@@ -21,7 +21,6 @@ struct mm_struct;
struct thread_struct {
struct pt_regs regs;
struct pt_regs *segv_regs;
- int singlestep_syscall;
void *fault_addr;
jmp_buf *fault_catcher;
struct task_struct *prev_sched;
@@ -35,7 +35,6 @@ extern int handle_page_fault(unsigned long address, unsigned long ip,
extern unsigned int do_IRQ(int irq, struct uml_pt_regs *regs);
extern int smp_sigio_handler(void);
extern void initial_thread_cb(void (*proc)(void *), void *arg);
-extern int is_syscall(unsigned long addr);
extern void timer_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs);
@@ -12,45 +12,4 @@
extern int ptrace_getregs(long pid, unsigned long *regs_out);
extern int ptrace_setregs(long pid, unsigned long *regs_in);
-/* syscall emulation path in ptrace */
-
-#ifndef PTRACE_SYSEMU
-#define PTRACE_SYSEMU 31
-#endif
-#ifndef PTRACE_SYSEMU_SINGLESTEP
-#define PTRACE_SYSEMU_SINGLESTEP 32
-#endif
-
-/* On architectures, that started to support PTRACE_O_TRACESYSGOOD
- * in linux 2.4, there are two different definitions of
- * PTRACE_SETOPTIONS: linux 2.4 uses 21 while linux 2.6 uses 0x4200.
- * For binary compatibility, 2.6 also supports the old "21", named
- * PTRACE_OLDSETOPTION. On these architectures, UML always must use
- * "21", to ensure the kernel runs on 2.4 and 2.6 host without
- * recompilation. So, we use PTRACE_OLDSETOPTIONS in UML.
- * We also want to be able to build the kernel on 2.4, which doesn't
- * have PTRACE_OLDSETOPTIONS. So, if it is missing, we declare
- * PTRACE_OLDSETOPTIONS to be the same as PTRACE_SETOPTIONS.
- *
- * On architectures, that start to support PTRACE_O_TRACESYSGOOD on
- * linux 2.6, PTRACE_OLDSETOPTIONS never is defined, and also isn't
- * supported by the host kernel. In that case, our trick lets us use
- * the new 0x4200 with the name PTRACE_OLDSETOPTIONS.
- */
-#ifndef PTRACE_OLDSETOPTIONS
-#define PTRACE_OLDSETOPTIONS PTRACE_SETOPTIONS
-#endif
-
-void set_using_sysemu(int value);
-int get_using_sysemu(void);
-extern int sysemu_supported;
-
-#define SELECT_PTRACE_OPERATION(sysemu_mode, singlestep_mode) \
- (((int[3][3] ) { \
- { PTRACE_SYSCALL, PTRACE_SYSCALL, PTRACE_SINGLESTEP }, \
- { PTRACE_SYSEMU, PTRACE_SYSEMU, PTRACE_SINGLESTEP }, \
- { PTRACE_SYSEMU, PTRACE_SYSEMU_SINGLESTEP, \
- PTRACE_SYSEMU_SINGLESTEP } }) \
- [sysemu_mode][singlestep_mode])
-
#endif
@@ -268,84 +268,11 @@ int cpu(void)
return current_thread_info()->cpu;
}
-static atomic_t using_sysemu = ATOMIC_INIT(0);
-int sysemu_supported;
-
-void set_using_sysemu(int value)
-{
- if (value > sysemu_supported)
- return;
- atomic_set(&using_sysemu, value);
-}
-
-int get_using_sysemu(void)
-{
- return atomic_read(&using_sysemu);
-}
-
-static int sysemu_proc_show(struct seq_file *m, void *v)
-{
- seq_printf(m, "%d\n", get_using_sysemu());
- return 0;
-}
-
-static int sysemu_proc_open(struct inode *inode, struct file *file)
-{
- return single_open(file, sysemu_proc_show, NULL);
-}
-
-static ssize_t sysemu_proc_write(struct file *file, const char __user *buf,
- size_t count, loff_t *pos)
-{
- char tmp[2];
-
- if (copy_from_user(tmp, buf, 1))
- return -EFAULT;
-
- if (tmp[0] >= '0' && tmp[0] <= '2')
- set_using_sysemu(tmp[0] - '0');
- /* We use the first char, but pretend to write everything */
- return count;
-}
-
-static const struct proc_ops sysemu_proc_ops = {
- .proc_open = sysemu_proc_open,
- .proc_read = seq_read,
- .proc_lseek = seq_lseek,
- .proc_release = single_release,
- .proc_write = sysemu_proc_write,
-};
-
-int __init make_proc_sysemu(void)
-{
- struct proc_dir_entry *ent;
