[PATCH] UML utrace support, step 1

[PATCH] UML utrace support, step 1

[Jeff Dike]

Below is the first step in your Fix-Your-Broken-Arch-HOWTO for UML.

Do you want incremental patches as I go along, or replacement ones?

BTW, UML runs on the utrace in -mm (i.e. utrace on the host), which it
didn't with several Fedora kernels.

				Jeff

-- 
Work email - jdike at linux dot intel dot com



The first step in making the utrace arch changes for UML.  It builds
and runs now, but ptrace is broken.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
--
 arch/um/kernel/exec.c           |    1 
 arch/um/kernel/process.c        |    6 
 arch/um/kernel/ptrace.c         |  333 +++++-----------------------------------
 arch/um/kernel/signal.c         |    5 
 arch/um/kernel/skas/syscall.c   |    4 
 arch/um/sys-i386/signal.c       |    4 
 include/asm-um/ptrace-generic.h |    3 
 include/asm-um/tracehook.h      |   66 +++++++
 8 files changed, 115 insertions(+), 307 deletions(-)

Index: linux-2.6.18-mm/arch/um/kernel/exec.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/kernel/exec.c	2007-02-20 16:18:07.000000000 -0500
+++ linux-2.6.18-mm/arch/um/kernel/exec.c	2007-02-20 16:18:50.000000000 -0500
@@ -51,7 +51,6 @@ static long execve1(char *file, char __u
         error = do_execve(file, argv, env, &current->thread.regs);
         if (error == 0){
 		task_lock(current);
-                current->ptrace &= ~PT_DTRACE;
 #ifdef SUBARCH_EXECVE1
 		SUBARCH_EXECVE1(&current->thread.regs.regs);
 #endif
Index: linux-2.6.18-mm/arch/um/kernel/process.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/kernel/process.c	2007-02-20 16:18:07.000000000 -0500
+++ linux-2.6.18-mm/arch/um/kernel/process.c	2007-02-20 16:18:50.000000000 -0500
@@ -458,11 +458,11 @@ int singlestepping(void * t)
 {
 	struct task_struct *task = t ? t : current;
 
-	if ( ! (task->ptrace & PT_DTRACE) )
-		return(0);
+	if (!test_thread_flag(TIF_SINGLESTEP))
+		return 0;
 
 	if (task->thread.singlestep_syscall)
-		return(1);
+		return 1;
 
 	return 2;
 }
Index: linux-2.6.18-mm/arch/um/kernel/ptrace.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/kernel/ptrace.c	2007-02-20 16:18:07.000000000 -0500
+++ linux-2.6.18-mm/arch/um/kernel/ptrace.c	2007-02-20 16:18:50.000000000 -0500
@@ -3,261 +3,29 @@
  * Licensed under the GPL
  */
 
-#include "linux/sched.h"
-#include "linux/mm.h"
-#include "linux/errno.h"
-#include "linux/smp_lock.h"
-#include "linux/security.h"
-#include "linux/ptrace.h"
-#include "linux/audit.h"
-#ifdef CONFIG_PROC_MM
-#include "linux/proc_mm.h"
-#endif
-#include "asm/ptrace.h"
-#include "asm/uaccess.h"
-#include "kern_util.h"
-#include "skas_ptrace.h"
-#include "sysdep/ptrace.h"
-#include "os.h"
-
-static inline void set_singlestepping(struct task_struct *child, int on)
+#include <linux/audit.h>
+#include <linux/elf.h>
+#include <linux/module.h>
+#include <linux/ptrace.h>
+#include <linux/tracehook.h>
+
+const struct utrace_regset_view utrace_um_native = {
+	.name		= "um",
+	.e_machine	= ELF_ARCH,
+	.regsets	= NULL,
+	.n		= 0,
+};
+EXPORT_SYMBOL_GPL(utrace_um_native);
+
+int arch_ptrace(long *req, struct task_struct *child,
+		struct utrace_attached_engine *engine,
+		unsigned long addr, unsigned long data, long *val)
 {
-        if (on)
-                child->ptrace |= PT_DTRACE;
-        else
-                child->ptrace &= ~PT_DTRACE;
-        child->thread.singlestep_syscall = 0;
-
-#ifdef SUBARCH_SET_SINGLESTEPPING
-        SUBARCH_SET_SINGLESTEPPING(child, on);
-#endif
+	return -ENOSYS;
 }
 
-/*
- * Called by kernel/ptrace.c when detaching..
- */
-void ptrace_disable(struct task_struct *child)
-{ 
-        set_singlestepping(child,0);
-}
-
-extern int peek_user(struct task_struct * child, long addr, long data);
-extern int poke_user(struct task_struct * child, long addr, long data);
-
-long arch_ptrace(struct task_struct *child, long request, long addr, long data)
-{
-	int i, ret;
-	unsigned long __user *p = (void __user *)(unsigned long)data;
-
-	switch (request) {
-		/* when I and D space are separate, these will need to be fixed. */
-	case PTRACE_PEEKTEXT: /* read word at location addr. */ 
-	case PTRACE_PEEKDATA: {
-		unsigned long tmp;
-		int copied;
-
-		ret = -EIO;
-		copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
-		if (copied != sizeof(tmp))
-			break;
-		ret = put_user(tmp, p);
-		break;
-	}
-
-	/* read the word at location addr in the USER area. */
-        case PTRACE_PEEKUSR:
-                ret = peek_user(child, addr, data);
-                break;
-
-	/* when I and D space are separate, this will have to be fixed. */
-	case PTRACE_POKETEXT: /* write the word at location addr. */
-	case PTRACE_POKEDATA:
-		ret = -EIO;
-		if (access_process_vm(child, addr, &data, sizeof(data), 
-				      1) != sizeof(data))
-			break;
-		ret = 0;
-		break;
-
-	case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
-                ret = poke_user(child, addr, data);
-                break;
-
-	case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
-	case PTRACE_CONT: { /* restart after signal. */
-		ret = -EIO;
-		if (!valid_signal(data))
-			break;
-
-                set_singlestepping(child, 0);
-		if (request == PTRACE_SYSCALL) {
-			set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
-		}
-		else {
-			clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
-		}
-		child->exit_code = data;
-		wake_up_process(child);
-		ret = 0;
-		break;
-	}
-
-/*
- * make the child exit.  Best I can do is send it a sigkill. 
- * perhaps it should be put in the status that it wants to 
- * exit.
- */
-	case PTRACE_KILL: {
-		ret = 0;
-		if (child->exit_state == EXIT_ZOMBIE)	/* already dead */
-			break;
-
-                set_singlestepping(child, 0);
-		child->exit_code = SIGKILL;
-		wake_up_process(child);
-		break;
-	}
-
-	case PTRACE_SINGLESTEP: {  /* set the trap flag. */
-		ret = -EIO;
-		if (!valid_signal(data))
-			break;
-		clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
-                set_singlestepping(child, 1);
-		child->exit_code = data;
-		/* give it a chance to run. */
-		wake_up_process(child);
-		ret = 0;
-		break;
-	}
-
-	case PTRACE_DETACH:
-		/* detach a process that was attached. */
-		ret = ptrace_detach(child, data);
- 		break;
-
-#ifdef PTRACE_GETREGS
-	case PTRACE_GETREGS: { /* Get all gp regs from the child. */
-		if (!access_ok(VERIFY_WRITE, p, MAX_REG_OFFSET)) {
-			ret = -EIO;
-			break;
-		}
-		for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
-			__put_user(getreg(child, i), p);
-			p++;
-		}
-		ret = 0;
-		break;
-	}
-#endif
-#ifdef PTRACE_SETREGS
-	case PTRACE_SETREGS: { /* Set all gp regs in the child. */
-		unsigned long tmp = 0;
-		if (!access_ok(VERIFY_READ, p, MAX_REG_OFFSET)) {
-			ret = -EIO;
-			break;
-		}
-		for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
-			__get_user(tmp, p);
-			putreg(child, i, tmp);
-			p++;
-		}
-		ret = 0;
-		break;
-	}
-#endif
-#ifdef PTRACE_GETFPREGS
-	case PTRACE_GETFPREGS: /* Get the child FPU state. */
-		ret = get_fpregs(data, child);
-		break;
-#endif
-#ifdef PTRACE_SETFPREGS
-	case PTRACE_SETFPREGS: /* Set the child FPU state. */
-	        ret = set_fpregs(data, child);
-		break;
-#endif
-#ifdef PTRACE_GETFPXREGS
-	case PTRACE_GETFPXREGS: /* Get the child FPU state. */
-		ret = get_fpxregs(data, child);
-		break;
-#endif
-#ifdef PTRACE_SETFPXREGS
-	case PTRACE_SETFPXREGS: /* Set the child FPU state. */
-		ret = set_fpxregs(data, child);
-		break;
-#endif
-	case PTRACE_GET_THREAD_AREA:
-		ret = ptrace_get_thread_area(child, addr,
-					     (struct user_desc __user *) data);
-		break;
-
-	case PTRACE_SET_THREAD_AREA:
-		ret = ptrace_set_thread_area(child, addr,
-					     (struct user_desc __user *) data);
-		break;
-
-	case PTRACE_FAULTINFO: {
-		/* Take the info from thread->arch->faultinfo,
-		 * but transfer max. sizeof(struct ptrace_faultinfo).
-		 * On i386, ptrace_faultinfo is smaller!
-		 */
-		ret = copy_to_user(p, &child->thread.arch.faultinfo,
-				   sizeof(struct ptrace_faultinfo));
-		if(ret)
-			break;
-		break;
-	}
-
-#ifdef PTRACE_LDT
-	case PTRACE_LDT: {
-		struct ptrace_ldt ldt;
-
-		if(copy_from_user(&ldt, p, sizeof(ldt))){
-			ret = -EIO;
-			break;
-		}
-
-		/* This one is confusing, so just punt and return -EIO for 
-		 * now
-		 */
-		ret = -EIO;
-		break;
-	}
-#endif
-#ifdef CONFIG_PROC_MM
-	case PTRACE_SWITCH_MM: {
-		struct mm_struct *old = child->mm;
-		struct mm_struct *new = proc_mm_get_mm(data);
-
-		if(IS_ERR(new)){
-			ret = PTR_ERR(new);
-			break;
-		}
-
-		atomic_inc(&new->mm_users);
-		child->mm = new;
-		child->active_mm = new;
-		mmput(old);
-		ret = 0;
-		break;
-	}
-#endif
-#ifdef PTRACE_ARCH_PRCTL
-        case PTRACE_ARCH_PRCTL:
-                /* XXX Calls ptrace on the host - needs some SMP thinking */
-                ret = arch_prctl_skas(child, data, (void *) addr);
-                break;
-#endif
-	default:
-		ret = ptrace_request(child, request, addr, data);
-		break;
-	}
-
-	return ret;
-}
-
-void send_sigtrap(struct task_struct *tsk, union uml_pt_regs *regs,
-		  int error_code)
+static void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs,
+			 int error_code)
 {
 	struct siginfo info;
 
@@ -266,56 +34,39 @@ void send_sigtrap(struct task_struct *ts
 	info.si_code = TRAP_BRKPT;
 
 	/* User-mode eip? */
-	info.si_addr = UPT_IS_USER(regs) ? (void __user *) UPT_IP(regs) : NULL;
+	info.si_addr = UPT_IS_USER(&regs->regs) ?
+		(void __user *) UPT_IP(&regs->regs) : NULL;
 
 	/* Send us the fakey SIGTRAP */
 	force_sig_info(SIGTRAP, &info, tsk);
 }
 
-/* XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and
- * PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
+/* notification of system call entry/exit
+ * - triggered by current->work.syscall_trace
  */
-void syscall_trace(union uml_pt_regs *regs, int entryexit)
+void do_syscall_trace(struct pt_regs *regs, int entryexit)
 {
-	int is_singlestep = (current->ptrace & PT_DTRACE) && entryexit;
-	int tracesysgood;
+	/* do the secure computing check first */
+	if (!entryexit)
+		secure_computing(PT_REGS_SYSCALL_NR(regs));
+
+	if (unlikely(current->audit_context) && entryexit)
+		audit_syscall_exit(AUDITSC_RESULT(UPT_SYSCALL_RET(regs)),
+				   UPT_SYSCALL_RET(regs));
+
+	if (test_thread_flag(TIF_SYSCALL_TRACE))
+		tracehook_report_syscall(regs, entryexit);
+
+	if (test_thread_flag(TIF_SINGLESTEP) && entryexit) {
+		send_sigtrap(current, regs, 0);	/* XXX */
+		tracehook_report_syscall_step(regs);
+	}
 
-	if (unlikely(current->audit_context)) {
-		if (!entryexit)
-			audit_syscall_entry(HOST_AUDIT_ARCH,
+	if (unlikely(current->audit_context) && !entryexit)
+		audit_syscall_entry(HOST_AUDIT_ARCH,
 					    UPT_SYSCALL_NR(regs),
 					    UPT_SYSCALL_ARG1(regs),
 					    UPT_SYSCALL_ARG2(regs),
 					    UPT_SYSCALL_ARG3(regs),
 					    UPT_SYSCALL_ARG4(regs));
-		else audit_syscall_exit(AUDITSC_RESULT(UPT_SYSCALL_RET(regs)),
-                                        UPT_SYSCALL_RET(regs));
-	}
-
-	/* Fake a debug trap */
-	if (is_singlestep)
-		send_sigtrap(current, regs, 0);
-
-	if (!test_thread_flag(TIF_SYSCALL_TRACE))
-		return;
-
-	if (!(current->ptrace & PT_PTRACED))
-		return;
-
-	/* the 0x80 provides a way for the tracing parent to distinguish
-	   between a syscall stop and SIGTRAP delivery */
-	tracesysgood = (current->ptrace & PT_TRACESYSGOOD);
-	ptrace_notify(SIGTRAP | (tracesysgood ? 0x80 : 0));
-
-	if (entryexit) /* force do_signal() --> is_syscall() */
-		set_thread_flag(TIF_SIGPENDING);
-
-	/* 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;
-	}
 }
Index: linux-2.6.18-mm/include/asm-um/tracehook.h
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.18-mm/include/asm-um/tracehook.h	2007-02-20 16:18:50.000000000 -0500
@@ -0,0 +1,66 @@
+/*
+ * Tracing hooks, i386 CPU support
+ *
+ * Copyright (C) 2006, 2007 Red Hat, Inc.  All rights reserved.
+ *
+ * This copyrighted material is made available to anyone wishing to use,
+ * modify, copy, or redistribute it subject to the terms and conditions
+ * of the GNU General Public License v.2.
+ *
+ * Red Hat Author: Roland McGrath.
+ *
+ * Munged for UML - jdike@{addtoit,linux.intel}.com
+ */
+
+#ifndef _ASM_TRACEHOOK_H
+#define _ASM_TRACEHOOK_H	1
+
+#include <linux/sched.h>
+#include <asm/ptrace.h>
+#include <asm/thread_info.h>
+
+/*
+ * See linux/tracehook.h for the descriptions of what these need to do.
+ */
+
+#define ARCH_HAS_SINGLE_STEP	(1)
+
+static inline void tracehook_enable_single_step(struct task_struct *tsk)
+{
+	set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
+}
+
+static inline void tracehook_disable_single_step(struct task_struct *tsk)
+{
+	clear_tsk_thread_flag(tsk, TIF_SINGLESTEP);
+}
+
+static inline int tracehook_single_step_enabled(struct task_struct *tsk)
+{
+	return test_tsk_thread_flag(tsk, TIF_SINGLESTEP);
+}
+
+static inline void tracehook_enable_syscall_trace(struct task_struct *tsk)
+{
+	set_tsk_thread_flag(tsk, TIF_SYSCALL_TRACE);
+}
+
+static inline void tracehook_disable_syscall_trace(struct task_struct *tsk)
+{
+	clear_tsk_thread_flag(tsk, TIF_SYSCALL_TRACE);
+}
+
+static inline void tracehook_abort_syscall(struct pt_regs *regs)
+{
+	PT_REGS_SYSCALL_NR(regs) = -1;
+}
+
+extern const struct utrace_regset_view utrace_um_native;
+static inline const struct utrace_regset_view *
+utrace_native_view(struct task_struct *tsk)
+{
+	return &utrace_um_native;
+}
+
+
+#endif
Index: linux-2.6.18-mm/arch/um/kernel/signal.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/kernel/signal.c	2007-02-20 16:18:37.000000000 -0500
+++ linux-2.6.18-mm/arch/um/kernel/signal.c	2007-02-20 16:18:50.000000000 -0500
@@ -14,6 +14,7 @@
 #include "linux/tty.h"
 #include "linux/binfmts.h"
 #include "linux/ptrace.h"
+#include "linux/tracehook.h"
 #include "asm/signal.h"
 #include "asm/uaccess.h"
 #include "asm/unistd.h"
@@ -93,6 +94,8 @@ static int handle_signal(struct pt_regs 
 			sigaddset(&current->blocked, signr);
 		recalc_sigpending();
 		spin_unlock_irq(&current->sighand->siglock);
+
+		tracehook_report_handle_signal(signr, ka, oldset, regs);
 	}
 
 	return err;
@@ -148,7 +151,7 @@ static int kern_do_signal(struct pt_regs
 	 * on the host.  The tracing thread will check this flag and
 	 * PTRACE_SYSCALL if necessary.
 	 */
-	if(current->ptrace & PT_DTRACE)
+	if(test_thread_flag(TIF_SYSCALL_TRACE))
 		current->thread.singlestep_syscall =
 			is_syscall(PT_REGS_IP(&current->thread.regs));
 
Index: linux-2.6.18-mm/arch/um/kernel/skas/syscall.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/kernel/skas/syscall.c	2007-02-20 16:18:07.000000000 -0500
+++ linux-2.6.18-mm/arch/um/kernel/skas/syscall.c	2007-02-20 16:18:50.000000000 -0500
@@ -19,8 +19,6 @@ void handle_syscall(union uml_pt_regs *r
 	long result;
 	int syscall;
 
-	syscall_trace(r, 0);
-
 	current->thread.nsyscalls++;
 	nsyscalls++;
 
@@ -38,6 +36,4 @@ void handle_syscall(union uml_pt_regs *r
 	else result = EXECUTE_SYSCALL(syscall, regs);
 
 	REGS_SET_SYSCALL_RETURN(r->skas.regs, result);
-
-	syscall_trace(r, 1);
 }
Index: linux-2.6.18-mm/arch/um/sys-i386/signal.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/sys-i386/signal.c	2007-02-20 16:18:07.000000000 -0500
+++ linux-2.6.18-mm/arch/um/sys-i386/signal.c	2007-02-20 16:18:50.000000000 -0500
@@ -267,8 +267,6 @@ int setup_signal_stack_sc(unsigned long 
 	PT_REGS_EDX(regs) = (unsigned long) 0;
 	PT_REGS_ECX(regs) = (unsigned long) 0;
 
-	if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
-		ptrace_notify(SIGTRAP);
 	return 0;
 
 err:
@@ -324,8 +322,6 @@ int setup_signal_stack_si(unsigned long 
 	PT_REGS_EDX(regs) = (unsigned long) &frame->info;
 	PT_REGS_ECX(regs) = (unsigned long) &frame->uc;
 
-	if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
-		ptrace_notify(SIGTRAP);
 	return 0;
 
 err:
Index: linux-2.6.18-mm/include/asm-um/ptrace-generic.h
===================================================================
--- linux-2.6.18-mm.orig/include/asm-um/ptrace-generic.h	2007-02-20 16:18:07.000000000 -0500
+++ linux-2.6.18-mm/include/asm-um/ptrace-generic.h	2007-02-20 16:18:50.000000000 -0500
@@ -44,9 +44,6 @@ extern int set_fpxregs(unsigned long buf
 
 extern void show_regs(struct pt_regs *regs);
 
-extern void send_sigtrap(struct task_struct *tsk, union uml_pt_regs *regs,
-			 int error_code);
-
 extern int arch_copy_tls(struct task_struct *new);
 extern void clear_flushed_tls(struct task_struct *task);
 

[uml-devel] [PATCH] UML utrace support, step 1

[Jeff Dike]

Below is the first step in your Fix-Your-Broken-Arch-HOWTO for UML.

Do you want incremental patches as I go along, or replacement ones?

BTW, UML runs on the utrace in -mm (i.e. utrace on the host), which it
didn't with several Fedora kernels.

				Jeff

-- 
Work email - jdike at linux dot intel dot com



The first step in making the utrace arch changes for UML.  It builds
and runs now, but ptrace is broken.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
--
 arch/um/kernel/exec.c           |    1 
 arch/um/kernel/process.c        |    6 
 arch/um/kernel/ptrace.c         |  333 +++++-----------------------------------
 arch/um/kernel/signal.c         |    5 
 arch/um/kernel/skas/syscall.c   |    4 
 arch/um/sys-i386/signal.c       |    4 
 include/asm-um/ptrace-generic.h |    3 
 include/asm-um/tracehook.h      |   66 +++++++
 8 files changed, 115 insertions(+), 307 deletions(-)

Index: linux-2.6.18-mm/arch/um/kernel/exec.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/kernel/exec.c	2007-02-20 16:18:07.000000000 -0500
+++ linux-2.6.18-mm/arch/um/kernel/exec.c	2007-02-20 16:18:50.000000000 -0500
@@ -51,7 +51,6 @@ static long execve1(char *file, char __u
         error = do_execve(file, argv, env, &current->thread.regs);
         if (error == 0){
 		task_lock(current);
-                current->ptrace &= ~PT_DTRACE;
 #ifdef SUBARCH_EXECVE1
 		SUBARCH_EXECVE1(&current->thread.regs.regs);
 #endif
Index: linux-2.6.18-mm/arch/um/kernel/process.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/kernel/process.c	2007-02-20 16:18:07.000000000 -0500
+++ linux-2.6.18-mm/arch/um/kernel/process.c	2007-02-20 16:18:50.000000000 -0500
@@ -458,11 +458,11 @@ int singlestepping(void * t)
 {
 	struct task_struct *task = t ? t : current;
 
-	if ( ! (task->ptrace & PT_DTRACE) )
-		return(0);
+	if (!test_thread_flag(TIF_SINGLESTEP))
+		return 0;
 
 	if (task->thread.singlestep_syscall)
-		return(1);
+		return 1;
 
 	return 2;
 }
Index: linux-2.6.18-mm/arch/um/kernel/ptrace.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/kernel/ptrace.c	2007-02-20 16:18:07.000000000 -0500
+++ linux-2.6.18-mm/arch/um/kernel/ptrace.c	2007-02-20 16:18:50.000000000 -0500
@@ -3,261 +3,29 @@
  * Licensed under the GPL
  */
 
-#include "linux/sched.h"
-#include "linux/mm.h"
-#include "linux/errno.h"
-#include "linux/smp_lock.h"
-#include "linux/security.h"
-#include "linux/ptrace.h"
-#include "linux/audit.h"
-#ifdef CONFIG_PROC_MM
-#include "linux/proc_mm.h"
-#endif
-#include "asm/ptrace.h"
-#include "asm/uaccess.h"
-#include "kern_util.h"
-#include "skas_ptrace.h"
-#include "sysdep/ptrace.h"
-#include "os.h"
-
-static inline void set_singlestepping(struct task_struct *child, int on)
+#include <linux/audit.h>
+#include <linux/elf.h>
+#include <linux/module.h>
+#include <linux/ptrace.h>
+#include <linux/tracehook.h>
+
+const struct utrace_regset_view utrace_um_native = {
+	.name		= "um",
+	.e_machine	= ELF_ARCH,
+	.regsets	= NULL,
+	.n		= 0,
+};
+EXPORT_SYMBOL_GPL(utrace_um_native);
+
+int arch_ptrace(long *req, struct task_struct *child,
+		struct utrace_attached_engine *engine,
+		unsigned long addr, unsigned long data, long *val)
 {
-        if (on)
-                child->ptrace |= PT_DTRACE;
-        else
-                child->ptrace &= ~PT_DTRACE;
-        child->thread.singlestep_syscall = 0;
-
-#ifdef SUBARCH_SET_SINGLESTEPPING
-        SUBARCH_SET_SINGLESTEPPING(child, on);
-#endif
+	return -ENOSYS;
 }
 
