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Commit 4f72c427 authored by Roland McGrath's avatar Roland McGrath Committed by Benjamin Herrenschmidt
Browse files

powerpc: Make syscall tracing use tracehook.h helpers 



This changes powerpc syscall tracing to use the new tracehook.h entry
points.  There is no change, only cleanup.

In addition, the assembly changes allow do_syscall_trace_enter() to
abort the syscall without losing the information about the original
r0 value.

Signed-off-by: default avatarRoland McGrath <roland@redhat.com>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 6558ba2b

arch/powerpc/kernel/entry_32.S

+6 −1
Original line number Diff line number Diff line
@@ -343,7 +343,12 @@ syscall_dotrace: 
	stw	r0,_TRAP(r1)

	addi	r3,r1,STACK_FRAME_OVERHEAD

	bl	do_syscall_trace_enter

	lwz	r0,GPR0(r1)	/* Restore original registers */

	/*

	 * Restore argument registers possibly just changed.

	 * We use the return value of do_syscall_trace_enter

	 * for call number to look up in the table (r0).

	 */

	mr	r0,r3

	lwz	r3,GPR3(r1)

	lwz	r4,GPR4(r1)

	lwz	r5,GPR5(r1)

arch/powerpc/kernel/entry_64.S

+6 −1
Original line number Diff line number Diff line
@@ -214,7 +214,12 @@ syscall_dotrace: 
	bl	.save_nvgprs

	addi	r3,r1,STACK_FRAME_OVERHEAD

	bl	.do_syscall_trace_enter

	ld	r0,GPR0(r1)	/* Restore original registers */

	/*

	 * Restore argument registers possibly just changed.

	 * We use the return value of do_syscall_trace_enter

	 * for the call number to look up in the table (r0).

	 */

	mr	r0,r3

	ld	r3,GPR3(r1)

	ld	r4,GPR4(r1)

	ld	r5,GPR5(r1)

arch/powerpc/kernel/ptrace.c

+22 −25
Original line number Diff line number Diff line
@@ -22,6 +22,7 @@ 
#include <linux/errno.h>

#include <linux/ptrace.h>

#include <linux/regset.h>

#include <linux/tracehook.h>

#include <linux/elf.h>

#include <linux/user.h>

#include <linux/security.h>
@@ -1014,31 +1015,24 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data) 
	return ret;

}



static void do_syscall_trace(void)

{

	/* the 0x80 provides a way for the tracing parent to distinguish

	   between a syscall stop and SIGTRAP delivery */

	ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)

				 ? 0x80 : 0));



/*

	 * this isn't the same as continuing with a signal, but it will do

	 * for normal use.  strace only continues with a signal if the

	 * stopping signal is not SIGTRAP.  -brl

 * We must return the syscall number to actually look up in the table.

 * This can be -1L to skip running any syscall at all.

 */

	if (current->exit_code) {

		send_sig(current->exit_code, current, 1);

		current->exit_code = 0;

	}

}



void do_syscall_trace_enter(struct pt_regs *regs)

long do_syscall_trace_enter(struct pt_regs *regs)

{

	long ret = 0;



	secure_computing(regs->gpr[0]);



	if (test_thread_flag(TIF_SYSCALL_TRACE)

	    && (current->ptrace & PT_PTRACED))

		do_syscall_trace();

	if (test_thread_flag(TIF_SYSCALL_TRACE) &&

	    tracehook_report_syscall_entry(regs))

		/*

		 * Tracing decided this syscall should not happen.

		 * We'll return a bogus call number to get an ENOSYS

		 * error, but leave the original number in regs->gpr[0].

		 */

		ret = -1L;



	if (unlikely(current->audit_context)) {

#ifdef CONFIG_PPC64
@@ -1056,16 +1050,19 @@ void do_syscall_trace_enter(struct pt_regs *regs) 
					    regs->gpr[5] & 0xffffffff,

					    regs->gpr[6] & 0xffffffff);

	}



	return ret ?: regs->gpr[0];

}



void do_syscall_trace_leave(struct pt_regs *regs)

{

	int step;



	if (unlikely(current->audit_context))

		audit_syscall_exit((regs->ccr&0x10000000)?AUDITSC_FAILURE:AUDITSC_SUCCESS,

				   regs->result);



	if ((test_thread_flag(TIF_SYSCALL_TRACE)

	     || test_thread_flag(TIF_SINGLESTEP))

	    && (current->ptrace & PT_PTRACED))

		do_syscall_trace();

	step = test_thread_flag(TIF_SINGLESTEP);

	if (step || test_thread_flag(TIF_SYSCALL_TRACE))

		tracehook_report_syscall_exit(regs, step);

}