- if (!sysemu_supported)
- return 0;
-
- ent = proc_create("sysemu", 0600, NULL, &sysemu_proc_ops);
-
- if (ent == NULL)
- {
- printk(KERN_WARNING "Failed to register /proc/sysemu\n");
- return 0;
- }
-
- return 0;
-}
-
-late_initcall(make_proc_sysemu);
-
int singlestepping(void * t)
{
struct task_struct *task = t ? t : current;
- if (!(task->ptrace & PT_DTRACE))
- return 0;
-
- if (task->thread.singlestep_syscall)
- return 1;
-
- return 2;
+ return !!(task->ptrace & PT_DTRACE);
}
/*
@@ -13,7 +13,6 @@
void user_enable_single_step(struct task_struct *child)
{
child->ptrace |= PT_DTRACE;
- child->thread.singlestep_syscall = 0;
#ifdef SUBARCH_SET_SINGLESTEPPING
SUBARCH_SET_SINGLESTEPPING(child, 1);
@@ -23,7 +22,6 @@ void user_enable_single_step(struct task_struct *child)
void user_disable_single_step(struct task_struct *child)
{
child->ptrace &= ~PT_DTRACE;
- child->thread.singlestep_syscall = 0;
#ifdef SUBARCH_SET_SINGLESTEPPING
SUBARCH_SET_SINGLESTEPPING(child, 0);
@@ -120,18 +120,6 @@ void do_signal(struct pt_regs *regs)
}
}
- /*
- * This closes a way to execute a system call on the host. If
- * you set a breakpoint on a system call instruction and singlestep
- * from it, the tracing thread used to PTRACE_SINGLESTEP the process
- * rather than PTRACE_SYSCALL it, allowing the system call to execute
- * on the host. The tracing thread will check this flag and
- * PTRACE_SYSCALL if necessary.
- */
- if (current->ptrace & PT_DTRACE)
- current->thread.singlestep_syscall =
- is_syscall(PT_REGS_IP(¤t->thread.regs));
-
/*
* if there's no signal to deliver, we just put the saved sigmask
* back
@@ -176,48 +176,11 @@ static void handle_segv(int pid, struct uml_pt_regs *regs, unsigned long *aux_fp
segv(regs->faultinfo, 0, 1, NULL);
}
-/*
- * 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, struct uml_pt_regs *regs,
- int local_using_sysemu)
+static void handle_trap(int pid, struct uml_pt_regs *regs)
{
- int err, status;
-
if ((UPT_IP(regs) >= STUB_START) && (UPT_IP(regs) < STUB_END))
fatal_sigsegv();
- if (!local_using_sysemu)
- {
- err = ptrace(PTRACE_POKEUSER, pid, PT_SYSCALL_NR_OFFSET,
- __NR_getpid);
- if (err < 0) {
- printk(UM_KERN_ERR "%s - nullifying syscall failed, errno = %d\n",
- __func__, errno);
- fatal_sigsegv();
- }
-
- err = ptrace(PTRACE_SYSCALL, pid, 0, 0);
- if (err < 0) {
- printk(UM_KERN_ERR "%s - continuing to end of syscall failed, errno = %d\n",
- __func__, errno);
- fatal_sigsegv();
- }
-
- CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED | __WALL));
- if ((err < 0) || !WIFSTOPPED(status) ||
- (WSTOPSIG(status) != SIGTRAP + 0x80)) {
- err = ptrace_dump_regs(pid);
- if (err)
- printk(UM_KERN_ERR "Failed to get registers from process, errno = %d\n",
- -err);
- printk(UM_KERN_ERR "%s - failed to wait at end of syscall, errno = %d, status = %d\n",
- __func__, errno, status);
- fatal_sigsegv();
- }
- }
-
handle_syscall(regs);
}
@@ -354,7 +317,7 @@ int start_userspace(unsigned long stub_stack)
goto out_kill;
}
- if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL,
+ if (ptrace(PTRACE_SETOPTIONS, pid, NULL,
(void *) PTRACE_O_TRACESYSGOOD) < 0) {
err = -errno;
printk(UM_KERN_ERR "%s : PTRACE_OLDSETOPTIONS failed, errno = %d\n",
@@ -379,8 +342,6 @@ int start_userspace(unsigned long stub_stack)
void userspace(struct uml_pt_regs *regs, unsigned long *aux_fp_regs)
{
int err, status, op, pid = userspace_pid[0];
- /* To prevent races if using_sysemu changes under us.*/
- int local_using_sysemu;
siginfo_t si;
/* Handle any immediate reschedules or signals */