-/*
- * Called by kernel/ptrace.c when detaching..
- */
-void ptrace_disable(struct task_struct *child)
-{ 
-        set_singlestepping(child,0);
-}
-
-extern int peek_user(struct task_struct * child, long addr, long data);
-extern int poke_user(struct task_struct * child, long addr, long data);
-
-long arch_ptrace(struct task_struct *child, long request, long addr, long data)
-{
-	int i, ret;
-	unsigned long __user *p = (void __user *)(unsigned long)data;
-
-	switch (request) {
-		/* when I and D space are separate, these will need to be fixed. */
-	case PTRACE_PEEKTEXT: /* read word at location addr. */ 
-	case PTRACE_PEEKDATA: {
-		unsigned long tmp;
-		int copied;
-
-		ret = -EIO;
-		copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
-		if (copied != sizeof(tmp))
-			break;
-		ret = put_user(tmp, p);
-		break;
-	}
-
-	/* read the word at location addr in the USER area. */
-        case PTRACE_PEEKUSR:
-                ret = peek_user(child, addr, data);
-                break;
-
-	/* when I and D space are separate, this will have to be fixed. */
-	case PTRACE_POKETEXT: /* write the word at location addr. */
-	case PTRACE_POKEDATA:
-		ret = -EIO;
-		if (access_process_vm(child, addr, &data, sizeof(data), 
-				      1) != sizeof(data))
-			break;
-		ret = 0;
-		break;
-
-	case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
-                ret = poke_user(child, addr, data);
-                break;
-
-	case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
-	case PTRACE_CONT: { /* restart after signal. */
-		ret = -EIO;
-		if (!valid_signal(data))
-			break;
-
-                set_singlestepping(child, 0);
-		if (request == PTRACE_SYSCALL) {
-			set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
-		}
-		else {
-			clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
-		}
-		child->exit_code = data;
-		wake_up_process(child);
-		ret = 0;
-		break;
-	}
-
-/*
- * make the child exit.  Best I can do is send it a sigkill. 
- * perhaps it should be put in the status that it wants to 
- * exit.
- */
-	case PTRACE_KILL: {
-		ret = 0;
-		if (child->exit_state == EXIT_ZOMBIE)	/* already dead */
-			break;
-
-                set_singlestepping(child, 0);
-		child->exit_code = SIGKILL;
-		wake_up_process(child);
-		break;
-	}
-
-	case PTRACE_SINGLESTEP: {  /* set the trap flag. */
-		ret = -EIO;
-		if (!valid_signal(data))
-			break;
-		clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
-                set_singlestepping(child, 1);
-		child->exit_code = data;
-		/* give it a chance to run. */
-		wake_up_process(child);
-		ret = 0;
-		break;
-	}
-
-	case PTRACE_DETACH:
-		/* detach a process that was attached. */
-		ret = ptrace_detach(child, data);
- 		break;
-
-#ifdef PTRACE_GETREGS
-	case PTRACE_GETREGS: { /* Get all gp regs from the child. */
-		if (!access_ok(VERIFY_WRITE, p, MAX_REG_OFFSET)) {
-			ret = -EIO;
-			break;
-		}
-		for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
-			__put_user(getreg(child, i), p);
-			p++;
-		}
-		ret = 0;
-		break;
-	}
-#endif
-#ifdef PTRACE_SETREGS
-	case PTRACE_SETREGS: { /* Set all gp regs in the child. */
-		unsigned long tmp = 0;
-		if (!access_ok(VERIFY_READ, p, MAX_REG_OFFSET)) {
-			ret = -EIO;
-			break;
-		}
-		for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
-			__get_user(tmp, p);
-			putreg(child, i, tmp);
-			p++;
-		}
-		ret = 0;
-		break;
-	}
-#endif
-#ifdef PTRACE_GETFPREGS
-	case PTRACE_GETFPREGS: /* Get the child FPU state. */
-		ret = get_fpregs(data, child);
-		break;
-#endif
-#ifdef PTRACE_SETFPREGS
-	case PTRACE_SETFPREGS: /* Set the child FPU state. */
-	        ret = set_fpregs(data, child);
-		break;
-#endif
-#ifdef PTRACE_GETFPXREGS
-	case PTRACE_GETFPXREGS: /* Get the child FPU state. */
-		ret = get_fpxregs(data, child);
-		break;
-#endif
-#ifdef PTRACE_SETFPXREGS
-	case PTRACE_SETFPXREGS: /* Set the child FPU state. */
-		ret = set_fpxregs(data, child);
-		break;
-#endif
-	case PTRACE_GET_THREAD_AREA:
-		ret = ptrace_get_thread_area(child, addr,
-					     (struct user_desc __user *) data);
-		break;
-
-	case PTRACE_SET_THREAD_AREA:
-		ret = ptrace_set_thread_area(child, addr,
-					     (struct user_desc __user *) data);
-		break;
-
-	case PTRACE_FAULTINFO: {
-		/* Take the info from thread->arch->faultinfo,
-		 * but transfer max. sizeof(struct ptrace_faultinfo).
-		 * On i386, ptrace_faultinfo is smaller!
-		 */
-		ret = copy_to_user(p, &child->thread.arch.faultinfo,
-				   sizeof(struct ptrace_faultinfo));
-		if(ret)
-			break;
-		break;
-	}
-
-#ifdef PTRACE_LDT
-	case PTRACE_LDT: {
-		struct ptrace_ldt ldt;
-
-		if(copy_from_user(&ldt, p, sizeof(ldt))){
-			ret = -EIO;
-			break;
-		}
-
-		/* This one is confusing, so just punt and return -EIO for 
-		 * now
-		 */
-		ret = -EIO;
-		break;
-	}
-#endif
-#ifdef CONFIG_PROC_MM
-	case PTRACE_SWITCH_MM: {
-		struct mm_struct *old = child->mm;
-		struct mm_struct *new = proc_mm_get_mm(data);
-
-		if(IS_ERR(new)){
-			ret = PTR_ERR(new);
-			break;
-		}
-
-		atomic_inc(&new->mm_users);
-		child->mm = new;
-		child->active_mm = new;
-		mmput(old);
-		ret = 0;
-		break;
-	}
-#endif
-#ifdef PTRACE_ARCH_PRCTL
-        case PTRACE_ARCH_PRCTL:
-                /* XXX Calls ptrace on the host - needs some SMP thinking */
-                ret = arch_prctl_skas(child, data, (void *) addr);
-                break;
-#endif
-	default:
-		ret = ptrace_request(child, request, addr, data);
-		break;
-	}
-
-	return ret;
-}
-
-void send_sigtrap(struct task_struct *tsk, union uml_pt_regs *regs,
-		  int error_code)
+static void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs,
+			 int error_code)
 {
 	struct siginfo info;
 
@@ -266,56 +34,39 @@ void send_sigtrap(struct task_struct *ts
 	info.si_code = TRAP_BRKPT;
 
 	/* User-mode eip? */
-	info.si_addr = UPT_IS_USER(regs) ? (void __user *) UPT_IP(regs) : NULL;
+	info.si_addr = UPT_IS_USER(&regs->regs) ?
+		(void __user *) UPT_IP(&regs->regs) : NULL;
 
 	/* Send us the fakey SIGTRAP */
 	force_sig_info(SIGTRAP, &info, tsk);
 }
 
-/* XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and
- * PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
+/* notification of system call entry/exit
+ * - triggered by current->work.syscall_trace
  */
-void syscall_trace(union uml_pt_regs *regs, int entryexit)
+void do_syscall_trace(struct pt_regs *regs, int entryexit)
 {
-	int is_singlestep = (current->ptrace & PT_DTRACE) && entryexit;
-	int tracesysgood;
+	/* do the secure computing check first */
+	if (!entryexit)
+		secure_computing(PT_REGS_SYSCALL_NR(regs));
+
+	if (unlikely(current->audit_context) && entryexit)
+		audit_syscall_exit(AUDITSC_RESULT(UPT_SYSCALL_RET(regs)),
+				   UPT_SYSCALL_RET(regs));
+
+	if (test_thread_flag(TIF_SYSCALL_TRACE))
+		tracehook_report_syscall(regs, entryexit);
+
+	if (test_thread_flag(TIF_SINGLESTEP) && entryexit) {
+		send_sigtrap(current, regs, 0);	/* XXX */
+		tracehook_report_syscall_step(regs);
+	}
 
-	if (unlikely(current->audit_context)) {
-		if (!entryexit)
-			audit_syscall_entry(HOST_AUDIT_ARCH,
+	if (unlikely(current->audit_context) && !entryexit)
+		audit_syscall_entry(HOST_AUDIT_ARCH,
 					    UPT_SYSCALL_NR(regs),
 					    UPT_SYSCALL_ARG1(regs),
 					    UPT_SYSCALL_ARG2(regs),
 					    UPT_SYSCALL_ARG3(regs),
 					    UPT_SYSCALL_ARG4(regs));
-		else audit_syscall_exit(AUDITSC_RESULT(UPT_SYSCALL_RET(regs)),
-                                        UPT_SYSCALL_RET(regs));
-	}
-
-	/* Fake a debug trap */
-	if (is_singlestep)
-		send_sigtrap(current, regs, 0);
-
-	if (!test_thread_flag(TIF_SYSCALL_TRACE))
-		return;
-
-	if (!(current->ptrace & PT_PTRACED))
-		return;
-
-	/* the 0x80 provides a way for the tracing parent to distinguish
-	   between a syscall stop and SIGTRAP delivery */
-	tracesysgood = (current->ptrace & PT_TRACESYSGOOD);
-	ptrace_notify(SIGTRAP | (tracesysgood ? 0x80 : 0));
-
-	if (entryexit) /* force do_signal() --> is_syscall() */
-		set_thread_flag(TIF_SIGPENDING);
-
-	/* 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;
-	}
 }
Index: linux-2.6.18-mm/include/asm-um/tracehook.h
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.18-mm/include/asm-um/tracehook.h	2007-02-20 16:18:50.000000000 -0500
@@ -0,0 +1,66 @@
+/*
+ * Tracing hooks, i386 CPU support
+ *
+ * Copyright (C) 2006, 2007 Red Hat, Inc.  All rights reserved.
+ *
+ * This copyrighted material is made available to anyone wishing to use,
+ * modify, copy, or redistribute it subject to the terms and conditions
+ * of the GNU General Public License v.2.
+ *
+ * Red Hat Author: Roland McGrath.
+ *
+ * Munged for UML - jdike@{addtoit,linux.intel}.com
+ */
+
+#ifndef _ASM_TRACEHOOK_H
+#define _ASM_TRACEHOOK_H	1
+
+#include <linux/sched.h>
+#include <asm/ptrace.h>
+#include <asm/thread_info.h>
+
+/*
+ * See linux/tracehook.h for the descriptions of what these need to do.
+ */
+
+#define ARCH_HAS_SINGLE_STEP	(1)
+
+static inline void tracehook_enable_single_step(struct task_struct *tsk)
+{
+	set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
+}
+
+static inline void tracehook_disable_single_step(struct task_struct *tsk)
+{
+	clear_tsk_thread_flag(tsk, TIF_SINGLESTEP);
+}
+
+static inline int tracehook_single_step_enabled(struct task_struct *tsk)
+{
+	return test_tsk_thread_flag(tsk, TIF_SINGLESTEP);
+}
+
+static inline void tracehook_enable_syscall_trace(struct task_struct *tsk)
+{
+	set_tsk_thread_flag(tsk, TIF_SYSCALL_TRACE);
+}
+
+static inline void tracehook_disable_syscall_trace(struct task_struct *tsk)
+{
+	clear_tsk_thread_flag(tsk, TIF_SYSCALL_TRACE);
+}
+
+static inline void tracehook_abort_syscall(struct pt_regs *regs)
+{
+	PT_REGS_SYSCALL_NR(regs) = -1;
+}
+
+extern const struct utrace_regset_view utrace_um_native;
+static inline const struct utrace_regset_view *
+utrace_native_view(struct task_struct *tsk)
+{
+	return &utrace_um_native;
+}
+
+
+#endif
Index: linux-2.6.18-mm/arch/um/kernel/signal.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/kernel/signal.c	2007-02-20 16:18:37.000000000 -0500
+++ linux-2.6.18-mm/arch/um/kernel/signal.c	2007-02-20 16:18:50.000000000 -0500
@@ -14,6 +14,7 @@
 #include "linux/tty.h"
 #include "linux/binfmts.h"
 #include "linux/ptrace.h"
+#include "linux/tracehook.h"
 #include "asm/signal.h"
 #include "asm/uaccess.h"
 #include "asm/unistd.h"
@@ -93,6 +94,8 @@ static int handle_signal(struct pt_regs 
 			sigaddset(&current->blocked, signr);
 		recalc_sigpending();
 		spin_unlock_irq(&current->sighand->siglock);
+
+		tracehook_report_handle_signal(signr, ka, oldset, regs);
 	}
 
 	return err;
@@ -148,7 +151,7 @@ static int kern_do_signal(struct pt_regs
 	 * on the host.  The tracing thread will check this flag and
 	 * PTRACE_SYSCALL if necessary.
 	 */
-	if(current->ptrace & PT_DTRACE)
+	if(test_thread_flag(TIF_SYSCALL_TRACE))
 		current->thread.singlestep_syscall =
 			is_syscall(PT_REGS_IP(&current->thread.regs));
 
Index: linux-2.6.18-mm/arch/um/kernel/skas/syscall.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/kernel/skas/syscall.c	2007-02-20 16:18:07.000000000 -0500
+++ linux-2.6.18-mm/arch/um/kernel/skas/syscall.c	2007-02-20 16:18:50.000000000 -0500
@@ -19,8 +19,6 @@ void handle_syscall(union uml_pt_regs *r
 	long result;
 	int syscall;
 
-	syscall_trace(r, 0);
-
 	current->thread.nsyscalls++;
 	nsyscalls++;
 
@@ -38,6 +36,4 @@ void handle_syscall(union uml_pt_regs *r
 	else result = EXECUTE_SYSCALL(syscall, regs);
 
 	REGS_SET_SYSCALL_RETURN(r->skas.regs, result);
-
-	syscall_trace(r, 1);
 }
Index: linux-2.6.18-mm/arch/um/sys-i386/signal.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/sys-i386/signal.c	2007-02-20 16:18:07.000000000 -0500
+++ linux-2.6.18-mm/arch/um/sys-i386/signal.c	2007-02-20 16:18:50.000000000 -0500
@@ -267,8 +267,6 @@ int setup_signal_stack_sc(unsigned long 
 	PT_REGS_EDX(regs) = (unsigned long) 0;
 	PT_REGS_ECX(regs) = (unsigned long) 0;
 
-	if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
-		ptrace_notify(SIGTRAP);
 	return 0;
 
 err:
@@ -324,8 +322,6 @@ int setup_signal_stack_si(unsigned long 
 	PT_REGS_EDX(regs) = (unsigned long) &frame->info;
 	PT_REGS_ECX(regs) = (unsigned long) &frame->uc;
 
-	if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
-		ptrace_notify(SIGTRAP);
 	return 0;
 
 err:
Index: linux-2.6.18-mm/include/asm-um/ptrace-generic.h
===================================================================
--- linux-2.6.18-mm.orig/include/asm-um/ptrace-generic.h	2007-02-20 16:18:07.000000000 -0500
+++ linux-2.6.18-mm/include/asm-um/ptrace-generic.h	2007-02-20 16:18:50.000000000 -0500
@@ -44,9 +44,6 @@ extern int set_fpxregs(unsigned long buf
 
 extern void show_regs(struct pt_regs *regs);
 
-extern void send_sigtrap(struct task_struct *tsk, union uml_pt_regs *regs,
-			 int error_code);
-
 extern int arch_copy_tls(struct task_struct *new);
 extern void clear_flushed_tls(struct task_struct *task);
 

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Re: [PATCH] UML utrace support, step 1

[Roland McGrath]

> Below is the first step in your Fix-Your-Broken-Arch-HOWTO for UML.

Great!  Thanks for tackling this.

> Do you want incremental patches as I go along, or replacement ones?

The way I've organized my patch series is with the arch support split up
along with the separate infrastructure patches in the series.  That is,
just asm/tracehook.h with no utrace_regset stuff in the first patch so that
the kernel builds with only utrace-tracehook.patch; then the regset stuff
but no arch_ptrace et al in another patch so that it builds with
utrace-regset.patch but without the later patches; then arch_ptrace et al
in the final arch patch.  Your patch is mostly just the first of these
(utrace-tracehook-um), but includes utrace_regset and arch_ptrace stubs
that won't compile without the later infrastructure patches applied.

If you want to divide things up this way, then I'd like just to see a
replacement utrace-tracehook-um.patch followed by utrace-regset-um.patch
and utrace-ptrace-compat-um.patch, replacing each one whole as needed until
it's merged into my trees, and then I can take incremental changes after
that.  If you don't want to bother with dividing things so it compiles in
between patches in the series, then just one big replacement patch is fine.

> +const struct utrace_regset_view utrace_um_native = {
> +	.name		= "um",

This name wants to be the subarch name--it's usually the $ARCH or
UTS_MACHINE, i.e. the canonical arch name (i386 not i686, but ppc64 or ppc,
not powerpc).  In fact, I'm sure you really want to define the
utrace_regset_view structs separately somewhere in arch/um/sys-$SUBARCH.
On biarch platforms you'll need more than one, as the native biarch
platforms have.  (But that is all part of the second step that isn't really
tackled in this patch.)

> +#define ARCH_HAS_SINGLE_STEP	(1)

Note you'll eventually want to define the block-step macro and functions
depending on subarch.  (ia64 supports it, and x86 one day will.)

> +extern const struct utrace_regset_view utrace_um_native;
> +static inline const struct utrace_regset_view *
> +utrace_native_view(struct task_struct *tsk)
> +{
> +	return &utrace_um_native;
> +}

You probably just want an extern decl for utrace_native_view here,
since what it really does with depend on the subarch.

> BTW, UML runs on the utrace in -mm (i.e. utrace on the host), which it
> didn't with several Fedora kernels.

Oh, really?  That's good, but are you sure?  Have you tried a
CONFIG_PREEMPT=y host?  I reproduced a failure with the current code
recently after Alexey Dobriyan reported the problem.  But I didn't get
anywhere debugging it and got busy with other work.  I could use some help
tracking down what ptrace does differently that broke UML, if it does
indeed still come up.  I have plenty of experience debugging ptrace and
users of it, but I don't know much of anything about UML's usage pattern
and got quickly lost in its code trying to tell what it expected to happen.


Thanks,
Roland

Re: [uml-devel] [PATCH] UML utrace support, step 1

[Roland McGrath]

> Below is the first step in your Fix-Your-Broken-Arch-HOWTO for UML.

Great!  Thanks for tackling this.

> Do you want incremental patches as I go along, or replacement ones?

The way I've organized my patch series is with the arch support split up
along with the separate infrastructure patches in the series.  That is,
just asm/tracehook.h with no utrace_regset stuff in the first patch so that
the kernel builds with only utrace-tracehook.patch; then the regset stuff
but no arch_ptrace et al in another patch so that it builds with
utrace-regset.patch but without the later patches; then arch_ptrace et al
in the final arch patch.  Your patch is mostly just the first of these
(utrace-tracehook-um), but includes utrace_regset and arch_ptrace stubs
that won't compile without the later infrastructure patches applied.

If you want to divide things up this way, then I'd like just to see a
replacement utrace-tracehook-um.patch followed by utrace-regset-um.patch
and utrace-ptrace-compat-um.patch, replacing each one whole as needed until
it's merged into my trees, and then I can take incremental changes after
that.  If you don't want to bother with dividing things so it compiles in
between patches in the series, then just one big replacement patch is fine.

> +const struct utrace_regset_view utrace_um_native = {
> +	.name		= "um",

This name wants to be the subarch name--it's usually the $ARCH or
UTS_MACHINE, i.e. the canonical arch name (i386 not i686, but ppc64 or ppc,
not powerpc).  In fact, I'm sure you really want to define the
utrace_regset_view structs separately somewhere in arch/um/sys-$SUBARCH.
On biarch platforms you'll need more than one, as the native biarch
platforms have.  (But that is all part of the second step that isn't really
tackled in this patch.)

> +#define ARCH_HAS_SINGLE_STEP	(1)

Note you'll eventually want to define the block-step macro and functions
depending on subarch.  (ia64 supports it, and x86 one day will.)

> +extern const struct utrace_regset_view utrace_um_native;
> +static inline const struct utrace_regset_view *
> +utrace_native_view(struct task_struct *tsk)
> +{
> +	return &utrace_um_native;
> +}

You probably just want an extern decl for utrace_native_view here,
since what it really does with depend on the subarch.

> BTW, UML runs on the utrace in -mm (i.e. utrace on the host), which it
> didn't with several Fedora kernels.

Oh, really?  That's good, but are you sure?  Have you tried a
CONFIG_PREEMPT=y host?  I reproduced a failure with the current code
recently after Alexey Dobriyan reported the problem.  But I didn't get
anywhere debugging it and got busy with other work.  I could use some help
tracking down what ptrace does differently that broke UML, if it does
indeed still come up.  I have plenty of experience debugging ptrace and
users of it, but I don't know much of anything about UML's usage pattern
and got quickly lost in its code trying to tell what it expected to happen.


Thanks,
Roland

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Re: [PATCH] UML utrace support, step 1

[Jeff Dike]

On Wed, Feb 21, 2007 at 03:12:28AM -0800, Roland McGrath wrote:
> The way I've organized my patch series is with the arch support split up
> along with the separate infrastructure patches in the series.  That is,
> just asm/tracehook.h with no utrace_regset stuff in the first patch so that
> the kernel builds with only utrace-tracehook.patch; then the regset stuff
> but no arch_ptrace et al in another patch so that it builds with
> utrace-regset.patch but without the later patches; then arch_ptrace et al
> in the final arch patch.

OK, I'll do it this way.


> If you want to divide things up this way, then I'd like just to see a
> replacement utrace-tracehook-um.patch

Below.

> > +const struct utrace_regset_view utrace_um_native = {
> > +	.name		= "um",
> 
> This name wants to be the subarch name--it's usually the $ARCH or
> UTS_MACHINE, i.e. the canonical arch name (i386 not i686, but ppc64 or ppc,
> not powerpc).  In fact, I'm sure you really want to define the
> utrace_regset_view structs separately somewhere in arch/um/sys-$SUBARCH.

Yup, I'll leave this here, with .name initialized as SUBARCH, with the regsets
defined in sys-$(ARCH) somewhere.

> > +#define ARCH_HAS_SINGLE_STEP	(1)
> 
> Note you'll eventually want to define the block-step macro and functions
> depending on subarch.  (ia64 supports it, and x86 one day will.)

Fixed.  block-step is hardware-trap-on-branch or something similar?

> You probably just want an extern decl for utrace_native_view here,
> since what it really does with depend on the subarch.

I'm leaving it here, with pieces imported from the underlying arch.

> > BTW, UML runs on the utrace in -mm (i.e. utrace on the host), which it
> > didn't with several Fedora kernels.
> 
> Oh, really?  That's good, but are you sure?

Yeah, it seems fine to me.  It's been happily running a 64-way kernel build
loop the last couple of days.  The Fedora kernels I tried couldn't even
boot UML.

> Have you tried a CONFIG_PREEMPT=y host?

No, this is with preempt off.

> I have plenty of experience debugging ptrace and
> users of it, but I don't know much of anything about UML's usage pattern
> and got quickly lost in its code trying to tell what it expected to happen.

I don't think UML's ptrace usage is too strange, just all the stuff around
it might get in the way conceptually.

If you want some help figuring things out, I'll be happy to help.  Stop
by #uml in irc.oftc.net.

