2.6.25 fixes and stack level limits.

9 files changed, 59 insertions, 54 deletions

diff --git a/runtime/ChangeLog b/runtime/ChangeLog
index b33fa22a..5066279e 100644
--- a/runtime/ChangeLog
+++ b/runtime/ChangeLog
@@ -1,3 +1,19 @@
+2008-04-15  Martin Hunt  <hunt@redhat.com>
+
+	Finish support for limits on backtrace depth.
+	* runtime.h (MAXTRACE): Default to 20.
+	* stack.c (_stp_stack_print): Call __stp_stack_print
+	with levels set properly.
+	* sym.c (_stp_func_print): Return a value indicating 
+	if something was printed.
+
+	Support for i386 and x86_64 on 2.6.25 kernel
+	* unwind/i386.h: Support unified registers on 2.6.25.
+	Remove unused frame stuff, including STACK_*.
+	* stack-i386.c (__stp_stack_print): Support unified
+	registers on 2.6.25.
+	* regs.h (REG_FP): Define for i386.
+
 2008-04-15  Frank Ch. Eigler  <fche@elastic.org>
 
 	PR 6405
diff --git a/runtime/regs.h b/runtime/regs.h
index c1e2344b..4954020f 100644
--- a/runtime/regs.h
+++ b/runtime/regs.h
@@ -1,5 +1,5 @@
 /* common register includes used in multiple modules
- * Copyright (C) 2005 Red Hat Inc.
+ * Copyright (C) 2005-2008 Red Hat Inc.
  * Copyright (C) 2005 Intel Corporation.
  *
  * This file is part of systemtap, and is free software.  You can
@@ -14,6 +14,7 @@
 #if defined  (STAPCONF_X86_UNIREGS) && (defined (__x86_64__) || defined (__i386__))
 #define REG_IP(regs) regs->ip
 #define REG_SP(regs) regs->sp
+#define REG_FP(regs) regs->bp;
 
 #elif defined  (__x86_64__)
 
@@ -24,6 +25,7 @@
 
 #define REG_IP(regs) regs->eip
 #define REG_SP(regs) regs->esp
+#define REG_FP(regs) regs->ebp;
 
 #elif defined (__ia64__)
 #define REG_IP(regs)    ((regs)->cr_iip +ia64_psr(regs)->ri)
diff --git a/runtime/runtime.h b/runtime/runtime.h
index 8d267173..50eb9d31 100644
--- a/runtime/runtime.h
+++ b/runtime/runtime.h
@@ -70,6 +70,10 @@ static struct
 #define MAXSTRINGLEN 128
 #endif
 
+#ifndef MAXTRACE
+#define MAXTRACE 20
+#endif
+
 #ifdef CONFIG_FRAME_POINTER
 /* Just because frame pointers are available does not mean we can trust them. */
 #if defined (__i386__) || defined (__arm__)
diff --git a/runtime/stack-i386.c b/runtime/stack-i386.c
index 78f89b0d..ad101889 100644
--- a/runtime/stack-i386.c
+++ b/runtime/stack-i386.c
@@ -14,65 +14,61 @@ static int _stp_valid_stack_ptr(unsigned long context, unsigned long p)
 }
 
 /* DWARF unwinder failed.  Just dump intereting addresses on kernel stack. */
-static void _stp_stack_print_fallback(unsigned long context, unsigned long stack, int verbose)
+static void _stp_stack_print_fallback(unsigned long context, unsigned long stack, int verbose, int levels)
 {
 	unsigned long addr;
-	while (_stp_valid_stack_ptr(context, stack) &&
-               !_stp_pbuf_full()) {
+	while (levels && _stp_valid_stack_ptr(context, stack)) {
 		if (unlikely(_stp_read_address(addr, (unsigned long *)stack, KERNEL_DS))) {
 			/* cannot access stack.  give up. */
 			return;
 		}
-		_stp_func_print(addr, verbose, 0);
+		if (_stp_func_print(addr, verbose, 0))
+			levels--;
 		stack++;
 	}
 }
 
 static void __stp_stack_print (struct pt_regs *regs, int verbose, int levels)
 {
-	unsigned long *stack = (unsigned long *)&REG_SP(regs);
-	unsigned long context = (unsigned long)stack & ~(THREAD_SIZE - 1);
+	unsigned long context = (unsigned long)&REG_SP(regs) & ~(THREAD_SIZE - 1);
 
