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powerpc: Make syscall tracing use tracehook.h helpers

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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);
}