				Jeff

-- 
Work email - jdike at linux dot intel dot com


Step 1 of utrace support.  Add tracehooks.h plus enough other changes to
get UML to build and run.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
--
 arch/um/kernel/exec.c           |    1 
 arch/um/kernel/process.c        |    6 
 arch/um/kernel/ptrace.c         |  333 +++++-----------------------------------
 arch/um/kernel/signal.c         |    5 
 arch/um/kernel/skas/syscall.c   |    4 
 arch/um/sys-i386/signal.c       |    4 
 include/asm-um/ptrace-generic.h |    3 
 include/asm-um/ptrace-i386.h    |    2 
 include/asm-um/ptrace-x86_64.h  |    2 
 include/asm-um/tracehook.h      |   64 +++++++
 10 files changed, 117 insertions(+), 307 deletions(-)

Index: linux-2.6.18-mm/arch/um/kernel/exec.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/kernel/exec.c	2007-02-21 12:53:38.000000000 -0500
+++ linux-2.6.18-mm/arch/um/kernel/exec.c	2007-02-21 12:53:50.000000000 -0500
@@ -51,7 +51,6 @@ static long execve1(char *file, char __u
         error = do_execve(file, argv, env, &current->thread.regs);
         if (error == 0){
 		task_lock(current);
-                current->ptrace &= ~PT_DTRACE;
 #ifdef SUBARCH_EXECVE1
 		SUBARCH_EXECVE1(&current->thread.regs.regs);
 #endif
Index: linux-2.6.18-mm/arch/um/kernel/process.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/kernel/process.c	2007-02-21 12:53:38.000000000 -0500
+++ linux-2.6.18-mm/arch/um/kernel/process.c	2007-02-21 12:53:50.000000000 -0500
@@ -458,11 +458,11 @@ int singlestepping(void * t)
 {
 	struct task_struct *task = t ? t : current;
 
-	if ( ! (task->ptrace & PT_DTRACE) )
-		return(0);
+	if (!test_thread_flag(TIF_SINGLESTEP))
+		return 0;
 
 	if (task->thread.singlestep_syscall)
-		return(1);
+		return 1;
 
 	return 2;
 }
Index: linux-2.6.18-mm/arch/um/kernel/ptrace.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/kernel/ptrace.c	2007-02-21 12:53:38.000000000 -0500
+++ linux-2.6.18-mm/arch/um/kernel/ptrace.c	2007-02-21 13:05:30.000000000 -0500
@@ -3,261 +3,29 @@
  * Licensed under the GPL
  */
 
-#include "linux/sched.h"
-#include "linux/mm.h"
-#include "linux/errno.h"
-#include "linux/smp_lock.h"
-#include "linux/security.h"
-#include "linux/ptrace.h"
-#include "linux/audit.h"
-#ifdef CONFIG_PROC_MM
-#include "linux/proc_mm.h"
-#endif
-#include "asm/ptrace.h"
-#include "asm/uaccess.h"
-#include "kern_util.h"
-#include "skas_ptrace.h"
-#include "sysdep/ptrace.h"
-#include "os.h"
-
-static inline void set_singlestepping(struct task_struct *child, int on)
+#include <linux/audit.h>
+#include <linux/elf.h>
+#include <linux/module.h>
+#include <linux/ptrace.h>
+#include <linux/tracehook.h>
+
+const struct utrace_regset_view utrace_um_native = {
+	.name		= SUBARCH,
+	.e_machine	= ELF_ARCH,
+	.regsets	= NULL,
+	.n		= 0,
+};
+EXPORT_SYMBOL_GPL(utrace_um_native);
+
+int arch_ptrace(long *req, struct task_struct *child,
+		struct utrace_attached_engine *engine,
+		unsigned long addr, unsigned long data, long *val)
 {
-        if (on)
-                child->ptrace |= PT_DTRACE;
-        else
-                child->ptrace &= ~PT_DTRACE;
-        child->thread.singlestep_syscall = 0;
-
-#ifdef SUBARCH_SET_SINGLESTEPPING
-        SUBARCH_SET_SINGLESTEPPING(child, on);
-#endif
+	return -ENOSYS;
 }
 
-/*
- * Called by kernel/ptrace.c when detaching..
- */
-void ptrace_disable(struct task_struct *child)
-{ 
-        set_singlestepping(child,0);
-}
-
-extern int peek_user(struct task_struct * child, long addr, long data);
-extern int poke_user(struct task_struct * child, long addr, long data);
-
-long arch_ptrace(struct task_struct *child, long request, long addr, long data)
-{
-	int i, ret;
-	unsigned long __user *p = (void __user *)(unsigned long)data;
-
-	switch (request) {
-		/* when I and D space are separate, these will need to be fixed. */
-	case PTRACE_PEEKTEXT: /* read word at location addr. */ 
-	case PTRACE_PEEKDATA: {
-		unsigned long tmp;
-		int copied;
-
-		ret = -EIO;
-		copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
-		if (copied != sizeof(tmp))
-			break;
-		ret = put_user(tmp, p);
-		break;
-	}
-
-	/* read the word at location addr in the USER area. */
-        case PTRACE_PEEKUSR:
-                ret = peek_user(child, addr, data);
-                break;
-
-	/* when I and D space are separate, this will have to be fixed. */
-	case PTRACE_POKETEXT: /* write the word at location addr. */
-	case PTRACE_POKEDATA:
-		ret = -EIO;
-		if (access_process_vm(child, addr, &data, sizeof(data), 
-				      1) != sizeof(data))
-			break;
-		ret = 0;
-		break;
-
-	case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
-                ret = poke_user(child, addr, data);
-                break;
-
-	case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
-	case PTRACE_CONT: { /* restart after signal. */
-		ret = -EIO;
-		if (!valid_signal(data))
-			break;
-
-                set_singlestepping(child, 0);
-		if (request == PTRACE_SYSCALL) {
-			set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
-		}
-		else {
-			clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
-		}
-		child->exit_code = data;
-		wake_up_process(child);
-		ret = 0;
-		break;
-	}
-
-/*
- * make the child exit.  Best I can do is send it a sigkill. 
- * perhaps it should be put in the status that it wants to 
- * exit.
- */
-	case PTRACE_KILL: {
-		ret = 0;
-		if (child->exit_state == EXIT_ZOMBIE)	/* already dead */
-			break;
-
-                set_singlestepping(child, 0);
-		child->exit_code = SIGKILL;
-		wake_up_process(child);
-		break;
-	}
-
-	case PTRACE_SINGLESTEP: {  /* set the trap flag. */
-		ret = -EIO;
-		if (!valid_signal(data))
-			break;
-		clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
-                set_singlestepping(child, 1);
-		child->exit_code = data;
-		/* give it a chance to run. */
-		wake_up_process(child);
-		ret = 0;
-		break;
-	}
-
-	case PTRACE_DETACH:
-		/* detach a process that was attached. */
-		ret = ptrace_detach(child, data);
- 		break;
-
-#ifdef PTRACE_GETREGS
-	case PTRACE_GETREGS: { /* Get all gp regs from the child. */
-		if (!access_ok(VERIFY_WRITE, p, MAX_REG_OFFSET)) {
-			ret = -EIO;
-			break;
-		}
-		for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
-			__put_user(getreg(child, i), p);
-			p++;
-		}
-		ret = 0;
-		break;
-	}
-#endif
-#ifdef PTRACE_SETREGS
-	case PTRACE_SETREGS: { /* Set all gp regs in the child. */
-		unsigned long tmp = 0;
-		if (!access_ok(VERIFY_READ, p, MAX_REG_OFFSET)) {
-			ret = -EIO;
-			break;
-		}
-		for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
-			__get_user(tmp, p);
-			putreg(child, i, tmp);
-			p++;
-		}
-		ret = 0;
-		break;
-	}
-#endif
-#ifdef PTRACE_GETFPREGS
-	case PTRACE_GETFPREGS: /* Get the child FPU state. */
-		ret = get_fpregs(data, child);
-		break;
-#endif
-#ifdef PTRACE_SETFPREGS
-	case PTRACE_SETFPREGS: /* Set the child FPU state. */
-	        ret = set_fpregs(data, child);
-		break;
-#endif
-#ifdef PTRACE_GETFPXREGS
-	case PTRACE_GETFPXREGS: /* Get the child FPU state. */
-		ret = get_fpxregs(data, child);
-		break;
-#endif
-#ifdef PTRACE_SETFPXREGS
-	case PTRACE_SETFPXREGS: /* Set the child FPU state. */
-		ret = set_fpxregs(data, child);
-		break;
-#endif
-	case PTRACE_GET_THREAD_AREA:
-		ret = ptrace_get_thread_area(child, addr,
-					     (struct user_desc __user *) data);
-		break;
-
-	case PTRACE_SET_THREAD_AREA:
-		ret = ptrace_set_thread_area(child, addr,
-					     (struct user_desc __user *) data);
-		break;
-
-	case PTRACE_FAULTINFO: {
-		/* Take the info from thread->arch->faultinfo,
-		 * but transfer max. sizeof(struct ptrace_faultinfo).
-		 * On i386, ptrace_faultinfo is smaller!
-		 */
-		ret = copy_to_user(p, &child->thread.arch.faultinfo,
-				   sizeof(struct ptrace_faultinfo));
-		if(ret)
-			break;
-		break;
-	}
-
-#ifdef PTRACE_LDT
-	case PTRACE_LDT: {
-		struct ptrace_ldt ldt;
-
-		if(copy_from_user(&ldt, p, sizeof(ldt))){
-			ret = -EIO;
-			break;
-		}
-
-		/* This one is confusing, so just punt and return -EIO for 
-		 * now
-		 */
-		ret = -EIO;
-		break;
-	}
-#endif
-#ifdef CONFIG_PROC_MM
-	case PTRACE_SWITCH_MM: {
-		struct mm_struct *old = child->mm;
-		struct mm_struct *new = proc_mm_get_mm(data);
-
-		if(IS_ERR(new)){
-			ret = PTR_ERR(new);
-			break;
-		}
-
-		atomic_inc(&new->mm_users);
-		child->mm = new;
-		child->active_mm = new;
-		mmput(old);
-		ret = 0;
-		break;
-	}
-#endif
-#ifdef PTRACE_ARCH_PRCTL
-        case PTRACE_ARCH_PRCTL:
-                /* XXX Calls ptrace on the host - needs some SMP thinking */
-                ret = arch_prctl_skas(child, data, (void *) addr);
-                break;
-#endif
-	default:
-		ret = ptrace_request(child, request, addr, data);
-		break;
-	}
-
-	return ret;
-}
-
-void send_sigtrap(struct task_struct *tsk, union uml_pt_regs *regs,
-		  int error_code)
+static void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs,
+			 int error_code)
 {
 	struct siginfo info;
 
@@ -266,56 +34,39 @@ void send_sigtrap(struct task_struct *ts
 	info.si_code = TRAP_BRKPT;
 
 	/* User-mode eip? */
-	info.si_addr = UPT_IS_USER(regs) ? (void __user *) UPT_IP(regs) : NULL;
+	info.si_addr = UPT_IS_USER(&regs->regs) ?
+		(void __user *) UPT_IP(&regs->regs) : NULL;
 
 	/* Send us the fakey SIGTRAP */
 	force_sig_info(SIGTRAP, &info, tsk);
 }
 
-/* XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and
- * PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
+/* notification of system call entry/exit
+ * - triggered by current->work.syscall_trace
  */
-void syscall_trace(union uml_pt_regs *regs, int entryexit)
+void do_syscall_trace(struct pt_regs *regs, int entryexit)
 {
-	int is_singlestep = (current->ptrace & PT_DTRACE) && entryexit;
-	int tracesysgood;
+	/* do the secure computing check first */
+	if (!entryexit)
+		secure_computing(PT_REGS_SYSCALL_NR(regs));
+
+	if (unlikely(current->audit_context) && entryexit)
+		audit_syscall_exit(AUDITSC_RESULT(UPT_SYSCALL_RET(regs)),
+				   UPT_SYSCALL_RET(regs));
+
+	if (test_thread_flag(TIF_SYSCALL_TRACE))
+		tracehook_report_syscall(regs, entryexit);
+
+	if (test_thread_flag(TIF_SINGLESTEP) && entryexit) {
+		send_sigtrap(current, regs, 0);	/* XXX */
+		tracehook_report_syscall_step(regs);
+	}
 
-	if (unlikely(current->audit_context)) {
-		if (!entryexit)
-			audit_syscall_entry(HOST_AUDIT_ARCH,
+	if (unlikely(current->audit_context) && !entryexit)
+		audit_syscall_entry(HOST_AUDIT_ARCH,
 					    UPT_SYSCALL_NR(regs),
 					    UPT_SYSCALL_ARG1(regs),
 					    UPT_SYSCALL_ARG2(regs),
 					    UPT_SYSCALL_ARG3(regs),
 					    UPT_SYSCALL_ARG4(regs));
-		else audit_syscall_exit(AUDITSC_RESULT(UPT_SYSCALL_RET(regs)),
-                                        UPT_SYSCALL_RET(regs));
-	}
-
-	/* Fake a debug trap */
-	if (is_singlestep)
-		send_sigtrap(current, regs, 0);
-
-	if (!test_thread_flag(TIF_SYSCALL_TRACE))
-		return;
-
-	if (!(current->ptrace & PT_PTRACED))
-		return;
-
-	/* the 0x80 provides a way for the tracing parent to distinguish
-	   between a syscall stop and SIGTRAP delivery */
-	tracesysgood = (current->ptrace & PT_TRACESYSGOOD);
-	ptrace_notify(SIGTRAP | (tracesysgood ? 0x80 : 0));
-
-	if (entryexit) /* force do_signal() --> is_syscall() */
-		set_thread_flag(TIF_SIGPENDING);
-
-	/* 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;
-	}
 }
Index: linux-2.6.18-mm/include/asm-um/tracehook.h
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.18-mm/include/asm-um/tracehook.h	2007-02-21 13:08:31.000000000 -0500
@@ -0,0 +1,64 @@
+/*
+ * Tracing hooks, i386 CPU support
+ *
+ * Copyright (C) 2006, 2007 Red Hat, Inc.  All rights reserved.
+ *
+ * This copyrighted material is made available to anyone wishing to use,
+ * modify, copy, or redistribute it subject to the terms and conditions
+ * of the GNU General Public License v.2.
+ *
+ * Red Hat Author: Roland McGrath.
+ *
+ * Munged for UML - jdike@{addtoit,linux.intel}.com
+ */
+
+#ifndef _ASM_TRACEHOOK_H
+#define _ASM_TRACEHOOK_H	1
+
+#include <linux/sched.h>
+#include <asm/ptrace.h>
+#include <asm/thread_info.h>
+
+/*
+ * See linux/tracehook.h for the descriptions of what these need to do.
+ */
+
+static inline void tracehook_enable_single_step(struct task_struct *tsk)
+{
+	set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
+}
+
+static inline void tracehook_disable_single_step(struct task_struct *tsk)
+{
+	clear_tsk_thread_flag(tsk, TIF_SINGLESTEP);
+}
+
+static inline int tracehook_single_step_enabled(struct task_struct *tsk)
+{
+	return test_tsk_thread_flag(tsk, TIF_SINGLESTEP);
+}
+
+static inline void tracehook_enable_syscall_trace(struct task_struct *tsk)
+{
+	set_tsk_thread_flag(tsk, TIF_SYSCALL_TRACE);
+}
+
+static inline void tracehook_disable_syscall_trace(struct task_struct *tsk)
+{
+	clear_tsk_thread_flag(tsk, TIF_SYSCALL_TRACE);
+}
+
+static inline void tracehook_abort_syscall(struct pt_regs *regs)
+{
+	PT_REGS_SYSCALL_NR(regs) = -1;
+}
+
+extern const struct utrace_regset_view utrace_um_native;
+static inline const struct utrace_regset_view *
+utrace_native_view(struct task_struct *tsk)
+{
+	return &utrace_um_native;
+}
+
+
+#endif
Index: linux-2.6.18-mm/arch/um/kernel/signal.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/kernel/signal.c	2007-02-21 12:53:38.000000000 -0500
+++ linux-2.6.18-mm/arch/um/kernel/signal.c	2007-02-21 12:53:50.000000000 -0500
@@ -14,6 +14,7 @@
 #include "linux/tty.h"
 #include "linux/binfmts.h"
 #include "linux/ptrace.h"
+#include "linux/tracehook.h"
 #include "asm/signal.h"
 #include "asm/uaccess.h"
 #include "asm/unistd.h"
@@ -93,6 +94,8 @@ static int handle_signal(struct pt_regs 
 			sigaddset(&current->blocked, signr);
 		recalc_sigpending();
 		spin_unlock_irq(&current->sighand->siglock);
+
+		tracehook_report_handle_signal(signr, ka, oldset, regs);
 	}
 
 	return err;
@@ -148,7 +151,7 @@ static int kern_do_signal(struct pt_regs
 	 * on the host.  The tracing thread will check this flag and
 	 * PTRACE_SYSCALL if necessary.
 	 */
-	if(current->ptrace & PT_DTRACE)
+	if(test_thread_flag(TIF_SYSCALL_TRACE))
 		current->thread.singlestep_syscall =
 			is_syscall(PT_REGS_IP(&current->thread.regs));
 
Index: linux-2.6.18-mm/arch/um/kernel/skas/syscall.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/kernel/skas/syscall.c	2007-02-21 12:53:38.000000000 -0500
+++ linux-2.6.18-mm/arch/um/kernel/skas/syscall.c	2007-02-21 12:53:50.000000000 -0500
@@ -19,8 +19,6 @@ void handle_syscall(union uml_pt_regs *r
 	long result;
 	int syscall;
 
-	syscall_trace(r, 0);
-
 	current->thread.nsyscalls++;
 	nsyscalls++;
 
@@ -38,6 +36,4 @@ void handle_syscall(union uml_pt_regs *r
 	else result = EXECUTE_SYSCALL(syscall, regs);
 
 	REGS_SET_SYSCALL_RETURN(r->skas.regs, result);
-
-	syscall_trace(r, 1);
 }
Index: linux-2.6.18-mm/arch/um/sys-i386/signal.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/sys-i386/signal.c	2007-02-21 12:53:38.000000000 -0500
+++ linux-2.6.18-mm/arch/um/sys-i386/signal.c	2007-02-21 12:53:50.000000000 -0500
@@ -267,8 +267,6 @@ int setup_signal_stack_sc(unsigned long 
 	PT_REGS_EDX(regs) = (unsigned long) 0;
 	PT_REGS_ECX(regs) = (unsigned long) 0;
 
-	if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
-		ptrace_notify(SIGTRAP);
 	return 0;
 
 err:
@@ -324,8 +322,6 @@ int setup_signal_stack_si(unsigned long 
 	PT_REGS_EDX(regs) = (unsigned long) &frame->info;
 	PT_REGS_ECX(regs) = (unsigned long) &frame->uc;
 
-	if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
-		ptrace_notify(SIGTRAP);
 	return 0;
 
 err:
Index: linux-2.6.18-mm/include/asm-um/ptrace-generic.h
===================================================================
--- linux-2.6.18-mm.orig/include/asm-um/ptrace-generic.h	2007-02-21 12:53:38.000000000 -0500
+++ linux-2.6.18-mm/include/asm-um/ptrace-generic.h	2007-02-21 12:53:50.000000000 -0500
@@ -44,9 +44,6 @@ extern int set_fpxregs(unsigned long buf
 
 extern void show_regs(struct pt_regs *regs);
 
-extern void send_sigtrap(struct task_struct *tsk, union uml_pt_regs *regs,
-			 int error_code);
-
 extern int arch_copy_tls(struct task_struct *new);
 extern void clear_flushed_tls(struct task_struct *task);
 
Index: linux-2.6.18-mm/include/asm-um/ptrace-i386.h
===================================================================
--- linux-2.6.18-mm.orig/include/asm-um/ptrace-i386.h	2006-06-17 21:49:35.000000000 -0400
+++ linux-2.6.18-mm/include/asm-um/ptrace-i386.h	2007-02-21 13:08:31.000000000 -0500
@@ -6,6 +6,8 @@
 #ifndef __UM_PTRACE_I386_H
 #define __UM_PTRACE_I386_H
 
+#define ARCH_HAS_SINGLE_STEP	(1)
+
 #define HOST_AUDIT_ARCH AUDIT_ARCH_I386
 
 #include "linux/compiler.h"
Index: linux-2.6.18-mm/include/asm-um/ptrace-x86_64.h
===================================================================
--- linux-2.6.18-mm.orig/include/asm-um/ptrace-x86_64.h	2007-02-19 11:52:47.000000000 -0500
+++ linux-2.6.18-mm/include/asm-um/ptrace-x86_64.h	2007-02-21 13:07:41.000000000 -0500
@@ -14,6 +14,8 @@
 #define __FRAME_OFFSETS /* Needed to get the R* macros */
 #include "asm/ptrace-generic.h"
 
+#define ARCH_HAS_SINGLE_STEP	(1)
+
 #define HOST_AUDIT_ARCH AUDIT_ARCH_X86_64
 
 /* Also defined in sysdep/ptrace.h, so may already be defined. */

Re: [uml-devel] [PATCH] UML utrace support, step 1

[Jeff Dike]

On Wed, Feb 21, 2007 at 03:12:28AM -0800, Roland McGrath wrote:
> The way I've organized my patch series is with the arch support split up
> along with the separate infrastructure patches in the series.  That is,
> just asm/tracehook.h with no utrace_regset stuff in the first patch so that
> the kernel builds with only utrace-tracehook.patch; then the regset stuff
> but no arch_ptrace et al in another patch so that it builds with
> utrace-regset.patch but without the later patches; then arch_ptrace et al
> in the final arch patch.

OK, I'll do it this way.


> If you want to divide things up this way, then I'd like just to see a
> replacement utrace-tracehook-um.patch

Below.

> > +const struct utrace_regset_view utrace_um_native = {
> > +	.name		= "um",
> 
> This name wants to be the subarch name--it's usually the $ARCH or
> UTS_MACHINE, i.e. the canonical arch name (i386 not i686, but ppc64 or ppc,
> not powerpc).  In fact, I'm sure you really want to define the
> utrace_regset_view structs separately somewhere in arch/um/sys-$SUBARCH.

Yup, I'll leave this here, with .name initialized as SUBARCH, with the regsets
defined in sys-$(ARCH) somewhere.

> > +#define ARCH_HAS_SINGLE_STEP	(1)
> 
> Note you'll eventually want to define the block-step macro and functions
> depending on subarch.  (ia64 supports it, and x86 one day will.)

Fixed.  block-step is hardware-trap-on-branch or something similar?

> You probably just want an extern decl for utrace_native_view here,
> since what it really does with depend on the subarch.

I'm leaving it here, with pieces imported from the underlying arch.

> > BTW, UML runs on the utrace in -mm (i.e. utrace on the host), which it
> > didn't with several Fedora kernels.
> 
> Oh, really?  That's good, but are you sure?

Yeah, it seems fine to me.  It's been happily running a 64-way kernel build
loop the last couple of days.  The Fedora kernels I tried couldn't even
boot UML.

> Have you tried a CONFIG_PREEMPT=y host?

No, this is with preempt off.

> I have plenty of experience debugging ptrace and
> users of it, but I don't know much of anything about UML's usage pattern
> and got quickly lost in its code trying to tell what it expected to happen.

I don't think UML's ptrace usage is too strange, just all the stuff around
it might get in the way conceptually.

If you want some help figuring things out, I'll be happy to help.  Stop
by #uml in irc.oftc.net.

