From: <blaisorblade_spam@yahoo.it>
Adds /proc/sysemu to toggle SYSEMU usage.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade_spam@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/arch/um/kernel/process.c | 4 -
25-akpm/arch/um/kernel/skas/include/ptrace-skas.h | 4 +
25-akpm/arch/um/kernel/skas/process.c | 62 ++++++++++------------
25-akpm/arch/um/kernel/skas/process_kern.c | 59 ++++++++++++++++++++
4 files changed, 93 insertions(+), 36 deletions(-)
diff -puN arch/um/kernel/process.c~uml-adds-proc-sysemu-to-toggle-sysemu-usage arch/um/kernel/process.c
--- 25/arch/um/kernel/process.c~uml-adds-proc-sysemu-to-toggle-sysemu-usage 2004-07-05 16:00:45.667078000 -0700
+++ 25-akpm/arch/um/kernel/process.c 2004-07-05 16:00:45.684075416 -0700
@@ -246,7 +246,7 @@ void __init check_ptrace(void)
printk("OK\n");
printk("Checking syscall emulation patch for ptrace...");
- use_sysemu = 0;
+ set_using_sysemu(0);
pid = start_ptraced_child(&stack);
if(ptrace(PTRACE_SYSEMU, pid, 0, 0) >= 0) {
struct user_regs_struct regs;
@@ -269,7 +269,7 @@ void __init check_ptrace(void)
if (!force_sysemu_disabled) {
printk("found\n");
- use_sysemu = 1;
+ set_using_sysemu(1);
} else {
printk("found but disabled\n");
}
diff -puN arch/um/kernel/skas/include/ptrace-skas.h~uml-adds-proc-sysemu-to-toggle-sysemu-usage arch/um/kernel/skas/include/ptrace-skas.h
--- 25/arch/um/kernel/skas/include/ptrace-skas.h~uml-adds-proc-sysemu-to-toggle-sysemu-usage 2004-07-05 16:00:45.678076328 -0700
+++ 25-akpm/arch/um/kernel/skas/include/ptrace-skas.h 2004-07-05 16:00:45.684075416 -0700
@@ -15,7 +15,9 @@
#ifndef PTRACE_SYSEMU
#define PTRACE_SYSEMU 31
#endif
-extern int use_sysemu;
+
+void set_using_sysemu(int value);
+int get_using_sysemu(void);
#include "skas_ptregs.h"
diff -puN arch/um/kernel/skas/process.c~uml-adds-proc-sysemu-to-toggle-sysemu-usage arch/um/kernel/skas/process.c
--- 25/arch/um/kernel/skas/process.c~uml-adds-proc-sysemu-to-toggle-sysemu-usage 2004-07-05 16:00:45.679076176 -0700
+++ 25-akpm/arch/um/kernel/skas/process.c 2004-07-05 16:00:45.686075112 -0700
@@ -28,10 +28,6 @@
#include "chan_user.h"
#include "signal_user.h"
-#ifdef PTRACE_SYSEMU
-int use_sysemu = 0;
-#endif
-
int is_skas_winch(int pid, int fd, void *data)
{
if(pid != getpid())
@@ -61,7 +57,8 @@ static void handle_segv(int pid)
segv(fault.addr, 0, FAULT_WRITE(fault.is_write), 1, NULL);
}
-static void handle_trap(int pid, union uml_pt_regs *regs)
+/*To use the same value of using_sysemu as the caller, ask it that value (in local_using_sysemu)*/
+static void handle_trap(int pid, union uml_pt_regs *regs, int local_using_sysemu)
{
int err, syscall_nr, status;
@@ -72,27 +69,23 @@ static void handle_trap(int pid, union u
return;
}
-#ifdef PTRACE_SYSEMU
- if (!use_sysemu)
+ if (!local_using_sysemu)
{
-#endif
- err = ptrace(PTRACE_POKEUSER, pid, PT_SYSCALL_NR_OFFSET, __NR_getpid);
- if(err < 0)
- panic("handle_trap - nullifying syscall failed errno = %d\n",
- errno);
+ err = ptrace(PTRACE_POKEUSER, pid, PT_SYSCALL_NR_OFFSET, __NR_getpid);
+ if(err < 0)
+ panic("handle_trap - nullifying syscall failed errno = %d\n",
+ errno);
+
+ err = ptrace(PTRACE_SYSCALL, pid, 0, 0);
+ if(err < 0)
+ panic("handle_trap - continuing to end of syscall failed, "
+ "errno = %d\n", errno);
- err = ptrace(PTRACE_SYSCALL, pid, 0, 0);
- if(err < 0)
- panic("handle_trap - continuing to end of syscall failed, "
- "errno = %d\n", errno);
-
- err = waitpid(pid, &status, WUNTRACED);
- if((err < 0) || !WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP))
- panic("handle_trap - failed to wait at end of syscall, "
