---

yaml
---
r: 257092
b: refs/heads/master
c: a0e3e70
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 5f307491f3a0c8551cedf5d90d660d656e0d56ec
+refs/heads/master: a0e3e70243f5b270bc3eca718f0a9fa5e6b8262e

trunk/arch/mips/include/asm/stacktrace.h

@@ -7,10 +7,6 @@
 extern int raw_show_trace;
 extern unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
 				  unsigned long pc, unsigned long *ra);
-extern unsigned long unwind_stack_by_address(unsigned long stack_page,
-					     unsigned long *sp,
-					     unsigned long pc,
-					     unsigned long *ra);
 #else
 #define raw_show_trace 1
 static inline unsigned long unwind_stack(struct task_struct *task,

trunk/arch/mips/kernel/process.c

@@ -373,18 +373,18 @@ unsigned long thread_saved_pc(struct task_struct *tsk)
 
 
 #ifdef CONFIG_KALLSYMS
-/* generic stack unwinding function */
-unsigned long notrace unwind_stack_by_address(unsigned long stack_page,
-					      unsigned long *sp,
-					      unsigned long pc,
-					      unsigned long *ra)
+/* used by show_backtrace() */
+unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
+			   unsigned long pc, unsigned long *ra)
 {
+	unsigned long stack_page;
 	struct mips_frame_info info;
 	unsigned long size, ofs;
 	int leaf;
 	extern void ret_from_irq(void);
 	extern void ret_from_exception(void);
 
+	stack_page = (unsigned long)task_stack_page(task);
 	if (!stack_page)
 		return 0;
 
@@ -443,15 +443,6 @@ unsigned long notrace unwind_stack_by_address(unsigned long stack_page,
 	*ra = 0;
 	return __kernel_text_address(pc) ? pc : 0;
 }
-EXPORT_SYMBOL(unwind_stack_by_address);
-
-/* used by show_backtrace() */
-unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
-			   unsigned long pc, unsigned long *ra)
-{
-	unsigned long stack_page = (unsigned long)task_stack_page(task);
-	return unwind_stack_by_address(stack_page, sp, pc, ra);
-}
 #endif
 
 /*

trunk/arch/mips/oprofile/Makefile

@@ -8,7 +8,7 @@ DRIVER_OBJS = $(addprefix ../../../drivers/oprofile/, \
 		oprofilefs.o oprofile_stats.o \
 		timer_int.o )
 
-oprofile-y				:= $(DRIVER_OBJS) common.o backtrace.o
+oprofile-y				:= $(DRIVER_OBJS) common.o
 
 oprofile-$(CONFIG_CPU_MIPS32)		+= op_model_mipsxx.o
 oprofile-$(CONFIG_CPU_MIPS64)		+= op_model_mipsxx.o

trunk/arch/mips/oprofile/common.c

@@ -115,7 +115,6 @@ int __init oprofile_arch_init(struct oprofile_operations *ops)
 	ops->start		= op_mips_start;
 	ops->stop		= op_mips_stop;
 	ops->cpu_type		= lmodel->cpu_type;
-	ops->backtrace		= op_mips_backtrace;
 
 	printk(KERN_INFO "oprofile: using %s performance monitoring.\n",
 	       lmodel->cpu_type);

trunk/arch/mips/oprofile/op_impl.h

@@ -36,6 +36,4 @@ struct op_mips_model {
 	unsigned char num_counters;
 };
 
-void op_mips_backtrace(struct pt_regs * const regs, unsigned int depth);
-
 #endif

trunk/arch/x86/oprofile/backtrace.c

@@ -11,10 +11,12 @@
 #include <linux/oprofile.h>
 #include <linux/sched.h>
 #include <linux/mm.h>
+#include <linux/compat.h>
+#include <linux/highmem.h>
+
 #include <asm/ptrace.h>
 #include <asm/uaccess.h>
 #include <asm/stacktrace.h>
-#include <linux/compat.h>
 
 static int backtrace_stack(void *data, char *name)
 {
@@ -36,17 +38,53 @@ static struct stacktrace_ops backtrace_ops = {
 	.walk_stack	= print_context_stack,
 };
 