				Jeff

-- 
Work email - jdike at linux dot intel dot com


Step 1 of utrace support.  Add tracehooks.h plus enough other changes to
get UML to build and run.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
--
 arch/um/kernel/exec.c           |    1 
 arch/um/kernel/process.c        |    6 
 arch/um/kernel/ptrace.c         |  333 +++++-----------------------------------
 arch/um/kernel/signal.c         |    5 
 arch/um/kernel/skas/syscall.c   |    4 
 arch/um/sys-i386/signal.c       |    4 
 include/asm-um/ptrace-generic.h |    3 
 include/asm-um/ptrace-i386.h    |    2 
 include/asm-um/ptrace-x86_64.h  |    2 
 include/asm-um/tracehook.h      |   64 +++++++
 10 files changed, 117 insertions(+), 307 deletions(-)

Index: linux-2.6.18-mm/arch/um/kernel/exec.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/kernel/exec.c	2007-02-21 12:53:38.000000000 -0500
+++ linux-2.6.18-mm/arch/um/kernel/exec.c	2007-02-21 12:53:50.000000000 -0500
@@ -51,7 +51,6 @@ static long execve1(char *file, char __u
         error = do_execve(file, argv, env, &current->thread.regs);
         if (error == 0){
 		task_lock(current);
-                current->ptrace &= ~PT_DTRACE;
 #ifdef SUBARCH_EXECVE1
 		SUBARCH_EXECVE1(&current->thread.regs.regs);
 #endif
Index: linux-2.6.18-mm/arch/um/kernel/process.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/kernel/process.c	2007-02-21 12:53:38.000000000 -0500
+++ linux-2.6.18-mm/arch/um/kernel/process.c	2007-02-21 12:53:50.000000000 -0500
@@ -458,11 +458,11 @@ int singlestepping(void * t)
 {
 	struct task_struct *task = t ? t : current;
 
-	if ( ! (task->ptrace & PT_DTRACE) )
-		return(0);
+	if (!test_thread_flag(TIF_SINGLESTEP))
+		return 0;
 
 	if (task->thread.singlestep_syscall)
-		return(1);
+		return 1;
 
 	return 2;
 }
Index: linux-2.6.18-mm/arch/um/kernel/ptrace.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/kernel/ptrace.c	2007-02-21 12:53:38.000000000 -0500
+++ linux-2.6.18-mm/arch/um/kernel/ptrace.c	2007-02-21 13:05:30.000000000 -0500
@@ -3,261 +3,29 @@
  * Licensed under the GPL
  */
 
-#include "linux/sched.h"
-#include "linux/mm.h"
-#include "linux/errno.h"
-#include "linux/smp_lock.h"
-#include "linux/security.h"
-#include "linux/ptrace.h"
-#include "linux/audit.h"
-#ifdef CONFIG_PROC_MM
-#include "linux/proc_mm.h"
-#endif
-#include "asm/ptrace.h"
-#include "asm/uaccess.h"
-#include "kern_util.h"
-#include "skas_ptrace.h"
-#include "sysdep/ptrace.h"
-#include "os.h"
-
-static inline void set_singlestepping(struct task_struct *child, int on)
+#include <linux/audit.h>
+#include <linux/elf.h>
+#include <linux/module.h>
+#include <linux/ptrace.h>
+#include <linux/tracehook.h>
+
+const struct utrace_regset_view utrace_um_native = {
+	.name		= SUBARCH,
+	.e_machine	= ELF_ARCH,
+	.regsets	= NULL,
+	.n		= 0,
+};
+EXPORT_SYMBOL_GPL(utrace_um_native);
+
+int arch_ptrace(long *req, struct task_struct *child,
+		struct utrace_attached_engine *engine,
+		unsigned long addr, unsigned long data, long *val)
 {
-        if (on)
-                child->ptrace |= PT_DTRACE;
-        else
-                child->ptrace &= ~PT_DTRACE;
-        child->thread.singlestep_syscall = 0;
-
-#ifdef SUBARCH_SET_SINGLESTEPPING
-        SUBARCH_SET_SINGLESTEPPING(child, on);
-#endif
+	return -ENOSYS;
 }
 
-/*
- * Called by kernel/ptrace.c when detaching..
- */
-void ptrace_disable(struct task_struct *child)
-{ 
-        set_singlestepping(child,0);
-}
-
-extern int peek_user(struct task_struct * child, long addr, long data);
-extern int poke_user(struct task_struct * child, long addr, long data);
-
-long arch_ptrace(struct task_struct *child, long request, long addr, long data)
-{
-	int i, ret;
-	unsigned long __user *p = (void __user *)(unsigned long)data;
-
-	switch (request) {
-		/* when I and D space are separate, these will need to be fixed. */
-	case PTRACE_PEEKTEXT: /* read word at location addr. */ 
-	case PTRACE_PEEKDATA: {
-		unsigned long tmp;
-		int copied;
-
-		ret = -EIO;
-		copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
-		if (copied != sizeof(tmp))
-			break;
-		ret = put_user(tmp, p);
-		break;
-	}
-
-	/* read the word at location addr in the USER area. */
-        case PTRACE_PEEKUSR:
-                ret = peek_user(child, addr, data);
-                break;
-
-	/* when I and D space are separate, this will have to be fixed. */
-	case PTRACE_POKETEXT: /* write the word at location addr. */
-	case PTRACE_POKEDATA:
-		ret = -EIO;
-		if (access_process_vm(child, addr, &data, sizeof(data), 
-				      1) != sizeof(data))
-			break;
-		ret = 0;
-		break;
-
-	case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
-                ret = poke_user(child, addr, data);
-                break;
-
-	case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
-	case PTRACE_CONT: { /* restart after signal. */
-		ret = -EIO;
-		if (!valid_signal(data))
-			break;
-
-                set_singlestepping(child, 0);
-		if (request == PTRACE_SYSCALL) {
-			set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
-		}
-		else {
-			clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
-		}
-		child->exit_code = data;
-		wake_up_process(child);
-		ret = 0;
-		break;
-	}
-
-/*
- * make the child exit.  Best I can do is send it a sigkill. 
- * perhaps it should be put in the status that it wants to 
- * exit.
- */
-	case PTRACE_KILL: {
-		ret = 0;
-		if (child->exit_state == EXIT_ZOMBIE)	/* already dead */
-			break;
-
-                set_singlestepping(child, 0);
-		child->exit_code = SIGKILL;
-		wake_up_process(child);
-		break;
-	}
-
-	case PTRACE_SINGLESTEP: {  /* set the trap flag. */
-		ret = -EIO;
-		if (!valid_signal(data))
-			break;
-		clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
-                set_singlestepping(child, 1);
-		child->exit_code = data;
-		/* give it a chance to run. */
-		wake_up_process(child);
-		ret = 0;
-		break;
-	}
-
-	case PTRACE_DETACH:
-		/* detach a process that was attached. */
-		ret = ptrace_detach(child, data);
- 		break;
-
-#ifdef PTRACE_GETREGS
-	case PTRACE_GETREGS: { /* Get all gp regs from the child. */
-		if (!access_ok(VERIFY_WRITE, p, MAX_REG_OFFSET)) {
-			ret = -EIO;
-			break;
-		}
-		for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
-			__put_user(getreg(child, i), p);
-			p++;
-		}
-		ret = 0;
-		break;
-	}
-#endif
-#ifdef PTRACE_SETREGS
-	case PTRACE_SETREGS: { /* Set all gp regs in the child. */
-		unsigned long tmp = 0;
-		if (!access_ok(VERIFY_READ, p, MAX_REG_OFFSET)) {
-			ret = -EIO;
-			break;
-		}
-		for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
-			__get_user(tmp, p);
-			putreg(child, i, tmp);
-			p++;
-		}
-		ret = 0;
-		break;
-	}
-#endif
-#ifdef PTRACE_GETFPREGS
-	case PTRACE_GETFPREGS: /* Get the child FPU state. */
-		ret = get_fpregs(data, child);
-		break;
-#endif
-#ifdef PTRACE_SETFPREGS
-	case PTRACE_SETFPREGS: /* Set the child FPU state. */
-	        ret = set_fpregs(data, child);
-		break;
-#endif
-#ifdef PTRACE_GETFPXREGS
-	case PTRACE_GETFPXREGS: /* Get the child FPU state. */
-		ret = get_fpxregs(data, child);
-		break;
-#endif
-#ifdef PTRACE_SETFPXREGS
-	case PTRACE_SETFPXREGS: /* Set the child FPU state. */
-		ret = set_fpxregs(data, child);
-		break;
-#endif
-	case PTRACE_GET_THREAD_AREA:
-		ret = ptrace_get_thread_area(child, addr,
-					     (struct user_desc __user *) data);
-		break;
-
-	case PTRACE_SET_THREAD_AREA:
-		ret = ptrace_set_thread_area(child, addr,
-					     (struct user_desc __user *) data);
-		break;
-
-	case PTRACE_FAULTINFO: {
-		/* Take the info from thread->arch->faultinfo,
-		 * but transfer max. sizeof(struct ptrace_faultinfo).
-		 * On i386, ptrace_faultinfo is smaller!
-		 */
-		ret = copy_to_user(p, &child->thread.arch.faultinfo,
-				   sizeof(struct ptrace_faultinfo));
-		if(ret)
-			break;
-		break;
-	}
-
-#ifdef PTRACE_LDT
-	case PTRACE_LDT: {
-		struct ptrace_ldt ldt;
-
-		if(copy_from_user(&ldt, p, sizeof(ldt))){
-			ret = -EIO;
-			break;
-		}
-
-		/* This one is confusing, so just punt and return -EIO for 
-		 * now
-		 */
-		ret = -EIO;
-		break;
-	}
-#endif
-#ifdef CONFIG_PROC_MM
-	case PTRACE_SWITCH_MM: {
-		struct mm_struct *old = child->mm;
-		struct mm_struct *new = proc_mm_get_mm(data);
-
-		if(IS_ERR(new)){
-			ret = PTR_ERR(new);
-			break;
-		}
-
-		atomic_inc(&new->mm_users);
-		child->mm = new;
-		child->active_mm = new;
-		mmput(old);
-		ret = 0;
-		break;
-	}
-#endif
-#ifdef PTRACE_ARCH_PRCTL
-        case PTRACE_ARCH_PRCTL:
-                /* XXX Calls ptrace on the host - needs some SMP thinking */
-                ret = arch_prctl_skas(child, data, (void *) addr);
-                break;
-#endif
-	default:
-		ret = ptrace_request(child, request, addr, data);
-		break;
-	}
-
-	return ret;
-}
-
-void send_sigtrap(struct task_struct *tsk, union uml_pt_regs *regs,
-		  int error_code)
+static void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs,
+			 int error_code)
 {
 	struct siginfo info;
 
@@ -266,56 +34,39 @@ void send_sigtrap(struct task_struct *ts
 	info.si_code = TRAP_BRKPT;
 
 	/* User-mode eip? */
-	info.si_addr = UPT_IS_USER(regs) ? (void __user *) UPT_IP(regs) : NULL;
+	info.si_addr = UPT_IS_USER(&regs->regs) ?
+		(void __user *) UPT_IP(&regs->regs) : NULL;
 
 	/* Send us the fakey SIGTRAP */
 	force_sig_info(SIGTRAP, &info, tsk);
 }
 
-/* XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and
- * PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
+/* notification of system call entry/exit
+ * - triggered by current->work.syscall_trace
  */
-void syscall_trace(union uml_pt_regs *regs, int entryexit)
+void do_syscall_trace(struct pt_regs *regs, int entryexit)
 {
-	int is_singlestep = (current->ptrace & PT_DTRACE) && entryexit;
-	int tracesysgood;
+	/* do the secure computing check first */
+	if (!entryexit)
+		secure_computing(PT_REGS_SYSCALL_NR(regs));
+
+	if (unlikely(current->audit_context) && entryexit)
+		audit_syscall_exit(AUDITSC_RESULT(UPT_SYSCALL_RET(regs)),
+				   UPT_SYSCALL_RET(regs));
+
+	if (test_thread_flag(TIF_SYSCALL_TRACE))
+		tracehook_report_syscall(regs, entryexit);
+
+	if (test_thread_flag(TIF_SINGLESTEP) && entryexit) {
+		send_sigtrap(current, regs, 0);	/* XXX */
+		tracehook_report_syscall_step(regs);
+	}
 
-	if (unlikely(current->audit_context)) {
-		if (!entryexit)
-			audit_syscall_entry(HOST_AUDIT_ARCH,
+	if (unlikely(current->audit_context) && !entryexit)
+		audit_syscall_entry(HOST_AUDIT_ARCH,
 					    UPT_SYSCALL_NR(regs),
 					    UPT_SYSCALL_ARG1(regs),
 					    UPT_SYSCALL_ARG2(regs),
 					    UPT_SYSCALL_ARG3(regs),
 					    UPT_SYSCALL_ARG4(regs));
-		else audit_syscall_exit(AUDITSC_RESULT(UPT_SYSCALL_RET(regs)),
-                                        UPT_SYSCALL_RET(regs));
-	}
-
-	/* Fake a debug trap */
-	if (is_singlestep)
-		send_sigtrap(current, regs, 0);
-
-	if (!test_thread_flag(TIF_SYSCALL_TRACE))
-		return;
-
-	if (!(current->ptrace & PT_PTRACED))
-		return;
-
-	/* the 0x80 provides a way for the tracing parent to distinguish
-	   between a syscall stop and SIGTRAP delivery */
-	tracesysgood = (current->ptrace & PT_TRACESYSGOOD);
-	ptrace_notify(SIGTRAP | (tracesysgood ? 0x80 : 0));
-
-	if (entryexit) /* force do_signal() --> is_syscall() */
-		set_thread_flag(TIF_SIGPENDING);
-
-	/* 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;
-	}
 }
Index: linux-2.6.18-mm/include/asm-um/tracehook.h
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.18-mm/include/asm-um/tracehook.h	2007-02-21 13:08:31.000000000 -0500
@@ -0,0 +1,64 @@
+/*
+ * Tracing hooks, i386 CPU support
+ *
+ * Copyright (C) 2006, 2007 Red Hat, Inc.  All rights reserved.
+ *
+ * This copyrighted material is made available to anyone wishing to use,
+ * modify, copy, or redistribute it subject to the terms and conditions
+ * of the GNU General Public License v.2.
+ *
+ * Red Hat Author: Roland McGrath.
+ *
+ * Munged for UML - jdike@{addtoit,linux.intel}.com
+ */
+
+#ifndef _ASM_TRACEHOOK_H
+#define _ASM_TRACEHOOK_H	1
+
+#include <linux/sched.h>
+#include <asm/ptrace.h>
+#include <asm/thread_info.h>
+
+/*
+ * See linux/tracehook.h for the descriptions of what these need to do.
+ */
+
+static inline void tracehook_enable_single_step(struct task_struct *tsk)
+{
+	set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
+}
+
+static inline void tracehook_disable_single_step(struct task_struct *tsk)
+{
+	clear_tsk_thread_flag(tsk, TIF_SINGLESTEP);
+}
+
+static inline int tracehook_single_step_enabled(struct task_struct *tsk)
+{
+	return test_tsk_thread_flag(tsk, TIF_SINGLESTEP);
+}
+
+static inline void tracehook_enable_syscall_trace(struct task_struct *tsk)
+{
+	set_tsk_thread_flag(tsk, TIF_SYSCALL_TRACE);
+}
+
+static inline void tracehook_disable_syscall_trace(struct task_struct *tsk)
+{
+	clear_tsk_thread_flag(tsk, TIF_SYSCALL_TRACE);
+}
+
+static inline void tracehook_abort_syscall(struct pt_regs *regs)
+{
+	PT_REGS_SYSCALL_NR(regs) = -1;
+}
+
+extern const struct utrace_regset_view utrace_um_native;
+static inline const struct utrace_regset_view *
+utrace_native_view(struct task_struct *tsk)
+{
+	return &utrace_um_native;
+}
+
+
+#endif
Index: linux-2.6.18-mm/arch/um/kernel/signal.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/kernel/signal.c	2007-02-21 12:53:38.000000000 -0500
+++ linux-2.6.18-mm/arch/um/kernel/signal.c	2007-02-21 12:53:50.000000000 -0500
@@ -14,6 +14,7 @@
 #include "linux/tty.h"
 #include "linux/binfmts.h"
 #include "linux/ptrace.h"
+#include "linux/tracehook.h"
 #include "asm/signal.h"
 #include "asm/uaccess.h"
 #include "asm/unistd.h"
@@ -93,6 +94,8 @@ static int handle_signal(struct pt_regs 
 			sigaddset(&current->blocked, signr);
 		recalc_sigpending();
 		spin_unlock_irq(&current->sighand->siglock);
+
+		tracehook_report_handle_signal(signr, ka, oldset, regs);
 	}
 
 	return err;
@@ -148,7 +151,7 @@ static int kern_do_signal(struct pt_regs
 	 * on the host.  The tracing thread will check this flag and
 	 * PTRACE_SYSCALL if necessary.
 	 */
-	if(current->ptrace & PT_DTRACE)
+	if(test_thread_flag(TIF_SYSCALL_TRACE))
 		current->thread.singlestep_syscall =
 			is_syscall(PT_REGS_IP(&current->thread.regs));
 
Index: linux-2.6.18-mm/arch/um/kernel/skas/syscall.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/kernel/skas/syscall.c	2007-02-21 12:53:38.000000000 -0500
+++ linux-2.6.18-mm/arch/um/kernel/skas/syscall.c	2007-02-21 12:53:50.000000000 -0500
@@ -19,8 +19,6 @@ void handle_syscall(union uml_pt_regs *r
 	long result;
 	int syscall;
 
-	syscall_trace(r, 0);
-
 	current->thread.nsyscalls++;
 	nsyscalls++;
 
@@ -38,6 +36,4 @@ void handle_syscall(union uml_pt_regs *r
 	else result = EXECUTE_SYSCALL(syscall, regs);
 
 	REGS_SET_SYSCALL_RETURN(r->skas.regs, result);
-
-	syscall_trace(r, 1);
 }
Index: linux-2.6.18-mm/arch/um/sys-i386/signal.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/sys-i386/signal.c	2007-02-21 12:53:38.000000000 -0500
+++ linux-2.6.18-mm/arch/um/sys-i386/signal.c	2007-02-21 12:53:50.000000000 -0500
@@ -267,8 +267,6 @@ int setup_signal_stack_sc(unsigned long 
 	PT_REGS_EDX(regs) = (unsigned long) 0;
 	PT_REGS_ECX(regs) = (unsigned long) 0;
 
-	if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
-		ptrace_notify(SIGTRAP);
 	return 0;
 
 err:
@@ -324,8 +322,6 @@ int setup_signal_stack_si(unsigned long 
 	PT_REGS_EDX(regs) = (unsigned long) &frame->info;
 	PT_REGS_ECX(regs) = (unsigned long) &frame->uc;
 
-	if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
-		ptrace_notify(SIGTRAP);
 	return 0;
 
 err:
Index: linux-2.6.18-mm/include/asm-um/ptrace-generic.h
===================================================================
--- linux-2.6.18-mm.orig/include/asm-um/ptrace-generic.h	2007-02-21 12:53:38.000000000 -0500
+++ linux-2.6.18-mm/include/asm-um/ptrace-generic.h	2007-02-21 12:53:50.000000000 -0500
@@ -44,9 +44,6 @@ extern int set_fpxregs(unsigned long buf
 
 extern void show_regs(struct pt_regs *regs);
 
-extern void send_sigtrap(struct task_struct *tsk, union uml_pt_regs *regs,
-			 int error_code);
-
 extern int arch_copy_tls(struct task_struct *new);
 extern void clear_flushed_tls(struct task_struct *task);
 
Index: linux-2.6.18-mm/include/asm-um/ptrace-i386.h
===================================================================
--- linux-2.6.18-mm.orig/include/asm-um/ptrace-i386.h	2006-06-17 21:49:35.000000000 -0400
+++ linux-2.6.18-mm/include/asm-um/ptrace-i386.h	2007-02-21 13:08:31.000000000 -0500
@@ -6,6 +6,8 @@
 #ifndef __UM_PTRACE_I386_H
 #define __UM_PTRACE_I386_H
 
+#define ARCH_HAS_SINGLE_STEP	(1)
+
 #define HOST_AUDIT_ARCH AUDIT_ARCH_I386
 
 #include "linux/compiler.h"
Index: linux-2.6.18-mm/include/asm-um/ptrace-x86_64.h
===================================================================
--- linux-2.6.18-mm.orig/include/asm-um/ptrace-x86_64.h	2007-02-19 11:52:47.000000000 -0500
+++ linux-2.6.18-mm/include/asm-um/ptrace-x86_64.h	2007-02-21 13:07:41.000000000 -0500
@@ -14,6 +14,8 @@
 #define __FRAME_OFFSETS /* Needed to get the R* macros */
 #include "asm/ptrace-generic.h"
 
+#define ARCH_HAS_SINGLE_STEP	(1)
+
 #define HOST_AUDIT_ARCH AUDIT_ARCH_X86_64
 
 /* Also defined in sysdep/ptrace.h, so may already be defined. */

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Re: [PATCH] UML utrace support, step 1

[Roland McGrath]

> OK, I'll do it this way.

Your replacement patch still has utrace_regset stuff in it, so it doesn't
compile without the later patches in the series.  Try applying only
utrace-tracehook.patch from the series, then get it to build and make your
utrace-tracehook-um.patch.  Then apply only utrace-regset.patch on top of
that, and get that building to make utrace-regset-um.patch.  Then apply
utrace-core.patch and utrace-ptrace-compat.patch to get ptrace finally
working again and make utrace-ptrace-compat-um.patch.

> Yup, I'll leave this here, with .name initialized as SUBARCH, with the
> regsets defined in sys-$(ARCH) somewhere.

You'll still find this insufficient when you get to biarch support (x86_64).
At least you'll have to add another one elsewhere too, and make
utrace_native_view refer to both.

> Fixed.  block-step is hardware-trap-on-branch or something similar?

Correct.

> No, this is with preempt off.

Ok.  We do seem to have a problem when the host has CONFIG_PREEMPT=y, which
makes me suspect it might be a race problem that could also hit with enough
hardware parallelism.  If you get a chance to try that and can characterize
the way it misbehaves at the level of specific ptrace/wait calls, that
would be a great help.  Otherwise I'll try to look into it when I get some
time, but it's falling down the queue a bit since people don't seem too put
out about it right now.


Thanks very much,
Roland

Re: [uml-devel] [PATCH] UML utrace support, step 1

[Roland McGrath]

> OK, I'll do it this way.

Your replacement patch still has utrace_regset stuff in it, so it doesn't
compile without the later patches in the series.  Try applying only
utrace-tracehook.patch from the series, then get it to build and make your
utrace-tracehook-um.patch.  Then apply only utrace-regset.patch on top of
that, and get that building to make utrace-regset-um.patch.  Then apply
utrace-core.patch and utrace-ptrace-compat.patch to get ptrace finally
working again and make utrace-ptrace-compat-um.patch.

> Yup, I'll leave this here, with .name initialized as SUBARCH, with the
> regsets defined in sys-$(ARCH) somewhere.

You'll still find this insufficient when you get to biarch support (x86_64).
At least you'll have to add another one elsewhere too, and make
utrace_native_view refer to both.

> Fixed.  block-step is hardware-trap-on-branch or something similar?

Correct.

> No, this is with preempt off.

Ok.  We do seem to have a problem when the host has CONFIG_PREEMPT=y, which
makes me suspect it might be a race problem that could also hit with enough
hardware parallelism.  If you get a chance to try that and can characterize
the way it misbehaves at the level of specific ptrace/wait calls, that
would be a great help.  Otherwise I'll try to look into it when I get some
time, but it's falling down the queue a bit since people don't seem too put
out about it right now.


Thanks very much,
Roland

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Re: [PATCH] UML utrace support, step 1

[Jeff Dike]

On Thu, Feb 22, 2007 at 07:19:03PM -0800, Roland McGrath wrote:
> Your replacement patch still has utrace_regset stuff in it, so it doesn't
> compile without the later patches in the series.  Try applying only
> utrace-tracehook.patch from the series, then get it to build and make your
> utrace-tracehook-um.patch.  Then apply only utrace-regset.patch on top of
> that, and get that building to make utrace-regset-um.patch.  Then apply
> utrace-core.patch and utrace-ptrace-compat.patch to get ptrace finally
> working again and make utrace-ptrace-compat-um.patch.

Ah, I was building with all of utrace, and observing that it didn't compile
without all the bits in that patch.  I'll back out the bits of utrace
I don't need yet and send another patch.

> You'll still find this insufficient when you get to biarch support (x86_64).
> At least you'll have to add another one elsewhere too, and make
> utrace_native_view refer to both.

OK, I'll deal with that when I get to it.

> Ok.  We do seem to have a problem when the host has CONFIG_PREEMPT=y, which
> makes me suspect it might be a race problem that could also hit with enough
> hardware parallelism.  If you get a chance to try that and can characterize
> the way it misbehaves at the level of specific ptrace/wait calls, that
> would be a great help.  Otherwise I'll try to look into it when I get some
> time, but it's falling down the queue a bit since people don't seem too put
> out about it right now.

I'll turn on preempt and see what happens.

				Jeff

-- 
Work email - jdike at linux dot intel dot com

Re: [uml-devel] [PATCH] UML utrace support, step 1

[Jeff Dike]

On Thu, Feb 22, 2007 at 07:19:03PM -0800, Roland McGrath wrote:
> Your replacement patch still has utrace_regset stuff in it, so it doesn't
> compile without the later patches in the series.  Try applying only
> utrace-tracehook.patch from the series, then get it to build and make your
> utrace-tracehook-um.patch.  Then apply only utrace-regset.patch on top of
> that, and get that building to make utrace-regset-um.patch.  Then apply
> utrace-core.patch and utrace-ptrace-compat.patch to get ptrace finally
> working again and make utrace-ptrace-compat-um.patch.

