| Message ID | 1394861948-28712-3-git-send-email-takahiro.akashi@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 14/03/15, AKASHI Takahiro wrote: > As done in arm, this change makes it easy to confirm we invoke syscall > related hooks, including syscall tracepoint, audit and seccomp which would > be implemented later, in correct order. That is, undoing operations in the > opposite order on exit that they were done on entry. > > Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> Minor variable mis-spelling of "scratch" noted below, but other than that: Acked-by: Richard Guy Briggs <rgb@redhat.com> > --- > arch/arm64/kernel/entry.S | 10 ++++------ > arch/arm64/kernel/ptrace.c | 50 +++++++++++++++++++++++++++------------------- > 2 files changed, 33 insertions(+), 27 deletions(-) > > diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S > index f9f2cae..00d6eb9 100644 > --- a/arch/arm64/kernel/entry.S > +++ b/arch/arm64/kernel/entry.S > @@ -649,9 +649,8 @@ ENDPROC(el0_svc) > * switches, and waiting for our parent to respond. > */ > __sys_trace: > - mov x1, sp > - mov w0, #0 // trace entry > - bl syscall_trace > + mov x0, sp > + bl syscall_trace_enter > adr lr, __sys_trace_return // return address > uxtw scno, w0 // syscall number (possibly new) > mov x1, sp // pointer to regs > @@ -666,9 +665,8 @@ __sys_trace: > > __sys_trace_return: > str x0, [sp] // save returned x0 > - mov x1, sp > - mov w0, #1 // trace exit > - bl syscall_trace > + mov x0, sp > + bl syscall_trace_exit > b ret_to_user > > /* > diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c > index 6a8928b..f606276 100644 > --- a/arch/arm64/kernel/ptrace.c > +++ b/arch/arm64/kernel/ptrace.c > @@ -1058,35 +1058,43 @@ long arch_ptrace(struct task_struct *child, long request, > return ptrace_request(child, request, addr, data); > } > > -asmlinkage int syscall_trace(int dir, struct pt_regs *regs) > +enum ptrace_syscall_dir { > + PTRACE_SYSCALL_ENTER = 0, > + PTRACE_SYSCALL_EXIT, > +}; > + > +static void tracehook_report_syscall(struct pt_regs *regs, > + enum ptrace_syscall_dir dir) > { > + int scrach; "scratch" > 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; > - } > + /* > + * A scrach register (ip(r12) on AArch32, x7 on AArch64) is > + * used to denote syscall entry/exit: > + */ > + scrach = (is_compat_task() ? 12 : 7); > + saved_reg = regs->regs[scrach]; > + regs->regs[scrach] = dir; > > - if (dir) > + if (dir == PTRACE_SYSCALL_EXIT) > 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; > + regs->regs[scrach] = saved_reg; > +} > + > +asmlinkage int syscall_trace_enter(struct pt_regs *regs) > +{ > + if (test_thread_flag(TIF_SYSCALL_TRACE)) > + tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER); > > return regs->syscallno; > } > + > +asmlinkage void syscall_trace_exit(struct pt_regs *regs) > +{ > + if (test_thread_flag(TIF_SYSCALL_TRACE)) > + tracehook_report_syscall(regs, PTRACE_SYSCALL_EXIT); > +} > -- > 1.8.3.2 - RGB -- Richard Guy Briggs <rbriggs@redhat.com> Senior Software Engineer, Kernel Security, AMER ENG Base Operating Systems, Red Hat Remote, Ottawa, Canada Voice: +1.647.777.2635, Internal: (81) 32635, Alt: +1.613.693.0684x3545
Hi Akashi, On Sat, Mar 15, 2014 at 05:39:06AM +0000, AKASHI Takahiro wrote: > As done in arm, this change makes it easy to confirm we invoke syscall > related hooks, including syscall tracepoint, audit and seccomp which would > be implemented later, in correct order. That is, undoing operations in the > opposite order on exit that they were done on entry. > > Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> [...] > +static void tracehook_report_syscall(struct pt_regs *regs, > + enum ptrace_syscall_dir dir) > { > + int scrach; s/scrach/scratch/ Although, I'd rather have a variable with a more meaningful name. How about regno? With that, Acked-by: Will Deacon <will.deacon@arm.com> Cheers, Will
On 04/16/2014 10:27 PM, Will Deacon wrote: > Hi Akashi, > > On Sat, Mar 15, 2014 at 05:39:06AM +0000, AKASHI Takahiro wrote: >> As done in arm, this change makes it easy to confirm we invoke syscall >> related hooks, including syscall tracepoint, audit and seccomp which would >> be implemented later, in correct order. That is, undoing operations in the >> opposite order on exit that they were done on entry. >> >> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> > > [...] > >> +static void tracehook_report_syscall(struct pt_regs *regs, >> + enum ptrace_syscall_dir dir) >> { >> + int scrach; > > s/scrach/scratch/ I will fix it. > Although, I'd rather have a variable with a more meaningful name. How about > regno? OK, I will use regno in the next revision, which I will submit soon. > With that, > > Acked-by: Will Deacon <will.deacon@arm.com> Thank you so much, -Takahiro AKASHI > Cheers, > > Will >
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index f9f2cae..00d6eb9 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -649,9 +649,8 @@ ENDPROC(el0_svc) * switches, and waiting for our parent to respond. */ __sys_trace: - mov x1, sp - mov w0, #0 // trace entry - bl syscall_trace + mov x0, sp + bl syscall_trace_enter adr lr, __sys_trace_return // return address uxtw scno, w0 // syscall number (possibly new) mov x1, sp // pointer to regs @@ -666,9 +665,8 @@ __sys_trace: __sys_trace_return: str x0, [sp] // save returned x0 - mov x1, sp - mov w0, #1 // trace exit - bl syscall_trace + mov x0, sp + bl syscall_trace_exit b ret_to_user /* diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index 6a8928b..f606276 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -1058,35 +1058,43 @@ long arch_ptrace(struct task_struct *child, long request, return ptrace_request(child, request, addr, data); } -asmlinkage int syscall_trace(int dir, struct pt_regs *regs) +enum ptrace_syscall_dir { + PTRACE_SYSCALL_ENTER = 0, + PTRACE_SYSCALL_EXIT, +}; + +static void tracehook_report_syscall(struct pt_regs *regs, + enum ptrace_syscall_dir dir) { + int scrach; 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; - } + /* + * A scrach register (ip(r12) on AArch32, x7 on AArch64) is + * used to denote syscall entry/exit: + */ + scrach = (is_compat_task() ? 12 : 7); + saved_reg = regs->regs[scrach]; + regs->regs[scrach] = dir; - if (dir) + if (dir == PTRACE_SYSCALL_EXIT) 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; + regs->regs[scrach] = saved_reg; +} + +asmlinkage int syscall_trace_enter(struct pt_regs *regs) +{ + if (test_thread_flag(TIF_SYSCALL_TRACE)) + tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER); return regs->syscallno; } + +asmlinkage void syscall_trace_exit(struct pt_regs *regs) +{ + if (test_thread_flag(TIF_SYSCALL_TRACE)) + tracehook_report_syscall(regs, PTRACE_SYSCALL_EXIT); +}
As done in arm, this change makes it easy to confirm we invoke syscall related hooks, including syscall tracepoint, audit and seccomp which would be implemented later, in correct order. That is, undoing operations in the opposite order on exit that they were done on entry. Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> --- arch/arm64/kernel/entry.S | 10 ++++------ arch/arm64/kernel/ptrace.c | 50 +++++++++++++++++++++++++++------------------- 2 files changed, 33 insertions(+), 27 deletions(-)