On 02/26/2014 08:25 PM, Will Deacon wrote:
On Wed, Feb 26, 2014 at 02:00:19AM +0000, AKASHI Takahiro wrote:
On 02/26/2014 12:00 AM, Will Deacon wrote:
On Tue, Feb 25, 2014 at 09:14:43AM +0000, AKASHI Takahiro wrote:
Currently syscall_trace() is called only for ptrace.
With additional TIF_xx flags defined, it is now called in all the cases
of audit, ftrace and seccomp in addition to ptrace.
Signed-off-by: AKASHI Takahiro <takahiro.aka...@linaro.org>
Acked-by: Richard Guy Briggs <r...@redhat.com>
---
arch/arm64/include/asm/thread_info.h | 13 ++++++++++
arch/arm64/kernel/entry.S | 5 ++--
arch/arm64/kernel/ptrace.c | 45
+++++++++++++++++-----------------
3 files changed, 38 insertions(+), 25 deletions(-)
[...]
diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index 6a8928b..c70133e 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -1062,31 +1062,30 @@ asmlinkage int syscall_trace(int dir, struct pt_regs
*regs)
{
unsigned long saved_reg;
- if (!test_thread_flag(TIF_SYSCALL_TRACE))
- return regs->syscallno;
-
- if (is_compat_task()) {
- /* AArch32 uses ip (r12) for scratch */
- saved_reg = regs->regs[12];
- regs->regs[12] = dir;
- } else {
- /*
- * Save X7. X7 is used to denote syscall entry/exit:
- * X7 = 0 -> entry, = 1 -> exit
- */
- saved_reg = regs->regs[7];
- regs->regs[7] = dir;
- }
+ if (test_thread_flag(TIF_SYSCALL_TRACE)) {
+ if (is_compat_task()) {
+ /* AArch32 uses ip (r12) for scratch */
+ saved_reg = regs->regs[12];
+ regs->regs[12] = dir;
+ } else {
+ /*
+ * Save X7. X7 is used to denote syscall entry/exit:
+ * X7 = 0 -> entry, = 1 -> exit
+ */
+ saved_reg = regs->regs[7];
+ regs->regs[7] = dir;
+ }
- if (dir)
- tracehook_report_syscall_exit(regs, 0);
- else if (tracehook_report_syscall_entry(regs))
- regs->syscallno = ~0UL;
+ if (dir)
+ tracehook_report_syscall_exit(regs, 0);
+ else if (tracehook_report_syscall_entry(regs))
+ regs->syscallno = ~0UL;
- if (is_compat_task())
- regs->regs[12] = saved_reg;
- else
- regs->regs[7] = saved_reg;
+ if (is_compat_task())
+ regs->regs[12] = saved_reg;
+ else
+ regs->regs[7] = saved_reg;
+ }
Aren't these changes (to ptrace.c) just a giant NOP?
Umm, the purpose of this big "if" is to run the code only if TIF_SYSCALL_TRACE
is set,
and to make it easy to add additional hooks, audit and ftrace, around
tracehook_report_*()
later on.
The existing code already checks TIF_SYSCALL_TRACE. I'd rather you added
this new code when it's actually nedded (e.g. when adding audit on top).
* This patch is required only if you really merge my audit and/or ftrace patch.
* Putting these changes in audit patch would impose an extra (unnecessary)
dependency on ftrace patch.
* Putting them both in audit and ftrace patch would cause a conflict when
applying both patches.
Even so, since I don't bother you on this minor issue, I will follow your
comment and make changes on:
* arm64: make a single hook to syscall_trace() for all syscall features
* arm64: Add audit support
* arm64: Add ftrace support
-Takahiro AKASHI
Will
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