Ah, I was building with all of utrace, and observing that it didn't compile
without all the bits in that patch.  I'll back out the bits of utrace
I don't need yet and send another patch.

> You'll still find this insufficient when you get to biarch support (x86_64).
> At least you'll have to add another one elsewhere too, and make
> utrace_native_view refer to both.

OK, I'll deal with that when I get to it.

> Ok.  We do seem to have a problem when the host has CONFIG_PREEMPT=y, which
> makes me suspect it might be a race problem that could also hit with enough
> hardware parallelism.  If you get a chance to try that and can characterize
> the way it misbehaves at the level of specific ptrace/wait calls, that
> would be a great help.  Otherwise I'll try to look into it when I get some
> time, but it's falling down the queue a bit since people don't seem too put
> out about it right now.

I'll turn on preempt and see what happens.

				Jeff

-- 
Work email - jdike at linux dot intel dot com

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Re: [PATCH] UML utrace support, step 1

[Jeff Dike]

On Thu, Feb 22, 2007 at 07:19:03PM -0800, Roland McGrath wrote:
> Your replacement patch still has utrace_regset stuff in it, so it doesn't
> compile without the later patches in the series.  Try applying only
> utrace-tracehook.patch from the series, then get it to build and make your
> utrace-tracehook-um.patch.

Below is a tracehook patch for UML which goes right after
utrace-utrace-tracehook.patch.

				Jeff

-- 
Work email - jdike at linux dot intel dot com


This is the tracehook part of the UML utrace work, enough to get UML
building with the utrace prep patches applied.

Checks of task->ptrace & PT_DTRACE were replaced with
test_thread_flag(TIF_SINGLESTEP, or removed, in the case of execve.

Most of arch/um/kernel/ptrace.c is gone, to be reinstated in future
utrace work.

Similarly, calls to syscall_trace and ptrace notifications in the
signal delivery code are gone.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
--
 arch/um/kernel/exec.c           |    1 
 arch/um/kernel/process.c        |    6 
 arch/um/kernel/ptrace.c         |  333 +++++-----------------------------------
 arch/um/kernel/signal.c         |    5 
 arch/um/kernel/skas/syscall.c   |    4 
 arch/um/sys-i386/signal.c       |    4 
 include/asm-um/ptrace-generic.h |    3 
 include/asm-um/ptrace-i386.h    |    2 
 include/asm-um/ptrace-x86_64.h  |    2 
 include/asm-um/tracehook.h      |   64 +++++++
 10 files changed, 117 insertions(+), 307 deletions(-)


Index: linux-2.6.18-mm/arch/um/kernel/exec.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/kernel/exec.c	2007-03-03 16:23:47.000000000 -0500
+++ linux-2.6.18-mm/arch/um/kernel/exec.c	2007-03-03 16:26:42.000000000 -0500
@@ -51,7 +51,6 @@ static long execve1(char *file, char __u
         error = do_execve(file, argv, env, &current->thread.regs);
         if (error == 0){
 		task_lock(current);
-                current->ptrace &= ~PT_DTRACE;
 #ifdef SUBARCH_EXECVE1
 		SUBARCH_EXECVE1(&current->thread.regs.regs);
 #endif
Index: linux-2.6.18-mm/arch/um/kernel/process.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/kernel/process.c	2007-03-03 16:20:36.000000000 -0500
+++ linux-2.6.18-mm/arch/um/kernel/process.c	2007-03-03 16:26:42.000000000 -0500
@@ -458,11 +458,11 @@ int singlestepping(void * t)
 {
 	struct task_struct *task = t ? t : current;
 
-	if ( ! (task->ptrace & PT_DTRACE) )
-		return(0);
+	if (!test_thread_flag(TIF_SINGLESTEP))
+		return 0;
 
 	if (task->thread.singlestep_syscall)
-		return(1);
+		return 1;
 
 	return 2;
 }
Index: linux-2.6.18-mm/arch/um/kernel/ptrace.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/kernel/ptrace.c	2007-03-03 16:23:47.000000000 -0500
+++ linux-2.6.18-mm/arch/um/kernel/ptrace.c	2007-03-03 16:26:42.000000000 -0500
@@ -3,261 +3,29 @@
  * Licensed under the GPL
  */
 
-#include "linux/sched.h"
-#include "linux/mm.h"
-#include "linux/errno.h"
-#include "linux/smp_lock.h"
-#include "linux/security.h"
-#include "linux/ptrace.h"
-#include "linux/audit.h"
-#ifdef CONFIG_PROC_MM
-#include "linux/proc_mm.h"
-#endif
-#include "asm/ptrace.h"
-#include "asm/uaccess.h"
-#include "kern_util.h"
-#include "skas_ptrace.h"
-#include "sysdep/ptrace.h"
-#include "os.h"
-
-static inline void set_singlestepping(struct task_struct *child, int on)
+#include <linux/audit.h>
+#include <linux/elf.h>
+#include <linux/module.h>
+#include <linux/ptrace.h>
+#include <linux/tracehook.h>
+
+const struct utrace_regset_view utrace_um_native = {
+	.name		= SUBARCH,
+	.e_machine	= ELF_ARCH,
+	.regsets	= NULL,
+	.n		= 0,
+};
+EXPORT_SYMBOL_GPL(utrace_um_native);
+
+int arch_ptrace(long *req, struct task_struct *child,
+		struct utrace_attached_engine *engine,
+		unsigned long addr, unsigned long data, long *val)
 {
-        if (on)
-                child->ptrace |= PT_DTRACE;
-        else
-                child->ptrace &= ~PT_DTRACE;
-        child->thread.singlestep_syscall = 0;
-
-#ifdef SUBARCH_SET_SINGLESTEPPING
-        SUBARCH_SET_SINGLESTEPPING(child, on);
-#endif
+	return -ENOSYS;
 }
 
-/*
- * Called by kernel/ptrace.c when detaching..
- */
-void ptrace_disable(struct task_struct *child)
-{ 
-        set_singlestepping(child,0);
-}
-
-extern int peek_user(struct task_struct * child, long addr, long data);
-extern int poke_user(struct task_struct * child, long addr, long data);
-
-long arch_ptrace(struct task_struct *child, long request, long addr, long data)
-{
-	int i, ret;
-	unsigned long __user *p = (void __user *)(unsigned long)data;
-
-	switch (request) {
-		/* when I and D space are separate, these will need to be fixed. */
-	case PTRACE_PEEKTEXT: /* read word at location addr. */ 
-	case PTRACE_PEEKDATA: {
-		unsigned long tmp;
-		int copied;
-
-		ret = -EIO;
-		copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
-		if (copied != sizeof(tmp))
-			break;
-		ret = put_user(tmp, p);
-		break;
-	}
-
-	/* read the word at location addr in the USER area. */
-        case PTRACE_PEEKUSR:
-                ret = peek_user(child, addr, data);
-                break;
-
-	/* when I and D space are separate, this will have to be fixed. */
-	case PTRACE_POKETEXT: /* write the word at location addr. */
-	case PTRACE_POKEDATA:
-		ret = -EIO;
-		if (access_process_vm(child, addr, &data, sizeof(data), 
-				      1) != sizeof(data))
-			break;
-		ret = 0;
-		break;
-
-	case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
-                ret = poke_user(child, addr, data);
-                break;
-
-	case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
-	case PTRACE_CONT: { /* restart after signal. */
-		ret = -EIO;
-		if (!valid_signal(data))
-			break;
-
-                set_singlestepping(child, 0);
-		if (request == PTRACE_SYSCALL) {
-			set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
-		}
-		else {
-			clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
-		}
-		child->exit_code = data;
-		wake_up_process(child);
-		ret = 0;
-		break;
-	}
-
-/*
- * make the child exit.  Best I can do is send it a sigkill. 
- * perhaps it should be put in the status that it wants to 
- * exit.
- */
-	case PTRACE_KILL: {
-		ret = 0;
-		if (child->exit_state == EXIT_ZOMBIE)	/* already dead */
-			break;
-
-                set_singlestepping(child, 0);
-		child->exit_code = SIGKILL;
-		wake_up_process(child);
-		break;
-	}
-
-	case PTRACE_SINGLESTEP: {  /* set the trap flag. */
-		ret = -EIO;
-		if (!valid_signal(data))
-			break;
-		clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
-                set_singlestepping(child, 1);
-		child->exit_code = data;
-		/* give it a chance to run. */
-		wake_up_process(child);
-		ret = 0;
-		break;
-	}
-
-	case PTRACE_DETACH:
-		/* detach a process that was attached. */
-		ret = ptrace_detach(child, data);
- 		break;
-
-#ifdef PTRACE_GETREGS
-	case PTRACE_GETREGS: { /* Get all gp regs from the child. */
-		if (!access_ok(VERIFY_WRITE, p, MAX_REG_OFFSET)) {
-			ret = -EIO;
-			break;
-		}
-		for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
-			__put_user(getreg(child, i), p);
-			p++;
-		}
-		ret = 0;
-		break;
-	}
-#endif
-#ifdef PTRACE_SETREGS
-	case PTRACE_SETREGS: { /* Set all gp regs in the child. */
-		unsigned long tmp = 0;
-		if (!access_ok(VERIFY_READ, p, MAX_REG_OFFSET)) {
-			ret = -EIO;
-			break;
-		}
-		for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
-			__get_user(tmp, p);
-			putreg(child, i, tmp);
-			p++;
-		}
-		ret = 0;
-		break;
-	}
-#endif
-#ifdef PTRACE_GETFPREGS
-	case PTRACE_GETFPREGS: /* Get the child FPU state. */
-		ret = get_fpregs(data, child);
-		break;
-#endif
-#ifdef PTRACE_SETFPREGS
-	case PTRACE_SETFPREGS: /* Set the child FPU state. */
-	        ret = set_fpregs(data, child);
-		break;
-#endif
-#ifdef PTRACE_GETFPXREGS
-	case PTRACE_GETFPXREGS: /* Get the child FPU state. */
-		ret = get_fpxregs(data, child);
-		break;
-#endif
-#ifdef PTRACE_SETFPXREGS
-	case PTRACE_SETFPXREGS: /* Set the child FPU state. */
-		ret = set_fpxregs(data, child);
-		break;
-#endif
-	case PTRACE_GET_THREAD_AREA:
-		ret = ptrace_get_thread_area(child, addr,
-					     (struct user_desc __user *) data);
-		break;
-
-	case PTRACE_SET_THREAD_AREA:
-		ret = ptrace_set_thread_area(child, addr,
-					     (struct user_desc __user *) data);
-		break;
-
-	case PTRACE_FAULTINFO: {
-		/* Take the info from thread->arch->faultinfo,
-		 * but transfer max. sizeof(struct ptrace_faultinfo).
-		 * On i386, ptrace_faultinfo is smaller!
-		 */
-		ret = copy_to_user(p, &child->thread.arch.faultinfo,
-				   sizeof(struct ptrace_faultinfo));
-		if(ret)
-			break;
-		break;
-	}
-
-#ifdef PTRACE_LDT
-	case PTRACE_LDT: {
-		struct ptrace_ldt ldt;
-
-		if(copy_from_user(&ldt, p, sizeof(ldt))){
-			ret = -EIO;
-			break;
-		}
-
-		/* This one is confusing, so just punt and return -EIO for 
-		 * now
-		 */
-		ret = -EIO;
-		break;
-	}
-#endif
-#ifdef CONFIG_PROC_MM
-	case PTRACE_SWITCH_MM: {
-		struct mm_struct *old = child->mm;
-		struct mm_struct *new = proc_mm_get_mm(data);
-
-		if(IS_ERR(new)){
-			ret = PTR_ERR(new);
-			break;
-		}
-
-		atomic_inc(&new->mm_users);
-		child->mm = new;
-		child->active_mm = new;
-		mmput(old);
-		ret = 0;
-		break;
-	}
-#endif
-#ifdef PTRACE_ARCH_PRCTL
-        case PTRACE_ARCH_PRCTL:
-                /* XXX Calls ptrace on the host - needs some SMP thinking */
-                ret = arch_prctl_skas(child, data, (void *) addr);
-                break;
-#endif
-	default:
-		ret = ptrace_request(child, request, addr, data);
-		break;
-	}
-
-	return ret;
-}
-
-void send_sigtrap(struct task_struct *tsk, union uml_pt_regs *regs,
-		  int error_code)
+static void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs,
+			 int error_code)
 {
 	struct siginfo info;
 
@@ -266,56 +34,39 @@ void send_sigtrap(struct task_struct *ts
 	info.si_code = TRAP_BRKPT;
 
 	/* User-mode eip? */
-	info.si_addr = UPT_IS_USER(regs) ? (void __user *) UPT_IP(regs) : NULL;
+	info.si_addr = UPT_IS_USER(&regs->regs) ?
+		(void __user *) UPT_IP(&regs->regs) : NULL;
 
 	/* Send us the fakey SIGTRAP */
 	force_sig_info(SIGTRAP, &info, tsk);
 }
 
-/* XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and
- * PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
+/* notification of system call entry/exit
+ * - triggered by current->work.syscall_trace
  */
-void syscall_trace(union uml_pt_regs *regs, int entryexit)
+void do_syscall_trace(struct pt_regs *regs, int entryexit)
 {
-	int is_singlestep = (current->ptrace & PT_DTRACE) && entryexit;
-	int tracesysgood;
+	/* do the secure computing check first */
+	if (!entryexit)
+		secure_computing(PT_REGS_SYSCALL_NR(regs));
+
+	if (unlikely(current->audit_context) && entryexit)
+		audit_syscall_exit(AUDITSC_RESULT(UPT_SYSCALL_RET(regs)),
+				   UPT_SYSCALL_RET(regs));
+
+	if (test_thread_flag(TIF_SYSCALL_TRACE))
+		tracehook_report_syscall(regs, entryexit);
+
+	if (test_thread_flag(TIF_SINGLESTEP) && entryexit) {
+		send_sigtrap(current, regs, 0);	/* XXX */
+		tracehook_report_syscall_step(regs);
+	}
 
-	if (unlikely(current->audit_context)) {
-		if (!entryexit)
-			audit_syscall_entry(HOST_AUDIT_ARCH,
+	if (unlikely(current->audit_context) && !entryexit)
+		audit_syscall_entry(HOST_AUDIT_ARCH,
 					    UPT_SYSCALL_NR(regs),
 					    UPT_SYSCALL_ARG1(regs),
 					    UPT_SYSCALL_ARG2(regs),
 					    UPT_SYSCALL_ARG3(regs),
 					    UPT_SYSCALL_ARG4(regs));
-		else audit_syscall_exit(AUDITSC_RESULT(UPT_SYSCALL_RET(regs)),
-                                        UPT_SYSCALL_RET(regs));
-	}
-
-	/* Fake a debug trap */
-	if (is_singlestep)
-		send_sigtrap(current, regs, 0);
-
-	if (!test_thread_flag(TIF_SYSCALL_TRACE))
-		return;
-
-	if (!(current->ptrace & PT_PTRACED))
-		return;
-
-	/* the 0x80 provides a way for the tracing parent to distinguish
-	   between a syscall stop and SIGTRAP delivery */
-	tracesysgood = (current->ptrace & PT_TRACESYSGOOD);
-	ptrace_notify(SIGTRAP | (tracesysgood ? 0x80 : 0));
-
-	if (entryexit) /* force do_signal() --> is_syscall() */
-		set_thread_flag(TIF_SIGPENDING);
-
-	/* 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;
-	}
 }
Index: linux-2.6.18-mm/arch/um/kernel/signal.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/kernel/signal.c	2007-03-03 16:20:36.000000000 -0500
+++ linux-2.6.18-mm/arch/um/kernel/signal.c	2007-03-03 16:26:42.000000000 -0500
@@ -14,6 +14,7 @@
 #include "linux/tty.h"
 #include "linux/binfmts.h"
 #include "linux/ptrace.h"
+#include "linux/tracehook.h"
 #include "asm/signal.h"
 #include "asm/uaccess.h"
 #include "asm/unistd.h"
@@ -93,6 +94,8 @@ static int handle_signal(struct pt_regs 
 			sigaddset(&current->blocked, signr);
 		recalc_sigpending();
 		spin_unlock_irq(&current->sighand->siglock);
+
+		tracehook_report_handle_signal(signr, ka, oldset, regs);
 	}
 
 	return err;
@@ -148,7 +151,7 @@ static int kern_do_signal(struct pt_regs
 	 * on the host.  The tracing thread will check this flag and
 	 * PTRACE_SYSCALL if necessary.
 	 */
-	if(current->ptrace & PT_DTRACE)
+	if(test_thread_flag(TIF_SYSCALL_TRACE))
 		current->thread.singlestep_syscall =
 			is_syscall(PT_REGS_IP(&current->thread.regs));
 
Index: linux-2.6.18-mm/arch/um/kernel/skas/syscall.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/kernel/skas/syscall.c	2007-03-03 16:20:36.000000000 -0500
+++ linux-2.6.18-mm/arch/um/kernel/skas/syscall.c	2007-03-03 16:26:42.000000000 -0500
@@ -19,8 +19,6 @@ void handle_syscall(union uml_pt_regs *r
 	long result;
 	int syscall;
 
-	syscall_trace(r, 0);
-
 	current->thread.nsyscalls++;
 	nsyscalls++;
 
@@ -38,6 +36,4 @@ void handle_syscall(union uml_pt_regs *r
 	else result = EXECUTE_SYSCALL(syscall, regs);
 
 	REGS_SET_SYSCALL_RETURN(r->skas.regs, result);
-
-	syscall_trace(r, 1);
 }
Index: linux-2.6.18-mm/arch/um/sys-i386/signal.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/sys-i386/signal.c	2007-03-03 16:20:36.000000000 -0500
+++ linux-2.6.18-mm/arch/um/sys-i386/signal.c	2007-03-03 16:26:42.000000000 -0500
@@ -267,8 +267,6 @@ int setup_signal_stack_sc(unsigned long 
 	PT_REGS_EDX(regs) = (unsigned long) 0;
 	PT_REGS_ECX(regs) = (unsigned long) 0;
 
-	if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
-		ptrace_notify(SIGTRAP);
 	return 0;
 
 err:
@@ -324,8 +322,6 @@ int setup_signal_stack_si(unsigned long 
 	PT_REGS_EDX(regs) = (unsigned long) &frame->info;
 	PT_REGS_ECX(regs) = (unsigned long) &frame->uc;
 
-	if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
-		ptrace_notify(SIGTRAP);
 	return 0;
 
 err:
Index: linux-2.6.18-mm/include/asm-um/ptrace-generic.h
===================================================================
--- linux-2.6.18-mm.orig/include/asm-um/ptrace-generic.h	2007-03-03 16:20:36.000000000 -0500
+++ linux-2.6.18-mm/include/asm-um/ptrace-generic.h	2007-03-03 16:26:42.000000000 -0500
@@ -44,9 +44,6 @@ extern int set_fpxregs(unsigned long buf
 
 extern void show_regs(struct pt_regs *regs);
 
-extern void send_sigtrap(struct task_struct *tsk, union uml_pt_regs *regs,
-			 int error_code);
-
 extern int arch_copy_tls(struct task_struct *new);
 extern void clear_flushed_tls(struct task_struct *task);
 
Index: linux-2.6.18-mm/include/asm-um/ptrace-i386.h
===================================================================
--- linux-2.6.18-mm.orig/include/asm-um/ptrace-i386.h	2007-03-03 16:20:36.000000000 -0500
+++ linux-2.6.18-mm/include/asm-um/ptrace-i386.h	2007-03-03 16:26:42.000000000 -0500
@@ -6,6 +6,8 @@
 #ifndef __UM_PTRACE_I386_H
 #define __UM_PTRACE_I386_H
 
+#define ARCH_HAS_SINGLE_STEP	(1)
+
 #define HOST_AUDIT_ARCH AUDIT_ARCH_I386
 
 #include "linux/compiler.h"
Index: linux-2.6.18-mm/include/asm-um/ptrace-x86_64.h
===================================================================
--- linux-2.6.18-mm.orig/include/asm-um/ptrace-x86_64.h	2007-03-03 16:23:49.000000000 -0500
+++ linux-2.6.18-mm/include/asm-um/ptrace-x86_64.h	2007-03-03 16:26:42.000000000 -0500
@@ -14,6 +14,8 @@
 #define __FRAME_OFFSETS /* Needed to get the R* macros */
 #include "asm/ptrace-generic.h"
 
+#define ARCH_HAS_SINGLE_STEP	(1)
+
 #define HOST_AUDIT_ARCH AUDIT_ARCH_X86_64
 
 /* Also defined in sysdep/ptrace.h, so may already be defined. */
Index: linux-2.6.18-mm/include/asm-um/tracehook.h
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.18-mm/include/asm-um/tracehook.h	2007-03-03 16:26:42.000000000 -0500
@@ -0,0 +1,64 @@
+/*
+ * Tracing hooks, i386 CPU support
+ *
+ * Copyright (C) 2006, 2007 Red Hat, Inc.  All rights reserved.
+ *
+ * This copyrighted material is made available to anyone wishing to use,
+ * modify, copy, or redistribute it subject to the terms and conditions
+ * of the GNU General Public License v.2.
+ *
+ * Red Hat Author: Roland McGrath.
+ *
+ * Munged for UML - jdike@{addtoit,linux.intel}.com
+ */
+
+#ifndef _ASM_TRACEHOOK_H
+#define _ASM_TRACEHOOK_H	1
+
+#include <linux/sched.h>
+#include <asm/ptrace.h>
+#include <asm/thread_info.h>
+
+/*
+ * See linux/tracehook.h for the descriptions of what these need to do.
+ */
+
+static inline void tracehook_enable_single_step(struct task_struct *tsk)
+{
+	set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
+}
+
+static inline void tracehook_disable_single_step(struct task_struct *tsk)
+{
+	clear_tsk_thread_flag(tsk, TIF_SINGLESTEP);
+}
+
+static inline int tracehook_single_step_enabled(struct task_struct *tsk)
+{
+	return test_tsk_thread_flag(tsk, TIF_SINGLESTEP);
+}
+
+static inline void tracehook_enable_syscall_trace(struct task_struct *tsk)
+{
+	set_tsk_thread_flag(tsk, TIF_SYSCALL_TRACE);
+}
+
+static inline void tracehook_disable_syscall_trace(struct task_struct *tsk)
+{
+	clear_tsk_thread_flag(tsk, TIF_SYSCALL_TRACE);
+}
+
+static inline void tracehook_abort_syscall(struct pt_regs *regs)
+{
+	PT_REGS_SYSCALL_NR(regs) = -1;
+}
+
+extern const struct utrace_regset_view utrace_um_native;
+static inline const struct utrace_regset_view *
+utrace_native_view(struct task_struct *tsk)
+{
+	return &utrace_um_native;
+}
+
+
+#endif

Re: [uml-devel] [PATCH] UML utrace support, step 1

[Jeff Dike]

On Thu, Feb 22, 2007 at 07:19:03PM -0800, Roland McGrath wrote:
> Your replacement patch still has utrace_regset stuff in it, so it doesn't
> compile without the later patches in the series.  Try applying only
> utrace-tracehook.patch from the series, then get it to build and make your
> utrace-tracehook-um.patch.

Below is a tracehook patch for UML which goes right after
utrace-utrace-tracehook.patch.

				Jeff

-- 
Work email - jdike at linux dot intel dot com


This is the tracehook part of the UML utrace work, enough to get UML
building with the utrace prep patches applied.

Checks of task->ptrace & PT_DTRACE were replaced with
test_thread_flag(TIF_SINGLESTEP, or removed, in the case of execve.

Most of arch/um/kernel/ptrace.c is gone, to be reinstated in future
utrace work.