+/* from arch/x86/kernel/cpu/perf_event.c: */
+
+/*
+ * best effort, GUP based copy_from_user() that assumes IRQ or NMI context
+ */
+static unsigned long
+copy_from_user_nmi(void *to, const void __user *from, unsigned long n)
+{
+	unsigned long offset, addr = (unsigned long)from;
+	unsigned long size, len = 0;
+	struct page *page;
+	void *map;
+	int ret;
+
+	do {
+		ret = __get_user_pages_fast(addr, 1, 0, &page);
+		if (!ret)
+			break;
+
+		offset = addr & (PAGE_SIZE - 1);
+		size = min(PAGE_SIZE - offset, n - len);
+
+		map = kmap_atomic(page);
+		memcpy(to, map+offset, size);
+		kunmap_atomic(map);
+		put_page(page);
+
+		len  += size;
+		to   += size;
+		addr += size;
+
+	} while (len < n);
+
+	return len;
+}
+
 #ifdef CONFIG_COMPAT
 static struct stack_frame_ia32 *
 dump_user_backtrace_32(struct stack_frame_ia32 *head)
 {
+	/* Also check accessibility of one struct frame_head beyond: */
 	struct stack_frame_ia32 bufhead[2];
 	struct stack_frame_ia32 *fp;
+	unsigned long bytes;
 
-	/* Also check accessibility of one struct frame_head beyond */
-	if (!access_ok(VERIFY_READ, head, sizeof(bufhead)))
-		return NULL;
-	if (__copy_from_user_inatomic(bufhead, head, sizeof(bufhead)))
+	bytes = copy_from_user_nmi(bufhead, head, sizeof(bufhead));
+	if (bytes != sizeof(bufhead))
 		return NULL;
 
 	fp = (struct stack_frame_ia32 *) compat_ptr(bufhead[0].next_frame);
@@ -87,12 +125,12 @@ x86_backtrace_32(struct pt_regs * const regs, unsigned int depth)
 
 static struct stack_frame *dump_user_backtrace(struct stack_frame *head)
 {
+	/* Also check accessibility of one struct frame_head beyond: */
 	struct stack_frame bufhead[2];
+	unsigned long bytes;
 
-	/* Also check accessibility of one struct stack_frame beyond */
-	if (!access_ok(VERIFY_READ, head, sizeof(bufhead)))
-		return NULL;
-	if (__copy_from_user_inatomic(bufhead, head, sizeof(bufhead)))
+	bytes = copy_from_user_nmi(bufhead, head, sizeof(bufhead));
+	if (bytes != sizeof(bufhead))
 		return NULL;
 
 	oprofile_add_trace(bufhead[0].return_address);

trunk/arch/x86/oprofile/nmi_int.c

@@ -112,8 +112,10 @@ static void nmi_cpu_start(void *dummy)
 static int nmi_start(void)
 {
 	get_online_cpus();
-	on_each_cpu(nmi_cpu_start, NULL, 1);
 	ctr_running = 1;
+	/* make ctr_running visible to the nmi handler: */
+	smp_mb();
+	on_each_cpu(nmi_cpu_start, NULL, 1);
 	put_online_cpus();
 	return 0;
 }
@@ -504,15 +506,18 @@ static int nmi_setup(void)
 
 	nmi_enabled = 0;
 	ctr_running = 0;
-	barrier();
+	/* make variables visible to the nmi handler: */
+	smp_mb();
 	err = register_die_notifier(&profile_exceptions_nb);
 	if (err)
 		goto fail;
 
 	get_online_cpus();
 	register_cpu_notifier(&oprofile_cpu_nb);
-	on_each_cpu(nmi_cpu_setup, NULL, 1);
 	nmi_enabled = 1;
+	/* make nmi_enabled visible to the nmi handler: */
+	smp_mb();
+	on_each_cpu(nmi_cpu_setup, NULL, 1);
 	put_online_cpus();
 
 	return 0;
@@ -531,7 +536,8 @@ static void nmi_shutdown(void)
 	nmi_enabled = 0;
 	ctr_running = 0;
 	put_online_cpus();
-	barrier();
+	/* make variables visible to the nmi handler: */
+	smp_mb();
 	unregister_die_notifier(&profile_exceptions_nb);
 	msrs = &get_cpu_var(cpu_msrs);
 	model->shutdown(msrs);