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authorAKASHI Takahiro <takahiro.akashi@linaro.org>2014-04-30 10:51:30 +0100
committerAlex Shi <alex.shi@linaro.org>2014-06-04 17:50:43 +0800
commit25a36250f5bfe884334e8ce36315eaddd96ecb68 (patch)
tree330ad74c2d740be56a00f9cb98d6774289bc4578
parenta9cc77e2cdf373dc5a5eb9c44cfeb64f1dba36cb (diff)
arm64: split syscall_trace() into separate functions for enter/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. 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> (cherry picked from commit 3157858feff89196635b01495d5ec9ebe206639e) Signed-off-by: Alex Shi <alex.shi@linaro.org>
-rw-r--r--arch/arm64/kernel/entry.S10
-rw-r--r--arch/arm64/kernel/ptrace.c50
2 files changed, 33 insertions, 27 deletions
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index f9f2caefeecb..00d6eb98f8df 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 6a8928bba03c..6d666dc1cea6 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 regno;
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 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)
+ 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[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;
}
+
+asmlinkage void syscall_trace_exit(struct pt_regs *regs)
+{
+ if (test_thread_flag(TIF_SYSCALL_TRACE))
+ tracehook_report_syscall(regs, PTRACE_SYSCALL_EXIT);
+}