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authorAKASHI Takahiro <takahiro.akashi@linaro.org>2014-04-30 10:51:30 +0100
committerCatalin Marinas <catalin.marinas@arm.com>2014-05-12 16:43:29 +0100
commit3157858feff89196635b01495d5ec9ebe206639e (patch)
treebd480fd2334d69ec10e7fc22befc9b795278ef58 /arch/arm64/kernel/ptrace.c
parent449f81a4da4d99980064943d504bb19d07e86aec (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>
Diffstat (limited to 'arch/arm64/kernel/ptrace.c')
-rw-r--r--arch/arm64/kernel/ptrace.c50
1 files changed, 29 insertions, 21 deletions
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);
+}