 #ifdef	STP_USE_FRAME_POINTER
-	/* FIXME: need to use _stp_func_print() and safe copy */
 	unsigned long addr;
-	
-#ifdef STAPCONF_X86_UNIREGS
-	unsigned long ebp = regs->bp;
-#else
-	unsigned long ebp = regs->ebp;
-#endif /* STAPCONF_X86_UNIREGS */
-	
-	while (_stp_valid_stack_ptr(context, (unsigned long)ebp) &&
-               !_stp_pbuf_full()) {
-		if (unlikely(_stp_read_address(addr, (unsigned long *)(ebp + 4), KERNEL_DS))) {
+	unsigned long next_fp, fp = REG_FP(regs);
+
+	while (levels && _stp_valid_stack_ptr(context, (unsigned long)fp)) {
+		if (unlikely(_stp_read_address(addr, (unsigned long *)(fp + 4), KERNEL_DS))) {
 			/* cannot access stack.  give up. */
 			return;
 		}
-		if (verbose) {
-			_stp_print_char(' ');
-			_stp_symbol_print (addr);
-			_stp_print_char('\n');
-		} else
-			_stp_printf ("0x%08lx ", addr);
-		ebp = *(unsigned long *)ebp;
+		_stp_func_print(addr, verbose, 1);
+		if (unlikely(_stp_read_address(next_fp, (unsigned long *)fp, KERNEL_DS))) {
+			/* cannot access stack.  give up. */
+			return;
+		}
+		levels--;
+
+		/* frame pointers move upwards */
+		if (next_fp <= fp)
+			break;
+		fp = next_fp;
 	}
 #else
 	struct unwind_frame_info info;
 	arch_unw_init_frame_info(&info, regs);
 	
-	while (!arch_unw_user_mode(&info) &&
-               !_stp_pbuf_full ()) {
+	while (levels && !arch_unw_user_mode(&info)) {
 		int ret = unwind(&info);
 		dbug_unwind(1, "ret=%d PC=%lx SP=%lx\n", ret, UNW_PC(&info), UNW_SP(&info));
 		if (ret == 0) {
 			_stp_func_print(UNW_PC(&info), verbose, 1);
+			levels--;
 			continue;
 		}
 		/* If an error happened or we hit a kretprobe trampoline, use fallback backtrace */
 		/* FIXME: is there a way to unwind across kretprobe trampolines? */
 		if (ret < 0 || (ret > 0 && UNW_PC(&info) == _stp_kretprobe_trampoline))
-			_stp_stack_print_fallback(context, UNW_SP(&info), verbose);
+			_stp_stack_print_fallback(context, UNW_SP(&info), verbose, levels);
 		break;
 	}
 #endif /* STP_USE_FRAME_POINTER */
diff --git a/runtime/stack.c b/runtime/stack.c
index 772c5baf..23ac2edc 100644
--- a/runtime/stack.c
+++ b/runtime/stack.c
@@ -47,7 +47,7 @@
  * @param regs A pointer to the struct pt_regs.
  */
 
-void _stp_stack_print(struct pt_regs *regs, int verbose, struct kretprobe_instance *pi)
+void _stp_stack_print(struct pt_regs *regs, int verbose, struct kretprobe_instance *pi, int levels)
 {
 	if (verbose) {
 		/* print the current address */
@@ -66,7 +66,7 @@ void _stp_stack_print(struct pt_regs *regs, int verbose, struct kretprobe_instan
 	else 
 		_stp_printf("%p ", (int64_t) REG_IP(regs));
 
-	__stp_stack_print(regs, verbose, 0);
+	__stp_stack_print(regs, verbose, levels);
 }
 
 /** Writes stack backtrace to a string
@@ -75,14 +75,14 @@ void _stp_stack_print(struct pt_regs *regs, int verbose, struct kretprobe_instan
  * @param regs A pointer to the struct pt_regs.
  * @returns void
  */
-void _stp_stack_snprint(char *str, int size, struct pt_regs *regs, int verbose, struct kretprobe_instance *pi)
+void _stp_stack_snprint(char *str, int size, struct pt_regs *regs, int verbose, struct kretprobe_instance *pi, int levels)
 {
 	/* To get a string, we use a simple trick. First flush the print buffer, */
 	/* then call _stp_stack_print, then copy the result into the output string  */
 	/* and clear the print buffer. */
 	_stp_pbuf *pb = per_cpu_ptr(Stp_pbuf, smp_processor_id());
 	_stp_print_flush();
-	_stp_stack_print(regs, verbose, pi);
+	_stp_stack_print(regs, verbose, pi, levels);
 	strlcpy(str, pb->buf, size < (int)pb->len ? size : (int)pb->len);
 	pb->len = 0;
 }
diff --git a/runtime/sym.c b/runtime/sym.c
index 3d5ff01d..7163bf92 100644
--- a/runtime/sym.c
+++ b/runtime/sym.c
@@ -223,8 +223,7 @@ void _stp_symbol_print(unsigned long address)
 }
 
