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S index b621871dd277..ee81dbc6fa10 100644 --- a/arch/arm/kernel/entry-common.S +++ b/arch/arm/kernel/entry-common.S @@ -448,7 +448,10 @@ __sys_trace: ldmccia r1, {r0 - r6} @ have to reload r0 - r6 stmccia sp, {r4, r5} @ and update the stack args ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine - b 2b + cmp scno, #-1 @ skip the syscall? + bne 2b + add sp, sp, #S_OFF @ restore stack + b ret_slow_syscall __sys_trace_return: str r0, [sp, #S_R0 + S_OFF]! @ save returned r0 |