| Message ID | 1393319683-2707-2-git-send-email-takahiro.akashi@linaro.org |
|---|---|
| State | New |
| Headers | show |
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.akashi@linaro.org> >> Acked-by: Richard Guy Briggs <rgb@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. -Takahiro AKASHI > Will > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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.akashi@linaro.org> >>>> Acked-by: Richard Guy Briggs <rgb@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 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h index 720e70b..0a8b2a9 100644 --- a/arch/arm64/include/asm/thread_info.h +++ b/arch/arm64/include/asm/thread_info.h @@ -91,6 +91,9 @@ static inline struct thread_info *current_thread_info(void) /* * thread information flags: * TIF_SYSCALL_TRACE - syscall trace active + * TIF_SYSCALL_TRACEPOINT - syscall tracepoint for ftrace + * TIF_SYSCALL_AUDIT - syscall auditing + * TIF_SECOMP - syscall secure computing * TIF_SIGPENDING - signal pending * TIF_NEED_RESCHED - rescheduling necessary * TIF_NOTIFY_RESUME - callback before returning to user @@ -101,6 +104,9 @@ static inline struct thread_info *current_thread_info(void) #define TIF_NEED_RESCHED 1 #define TIF_NOTIFY_RESUME 2 /* callback before returning to user */ #define TIF_SYSCALL_TRACE 8 +#define TIF_SYSCALL_AUDIT 9 +#define TIF_SYSCALL_TRACEPOINT 10 +#define TIF_SECCOMP 11 #define TIF_POLLING_NRFLAG 16 #define TIF_MEMDIE 18 /* is terminating due to OOM killer */ #define TIF_FREEZE 19 @@ -112,10 +118,17 @@ static inline struct thread_info *current_thread_info(void) #define _TIF_SIGPENDING (1 << TIF_SIGPENDING) #define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED) #define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME) +#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE) +#define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT) +#define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT) +#define _TIF_SECCOMP (1 << TIF_SECCOMP) #define _TIF_32BIT (1 << TIF_32BIT) #define _TIF_WORK_MASK (_TIF_NEED_RESCHED | _TIF_SIGPENDING | \ _TIF_NOTIFY_RESUME) +#define _TIF_SYSCALL_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \ + _TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP) + #endif /* __KERNEL__ */ #endif /* __ASM_THREAD_INFO_H */ diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 0d7b789..6d613cd 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -630,8 +630,9 @@ el0_svc_naked: // compat entry point enable_irq get_thread_info tsk - ldr x16, [tsk, #TI_FLAGS] // check for syscall tracing - tbnz x16, #TIF_SYSCALL_TRACE, __sys_trace // are we tracing syscalls? + ldr x16, [tsk, #TI_FLAGS] // check for syscall hooks + tst x16, #_TIF_SYSCALL_WORK + b.ne __sys_trace adr lr, ret_fast_syscall // return address cmp scno, sc_nr // check upper syscall limit b.hs ni_sys 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; + } return regs->syscallno; }