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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: Roland McGrath <roland@redhat.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Roland McGrath 2008-07-27 16:51:03 +10:00 committed by Benjamin Herrenschmidt
parent 6558ba2b5c
commit 4f72c4279e
3 changed files with 34 additions and 27 deletions
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7
arch/powerpc/kernel/entry_32.S
View File

@ -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)

7
arch/powerpc/kernel/entry_64.S
View File

@ -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)

47
arch/powerpc/kernel/ptrace.c
View File

@ -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)
/*
* We must return the syscall number to actually look up in the table.
* This can be -1L to skip running any syscall at all.
*/
long do_syscall_trace_enter(struct pt_regs *regs)
{
/* 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));
long ret = 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
*/
if (current->exit_code) {
send_sig(current->exit_code, current, 1);
current->exit_code = 0;
}
}
void do_syscall_trace_enter(struct pt_regs *regs)
{
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);
}