@@ -410,11 +371,10 @@ void userspace(struct uml_pt_regs *regs, unsigned long *aux_fp_regs)
fatal_sigsegv();
}
- /* Now we set local_using_sysemu to be used for one loop */
- local_using_sysemu = get_using_sysemu();
-
- op = SELECT_PTRACE_OPERATION(local_using_sysemu,
- singlestepping(NULL));
+ if (singlestepping(NULL))
+ op = PTRACE_SYSEMU_SINGLESTEP;
+ else
+ op = PTRACE_SYSEMU;
if (ptrace(op, pid, 0, 0)) {
printk(UM_KERN_ERR "%s - ptrace continue failed, op = %d, errno = %d\n",
@@ -473,7 +433,7 @@ void userspace(struct uml_pt_regs *regs, unsigned long *aux_fp_regs)
else handle_segv(pid, regs, aux_fp_regs);
break;
case SIGTRAP + 0x80:
- handle_trap(pid, regs, local_using_sysemu);
+ handle_trap(pid, regs);
break;
case SIGTRAP:
relay_signal(SIGTRAP, (struct siginfo *)&si, regs);
@@ -596,7 +556,7 @@ int copy_context_skas0(unsigned long new_stack, int pid)
goto out_kill;
}
- if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL,
+ if (ptrace(PTRACE_SETOPTIONS, pid, NULL,
(void *)PTRACE_O_TRACESYSGOOD) < 0) {
err = -errno;
printk(UM_KERN_ERR "%s : PTRACE_OLDSETOPTIONS failed, errno = %d\n",
@@ -143,71 +143,16 @@ static int stop_ptraced_child(int pid, int exitcode, int mustexit)
return ret;
}
-/* Changed only during early boot */
-static int force_sysemu_disabled = 0;
-
-static int __init nosysemu_cmd_param(char *str, int* add)
-{
- force_sysemu_disabled = 1;
- return 0;
-}
-
-__uml_setup("nosysemu", nosysemu_cmd_param,
-"nosysemu\n"
-" Turns off syscall emulation patch for ptrace (SYSEMU).\n"
-" SYSEMU is a performance-patch introduced by Laurent Vivier. It changes\n"
-" behaviour of ptrace() and helps reduce host context switch rates.\n"
-" To make it work, you need a kernel patch for your host, too.\n"
-" See http://perso.wanadoo.fr/laurent.vivier/UML/ for further \n"
-" information.\n\n");
-
static void __init check_sysemu(void)
{
- unsigned long regs[MAX_REG_NR];
int pid, n, status, count=0;
- os_info("Checking syscall emulation patch for ptrace...");
- sysemu_supported = 0;
- pid = start_ptraced_child();
-
- if (ptrace(PTRACE_SYSEMU, pid, 0, 0) < 0)
- goto fail;
-
- CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
- if (n < 0)
- fatal_perror("check_sysemu : wait failed");
- if (!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP))
- fatal("check_sysemu : expected SIGTRAP, got status = %d\n",
- status);
-
- if (ptrace(PTRACE_GETREGS, pid, 0, regs) < 0)
- fatal_perror("check_sysemu : PTRACE_GETREGS failed");
- if (PT_SYSCALL_NR(regs) != __NR_getpid) {
- non_fatal("check_sysemu got system call number %d, "
- "expected %d...", PT_SYSCALL_NR(regs), __NR_getpid);
- goto fail;
- }
-
- n = ptrace(PTRACE_POKEUSER, pid, PT_SYSCALL_RET_OFFSET, os_getpid());
- if (n < 0) {
- non_fatal("check_sysemu : failed to modify system call "
- "return");
- goto fail;
- }
-
- if (stop_ptraced_child(pid, 0, 0) < 0)
- goto fail_stopped;
-
- sysemu_supported = 1;
- os_info("OK\n");
- set_using_sysemu(!force_sysemu_disabled);
-
- os_info("Checking advanced syscall emulation patch for ptrace...");
+ os_info("Checking syscall emulation for ptrace...");
pid = start_ptraced_child();
- if ((ptrace(PTRACE_OLDSETOPTIONS, pid, 0,
+ if ((ptrace(PTRACE_SETOPTIONS, pid, 0,
(void *) PTRACE_O_TRACESYSGOOD) < 0))
- fatal_perror("check_sysemu: PTRACE_OLDSETOPTIONS failed");
+ fatal_perror("check_sysemu: PTRACE_SETOPTIONS failed");
while (1) {
count++;
@@ -243,17 +188,14 @@ static void __init check_sysemu(void)
if (stop_ptraced_child(pid, 0, 0) < 0)
goto fail_stopped;
- sysemu_supported = 2;
os_info("OK\n");
