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[PATCH] Uml support: add PTRACE_SYSEMU_SINGLESTEP option to i386

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This patch implements the new ptrace option PTRACE_SYSEMU_SINGLESTEP, which
can be used by UML to singlestep a process: it will receive SINGLESTEP
interceptions for normal instructions and syscalls, but syscall execution will
be skipped just like with PTRACE_SYSEMU.

Signed-off-by: Bodo Stroesser <bstroesser@fujitsu-siemens.com>
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Bodo Stroesser 2005-09-03 15:57:20 -07:00 committed by Linus Torvalds
parent c8c86cecd1
commit 1b38f0064e
2 changed files with 18 additions and 4 deletions
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21
arch/i386/kernel/ptrace.c
View File

@ -547,11 +547,17 @@ asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
wake_up_process(child);
break;
case PTRACE_SYSEMU_SINGLESTEP: /* Same as SYSEMU, but singlestep if not syscall */
case PTRACE_SINGLESTEP: /* set the trap flag. */
ret = -EIO;
if (!valid_signal(data))
break;
clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
if (request == PTRACE_SYSEMU_SINGLESTEP)
set_tsk_thread_flag(child, TIF_SYSCALL_EMU);
else
clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
set_singlestep(child);
child->exit_code = data;
@ -686,7 +692,10 @@ void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs, int error_code)
__attribute__((regparm(3)))
int do_syscall_trace(struct pt_regs *regs, int entryexit)
{
int is_sysemu, is_singlestep, ret = 0;
int is_sysemu = test_thread_flag(TIF_SYSCALL_EMU), ret = 0;
/* With TIF_SYSCALL_EMU set we want to ignore TIF_SINGLESTEP */
int is_singlestep = !is_sysemu && test_thread_flag(TIF_SINGLESTEP);
/* do the secure computing check first */
secure_computing(regs->orig_eax);
@ -696,8 +705,11 @@ int do_syscall_trace(struct pt_regs *regs, int entryexit)
if (!(current->ptrace & PT_PTRACED))
goto out;
is_sysemu = test_thread_flag(TIF_SYSCALL_EMU);
is_singlestep = test_thread_flag(TIF_SINGLESTEP);
/* If a process stops on the 1st tracepoint with SYSCALL_TRACE
* and then is resumed with SYSEMU_SINGLESTEP, it will come in
* here. We have to check this and return */
if (is_sysemu && entryexit)
return 0;
/* Fake a debug trap */
if (is_singlestep)
@ -728,6 +740,7 @@ int do_syscall_trace(struct pt_regs *regs, int entryexit)
if (ret == 0)
return 0;
regs->orig_eax = -1; /* force skip of syscall restarting */
if (unlikely(current->audit_context))
audit_syscall_exit(current, AUDITSC_RESULT(regs->eax), regs->eax);
return 1;

1
include/linux/ptrace.h
View File

@ -21,6 +21,7 @@
#define PTRACE_SYSCALL 24
#define PTRACE_SYSEMU 31
#define PTRACE_SYSEMU_SINGLESTEP 32
/* 0x4200-0x4300 are reserved for architecture-independent additions. */
#define PTRACE_SETOPTIONS 0x4200