Similarly, calls to syscall_trace and ptrace notifications in the
signal delivery code are gone.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
--
 arch/um/kernel/exec.c           |    1 
 arch/um/kernel/process.c        |    6 
 arch/um/kernel/ptrace.c         |  333 +++++-----------------------------------
 arch/um/kernel/signal.c         |    5 
 arch/um/kernel/skas/syscall.c   |    4 
 arch/um/sys-i386/signal.c       |    4 
 include/asm-um/ptrace-generic.h |    3 
 include/asm-um/ptrace-i386.h    |    2 
 include/asm-um/ptrace-x86_64.h  |    2 
 include/asm-um/tracehook.h      |   64 +++++++
 10 files changed, 117 insertions(+), 307 deletions(-)


Index: linux-2.6.18-mm/arch/um/kernel/exec.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/kernel/exec.c	2007-03-03 16:23:47.000000000 -0500
+++ linux-2.6.18-mm/arch/um/kernel/exec.c	2007-03-03 16:26:42.000000000 -0500
@@ -51,7 +51,6 @@ static long execve1(char *file, char __u
         error = do_execve(file, argv, env, &current->thread.regs);
         if (error == 0){
 		task_lock(current);
-                current->ptrace &= ~PT_DTRACE;
 #ifdef SUBARCH_EXECVE1
 		SUBARCH_EXECVE1(&current->thread.regs.regs);
 #endif
Index: linux-2.6.18-mm/arch/um/kernel/process.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/kernel/process.c	2007-03-03 16:20:36.000000000 -0500
+++ linux-2.6.18-mm/arch/um/kernel/process.c	2007-03-03 16:26:42.000000000 -0500
@@ -458,11 +458,11 @@ int singlestepping(void * t)
 {
 	struct task_struct *task = t ? t : current;
 
-	if ( ! (task->ptrace & PT_DTRACE) )
-		return(0);
+	if (!test_thread_flag(TIF_SINGLESTEP))
+		return 0;
 
 	if (task->thread.singlestep_syscall)
-		return(1);
+		return 1;
 
 	return 2;
 }
Index: linux-2.6.18-mm/arch/um/kernel/ptrace.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/kernel/ptrace.c	2007-03-03 16:23:47.000000000 -0500
+++ linux-2.6.18-mm/arch/um/kernel/ptrace.c	2007-03-03 16:26:42.000000000 -0500
@@ -3,261 +3,29 @@
  * Licensed under the GPL
  */
 
-#include "linux/sched.h"
-#include "linux/mm.h"
-#include "linux/errno.h"
-#include "linux/smp_lock.h"
-#include "linux/security.h"
-#include "linux/ptrace.h"
-#include "linux/audit.h"
-#ifdef CONFIG_PROC_MM
-#include "linux/proc_mm.h"
-#endif
-#include "asm/ptrace.h"
-#include "asm/uaccess.h"
-#include "kern_util.h"
-#include "skas_ptrace.h"
-#include "sysdep/ptrace.h"
-#include "os.h"
-
-static inline void set_singlestepping(struct task_struct *child, int on)
+#include <linux/audit.h>
+#include <linux/elf.h>
+#include <linux/module.h>
+#include <linux/ptrace.h>
+#include <linux/tracehook.h>
+
+const struct utrace_regset_view utrace_um_native = {
+	.name		= SUBARCH,
+	.e_machine	= ELF_ARCH,
+	.regsets	= NULL,
+	.n		= 0,
+};
+EXPORT_SYMBOL_GPL(utrace_um_native);
+
+int arch_ptrace(long *req, struct task_struct *child,
+		struct utrace_attached_engine *engine,
+		unsigned long addr, unsigned long data, long *val)
 {
-        if (on)
-                child->ptrace |= PT_DTRACE;
-        else
-                child->ptrace &= ~PT_DTRACE;
-        child->thread.singlestep_syscall = 0;
-
-#ifdef SUBARCH_SET_SINGLESTEPPING
-        SUBARCH_SET_SINGLESTEPPING(child, on);
-#endif
+	return -ENOSYS;
 }
 
-/*
- * Called by kernel/ptrace.c when detaching..
- */
-void ptrace_disable(struct task_struct *child)
-{ 
-        set_singlestepping(child,0);
-}
-
-extern int peek_user(struct task_struct * child, long addr, long data);
-extern int poke_user(struct task_struct * child, long addr, long data);
-
-long arch_ptrace(struct task_struct *child, long request, long addr, long data)
-{
-	int i, ret;
-	unsigned long __user *p = (void __user *)(unsigned long)data;
-
-	switch (request) {
-		/* when I and D space are separate, these will need to be fixed. */
-	case PTRACE_PEEKTEXT: /* read word at location addr. */ 
-	case PTRACE_PEEKDATA: {
-		unsigned long tmp;
-		int copied;
-
-		ret = -EIO;
-		copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
-		if (copied != sizeof(tmp))
-			break;
-		ret = put_user(tmp, p);
-		break;
-	}
-
-	/* read the word at location addr in the USER area. */
-        case PTRACE_PEEKUSR:
-                ret = peek_user(child, addr, data);
-                break;
-
-	/* when I and D space are separate, this will have to be fixed. */
-	case PTRACE_POKETEXT: /* write the word at location addr. */
-	case PTRACE_POKEDATA:
-		ret = -EIO;
-		if (access_process_vm(child, addr, &data, sizeof(data), 
-				      1) != sizeof(data))
-			break;
-		ret = 0;
-		break;
-
-	case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
-                ret = poke_user(child, addr, data);
-                break;
-
-	case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
-	case PTRACE_CONT: { /* restart after signal. */
-		ret = -EIO;
-		if (!valid_signal(data))
-			break;
-
-                set_singlestepping(child, 0);
-		if (request == PTRACE_SYSCALL) {
-			set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
-		}
-		else {
-			clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
-		}
-		child->exit_code = data;
-		wake_up_process(child);
-		ret = 0;
-		break;
-	}
-
-/*
- * make the child exit.  Best I can do is send it a sigkill. 
- * perhaps it should be put in the status that it wants to 
- * exit.
- */
-	case PTRACE_KILL: {
-		ret = 0;
-		if (child->exit_state == EXIT_ZOMBIE)	/* already dead */
-			break;
-
-                set_singlestepping(child, 0);
-		child->exit_code = SIGKILL;
-		wake_up_process(child);
-		break;
-	}
-
-	case PTRACE_SINGLESTEP: {  /* set the trap flag. */
-		ret = -EIO;
-		if (!valid_signal(data))
-			break;
-		clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
-                set_singlestepping(child, 1);
-		child->exit_code = data;
-		/* give it a chance to run. */
-		wake_up_process(child);
-		ret = 0;
-		break;
-	}
-
-	case PTRACE_DETACH:
-		/* detach a process that was attached. */
-		ret = ptrace_detach(child, data);
- 		break;
-
-#ifdef PTRACE_GETREGS
-	case PTRACE_GETREGS: { /* Get all gp regs from the child. */
-		if (!access_ok(VERIFY_WRITE, p, MAX_REG_OFFSET)) {
-			ret = -EIO;
-			break;
-		}
-		for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
-			__put_user(getreg(child, i), p);
-			p++;
-		}
-		ret = 0;
-		break;
-	}
-#endif
-#ifdef PTRACE_SETREGS
-	case PTRACE_SETREGS: { /* Set all gp regs in the child. */
-		unsigned long tmp = 0;
-		if (!access_ok(VERIFY_READ, p, MAX_REG_OFFSET)) {
-			ret = -EIO;
-			break;
-		}
-		for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
-			__get_user(tmp, p);
-			putreg(child, i, tmp);
-			p++;
-		}
-		ret = 0;
-		break;
-	}
-#endif
-#ifdef PTRACE_GETFPREGS
-	case PTRACE_GETFPREGS: /* Get the child FPU state. */
-		ret = get_fpregs(data, child);
-		break;
-#endif
-#ifdef PTRACE_SETFPREGS
-	case PTRACE_SETFPREGS: /* Set the child FPU state. */
-	        ret = set_fpregs(data, child);
-		break;
-#endif
-#ifdef PTRACE_GETFPXREGS
-	case PTRACE_GETFPXREGS: /* Get the child FPU state. */
-		ret = get_fpxregs(data, child);
-		break;
-#endif
-#ifdef PTRACE_SETFPXREGS
-	case PTRACE_SETFPXREGS: /* Set the child FPU state. */
-		ret = set_fpxregs(data, child);
-		break;
-#endif
-	case PTRACE_GET_THREAD_AREA:
-		ret = ptrace_get_thread_area(child, addr,
-					     (struct user_desc __user *) data);
-		break;
-
-	case PTRACE_SET_THREAD_AREA:
-		ret = ptrace_set_thread_area(child, addr,
-					     (struct user_desc __user *) data);
-		break;
-
-	case PTRACE_FAULTINFO: {
-		/* Take the info from thread->arch->faultinfo,
-		 * but transfer max. sizeof(struct ptrace_faultinfo).
-		 * On i386, ptrace_faultinfo is smaller!
-		 */
-		ret = copy_to_user(p, &child->thread.arch.faultinfo,
-				   sizeof(struct ptrace_faultinfo));
-		if(ret)
-			break;
-		break;
-	}
-
-#ifdef PTRACE_LDT
-	case PTRACE_LDT: {
-		struct ptrace_ldt ldt;
-
-		if(copy_from_user(&ldt, p, sizeof(ldt))){
-			ret = -EIO;
-			break;
-		}
-
-		/* This one is confusing, so just punt and return -EIO for 
-		 * now
-		 */
-		ret = -EIO;
-		break;
-	}
-#endif
-#ifdef CONFIG_PROC_MM
-	case PTRACE_SWITCH_MM: {
-		struct mm_struct *old = child->mm;
-		struct mm_struct *new = proc_mm_get_mm(data);
-
-		if(IS_ERR(new)){
-			ret = PTR_ERR(new);
-			break;
-		}
-
-		atomic_inc(&new->mm_users);
-		child->mm = new;
-		child->active_mm = new;
-		mmput(old);
-		ret = 0;
-		break;
-	}
-#endif
-#ifdef PTRACE_ARCH_PRCTL
-        case PTRACE_ARCH_PRCTL:
-                /* XXX Calls ptrace on the host - needs some SMP thinking */
-                ret = arch_prctl_skas(child, data, (void *) addr);
-                break;
-#endif
-	default:
-		ret = ptrace_request(child, request, addr, data);
-		break;
-	}
-
-	return ret;
-}
-
-void send_sigtrap(struct task_struct *tsk, union uml_pt_regs *regs,
-		  int error_code)
+static void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs,
+			 int error_code)
 {
 	struct siginfo info;
 
@@ -266,56 +34,39 @@ void send_sigtrap(struct task_struct *ts
 	info.si_code = TRAP_BRKPT;
 
 	/* User-mode eip? */
-	info.si_addr = UPT_IS_USER(regs) ? (void __user *) UPT_IP(regs) : NULL;
+	info.si_addr = UPT_IS_USER(&regs->regs) ?
+		(void __user *) UPT_IP(&regs->regs) : NULL;
 
 	/* Send us the fakey SIGTRAP */
 	force_sig_info(SIGTRAP, &info, tsk);
 }
 
-/* XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and
- * PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
+/* notification of system call entry/exit
+ * - triggered by current->work.syscall_trace
  */
-void syscall_trace(union uml_pt_regs *regs, int entryexit)
+void do_syscall_trace(struct pt_regs *regs, int entryexit)
 {
-	int is_singlestep = (current->ptrace & PT_DTRACE) && entryexit;
-	int tracesysgood;
+	/* do the secure computing check first */
+	if (!entryexit)
+		secure_computing(PT_REGS_SYSCALL_NR(regs));
+
+	if (unlikely(current->audit_context) && entryexit)
+		audit_syscall_exit(AUDITSC_RESULT(UPT_SYSCALL_RET(regs)),
+				   UPT_SYSCALL_RET(regs));
+
+	if (test_thread_flag(TIF_SYSCALL_TRACE))
+		tracehook_report_syscall(regs, entryexit);
+
+	if (test_thread_flag(TIF_SINGLESTEP) && entryexit) {
+		send_sigtrap(current, regs, 0);	/* XXX */
+		tracehook_report_syscall_step(regs);
+	}
 
-	if (unlikely(current->audit_context)) {
-		if (!entryexit)
-			audit_syscall_entry(HOST_AUDIT_ARCH,
+	if (unlikely(current->audit_context) && !entryexit)
+		audit_syscall_entry(HOST_AUDIT_ARCH,
 					    UPT_SYSCALL_NR(regs),
 					    UPT_SYSCALL_ARG1(regs),
 					    UPT_SYSCALL_ARG2(regs),
 					    UPT_SYSCALL_ARG3(regs),
 					    UPT_SYSCALL_ARG4(regs));
-		else audit_syscall_exit(AUDITSC_RESULT(UPT_SYSCALL_RET(regs)),
-                                        UPT_SYSCALL_RET(regs));
-	}
-
-	/* Fake a debug trap */
-	if (is_singlestep)
-		send_sigtrap(current, regs, 0);
-
-	if (!test_thread_flag(TIF_SYSCALL_TRACE))
-		return;
-
-	if (!(current->ptrace & PT_PTRACED))
-		return;
-
-	/* the 0x80 provides a way for the tracing parent to distinguish
-	   between a syscall stop and SIGTRAP delivery */
-	tracesysgood = (current->ptrace & PT_TRACESYSGOOD);
-	ptrace_notify(SIGTRAP | (tracesysgood ? 0x80 : 0));
-
-	if (entryexit) /* force do_signal() --> is_syscall() */
-		set_thread_flag(TIF_SIGPENDING);
-
-	/* 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;
-	}
 }
Index: linux-2.6.18-mm/arch/um/kernel/signal.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/kernel/signal.c	2007-03-03 16:20:36.000000000 -0500
+++ linux-2.6.18-mm/arch/um/kernel/signal.c	2007-03-03 16:26:42.000000000 -0500
@@ -14,6 +14,7 @@
 #include "linux/tty.h"
 #include "linux/binfmts.h"
 #include "linux/ptrace.h"
+#include "linux/tracehook.h"
 #include "asm/signal.h"
 #include "asm/uaccess.h"
 #include "asm/unistd.h"
@@ -93,6 +94,8 @@ static int handle_signal(struct pt_regs 
 			sigaddset(&current->blocked, signr);
 		recalc_sigpending();
 		spin_unlock_irq(&current->sighand->siglock);
+
+		tracehook_report_handle_signal(signr, ka, oldset, regs);
 	}
 
 	return err;
@@ -148,7 +151,7 @@ static int kern_do_signal(struct pt_regs
 	 * on the host.  The tracing thread will check this flag and
 	 * PTRACE_SYSCALL if necessary.
 	 */
-	if(current->ptrace & PT_DTRACE)
+	if(test_thread_flag(TIF_SYSCALL_TRACE))
 		current->thread.singlestep_syscall =
 			is_syscall(PT_REGS_IP(&current->thread.regs));
 
Index: linux-2.6.18-mm/arch/um/kernel/skas/syscall.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/kernel/skas/syscall.c	2007-03-03 16:20:36.000000000 -0500
+++ linux-2.6.18-mm/arch/um/kernel/skas/syscall.c	2007-03-03 16:26:42.000000000 -0500
@@ -19,8 +19,6 @@ void handle_syscall(union uml_pt_regs *r
 	long result;
 	int syscall;
 
-	syscall_trace(r, 0);
-
 	current->thread.nsyscalls++;
 	nsyscalls++;
 
@@ -38,6 +36,4 @@ void handle_syscall(union uml_pt_regs *r
 	else result = EXECUTE_SYSCALL(syscall, regs);
 
 	REGS_SET_SYSCALL_RETURN(r->skas.regs, result);
-
-	syscall_trace(r, 1);
 }
Index: linux-2.6.18-mm/arch/um/sys-i386/signal.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/sys-i386/signal.c	2007-03-03 16:20:36.000000000 -0500
+++ linux-2.6.18-mm/arch/um/sys-i386/signal.c	2007-03-03 16:26:42.000000000 -0500
@@ -267,8 +267,6 @@ int setup_signal_stack_sc(unsigned long 
 	PT_REGS_EDX(regs) = (unsigned long) 0;
 	PT_REGS_ECX(regs) = (unsigned long) 0;
 
-	if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
-		ptrace_notify(SIGTRAP);
 	return 0;
 
 err:
@@ -324,8 +322,6 @@ int setup_signal_stack_si(unsigned long 
 	PT_REGS_EDX(regs) = (unsigned long) &frame->info;
 	PT_REGS_ECX(regs) = (unsigned long) &frame->uc;
 
-	if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
-		ptrace_notify(SIGTRAP);
 	return 0;
 
 err:
Index: linux-2.6.18-mm/include/asm-um/ptrace-generic.h
===================================================================
--- linux-2.6.18-mm.orig/include/asm-um/ptrace-generic.h	2007-03-03 16:20:36.000000000 -0500
+++ linux-2.6.18-mm/include/asm-um/ptrace-generic.h	2007-03-03 16:26:42.000000000 -0500
@@ -44,9 +44,6 @@ extern int set_fpxregs(unsigned long buf
 
 extern void show_regs(struct pt_regs *regs);
 
-extern void send_sigtrap(struct task_struct *tsk, union uml_pt_regs *regs,
-			 int error_code);
-
 extern int arch_copy_tls(struct task_struct *new);
 extern void clear_flushed_tls(struct task_struct *task);
 
Index: linux-2.6.18-mm/include/asm-um/ptrace-i386.h
===================================================================
--- linux-2.6.18-mm.orig/include/asm-um/ptrace-i386.h	2007-03-03 16:20:36.000000000 -0500
+++ linux-2.6.18-mm/include/asm-um/ptrace-i386.h	2007-03-03 16:26:42.000000000 -0500
@@ -6,6 +6,8 @@
 #ifndef __UM_PTRACE_I386_H
 #define __UM_PTRACE_I386_H
 
+#define ARCH_HAS_SINGLE_STEP	(1)
+
 #define HOST_AUDIT_ARCH AUDIT_ARCH_I386
 
 #include "linux/compiler.h"
Index: linux-2.6.18-mm/include/asm-um/ptrace-x86_64.h
===================================================================
--- linux-2.6.18-mm.orig/include/asm-um/ptrace-x86_64.h	2007-03-03 16:23:49.000000000 -0500
+++ linux-2.6.18-mm/include/asm-um/ptrace-x86_64.h	2007-03-03 16:26:42.000000000 -0500
@@ -14,6 +14,8 @@
 #define __FRAME_OFFSETS /* Needed to get the R* macros */
 #include "asm/ptrace-generic.h"
 
+#define ARCH_HAS_SINGLE_STEP	(1)
+
 #define HOST_AUDIT_ARCH AUDIT_ARCH_X86_64
 
 /* Also defined in sysdep/ptrace.h, so may already be defined. */
Index: linux-2.6.18-mm/include/asm-um/tracehook.h
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.18-mm/include/asm-um/tracehook.h	2007-03-03 16:26:42.000000000 -0500
@@ -0,0 +1,64 @@
+/*
+ * Tracing hooks, i386 CPU support
+ *
+ * Copyright (C) 2006, 2007 Red Hat, Inc.  All rights reserved.
+ *
+ * This copyrighted material is made available to anyone wishing to use,
+ * modify, copy, or redistribute it subject to the terms and conditions
+ * of the GNU General Public License v.2.
+ *
+ * Red Hat Author: Roland McGrath.
+ *
+ * Munged for UML - jdike@{addtoit,linux.intel}.com
+ */
+
+#ifndef _ASM_TRACEHOOK_H
+#define _ASM_TRACEHOOK_H	1
+
+#include <linux/sched.h>
+#include <asm/ptrace.h>
+#include <asm/thread_info.h>
+
+/*
+ * See linux/tracehook.h for the descriptions of what these need to do.
+ */
+
+static inline void tracehook_enable_single_step(struct task_struct *tsk)
+{
+	set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
+}
+
+static inline void tracehook_disable_single_step(struct task_struct *tsk)
+{
+	clear_tsk_thread_flag(tsk, TIF_SINGLESTEP);
+}
+
+static inline int tracehook_single_step_enabled(struct task_struct *tsk)
+{
+	return test_tsk_thread_flag(tsk, TIF_SINGLESTEP);
+}
+
+static inline void tracehook_enable_syscall_trace(struct task_struct *tsk)
+{
+	set_tsk_thread_flag(tsk, TIF_SYSCALL_TRACE);
+}
+
+static inline void tracehook_disable_syscall_trace(struct task_struct *tsk)
+{
+	clear_tsk_thread_flag(tsk, TIF_SYSCALL_TRACE);
+}
+
+static inline void tracehook_abort_syscall(struct pt_regs *regs)
+{
+	PT_REGS_SYSCALL_NR(regs) = -1;
+}
+
+extern const struct utrace_regset_view utrace_um_native;
+static inline const struct utrace_regset_view *
+utrace_native_view(struct task_struct *tsk)
+{
+	return &utrace_um_native;
+}
+
+
+#endif

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Re: [PATCH] UML utrace support, step 1

[Roland McGrath]

> On Thu, Feb 22, 2007 at 07:19:03PM -0800, Roland McGrath wrote:
> > Your replacement patch still has utrace_regset stuff in it, so it doesn't
> > compile without the later patches in the series.  Try applying only
> > utrace-tracehook.patch from the series, then get it to build and make your
> > utrace-tracehook-um.patch.
> 
> Below is a tracehook patch for UML which goes right after
> utrace-utrace-tracehook.patch.

It does not.  That patch has regset and ptrace stuff in it.  It indeed
applies fine before or after utrace patches.  But it doesn't close to
compile without utrace-regset.patch and utrace-core.patch applied,
and even with utrace-ptrace-compat.patch it still doesn't compile for me
with a lot of complaints about TIF_SINGLESTEP not being defined where
it's used in asm/tracehook.h.


Thanks,
Roland

Re: [uml-devel] [PATCH] UML utrace support, step 1

[Roland McGrath]

> On Thu, Feb 22, 2007 at 07:19:03PM -0800, Roland McGrath wrote:
> > Your replacement patch still has utrace_regset stuff in it, so it doesn't
> > compile without the later patches in the series.  Try applying only
> > utrace-tracehook.patch from the series, then get it to build and make your
> > utrace-tracehook-um.patch.
> 
> Below is a tracehook patch for UML which goes right after
> utrace-utrace-tracehook.patch.

It does not.  That patch has regset and ptrace stuff in it.  It indeed
applies fine before or after utrace patches.  But it doesn't close to
compile without utrace-regset.patch and utrace-core.patch applied,
and even with utrace-ptrace-compat.patch it still doesn't compile for me
with a lot of complaints about TIF_SINGLESTEP not being defined where
it's used in asm/tracehook.h.


Thanks,
Roland

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Re: [PATCH] UML utrace support, step 1

[Jeff Dike]

On Wed, Mar 07, 2007 at 12:01:59AM -0800, Roland McGrath wrote:
> > Below is a tracehook patch for UML which goes right after
> > utrace-utrace-tracehook.patch.
> 
> It does not.  That patch has regset and ptrace stuff in it.  It indeed
> applies fine before or after utrace patches.  But it doesn't close to
> compile without utrace-regset.patch and utrace-core.patch applied,
> and even with utrace-ptrace-compat.patch it still doesn't compile for me
> with a lot of complaints about TIF_SINGLESTEP not being defined where
> it's used in asm/tracehook.h.

Did I send the right patch?  The one I meant to send (appended below),
indeed builds and runs without utrace-regset.patch and
utrace-core.patch applied.  It's utrace-1 in the following:

	+ utrace-prep.patch
	+ utrace-prep-2.patch
	+ utrace-utrace-tracehook.patch
	= utrace-1
	  utrace-utrace-tracehook-ia64.patch
	  utrace-utrace-tracehook-sparc64.patch
	  utrace-utrace-tracehook-s390.patch
	  utrace-utrace-regset.patch
	  utrace-utrace-regset-ia64.patch
	  utrace-utrace-regset-sparc64.patch
	  utrace-utrace-regset-s390.patch
	  utrace-utrace-core.patch
	  utrace-utrace-ptrace-compat.patch
	  utrace-utrace-ptrace-compat-ia64.patch
	  utrace-utrace-ptrace-compat-sparc64.patch
	  utrace-utrace-ptrace-compat-s390.patch
	  revert-utrace-prep-2.patch
	  utrace-vs-reduce-size-of-task_struct-on-64-bit-machines.patch

				Jeff

-- 
Work email - jdike at linux dot intel dot com



This is the tracehook part of the UML utrace work, enough to get UML
building with the utrace prep patches applied.

Checks of task->ptrace & PT_DTRACE were replaced with
test_thread_flag(TIF_SINGLESTEP, or removed, in the case of execve.

Most of arch/um/kernel/ptrace.c is gone, to be reinstated in future
utrace work.

Similarly, calls to syscall_trace and ptrace notifications in the
signal delivery code are gone. 