 /* Like _stp_symbol_print, except only print if the address is a valid function address */
-
-void _stp_func_print(unsigned long address, int verbose, int exact)
+int _stp_func_print(unsigned long address, int verbose, int exact)
 {
 	char *modname;
 	const char *name;
@@ -247,7 +246,9 @@ void _stp_func_print(unsigned long address, int verbose, int exact)
 				_stp_printf(" %p : %s+%#lx/%#lx%s\n", (int64_t) address, name, offset, size, exstr);
 		} else
 			_stp_printf("%p ", (int64_t) address);
+		return 1;
 	}
+	return 0;
 }
 
 void _stp_symbol_snprint(char *str, size_t len, unsigned long address)
diff --git a/runtime/unwind/i386.h b/runtime/unwind/i386.h
index 6511f76a..79e6ba73 100644
--- a/runtime/unwind/i386.h
+++ b/runtime/unwind/i386.h
@@ -34,15 +34,6 @@ struct unwind_frame_info
 
 #define UNW_PC(frame)        (frame)->regs.ip
 #define UNW_SP(frame)        (frame)->regs.sp
-#ifdef STP_USE_FRAME_POINTER
-#define UNW_FP(frame)        (frame)->regs.bp
-#define FRAME_RETADDR_OFFSET 4
-#define FRAME_LINK_OFFSET    0
-/* #define STACK_BOTTOM(tsk)    STACK_LIMIT((tsk)->thread.sp0) */
-/* #define STACK_TOP(tsk)       ((tsk)->thread.sp0) */
-#else
-#define UNW_FP(frame) ((void)(frame), 0)
-#endif
 
 #define UNW_REGISTER_INFO \
 	PTREGS_INFO(ax), \
@@ -59,15 +50,6 @@ struct unwind_frame_info
 
 #define UNW_PC(frame)        (frame)->regs.eip
 #define UNW_SP(frame)        (frame)->regs.esp
-#ifdef STP_USE_FRAME_POINTER
-#define UNW_FP(frame)        (frame)->regs.ebp
-#define FRAME_RETADDR_OFFSET 4
-#define FRAME_LINK_OFFSET    0
-/* #define STACK_BOTTOM(tsk)    STACK_LIMIT((tsk)->thread.esp0) */
-/* #define STACK_TOP(tsk)       ((tsk)->thread.esp0) */
-#else
-#define UNW_FP(frame) ((void)(frame), 0)
-#endif
 
 #define UNW_REGISTER_INFO \
 	PTREGS_INFO(eax), \
diff --git a/tapset/ChangeLog b/tapset/ChangeLog
index dae8b452..c4c526f4 100644
--- a/tapset/ChangeLog
+++ b/tapset/ChangeLog
@@ -1,3 +1,7 @@
+2008-04-15  Martin Hunt  <hunt@monkey>
+
+	* context.stp (print_backtrace, backtrace): Use MAXTRACE.
+
 2008-03-21  Eugene Teo  <eugeneteo@kernel.sg>
 
 	PR 5528
diff --git a/tapset/context.stp b/tapset/context.stp
index 4aa75158..dc560316 100644
--- a/tapset/context.stp
+++ b/tapset/context.stp
@@ -15,7 +15,7 @@ function print_regs () %{
 
 function print_backtrace () %{
 	if (CONTEXT->regs) {
-		_stp_stack_print(CONTEXT->regs, 1, CONTEXT->pi);
+		_stp_stack_print(CONTEXT->regs, 1, CONTEXT->pi, MAXTRACE);
 	} else {
 		_stp_printf("Systemtap probe: %s\n", CONTEXT->probe_point);
 	}
@@ -23,7 +23,7 @@ function print_backtrace () %{
 
 function backtrace:string () %{ /* pure */
 	if (CONTEXT->regs)
-		_stp_stack_snprint (THIS->__retvalue, MAXSTRINGLEN, CONTEXT->regs, 0, CONTEXT->pi);	
+		_stp_stack_snprint (THIS->__retvalue, MAXSTRINGLEN, CONTEXT->regs, 0, CONTEXT->pi, MAXTRACE);
 	else 
 		strlcpy (THIS->__retvalue, "", MAXSTRINGLEN);
 %}