From: Jeff Dike <jdike@addtoit.com>
From: Bodo Stroesser <bstroesser@fujitsu-siemens.com>
This implements checking for the new ptrace option SYSEMU_SINGLESTEP
(advanced sysemu) and allows the values 0,1,2 for /proc/sysemu,
if advanced sysemu is available:
0 = don't use sysemu
1 = use sysemu, but don't use advanced sysemu
2 = use sysemu and advanced sysemu
Signed-off-by: Bodo Stroesser <bstroesser@fujitsu-siemens.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/arch/um/include/ptrace_user.h | 3 ++
25-akpm/arch/um/include/sysdep-i386/ptrace.h | 3 ++
25-akpm/arch/um/kernel/process.c | 38 +++++++++++++++++++++++++--
25-akpm/arch/um/kernel/process_kern.c | 6 ++--
4 files changed, 46 insertions(+), 4 deletions(-)
diff -puN arch/um/include/ptrace_user.h~uml-detect-sysemu_singlestep arch/um/include/ptrace_user.h
--- 25/arch/um/include/ptrace_user.h~uml-detect-sysemu_singlestep Fri Dec 3 13:50:42 2004
+++ 25-akpm/arch/um/include/ptrace_user.h Fri Dec 3 13:50:42 2004
@@ -21,6 +21,9 @@ extern void ptrace_pokeuser(unsigned lon
#ifndef PTRACE_SYSEMU
#define PTRACE_SYSEMU 31
#endif
+#ifndef PTRACE_SYSEMU_SINGLESTEP
+#define PTRACE_SYSEMU_SINGLESTEP 32
+#endif
void set_using_sysemu(int value);
int get_using_sysemu(void);
diff -puN arch/um/include/sysdep-i386/ptrace.h~uml-detect-sysemu_singlestep arch/um/include/sysdep-i386/ptrace.h
--- 25/arch/um/include/sysdep-i386/ptrace.h~uml-detect-sysemu_singlestep Fri Dec 3 13:50:42 2004
+++ 25-akpm/arch/um/include/sysdep-i386/ptrace.h Fri Dec 3 13:50:42 2004
@@ -15,6 +15,9 @@
#ifdef UML_CONFIG_MODE_SKAS
#include "ptrace-skas.h"
#endif
+#ifndef PTRACE_SYSEMU_SINGLESTEP
+#define PTRACE_SYSEMU_SINGLESTEP 32
+#endif
#include "choose-mode.h"
diff -puN arch/um/kernel/process.c~uml-detect-sysemu_singlestep arch/um/kernel/process.c
--- 25/arch/um/kernel/process.c~uml-detect-sysemu_singlestep Fri Dec 3 13:50:42 2004
+++ 25-akpm/arch/um/kernel/process.c Fri Dec 3 13:50:42 2004
@@ -241,7 +241,7 @@ __uml_setup("nosysemu", nosysemu_cmd_par
static void __init check_sysemu(void)
{
void *stack;
- int pid, n, status;
+ int pid, syscall, n, status, count=0;
printk("Checking syscall emulation patch for ptrace...");
sysemu_supported = 0;
@@ -269,12 +269,46 @@ static void __init check_sysemu(void)
sysemu_supported = 1;
printk("OK\n");
set_using_sysemu(!force_sysemu_disabled);
+
+ printk("Checking advanced syscall emulation patch for ptrace...");
+ pid = start_ptraced_child(&stack);
+ while(1){
+ count++;
+ if(ptrace(PTRACE_SYSEMU_SINGLESTEP, pid, 0, 0) < 0)
+ goto fail;
+ CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
+ if(n < 0)
+ panic("check_ptrace : wait failed, errno = %d", errno);
+ if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP))
+ panic("check_ptrace : expected (SIGTRAP|SYSCALL_TRAP), "
+ "got status = %d", status);
+
+ syscall = ptrace(PTRACE_PEEKUSER, pid, PT_SYSCALL_NR_OFFSET,
+ 0);
+ if(syscall == __NR_getpid){
+ if (!count)
+ panic("check_ptrace : SYSEMU_SINGLESTEP doesn't singlestep");
+ n = ptrace(PTRACE_POKEUSER, pid, PT_SYSCALL_RET_OFFSET,
+ os_getpid());
+ if(n < 0)
+ panic("check_sysemu : failed to modify system "
+ "call return, errno = %d", errno);
+ break;
+ }
+ }
+ if (stop_ptraced_child(pid, stack, 0, 0) < 0)
+ goto fail_stopped;
+
+ sysemu_supported = 2;
+ printk("OK\n");
+
+ if ( !force_sysemu_disabled )
+ set_using_sysemu(sysemu_supported);
return;
fail:
stop_ptraced_child(pid, stack, 1, 0);
fail_stopped:
- sysemu_supported = 0;
printk("missing\n");
}
diff -puN arch/um/kernel/process_kern.c~uml-detect-sysemu_singlestep arch/um/kernel/process_kern.c
--- 25/arch/um/kernel/process_kern.c~uml-detect-sysemu_singlestep Fri Dec 3 13:50:42 2004
+++ 25-akpm/arch/um/kernel/process_kern.c Fri Dec 3 13:50:42 2004
@@ -404,7 +404,9 @@ int sysemu_supported;
void set_using_sysemu(int value)
{
- atomic_set(&using_sysemu, sysemu_supported && value);
+ if (value > sysemu_supported)
+ return;
+ atomic_set(&using_sysemu, value);
}
int get_using_sysemu(void)
@@ -427,7 +429,7 @@ static int proc_write_sysemu(struct file
if (copy_from_user(tmp, buf, 1))
return -EFAULT;
- if (tmp[0] == '0' || tmp[0] == '1')
+ if (tmp[0] >= '0' && tmp[0] <= '2')
set_using_sysemu(tmp[0] - '0');
return count; /*We use the first char, but pretend to write everything*/
}
_