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.
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* switches, and waiting for our parent to respond.
*/
__sys_trace:
* 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
adr lr, __sys_trace_return // return address
uxtw scno, w0 // syscall number (possibly new)
mov x1, sp // pointer to regs
__sys_trace_return:
str x0, [sp] // save returned x0
__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
return ptrace_request(child, request, addr, data);
}
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)
- 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 scratch register (ip(r12) on AArch32, x7 on AArch64) is
+ * used to denote syscall entry/exit:
+ */
+ regno = (is_compat_task() ? 12 : 7);
+ saved_reg = regs->regs[regno];
+ regs->regs[regno] = dir;
+ if (dir == PTRACE_SYSCALL_EXIT)
tracehook_report_syscall_exit(regs, 0);
else if (tracehook_report_syscall_entry(regs))
regs->syscallno = ~0UL;
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[regno] = 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;
}
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);
+}