Signed-off-by: Jeff Dike <jdike@addtoit.com>
--
 arch/um/kernel/exec.c           |    1 
 arch/um/kernel/process.c        |    6 
 arch/um/kernel/ptrace.c         |  333 +++++-----------------------------------
 arch/um/kernel/signal.c         |    5 
 arch/um/kernel/skas/syscall.c   |    4 
 arch/um/sys-i386/signal.c       |    4 
 include/asm-um/ptrace-generic.h |    3 
 include/asm-um/ptrace-i386.h    |    2 
 include/asm-um/ptrace-x86_64.h  |    2 
 include/asm-um/tracehook.h      |   64 +++++++
 10 files changed, 117 insertions(+), 307 deletions(-)

Index: linux-2.6.21-rc2/arch/um/kernel/exec.c
===================================================================
--- linux-2.6.21-rc2.orig/arch/um/kernel/exec.c	2007-03-05 13:24:49.000000000 -0500
+++ linux-2.6.21-rc2/arch/um/kernel/exec.c	2007-03-05 13:24:57.000000000 -0500
@@ -51,7 +51,6 @@ static long execve1(char *file, char __u
         error = do_execve(file, argv, env, &current->thread.regs);
         if (error == 0){
 		task_lock(current);
-                current->ptrace &= ~PT_DTRACE;
 #ifdef SUBARCH_EXECVE1
 		SUBARCH_EXECVE1(&current->thread.regs.regs);
 #endif
Index: linux-2.6.21-rc2/arch/um/kernel/process.c
===================================================================
--- linux-2.6.21-rc2.orig/arch/um/kernel/process.c	2007-03-05 13:24:49.000000000 -0500
+++ linux-2.6.21-rc2/arch/um/kernel/process.c	2007-03-05 13:24:57.000000000 -0500
@@ -458,11 +458,11 @@ int singlestepping(void * t)
 {
 	struct task_struct *task = t ? t : current;
 
-	if ( ! (task->ptrace & PT_DTRACE) )
-		return(0);
+	if (!test_thread_flag(TIF_SINGLESTEP))
+		return 0;
 
 	if (task->thread.singlestep_syscall)
-		return(1);
+		return 1;
 
 	return 2;
 }
Index: linux-2.6.21-rc2/arch/um/kernel/ptrace.c
===================================================================
--- linux-2.6.21-rc2.orig/arch/um/kernel/ptrace.c	2007-03-05 13:24:49.000000000 -0500
+++ linux-2.6.21-rc2/arch/um/kernel/ptrace.c	2007-03-05 13:47:30.000000000 -0500
@@ -3,261 +3,26 @@
  * Licensed under the GPL
  */
 
-#include "linux/sched.h"
-#include "linux/mm.h"
-#include "linux/errno.h"
-#include "linux/smp_lock.h"
-#include "linux/security.h"
-#include "linux/ptrace.h"
-#include "linux/audit.h"
-#ifdef CONFIG_PROC_MM
-#include "linux/proc_mm.h"
-#endif
-#include "asm/ptrace.h"
-#include "asm/uaccess.h"
-#include "kern_util.h"
-#include "skas_ptrace.h"
-#include "sysdep/ptrace.h"
-#include "os.h"
-
-static inline void set_singlestepping(struct task_struct *child, int on)
-{
-        if (on)
-                child->ptrace |= PT_DTRACE;
-        else
-                child->ptrace &= ~PT_DTRACE;
-        child->thread.singlestep_syscall = 0;
-
-#ifdef SUBARCH_SET_SINGLESTEPPING
-        SUBARCH_SET_SINGLESTEPPING(child, on);
-#endif
-}
+#include <linux/audit.h>
+#include <linux/elf.h>
+#include <linux/module.h>
+#include <linux/ptrace.h>
+#include <linux/tracehook.h>
 
 /*
  * Called by kernel/ptrace.c when detaching..
  */
 void ptrace_disable(struct task_struct *child)
 { 
-        set_singlestepping(child,0);
 }
 
-extern int peek_user(struct task_struct * child, long addr, long data);
-extern int poke_user(struct task_struct * child, long addr, long data);
-
 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 {
-	int i, ret;
-	unsigned long __user *p = (void __user *)(unsigned long)data;
-
-	switch (request) {
-		/* when I and D space are separate, these will need to be fixed. */
-	case PTRACE_PEEKTEXT: /* read word at location addr. */ 
-	case PTRACE_PEEKDATA: {
-		unsigned long tmp;
-		int copied;
-
-		ret = -EIO;
-		copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
-		if (copied != sizeof(tmp))
-			break;
-		ret = put_user(tmp, p);
-		break;
-	}
-
-	/* read the word at location addr in the USER area. */
-        case PTRACE_PEEKUSR:
-                ret = peek_user(child, addr, data);
-                break;
-
-	/* when I and D space are separate, this will have to be fixed. */
-	case PTRACE_POKETEXT: /* write the word at location addr. */
-	case PTRACE_POKEDATA:
-		ret = -EIO;
-		if (access_process_vm(child, addr, &data, sizeof(data), 
-				      1) != sizeof(data))
-			break;
-		ret = 0;
-		break;
-
-	case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
-                ret = poke_user(child, addr, data);
-                break;
-
-	case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
-	case PTRACE_CONT: { /* restart after signal. */
-		ret = -EIO;
-		if (!valid_signal(data))
-			break;
-
-                set_singlestepping(child, 0);
-		if (request == PTRACE_SYSCALL) {
-			set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
-		}
-		else {
-			clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
-		}
-		child->exit_code = data;
-		wake_up_process(child);
-		ret = 0;
-		break;
-	}
-
-/*
- * make the child exit.  Best I can do is send it a sigkill. 
- * perhaps it should be put in the status that it wants to 
- * exit.
- */
-	case PTRACE_KILL: {
-		ret = 0;
-		if (child->exit_state == EXIT_ZOMBIE)	/* already dead */
-			break;
-
-                set_singlestepping(child, 0);
-		child->exit_code = SIGKILL;
-		wake_up_process(child);
-		break;
-	}
-
-	case PTRACE_SINGLESTEP: {  /* set the trap flag. */
-		ret = -EIO;
-		if (!valid_signal(data))
-			break;
-		clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
-                set_singlestepping(child, 1);
-		child->exit_code = data;
-		/* give it a chance to run. */
-		wake_up_process(child);
-		ret = 0;
-		break;
-	}
-
-	case PTRACE_DETACH:
-		/* detach a process that was attached. */
-		ret = ptrace_detach(child, data);
- 		break;
-
-#ifdef PTRACE_GETREGS
-	case PTRACE_GETREGS: { /* Get all gp regs from the child. */
-		if (!access_ok(VERIFY_WRITE, p, MAX_REG_OFFSET)) {
-			ret = -EIO;
-			break;
-		}
-		for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
-			__put_user(getreg(child, i), p);
-			p++;
-		}
-		ret = 0;
-		break;
-	}
-#endif
-#ifdef PTRACE_SETREGS
-	case PTRACE_SETREGS: { /* Set all gp regs in the child. */
-		unsigned long tmp = 0;
-		if (!access_ok(VERIFY_READ, p, MAX_REG_OFFSET)) {
-			ret = -EIO;
-			break;
-		}
-		for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
-			__get_user(tmp, p);
-			putreg(child, i, tmp);
-			p++;
-		}
-		ret = 0;
-		break;
-	}
-#endif
-#ifdef PTRACE_GETFPREGS
-	case PTRACE_GETFPREGS: /* Get the child FPU state. */
-		ret = get_fpregs(data, child);
-		break;
-#endif
-#ifdef PTRACE_SETFPREGS
-	case PTRACE_SETFPREGS: /* Set the child FPU state. */
-	        ret = set_fpregs(data, child);
-		break;
-#endif
-#ifdef PTRACE_GETFPXREGS
-	case PTRACE_GETFPXREGS: /* Get the child FPU state. */
-		ret = get_fpxregs(data, child);
-		break;
-#endif
-#ifdef PTRACE_SETFPXREGS
-	case PTRACE_SETFPXREGS: /* Set the child FPU state. */
-		ret = set_fpxregs(data, child);
-		break;
-#endif
-	case PTRACE_GET_THREAD_AREA:
-		ret = ptrace_get_thread_area(child, addr,
-					     (struct user_desc __user *) data);
-		break;
-
-	case PTRACE_SET_THREAD_AREA:
-		ret = ptrace_set_thread_area(child, addr,
-					     (struct user_desc __user *) data);
-		break;
-
-	case PTRACE_FAULTINFO: {
-		/* Take the info from thread->arch->faultinfo,
-		 * but transfer max. sizeof(struct ptrace_faultinfo).
-		 * On i386, ptrace_faultinfo is smaller!
-		 */
-		ret = copy_to_user(p, &child->thread.arch.faultinfo,
-				   sizeof(struct ptrace_faultinfo));
-		if(ret)
-			break;
-		break;
-	}
-
-#ifdef PTRACE_LDT
-	case PTRACE_LDT: {
-		struct ptrace_ldt ldt;
-
-		if(copy_from_user(&ldt, p, sizeof(ldt))){
-			ret = -EIO;
-			break;
-		}
-
-		/* This one is confusing, so just punt and return -EIO for 
-		 * now
-		 */
-		ret = -EIO;
-		break;
-	}
-#endif
-#ifdef CONFIG_PROC_MM
-	case PTRACE_SWITCH_MM: {
-		struct mm_struct *old = child->mm;
-		struct mm_struct *new = proc_mm_get_mm(data);
-
-		if(IS_ERR(new)){
-			ret = PTR_ERR(new);
-			break;
-		}
-
-		atomic_inc(&new->mm_users);
-		child->mm = new;
-		child->active_mm = new;
-		mmput(old);
-		ret = 0;
-		break;
-	}
-#endif
-#ifdef PTRACE_ARCH_PRCTL
-        case PTRACE_ARCH_PRCTL:
-                /* XXX Calls ptrace on the host - needs some SMP thinking */
-                ret = arch_prctl_skas(child, data, (void *) addr);
-                break;
-#endif
-	default:
-		ret = ptrace_request(child, request, addr, data);
-		break;
-	}
-
-	return ret;
+	return -ENOSYS;
 }
 
-void send_sigtrap(struct task_struct *tsk, union uml_pt_regs *regs,
-		  int error_code)
+static void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs,
+			 int error_code)
 {
 	struct siginfo info;
 
@@ -266,56 +31,39 @@ void send_sigtrap(struct task_struct *ts
 	info.si_code = TRAP_BRKPT;
 
 	/* User-mode eip? */
-	info.si_addr = UPT_IS_USER(regs) ? (void __user *) UPT_IP(regs) : NULL;
+	info.si_addr = UPT_IS_USER(&regs->regs) ?
+		(void __user *) UPT_IP(&regs->regs) : NULL;
 
 	/* Send us the fakey SIGTRAP */
 	force_sig_info(SIGTRAP, &info, tsk);
 }
 
-/* XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and
- * PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
+/* notification of system call entry/exit
+ * - triggered by current->work.syscall_trace
  */
-void syscall_trace(union uml_pt_regs *regs, int entryexit)
+void do_syscall_trace(struct pt_regs *regs, int entryexit)
 {
-	int is_singlestep = (current->ptrace & PT_DTRACE) && entryexit;
-	int tracesysgood;
+	/* do the secure computing check first */
+	if (!entryexit)
+		secure_computing(PT_REGS_SYSCALL_NR(regs));
 
-	if (unlikely(current->audit_context)) {
-		if (!entryexit)
-			audit_syscall_entry(HOST_AUDIT_ARCH,
+	if (unlikely(current->audit_context) && entryexit)
+		audit_syscall_exit(AUDITSC_RESULT(UPT_SYSCALL_RET(regs)),
+				   UPT_SYSCALL_RET(regs));
+
+	if (test_thread_flag(TIF_SYSCALL_TRACE))
+		tracehook_report_syscall(regs, entryexit);
+
+	if (test_thread_flag(TIF_SINGLESTEP) && entryexit) {
+		send_sigtrap(current, regs, 0);	/* XXX */
+		tracehook_report_syscall_step(regs);
+	}
+
+	if (unlikely(current->audit_context) && !entryexit)
+		audit_syscall_entry(HOST_AUDIT_ARCH,
 					    UPT_SYSCALL_NR(regs),
 					    UPT_SYSCALL_ARG1(regs),
 					    UPT_SYSCALL_ARG2(regs),
 					    UPT_SYSCALL_ARG3(regs),
 					    UPT_SYSCALL_ARG4(regs));
-		else audit_syscall_exit(AUDITSC_RESULT(UPT_SYSCALL_RET(regs)),
-                                        UPT_SYSCALL_RET(regs));
-	}
-
-	/* Fake a debug trap */
-	if (is_singlestep)
-		send_sigtrap(current, regs, 0);
-
-	if (!test_thread_flag(TIF_SYSCALL_TRACE))
-		return;
-
-	if (!(current->ptrace & PT_PTRACED))
-		return;
-
-	/* the 0x80 provides a way for the tracing parent to distinguish
-	   between a syscall stop and SIGTRAP delivery */
-	tracesysgood = (current->ptrace & PT_TRACESYSGOOD);
-	ptrace_notify(SIGTRAP | (tracesysgood ? 0x80 : 0));
-
-	if (entryexit) /* force do_signal() --> is_syscall() */
-		set_thread_flag(TIF_SIGPENDING);
-
-	/* 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;
-	}
 }
Index: linux-2.6.21-rc2/arch/um/kernel/signal.c
===================================================================
--- linux-2.6.21-rc2.orig/arch/um/kernel/signal.c	2007-03-05 13:24:49.000000000 -0500
+++ linux-2.6.21-rc2/arch/um/kernel/signal.c	2007-03-05 13:24:57.000000000 -0500
@@ -14,6 +14,7 @@
 #include "linux/tty.h"
 #include "linux/binfmts.h"
 #include "linux/ptrace.h"
+#include "linux/tracehook.h"
 #include "asm/signal.h"
 #include "asm/uaccess.h"
 #include "asm/unistd.h"
@@ -93,6 +94,8 @@ static int handle_signal(struct pt_regs 
 			sigaddset(&current->blocked, signr);
 		recalc_sigpending();
 		spin_unlock_irq(&current->sighand->siglock);
+
+		tracehook_report_handle_signal(signr, ka, oldset, regs);
 	}
 
 	return err;
@@ -148,7 +151,7 @@ static int kern_do_signal(struct pt_regs
 	 * on the host.  The tracing thread will check this flag and
 	 * PTRACE_SYSCALL if necessary.
 	 */
-	if(current->ptrace & PT_DTRACE)
+	if(test_thread_flag(TIF_SYSCALL_TRACE))
 		current->thread.singlestep_syscall =
 			is_syscall(PT_REGS_IP(&current->thread.regs));
 
Index: linux-2.6.21-rc2/arch/um/kernel/skas/syscall.c
===================================================================
--- linux-2.6.21-rc2.orig/arch/um/kernel/skas/syscall.c	2007-03-05 13:24:49.000000000 -0500
+++ linux-2.6.21-rc2/arch/um/kernel/skas/syscall.c	2007-03-05 13:24:57.000000000 -0500
@@ -19,8 +19,6 @@ void handle_syscall(union uml_pt_regs *r
 	long result;
 	int syscall;
 
-	syscall_trace(r, 0);
-
 	current->thread.nsyscalls++;
 	nsyscalls++;
 
@@ -38,6 +36,4 @@ void handle_syscall(union uml_pt_regs *r
 	else result = EXECUTE_SYSCALL(syscall, regs);
 
 	REGS_SET_SYSCALL_RETURN(r->skas.regs, result);
-
-	syscall_trace(r, 1);
 }
Index: linux-2.6.21-rc2/arch/um/sys-i386/signal.c
===================================================================
--- linux-2.6.21-rc2.orig/arch/um/sys-i386/signal.c	2007-03-05 13:24:49.000000000 -0500
+++ linux-2.6.21-rc2/arch/um/sys-i386/signal.c	2007-03-05 13:24:57.000000000 -0500
@@ -267,8 +267,6 @@ int setup_signal_stack_sc(unsigned long 
 	PT_REGS_EDX(regs) = (unsigned long) 0;
 	PT_REGS_ECX(regs) = (unsigned long) 0;
 
-	if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
-		ptrace_notify(SIGTRAP);
 	return 0;
 
 err:
@@ -324,8 +322,6 @@ int setup_signal_stack_si(unsigned long 
 	PT_REGS_EDX(regs) = (unsigned long) &frame->info;
 	PT_REGS_ECX(regs) = (unsigned long) &frame->uc;
 
-	if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
-		ptrace_notify(SIGTRAP);
 	return 0;
 
 err:
Index: linux-2.6.21-rc2/include/asm-um/ptrace-generic.h
===================================================================
--- linux-2.6.21-rc2.orig/include/asm-um/ptrace-generic.h	2007-03-05 13:24:49.000000000 -0500
+++ linux-2.6.21-rc2/include/asm-um/ptrace-generic.h	2007-03-05 13:24:57.000000000 -0500
@@ -44,9 +44,6 @@ extern int set_fpxregs(unsigned long buf
 
 extern void show_regs(struct pt_regs *regs);
 
-extern void send_sigtrap(struct task_struct *tsk, union uml_pt_regs *regs,
-			 int error_code);
-
 extern int arch_copy_tls(struct task_struct *new);
 extern void clear_flushed_tls(struct task_struct *task);
 
Index: linux-2.6.21-rc2/include/asm-um/ptrace-i386.h
===================================================================
--- linux-2.6.21-rc2.orig/include/asm-um/ptrace-i386.h	2007-03-05 13:24:49.000000000 -0500
+++ linux-2.6.21-rc2/include/asm-um/ptrace-i386.h	2007-03-05 13:24:57.000000000 -0500
@@ -6,6 +6,8 @@
 #ifndef __UM_PTRACE_I386_H
 #define __UM_PTRACE_I386_H
 
+#define ARCH_HAS_SINGLE_STEP	(1)
+
 #define HOST_AUDIT_ARCH AUDIT_ARCH_I386
 
 #include "linux/compiler.h"
Index: linux-2.6.21-rc2/include/asm-um/ptrace-x86_64.h
===================================================================
--- linux-2.6.21-rc2.orig/include/asm-um/ptrace-x86_64.h	2007-03-05 13:24:49.000000000 -0500
+++ linux-2.6.21-rc2/include/asm-um/ptrace-x86_64.h	2007-03-05 13:24:57.000000000 -0500
@@ -14,6 +14,8 @@
 #define __FRAME_OFFSETS /* Needed to get the R* macros */
 #include "asm/ptrace-generic.h"
 
+#define ARCH_HAS_SINGLE_STEP	(1)
+
 #define HOST_AUDIT_ARCH AUDIT_ARCH_X86_64
 
 /* Also defined in sysdep/ptrace.h, so may already be defined. */
Index: linux-2.6.21-rc2/include/asm-um/tracehook.h
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.21-rc2/include/asm-um/tracehook.h	2007-03-05 13:24:57.000000000 -0500
@@ -0,0 +1,64 @@
+/*
+ * Tracing hooks, i386 CPU support
+ *
+ * Copyright (C) 2006, 2007 Red Hat, Inc.  All rights reserved.
+ *
+ * This copyrighted material is made available to anyone wishing to use,
+ * modify, copy, or redistribute it subject to the terms and conditions
+ * of the GNU General Public License v.2.
+ *
+ * Red Hat Author: Roland McGrath.
+ *
+ * Munged for UML - jdike@{addtoit,linux.intel}.com
+ */
+
+#ifndef _ASM_TRACEHOOK_H
+#define _ASM_TRACEHOOK_H	1
+
+#include <linux/sched.h>
+#include <asm/ptrace.h>
+#include <asm/thread_info.h>
+
+/*
+ * See linux/tracehook.h for the descriptions of what these need to do.
+ */
+
+static inline void tracehook_enable_single_step(struct task_struct *tsk)
+{
+	set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
+}
+
+static inline void tracehook_disable_single_step(struct task_struct *tsk)
+{
+	clear_tsk_thread_flag(tsk, TIF_SINGLESTEP);
+}
+
+static inline int tracehook_single_step_enabled(struct task_struct *tsk)
+{
+	return test_tsk_thread_flag(tsk, TIF_SINGLESTEP);
+}
+
+static inline void tracehook_enable_syscall_trace(struct task_struct *tsk)
+{
+	set_tsk_thread_flag(tsk, TIF_SYSCALL_TRACE);
+}
+
+static inline void tracehook_disable_syscall_trace(struct task_struct *tsk)
+{
+	clear_tsk_thread_flag(tsk, TIF_SYSCALL_TRACE);
+}
+
+static inline void tracehook_abort_syscall(struct pt_regs *regs)
+{
+	PT_REGS_SYSCALL_NR(regs) = -1;
+}
+
+extern const struct utrace_regset_view utrace_um_native;
+static inline const struct utrace_regset_view *
+utrace_native_view(struct task_struct *tsk)
+{
+	return &utrace_um_native;
+}
+
+
+#endif
Index: linux-2.6.21-rc2/include/asm-um/thread_info.h
===================================================================
--- linux-2.6.21-rc2.orig/include/asm-um/thread_info.h	2007-02-27 23:59:12.000000000 -0500
+++ linux-2.6.21-rc2/include/asm-um/thread_info.h	2007-03-05 15:11:39.000000000 -0500
@@ -69,6 +69,8 @@ static inline struct thread_info *curren
 #define TIF_MEMDIE	 	5
 #define TIF_SYSCALL_AUDIT	6
 #define TIF_RESTORE_SIGMASK	7
+#define TIF_SINGLESTEP          8       /* restore singlestep on return to user
+                                         * mode */
 
 #define _TIF_SYSCALL_TRACE	(1 << TIF_SYSCALL_TRACE)
 #define _TIF_SIGPENDING		(1 << TIF_SIGPENDING)
@@ -77,5 +79,6 @@ static inline struct thread_info *curren
 #define _TIF_MEMDIE		(1 << TIF_MEMDIE)
 #define _TIF_SYSCALL_AUDIT	(1 << TIF_SYSCALL_AUDIT)
 #define _TIF_RESTORE_SIGMASK	(1 << TIF_RESTORE_SIGMASK)
+#define _TIF_SINGLESTEP         (1 << TIF_SINGLESTEP)
 
 #endif

Re: [uml-devel] [PATCH] UML utrace support, step 1

[Jeff Dike]

On Wed, Mar 07, 2007 at 12:01:59AM -0800, Roland McGrath wrote:
> > Below is a tracehook patch for UML which goes right after
> > utrace-utrace-tracehook.patch.
> 
> It does not.  That patch has regset and ptrace stuff in it.  It indeed
> applies fine before or after utrace patches.  But it doesn't close to
> compile without utrace-regset.patch and utrace-core.patch applied,
> and even with utrace-ptrace-compat.patch it still doesn't compile for me
> with a lot of complaints about TIF_SINGLESTEP not being defined where
> it's used in asm/tracehook.h.

Did I send the right patch?  The one I meant to send (appended below),
indeed builds and runs without utrace-regset.patch and
utrace-core.patch applied.  It's utrace-1 in the following:

	+ utrace-prep.patch
	+ utrace-prep-2.patch
	+ utrace-utrace-tracehook.patch
	= utrace-1
	  utrace-utrace-tracehook-ia64.patch
	  utrace-utrace-tracehook-sparc64.patch
	  utrace-utrace-tracehook-s390.patch
	  utrace-utrace-regset.patch
	  utrace-utrace-regset-ia64.patch
	  utrace-utrace-regset-sparc64.patch
	  utrace-utrace-regset-s390.patch
	  utrace-utrace-core.patch
	  utrace-utrace-ptrace-compat.patch
	  utrace-utrace-ptrace-compat-ia64.patch
	  utrace-utrace-ptrace-compat-sparc64.patch
	  utrace-utrace-ptrace-compat-s390.patch
	  revert-utrace-prep-2.patch
	  utrace-vs-reduce-size-of-task_struct-on-64-bit-machines.patch

				Jeff

-- 
Work email - jdike at linux dot intel dot com



This is the tracehook part of the UML utrace work, enough to get UML
building with the utrace prep patches applied.

Checks of task->ptrace & PT_DTRACE were replaced with
test_thread_flag(TIF_SINGLESTEP, or removed, in the case of execve.

