X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;ds=sidebyside;f=arch%2Farm%2Foprofile%2Fbacktrace.c;h=f5ebf30151fa9f22b7311e59ed20b0773d8dda21;hb=676056132425ac425d7215cdaa8bd25582e07966;hp=df35c452a8bf6528c3cf92ee892af205350d7b50;hpb=1703ecc7e88ea2d583fc9ebe7de8edb004eff863;p=linux-2.6-omap-h63xx.git

diff --git a/arch/arm/oprofile/backtrace.c b/arch/arm/oprofile/backtrace.c
index df35c452a8b..f5ebf30151f 100644
--- a/arch/arm/oprofile/backtrace.c
+++ b/arch/arm/oprofile/backtrace.c
@@ -19,6 +19,19 @@
 #include <asm/ptrace.h>
 #include <asm/uaccess.h>
 
+#include "../kernel/stacktrace.h"
+
+static int report_trace(struct stackframe *frame, void *d)
+{
+	unsigned int *depth = d;
+
+	if (*depth) {
+		oprofile_add_trace(frame->lr);
+		(*depth)--;
+	}
+
+	return *depth == 0;
+}
 
 /*
  * The registers we're interested in are at the end of the variable
@@ -32,113 +45,37 @@ struct frame_tail {
 	unsigned long lr;
 } __attribute__((packed));
 
-
-#ifdef CONFIG_FRAME_POINTER
-static struct frame_tail* kernel_backtrace(struct frame_tail *tail)
-{
-	oprofile_add_trace(tail->lr);
-
-	/* frame pointers should strictly progress back up the stack
-	 * (towards higher addresses) */
-	if (tail >= tail->fp)
-		return NULL;
-
-	return tail->fp-1;
-}
-#endif
-
 static struct frame_tail* user_backtrace(struct frame_tail *tail)
 {
-	struct frame_tail buftail;
+	struct frame_tail buftail[2];
 
-	/* hardware pte might not be valid due to dirty/accessed bit emulation
-	 * so we use copy_from_user and benefit from exception fixups */
-	if (copy_from_user(&buftail, tail, sizeof(struct frame_tail)))
+	/* Also check accessibility of one struct frame_tail beyond */
+	if (!access_ok(VERIFY_READ, tail, sizeof(buftail)))
+		return NULL;
+	if (__copy_from_user_inatomic(buftail, tail, sizeof(buftail)))
 		return NULL;
 
-	oprofile_add_trace(buftail.lr);
+	oprofile_add_trace(buftail[0].lr);
 
 	/* frame pointers should strictly progress back up the stack
 	 * (towards higher addresses) */
-	if (tail >= buftail.fp)
+	if (tail >= buftail[0].fp)
 		return NULL;
 
-	return buftail.fp-1;
-}
-
-/* Compare two addresses and see if they're on the same page */
-#define CMP_ADDR_EQUAL(x,y,offset) ((((unsigned long) x) >> PAGE_SHIFT) \
-	== ((((unsigned long) y) + offset) >> PAGE_SHIFT))
-
-/* check that the page(s) containing the frame tail are present */
-static int pages_present(struct frame_tail *tail)
-{
-	struct mm_struct * mm = current->mm;
-
-	if (!check_user_page_readable(mm, (unsigned long)tail))
-		return 0;
-
-	if (CMP_ADDR_EQUAL(tail, tail, 8))
-		return 1;
-
-	if (!check_user_page_readable(mm, ((unsigned long)tail) + 8))
-		return 0;
-
-	return 1;
-}
-
-/*
- * |             | /\ Higher addresses
- * |             |
- * --------------- stack base (address of current_thread_info)
- * | thread info |
- * .             .
- * |    stack    |
- * --------------- saved regs->ARM_fp value if valid (frame_tail address)
- * .             .
- * --------------- struct pt_regs stored on stack (struct pt_regs *)
- * |             |
- * .             .
- * |             |
- * --------------- %esp
- * |             |
- * |             | \/ Lower addresses
- *
- * Thus, &pt_regs <-> stack base restricts the valid(ish) fp values
- */
-static int valid_kernel_stack(struct frame_tail *tail, struct pt_regs *regs)
-{
-	unsigned long tailaddr = (unsigned long)tail;
-	unsigned long stack = (unsigned long)regs;
-	unsigned long stack_base = (stack & ~(THREAD_SIZE - 1)) + THREAD_SIZE;
-
-	return (tailaddr > stack) && (tailaddr < stack_base);
+	return buftail[0].fp-1;
 }
 
 void arm_backtrace(struct pt_regs * const regs, unsigned int depth)
 {
-	struct frame_tail *tail;
-	unsigned long last_address = 0;
-
-	tail = ((struct frame_tail *) regs->ARM_fp) - 1;
+	struct frame_tail *tail = ((struct frame_tail *) regs->ARM_fp) - 1;
 
 	if (!user_mode(regs)) {
-
-#ifdef CONFIG_FRAME_POINTER
-		while (depth-- && tail && valid_kernel_stack(tail, regs)) {
-			tail = kernel_backtrace(tail);
-		}
-#endif
+		unsigned long base = ((unsigned long)regs) & ~(THREAD_SIZE - 1);
+		walk_stackframe(regs->ARM_fp, base, base + THREAD_SIZE,
+				report_trace, &depth);
 		return;
 	}
 
-	while (depth-- && tail && !((unsigned long) tail & 3)) {
-		if ((!CMP_ADDR_EQUAL(last_address, tail, 0)
-			|| !CMP_ADDR_EQUAL(last_address, tail, 8))
-				&& !pages_present(tail))
-			return;
-		last_address = (unsigned long) tail;
+	while (depth-- && tail && !((unsigned long) tail & 3))
 		tail = user_backtrace(tail);
-	}
 }
-