- "errno = %d, status = %d\n", errno, status);
-#ifdef PTRACE_SYSEMU
+ err = waitpid(pid, &status, WUNTRACED);
+ if((err < 0) || !WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP))
+ panic("handle_trap - failed to wait at end of syscall, "
+ "errno = %d, status = %d\n", errno, status);
}
-#endif
handle_syscall(regs);
}
@@ -147,15 +140,16 @@ void start_userspace(int cpu)
void userspace(union uml_pt_regs *regs)
{
int err, status, op, pid = userspace_pid[0];
+ int local_using_sysemu; /*To prevent races if using_sysemu changes under us.*/
restore_registers(regs);
-#ifdef PTRACE_SYSEMU
- if (use_sysemu)
+ local_using_sysemu = get_using_sysemu();
+
+ if (local_using_sysemu)
err = ptrace(PTRACE_SYSEMU, pid, 0, 0);
else
-#endif
- err = ptrace(PTRACE_SYSCALL, pid, 0, 0);
+ err = ptrace(PTRACE_SYSCALL, pid, 0, 0);
if(err)
panic("userspace - PTRACE_SYSCALL failed, errno = %d\n",
errno);
@@ -174,7 +168,7 @@ void userspace(union uml_pt_regs *regs)
handle_segv(pid);
break;
case SIGTRAP:
- handle_trap(pid, regs);
+ handle_trap(pid, regs, local_using_sysemu);
break;
case SIGIO:
case SIGVTALRM:
@@ -193,14 +187,16 @@ void userspace(union uml_pt_regs *regs)
restore_registers(regs);
-#ifdef PTRACE_SYSEMU
- if (use_sysemu)
+ /*Now we ended the syscall, so re-read local_using_sysemu.*/
+ local_using_sysemu = get_using_sysemu();
+
+ if (local_using_sysemu)
op = singlestepping_skas() ? PTRACE_SINGLESTEP :
PTRACE_SYSEMU;
else
-#endif
- op = singlestepping_skas() ? PTRACE_SINGLESTEP :
- PTRACE_SYSCALL;
+ op = singlestepping_skas() ? PTRACE_SINGLESTEP :
+ PTRACE_SYSCALL;
+
err = ptrace(op, pid, 0, 0);
if(err)
panic("userspace - PTRACE_SYSCALL failed, "
diff -puN arch/um/kernel/skas/process_kern.c~uml-adds-proc-sysemu-to-toggle-sysemu-usage arch/um/kernel/skas/process_kern.c
--- 25/arch/um/kernel/skas/process_kern.c~uml-adds-proc-sysemu-to-toggle-sysemu-usage 2004-07-05 16:00:45.680076024 -0700
+++ 25-akpm/arch/um/kernel/skas/process_kern.c 2004-07-05 16:00:45.686075112 -0700
@@ -6,6 +6,12 @@
#include "linux/sched.h"
#include "linux/slab.h"
#include "linux/ptrace.h"
+#include "linux/proc_fs.h"
+#include "linux/file.h"
+#include "linux/errno.h"
+#include "linux/init.h"
+#include "asm/uaccess.h"
+#include "asm/atomic.h"
#include "kern_util.h"
#include "time_user.h"
#include "signal_user.h"
@@ -17,6 +23,59 @@
#include "kern.h"
#include "mode.h"
+#ifdef PTRACE_SYSEMU
+static atomic_t using_sysemu;
+#endif
+
+void set_using_sysemu(int value)
+{
+ atomic_set(&using_sysemu, value);
+}
+
+int get_using_sysemu(void)
+{
+ return atomic_read(&using_sysemu);
+}
+
+int proc_read_sysemu(char *buf, char **start, off_t offset, int size,int *eof, void *data)
+{
+ if (snprintf(buf, size, "%d\n", get_using_sysemu()) < size) /*No overflow*/
+ *eof = 1;
+
+ return strlen(buf);
+}
+
+int proc_write_sysemu(struct file *file,const char *buf, unsigned long count,void *data)
+{
+ char tmp[2];
+
+ if (copy_from_user(tmp, buf, 1))
+ return -EFAULT;
+
+ if (tmp[0] == '0' || tmp[0] == '1')
+ set_using_sysemu(tmp[0] - '0');
+ return count; /*We use the first char, but pretend to write everything*/
+}
+
+int __init make_proc_sysemu(void)
+{
+ struct proc_dir_entry *ent;
+
+ ent = create_proc_entry("sysemu", 00600, &proc_root);
+ ent->read_proc = proc_read_sysemu;
+ ent->write_proc = proc_write_sysemu;
+
+ if (ent == NULL)
+ {
+ printk("Failed to register /proc/sysemu\n");
+ return(0);
+ }
+
+ return 0;
+}
+
+late_initcall(make_proc_sysemu);
+
int singlestepping_skas(void)
{
int ret = current->ptrace & PT_DTRACE;
_