Most of arch/um/kernel/ptrace.c is gone, to be reinstated in future
utrace work.

Similarly, calls to syscall_trace and ptrace notifications in the
signal delivery code are gone. 

Signed-off-by: Jeff Dike <jdike@addtoit.com>
--
 arch/um/kernel/exec.c           |    1 
 arch/um/kernel/process.c        |    6 
 arch/um/kernel/ptrace.c         |  333 +++++-----------------------------------
 arch/um/kernel/signal.c         |    5 
 arch/um/kernel/skas/syscall.c   |    4 
 arch/um/sys-i386/signal.c       |    4 
 include/asm-um/ptrace-generic.h |    3 
 include/asm-um/ptrace-i386.h    |    2 
 include/asm-um/ptrace-x86_64.h  |    2 
 include/asm-um/tracehook.h      |   64 +++++++
 10 files changed, 117 insertions(+), 307 deletions(-)

Index: linux-2.6.21-rc2/arch/um/kernel/exec.c
===================================================================
--- linux-2.6.21-rc2.orig/arch/um/kernel/exec.c	2007-03-05 13:24:49.000000000 -0500
+++ linux-2.6.21-rc2/arch/um/kernel/exec.c	2007-03-05 13:24:57.000000000 -0500
@@ -51,7 +51,6 @@ static long execve1(char *file, char __u
         error = do_execve(file, argv, env, &current->thread.regs);
         if (error == 0){
 		task_lock(current);
-                current->ptrace &= ~PT_DTRACE;
 #ifdef SUBARCH_EXECVE1
 		SUBARCH_EXECVE1(&current->thread.regs.regs);
 #endif
Index: linux-2.6.21-rc2/arch/um/kernel/process.c
===================================================================
--- linux-2.6.21-rc2.orig/arch/um/kernel/process.c	2007-03-05 13:24:49.000000000 -0500
+++ linux-2.6.21-rc2/arch/um/kernel/process.c	2007-03-05 13:24:57.000000000 -0500
@@ -458,11 +458,11 @@ int singlestepping(void * t)
 {
 	struct task_struct *task = t ? t : current;
 
-	if ( ! (task->ptrace & PT_DTRACE) )
-		return(0);
+	if (!test_thread_flag(TIF_SINGLESTEP))
+		return 0;
 
 	if (task->thread.singlestep_syscall)
-		return(1);
+		return 1;
 
 	return 2;
 }
Index: linux-2.6.21-rc2/arch/um/kernel/ptrace.c
===================================================================
--- linux-2.6.21-rc2.orig/arch/um/kernel/ptrace.c	2007-03-05 13:24:49.000000000 -0500
+++ linux-2.6.21-rc2/arch/um/kernel/ptrace.c	2007-03-05 13:47:30.000000000 -0500
@@ -3,261 +3,26 @@
  * Licensed under the GPL
  */
 
-#include "linux/sched.h"
-#include "linux/mm.h"
-#include "linux/errno.h"
-#include "linux/smp_lock.h"
-#include "linux/security.h"
-#include "linux/ptrace.h"
-#include "linux/audit.h"
-#ifdef CONFIG_PROC_MM
-#include "linux/proc_mm.h"
-#endif
-#include "asm/ptrace.h"
-#include "asm/uaccess.h"
-#include "kern_util.h"
-#include "skas_ptrace.h"
-#include "sysdep/ptrace.h"
-#include "os.h"
-
-static inline void set_singlestepping(struct task_struct *child, int on)
-{
-        if (on)
-                child->ptrace |= PT_DTRACE;
-        else
-                child->ptrace &= ~PT_DTRACE;
-        child->thread.singlestep_syscall = 0;
-
-#ifdef SUBARCH_SET_SINGLESTEPPING
-        SUBARCH_SET_SINGLESTEPPING(child, on);
-#endif
-}
+#include <linux/audit.h>
+#include <linux/elf.h>
+#include <linux/module.h>
+#include <linux/ptrace.h>
+#include <linux/tracehook.h>
 
 /*
  * Called by kernel/ptrace.c when detaching..
  */
 void ptrace_disable(struct task_struct *child)
 { 
-        set_singlestepping(child,0);
 }
 
-extern int peek_user(struct task_struct * child, long addr, long data);
-extern int poke_user(struct task_struct * child, long addr, long data);
-
 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 {
-	int i, ret;
-	unsigned long __user *p = (void __user *)(unsigned long)data;
-
-	switch (request) {
-		/* when I and D space are separate, these will need to be fixed. */
-	case PTRACE_PEEKTEXT: /* read word at location addr. */ 
-	case PTRACE_PEEKDATA: {
-		unsigned long tmp;
-		int copied;
-
-		ret = -EIO;
-		copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
-		if (copied != sizeof(tmp))
-			break;
-		ret = put_user(tmp, p);
-		break;
-	}
-
-	/* read the word at location addr in the USER area. */
-        case PTRACE_PEEKUSR:
-                ret = peek_user(child, addr, data);
-                break;
-
-	/* when I and D space are separate, this will have to be fixed. */
-	case PTRACE_POKETEXT: /* write the word at location addr. */
-	case PTRACE_POKEDATA:
-		ret = -EIO;
-		if (access_process_vm(child, addr, &data, sizeof(data), 
-				      1) != sizeof(data))
-			break;
-		ret = 0;
-		break;
-
-	case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
-                ret = poke_user(child, addr, data);
-                break;
-
-	case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
-	case PTRACE_CONT: { /* restart after signal. */
-		ret = -EIO;
-		if (!valid_signal(data))
-			break;
-
-                set_singlestepping(child, 0);
-		if (request == PTRACE_SYSCALL) {
-			set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
-		}
-		else {
-			clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
-		}
-		child->exit_code = data;
-		wake_up_process(child);
-		ret = 0;
-		break;
-	}
-
-/*
- * make the child exit.  Best I can do is send it a sigkill. 
- * perhaps it should be put in the status that it wants to 
- * exit.
- */
-	case PTRACE_KILL: {
-		ret = 0;
-		if (child->exit_state == EXIT_ZOMBIE)	/* already dead */
-			break;
-
-                set_singlestepping(child, 0);
-		child->exit_code = SIGKILL;
-		wake_up_process(child);
-		break;
-	}
-
-	case PTRACE_SINGLESTEP: {  /* set the trap flag. */
-		ret = -EIO;
-		if (!valid_signal(data))
-			break;
-		clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
-                set_singlestepping(child, 1);
-		child->exit_code = data;
-		/* give it a chance to run. */
-		wake_up_process(child);
-		ret = 0;
-		break;
-	}
-
-	case PTRACE_DETACH:
-		/* detach a process that was attached. */
-		ret = ptrace_detach(child, data);
- 		break;
-
-#ifdef PTRACE_GETREGS
-	case PTRACE_GETREGS: { /* Get all gp regs from the child. */
-		if (!access_ok(VERIFY_WRITE, p, MAX_REG_OFFSET)) {
-			ret = -EIO;
-			break;
-		}
-		for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
-			__put_user(getreg(child, i), p);
-			p++;
-		}
-		ret = 0;
-		break;
-	}
-#endif
-#ifdef PTRACE_SETREGS
-	case PTRACE_SETREGS: { /* Set all gp regs in the child. */
-		unsigned long tmp = 0;
-		if (!access_ok(VERIFY_READ, p, MAX_REG_OFFSET)) {
-			ret = -EIO;
-			break;
-		}
-		for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
-			__get_user(tmp, p);
-			putreg(child, i, tmp);
-			p++;
-		}
-		ret = 0;
-		break;
-	}
-#endif
-#ifdef PTRACE_GETFPREGS
-	case PTRACE_GETFPREGS: /* Get the child FPU state. */
-		ret = get_fpregs(data, child);
-		break;
-#endif
-#ifdef PTRACE_SETFPREGS
-	case PTRACE_SETFPREGS: /* Set the child FPU state. */
-	        ret = set_fpregs(data, child);
-		break;
-#endif
-#ifdef PTRACE_GETFPXREGS
-	case PTRACE_GETFPXREGS: /* Get the child FPU state. */
-		ret = get_fpxregs(data, child);
-		break;
-#endif
-#ifdef PTRACE_SETFPXREGS
-	case PTRACE_SETFPXREGS: /* Set the child FPU state. */
-		ret = set_fpxregs(data, child);
-		break;
-#endif
-	case PTRACE_GET_THREAD_AREA:
-		ret = ptrace_get_thread_area(child, addr,
-					     (struct user_desc __user *) data);
-		break;
-
-	case PTRACE_SET_THREAD_AREA:
-		ret = ptrace_set_thread_area(child, addr,
-					     (struct user_desc __user *) data);
-		break;
-
-	case PTRACE_FAULTINFO: {
-		/* Take the info from thread->arch->faultinfo,
-		 * but transfer max. sizeof(struct ptrace_faultinfo).
-		 * On i386, ptrace_faultinfo is smaller!
-		 */
-		ret = copy_to_user(p, &child->thread.arch.faultinfo,
-				   sizeof(struct ptrace_faultinfo));
-		if(ret)
-			break;
-		break;
-	}
-
-#ifdef PTRACE_LDT
-	case PTRACE_LDT: {
-		struct ptrace_ldt ldt;
-
-		if(copy_from_user(&ldt, p, sizeof(ldt))){
-			ret = -EIO;
-			break;
-		}
-
-		/* This one is confusing, so just punt and return -EIO for 
-		 * now
-		 */
-		ret = -EIO;
-		break;
-	}
-#endif
-#ifdef CONFIG_PROC_MM
-	case PTRACE_SWITCH_MM: {
-		struct mm_struct *old = child->mm;
-		struct mm_struct *new = proc_mm_get_mm(data);
-
-		if(IS_ERR(new)){
-			ret = PTR_ERR(new);
-			break;
-		}
-
-		atomic_inc(&new->mm_users);
-		child->mm = new;
-		child->active_mm = new;
-		mmput(old);
-		ret = 0;
-		break;
-	}
-#endif
-#ifdef PTRACE_ARCH_PRCTL
-        case PTRACE_ARCH_PRCTL:
-                /* XXX Calls ptrace on the host - needs some SMP thinking */
-                ret = arch_prctl_skas(child, data, (void *) addr);
-                break;
-#endif
-	default:
-		ret = ptrace_request(child, request, addr, data);
-		break;
-	}
-
-	return ret;
+	return -ENOSYS;
 }
 
-void send_sigtrap(struct task_struct *tsk, union uml_pt_regs *regs,
-		  int error_code)
+static void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs,
+			 int error_code)
 {
 	struct siginfo info;
 
@@ -266,56 +31,39 @@ void send_sigtrap(struct task_struct *ts
 	info.si_code = TRAP_BRKPT;
 
 	/* User-mode eip? */
-	info.si_addr = UPT_IS_USER(regs) ? (void __user *) UPT_IP(regs) : NULL;
+	info.si_addr = UPT_IS_USER(&regs->regs) ?
+		(void __user *) UPT_IP(&regs->regs) : NULL;
 
 	/* Send us the fakey SIGTRAP */
 	force_sig_info(SIGTRAP, &info, tsk);
 }
 
-/* XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and
- * PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
+/* notification of system call entry/exit
+ * - triggered by current->work.syscall_trace
  */
-void syscall_trace(union uml_pt_regs *regs, int entryexit)
+void do_syscall_trace(struct pt_regs *regs, int entryexit)
 {
-	int is_singlestep = (current->ptrace & PT_DTRACE) && entryexit;
-	int tracesysgood;
+	/* do the secure computing check first */
+	if (!entryexit)
+		secure_computing(PT_REGS_SYSCALL_NR(regs));
 
-	if (unlikely(current->audit_context)) {
-		if (!entryexit)
-			audit_syscall_entry(HOST_AUDIT_ARCH,
+	if (unlikely(current->audit_context) && entryexit)
+		audit_syscall_exit(AUDITSC_RESULT(UPT_SYSCALL_RET(regs)),
+				   UPT_SYSCALL_RET(regs));
+
+	if (test_thread_flag(TIF_SYSCALL_TRACE))
+		tracehook_report_syscall(regs, entryexit);
+
+	if (test_thread_flag(TIF_SINGLESTEP) && entryexit) {
+		send_sigtrap(current, regs, 0);	/* XXX */
+		tracehook_report_syscall_step(regs);
+	}
+
+	if (unlikely(current->audit_context) && !entryexit)
+		audit_syscall_entry(HOST_AUDIT_ARCH,
 					    UPT_SYSCALL_NR(regs),
 					    UPT_SYSCALL_ARG1(regs),
 					    UPT_SYSCALL_ARG2(regs),
 					    UPT_SYSCALL_ARG3(regs),
 					    UPT_SYSCALL_ARG4(regs));
-		else audit_syscall_exit(AUDITSC_RESULT(UPT_SYSCALL_RET(regs)),
-                                        UPT_SYSCALL_RET(regs));
-	}
-
-	/* Fake a debug trap */
-	if (is_singlestep)
-		send_sigtrap(current, regs, 0);
-
-	if (!test_thread_flag(TIF_SYSCALL_TRACE))
-		return;
-
-	if (!(current->ptrace & PT_PTRACED))
-		return;
-
-	/* the 0x80 provides a way for the tracing parent to distinguish
-	   between a syscall stop and SIGTRAP delivery */
-	tracesysgood = (current->ptrace & PT_TRACESYSGOOD);
-	ptrace_notify(SIGTRAP | (tracesysgood ? 0x80 : 0));
-
-	if (entryexit) /* force do_signal() --> is_syscall() */
-		set_thread_flag(TIF_SIGPENDING);
-
-	/* 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;
-	}
 }
Index: linux-2.6.21-rc2/arch/um/kernel/signal.c
===================================================================
--- linux-2.6.21-rc2.orig/arch/um/kernel/signal.c	2007-03-05 13:24:49.000000000 -0500
+++ linux-2.6.21-rc2/arch/um/kernel/signal.c	2007-03-05 13:24:57.000000000 -0500
@@ -14,6 +14,7 @@
 #include "linux/tty.h"
 #include "linux/binfmts.h"
 #include "linux/ptrace.h"
+#include "linux/tracehook.h"
 #include "asm/signal.h"
 #include "asm/uaccess.h"
 #include "asm/unistd.h"
@@ -93,6 +94,8 @@ static int handle_signal(struct pt_regs 
 			sigaddset(&current->blocked, signr);
 		recalc_sigpending();
 		spin_unlock_irq(&current->sighand->siglock);
+
+		tracehook_report_handle_signal(signr, ka, oldset, regs);
 	}
 
 	return err;
@@ -148,7 +151,7 @@ static int kern_do_signal(struct pt_regs
 	 * on the host.  The tracing thread will check this flag and
 	 * PTRACE_SYSCALL if necessary.
 	 */
-	if(current->ptrace & PT_DTRACE)
+	if(test_thread_flag(TIF_SYSCALL_TRACE))
 		current->thread.singlestep_syscall =
 			is_syscall(PT_REGS_IP(&current->thread.regs));
 
Index: linux-2.6.21-rc2/arch/um/kernel/skas/syscall.c
===================================================================
--- linux-2.6.21-rc2.orig/arch/um/kernel/skas/syscall.c	2007-03-05 13:24:49.000000000 -0500
+++ linux-2.6.21-rc2/arch/um/kernel/skas/syscall.c	2007-03-05 13:24:57.000000000 -0500
@@ -19,8 +19,6 @@ void handle_syscall(union uml_pt_regs *r
 	long result;
 	int syscall;
 
-	syscall_trace(r, 0);
-
 	current->thread.nsyscalls++;
 	nsyscalls++;
 
@@ -38,6 +36,4 @@ void handle_syscall(union uml_pt_regs *r
 	else result = EXECUTE_SYSCALL(syscall, regs);
 
 	REGS_SET_SYSCALL_RETURN(r->skas.regs, result);
-
-	syscall_trace(r, 1);
 }
Index: linux-2.6.21-rc2/arch/um/sys-i386/signal.c
===================================================================
--- linux-2.6.21-rc2.orig/arch/um/sys-i386/signal.c	2007-03-05 13:24:49.000000000 -0500
+++ linux-2.6.21-rc2/arch/um/sys-i386/signal.c	2007-03-05 13:24:57.000000000 -0500
@@ -267,8 +267,6 @@ int setup_signal_stack_sc(unsigned long 
 	PT_REGS_EDX(regs) = (unsigned long) 0;
 	PT_REGS_ECX(regs) = (unsigned long) 0;
 
-	if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
-		ptrace_notify(SIGTRAP);
 	return 0;
 
 err:
@@ -324,8 +322,6 @@ int setup_signal_stack_si(unsigned long 
 	PT_REGS_EDX(regs) = (unsigned long) &frame->info;
 	PT_REGS_ECX(regs) = (unsigned long) &frame->uc;
 
-	if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
-		ptrace_notify(SIGTRAP);
 	return 0;
 
 err:
Index: linux-2.6.21-rc2/include/asm-um/ptrace-generic.h
===================================================================
--- linux-2.6.21-rc2.orig/include/asm-um/ptrace-generic.h	2007-03-05 13:24:49.000000000 -0500
+++ linux-2.6.21-rc2/include/asm-um/ptrace-generic.h	2007-03-05 13:24:57.000000000 -0500
@@ -44,9 +44,6 @@ extern int set_fpxregs(unsigned long buf
 
 extern void show_regs(struct pt_regs *regs);
 
-extern void send_sigtrap(struct task_struct *tsk, union uml_pt_regs *regs,
-			 int error_code);
-
 extern int arch_copy_tls(struct task_struct *new);
 extern void clear_flushed_tls(struct task_struct *task);
 
Index: linux-2.6.21-rc2/include/asm-um/ptrace-i386.h
===================================================================
--- linux-2.6.21-rc2.orig/include/asm-um/ptrace-i386.h	2007-03-05 13:24:49.000000000 -0500
+++ linux-2.6.21-rc2/include/asm-um/ptrace-i386.h	2007-03-05 13:24:57.000000000 -0500
@@ -6,6 +6,8 @@
 #ifndef __UM_PTRACE_I386_H
 #define __UM_PTRACE_I386_H
 
+#define ARCH_HAS_SINGLE_STEP	(1)
+
 #define HOST_AUDIT_ARCH AUDIT_ARCH_I386
 
 #include "linux/compiler.h"
Index: linux-2.6.21-rc2/include/asm-um/ptrace-x86_64.h
===================================================================
--- linux-2.6.21-rc2.orig/include/asm-um/ptrace-x86_64.h	2007-03-05 13:24:49.000000000 -0500
+++ linux-2.6.21-rc2/include/asm-um/ptrace-x86_64.h	2007-03-05 13:24:57.000000000 -0500
@@ -14,6 +14,8 @@
 #define __FRAME_OFFSETS /* Needed to get the R* macros */
 #include "asm/ptrace-generic.h"
 
+#define ARCH_HAS_SINGLE_STEP	(1)
+
 #define HOST_AUDIT_ARCH AUDIT_ARCH_X86_64
 
 /* Also defined in sysdep/ptrace.h, so may already be defined. */
Index: linux-2.6.21-rc2/include/asm-um/tracehook.h
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.21-rc2/include/asm-um/tracehook.h	2007-03-05 13:24:57.000000000 -0500
@@ -0,0 +1,64 @@
+/*
+ * Tracing hooks, i386 CPU support
+ *
+ * Copyright (C) 2006, 2007 Red Hat, Inc.  All rights reserved.
+ *
+ * This copyrighted material is made available to anyone wishing to use,
+ * modify, copy, or redistribute it subject to the terms and conditions
+ * of the GNU General Public License v.2.
+ *
+ * Red Hat Author: Roland McGrath.
+ *
+ * Munged for UML - jdike@{addtoit,linux.intel}.com
+ */
+
+#ifndef _ASM_TRACEHOOK_H
+#define _ASM_TRACEHOOK_H	1
+
+#include <linux/sched.h>
+#include <asm/ptrace.h>
+#include <asm/thread_info.h>
+
+/*
+ * See linux/tracehook.h for the descriptions of what these need to do.
+ */
+
+static inline void tracehook_enable_single_step(struct task_struct *tsk)
+{
+	set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
+}
+
+static inline void tracehook_disable_single_step(struct task_struct *tsk)
+{
+	clear_tsk_thread_flag(tsk, TIF_SINGLESTEP);
+}
+
+static inline int tracehook_single_step_enabled(struct task_struct *tsk)
+{
+	return test_tsk_thread_flag(tsk, TIF_SINGLESTEP);
+}
+
+static inline void tracehook_enable_syscall_trace(struct task_struct *tsk)
+{
+	set_tsk_thread_flag(tsk, TIF_SYSCALL_TRACE);
+}
+
+static inline void tracehook_disable_syscall_trace(struct task_struct *tsk)
+{
+	clear_tsk_thread_flag(tsk, TIF_SYSCALL_TRACE);
+}
+
+static inline void tracehook_abort_syscall(struct pt_regs *regs)
+{
+	PT_REGS_SYSCALL_NR(regs) = -1;
+}
+
+extern const struct utrace_regset_view utrace_um_native;
+static inline const struct utrace_regset_view *
+utrace_native_view(struct task_struct *tsk)
+{
+	return &utrace_um_native;
+}
+
+
+#endif
Index: linux-2.6.21-rc2/include/asm-um/thread_info.h
===================================================================
--- linux-2.6.21-rc2.orig/include/asm-um/thread_info.h	2007-02-27 23:59:12.000000000 -0500
+++ linux-2.6.21-rc2/include/asm-um/thread_info.h	2007-03-05 15:11:39.000000000 -0500
@@ -69,6 +69,8 @@ static inline struct thread_info *curren
 #define TIF_MEMDIE	 	5
 #define TIF_SYSCALL_AUDIT	6
 #define TIF_RESTORE_SIGMASK	7
+#define TIF_SINGLESTEP          8       /* restore singlestep on return to user
+                                         * mode */
 
 #define _TIF_SYSCALL_TRACE	(1 << TIF_SYSCALL_TRACE)
 #define _TIF_SIGPENDING		(1 << TIF_SIGPENDING)
@@ -77,5 +79,6 @@ static inline struct thread_info *curren
 #define _TIF_MEMDIE		(1 << TIF_MEMDIE)
 #define _TIF_SYSCALL_AUDIT	(1 << TIF_SYSCALL_AUDIT)
 #define _TIF_RESTORE_SIGMASK	(1 << TIF_RESTORE_SIGMASK)
+#define _TIF_SINGLESTEP         (1 << TIF_SINGLESTEP)
 
 #endif

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Re: [PATCH] UML utrace support, step 1

[Roland McGrath]

> Did I send the right patch?  The one I meant to send (appended below),
> indeed builds and runs without utrace-regset.patch and
> utrace-core.patch applied.  It's utrace-1 in the following:

That is not the same patch I tried before.  This one does apply and build
fine (after make defconfig ARCH=um).  

Technically utrace_native_view doesn't belong in the tracehook patch (but
in the regset one to follow it), but it is harmless.

I've merged it into my current tree.  You can get this via GIT if you like
that.  I do regular merges from Linus's GIT tree, so any upstream UML
changes that merge cleanly or have trivial conflict fixes I can do will be
taken care of automatically.  For future updates, please send me
incremental changes based on my current stuff; the GIT branches and the
2.6-current patches on my utrace web page always match up.  My patch set
generation uses just one fixed log message for utrace-tracehook-um.patch,
so tell me if you want to adjust it from log text in today's patch.


Thanks,
Roland

Re: [uml-devel] [PATCH] UML utrace support, step 1

[Roland McGrath]

> Did I send the right patch?  The one I meant to send (appended below),
> indeed builds and runs without utrace-regset.patch and
> utrace-core.patch applied.  It's utrace-1 in the following:

That is not the same patch I tried before.  This one does apply and build
fine (after make defconfig ARCH=um).  

Technically utrace_native_view doesn't belong in the tracehook patch (but
in the regset one to follow it), but it is harmless.

I've merged it into my current tree.  You can get this via GIT if you like
that.  I do regular merges from Linus's GIT tree, so any upstream UML
changes that merge cleanly or have trivial conflict fixes I can do will be
taken care of automatically.  For future updates, please send me
incremental changes based on my current stuff; the GIT branches and the
2.6-current patches on my utrace web page always match up.  My patch set
generation uses just one fixed log message for utrace-tracehook-um.patch,
so tell me if you want to adjust it from log text in today's patch.


Thanks,
Roland

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