- if (!force_sysemu_disabled)
- set_using_sysemu(sysemu_supported);
return;
fail:
stop_ptraced_child(pid, 1, 0);
fail_stopped:
- non_fatal("missing\n");
+ fatal("missing\n");
}
static void __init check_ptrace(void)
@@ -263,9 +205,9 @@ static void __init check_ptrace(void)
os_info("Checking that ptrace can change system call numbers...");
pid = start_ptraced_child();
- if ((ptrace(PTRACE_OLDSETOPTIONS, pid, 0,
+ if ((ptrace(PTRACE_SETOPTIONS, pid, 0,
(void *) PTRACE_O_TRACESYSGOOD) < 0))
- fatal_perror("check_ptrace: PTRACE_OLDSETOPTIONS failed");
+ fatal_perror("check_ptrace: PTRACE_SETOPTIONS failed");
while (1) {
if (ptrace(PTRACE_SYSCALL, pid, 0, 0) < 0)
@@ -24,30 +24,6 @@ void arch_switch_to(struct task_struct *to)
printk(KERN_WARNING "arch_switch_tls failed, errno = EINVAL\n");
}
-int is_syscall(unsigned long addr)
-{
- unsigned short instr;
- int n;
-
- n = copy_from_user(&instr, (void __user *) addr, sizeof(instr));
- if (n) {
- /* access_process_vm() grants access to vsyscall and stub,
- * while copy_from_user doesn't. Maybe access_process_vm is
- * slow, but that doesn't matter, since it will be called only
- * in case of singlestepping, if copy_from_user failed.
- */
- n = access_process_vm(current, addr, &instr, sizeof(instr),
- FOLL_FORCE);
- if (n != sizeof(instr)) {
- printk(KERN_ERR "is_syscall : failed to read "
- "instruction from 0x%lx\n", addr);
- return 1;
- }
- }
- /* int 0x80 or sysenter */
- return (instr == 0x80cd) || (instr == 0x340f);
-}
-
/* determines which flags the user has access to. */
/* 1 = access 0 = no access */
#define FLAG_MASK 0x00044dd5
@@ -187,32 +187,6 @@ int peek_user(struct task_struct *child, long addr, long data)
return put_user(tmp, (unsigned long *) data);
}
-/* XXX Mostly copied from sys-i386 */
-int is_syscall(unsigned long addr)
-{
- unsigned short instr;
- int n;
-
- n = copy_from_user(&instr, (void __user *) addr, sizeof(instr));
- if (n) {
- /*
- * access_process_vm() grants access to vsyscall and stub,
- * while copy_from_user doesn't. Maybe access_process_vm is
- * slow, but that doesn't matter, since it will be called only
- * in case of singlestepping, if copy_from_user failed.
- */
- n = access_process_vm(current, addr, &instr, sizeof(instr),
- FOLL_FORCE);
- if (n != sizeof(instr)) {
- printk("is_syscall : failed to read instruction from "
- "0x%lx\n", addr);
- return 1;
- }
- }
- /* sysenter */
- return instr == 0x050f;
-}
-
static int get_fpregs(struct user_i387_struct __user *buf, struct task_struct *child)
{
int err, n, cpu = ((struct thread_info *) child->stack)->cpu;
@@ -8,10 +8,6 @@
#define MAX_FP_NR HOST_FPX_SIZE
-void set_using_sysemu(int value);
-int get_using_sysemu(void);
-extern int sysemu_supported;
-
#define UPT_SYSCALL_ARG1(r) UPT_BX(r)
#define UPT_SYSCALL_ARG2(r) UPT_CX(r)
#define UPT_SYSCALL_ARG3(r) UPT_DX(r)
These features have existed since Linux 2.6.14 and can be considered widely available at this point. Signed-off-by: Benjamin Berg <benjamin@sipsolutions.net> --- arch/um/include/asm/processor-generic.h | 1 - arch/um/include/shared/kern_util.h | 1 - arch/um/include/shared/ptrace_user.h | 41 -------------- arch/um/kernel/process.c | 75 +------------------------ arch/um/kernel/ptrace.c | 2 - arch/um/kernel/signal.c | 12 ---- arch/um/os-Linux/skas/process.c | 56 +++--------------- arch/um/os-Linux/start_up.c | 70 ++--------------------- arch/x86/um/ptrace_32.c | 24 -------- arch/x86/um/ptrace_64.c | 26 --------- arch/x86/um/shared/sysdep/ptrace_32.h | 4 -- 11 files changed, 15 insertions(+), 297 deletions(-)