From ad722541147e6e517a2077e3d944105e7bc4fa8e Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Fri, 6 Jul 2012 15:50:14 +0100 Subject: ARM: 7456/1: ptrace: provide separate functions for tracing syscall {entry,exit} The syscall_trace on ARM takes a `why' parameter to indicate whether or not we are entering or exiting a system call. This can be confusing for people looking at the code since (a) it conflicts with the why register alias in the entry assembly code and (b) it is not immediately clear what it represents. This patch splits up the syscall_trace function into separate wrappers for syscall entry and exit, allowing the low-level syscall handling code to branch to the appropriate function. Reported-by: Al Viro Reviewed-by: Catalin Marinas Signed-off-by: Will Deacon Signed-off-by: Russell King --- arch/arm/kernel/entry-common.S | 14 ++++++-------- arch/arm/kernel/ptrace.c | 37 +++++++++++++++++++++++++------------ 2 files changed, 31 insertions(+), 20 deletions(-) (limited to 'arch') diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S index 10911c9..49d9f93 100644 --- a/arch/arm/kernel/entry-common.S +++ b/arch/arm/kernel/entry-common.S @@ -442,10 +442,9 @@ ENDPROC(vector_swi) * context switches, and waiting for our parent to respond. */ __sys_trace: - mov r2, scno - add r1, sp, #S_OFF - mov r0, #0 @ trace entry [IP = 0] - bl syscall_trace + mov r1, scno + add r0, sp, #S_OFF + bl syscall_trace_enter adr lr, BSYM(__sys_trace_return) @ return address mov scno, r0 @ syscall number (possibly new) @@ -457,10 +456,9 @@ __sys_trace: __sys_trace_return: str r0, [sp, #S_R0 + S_OFF]! @ save returned r0 - mov r2, scno - mov r1, sp - mov r0, #1 @ trace exit [IP = 1] - bl syscall_trace + mov r1, scno + mov r0, sp + bl syscall_trace_exit b ret_slow_syscall .align 5 diff --git a/arch/arm/kernel/ptrace.c b/arch/arm/kernel/ptrace.c index 592a39d..dab711e 100644 --- a/arch/arm/kernel/ptrace.c +++ b/arch/arm/kernel/ptrace.c @@ -907,12 +907,18 @@ long arch_ptrace(struct task_struct *child, long request, return ret; } -asmlinkage int syscall_trace(int why, struct pt_regs *regs, int scno) +enum ptrace_syscall_dir { + PTRACE_SYSCALL_ENTER = 0, + PTRACE_SYSCALL_EXIT, +}; + +static int ptrace_syscall_trace(struct pt_regs *regs, int scno, + enum ptrace_syscall_dir dir) { unsigned long ip; if (!test_thread_flag(TIF_SYSCALL_TRACE)) - goto out_no_trace; + return scno; current_thread_info()->syscall = scno; @@ -921,21 +927,28 @@ asmlinkage int syscall_trace(int why, struct pt_regs *regs, int scno) * IP = 0 -> entry, =1 -> exit */ ip = regs->ARM_ip; - regs->ARM_ip = why; + regs->ARM_ip = dir; - if (why) + if (dir == PTRACE_SYSCALL_EXIT) tracehook_report_syscall_exit(regs, 0); else if (tracehook_report_syscall_entry(regs)) current_thread_info()->syscall = -1; regs->ARM_ip = ip; - scno = current_thread_info()->syscall; + return current_thread_info()->syscall; +} -out_no_trace: - if (why) - audit_syscall_exit(regs); - else - audit_syscall_entry(AUDIT_ARCH_ARM, scno, regs->ARM_r0, - regs->ARM_r1, regs->ARM_r2, regs->ARM_r3); - return scno; +asmlinkage int syscall_trace_enter(struct pt_regs *regs, int scno) +{ + int ret = ptrace_syscall_trace(regs, scno, PTRACE_SYSCALL_ENTER); + audit_syscall_entry(AUDIT_ARCH_ARM, scno, regs->ARM_r0, regs->ARM_r1, + regs->ARM_r2, regs->ARM_r3); + return ret; +} + +asmlinkage int syscall_trace_exit(struct pt_regs *regs, int scno) +{ + int ret = ptrace_syscall_trace(regs, scno, PTRACE_SYSCALL_EXIT); + audit_syscall_exit(regs); + return ret; } -- cgit v1.1