[PATCH v2] arm64:Modify the dump mem for 64 bit addresses

[Maninder Singh]

From: Rohit Thapliyal <r.thapliyal@xxxxxxxxxxx>

V1 = added new function dump_mem64
v1->v2
Removed the separate function dump_mem64 and accommodated
a field width based on which the dump shall be created of
width either 4 or 8 as suggested by Catalin.

On 64bit kernel, the dump_mem gives 32 bit addresses
on the stack dump. This gives unorganized information regarding
the 64bit values on the stack. Hence, modified to get a complete
64bit memory dump.

With patch:
[   93.534801] Process insmod (pid: 1587, stack limit = 0xffffffc976be4058)
[   93.541441] Stack: (0xffffffc976be7cf0 to 0xffffffc976be8000)
[   93.547136] 7ce0:                                   ffffffc976be7d00 ffffffc00008163c
[   93.554898] 7d00: ffffffc976be7d40 ffffffc0000f8a44 ffffffc00098ef38 ffffffbffc000088
[   93.562659] 7d20: ffffffc00098ef50 ffffffbffc0000c0 0000000000000001 ffffffbffc000070
[   93.570419] 7d40: ffffffc976be7e40 ffffffc0000f935c 0000000000000000 000000002b424090
[   93.578179] 7d60: 000000002b424010 0000007facc555f4 0000000080000000 0000000000000015
[   93.585937] 7d80: 0000000000000116 0000000000000069 ffffffc00097b000 ffffffc976be4000
[   93.593694] 7da0: 0000000000000064 0000000000000072 000000000000006e 000000000000003f
[   93.601453] 7dc0: 000000000000feff 000000000000fff1 ffffffbffc002028 0000000000000124
[   93.609211] 7de0: ffffffc976be7e10 0000000000000001 ffffff8000000000 ffffffbbffff0000
[   93.616969] 7e00: ffffffc976be7e60 0000000000000000 0000000000000000 0000000000000000
[   93.624726] 7e20: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
[   93.632484] 7e40: 0000007fcc474550 ffffffc0000841ec 000000002b424010 0000007facda0710
[   93.640241] 7e60: ffffffffffffffff ffffffc0000be6dc ffffff80007d2000 000000000001c010
[   93.647999] 7e80: ffffff80007e0ae0 ffffff80007e09d0 ffffff80007edf70 0000000000000288
[   93.655757] 7ea0: 00000000000002e8 0000000000000000 0000000000000000 0000001c0000001b
[   93.663514] 7ec0: 0000000000000009 0000000000000007 000000002b424090 000000000001c010
[   93.671272] 7ee0: 000000002b424010 0000007faccd3a48 0000000000000000 0000000000000000
[   93.679030] 7f00: 0000007fcc4743f8 0000007fcc4743f8 0000000000000069 0000000000000003
[   93.686787] 7f20: 0101010101010101 0000000000000004 0000000000000020 00000000000003f3
[   93.694544] 7f40: 0000007facb95664 0000007facda7030 0000007facc555d0 0000000000498378
[   93.702301] 7f60: 0000000000000000 000000002b424010 0000007facda0710 000000002b424090
[   93.710058] 7f80: 0000007fcc474698 0000000000498000 0000007fcc474ebb 0000000000474f58
[   93.717815] 7fa0: 0000000000498000 0000000000000000 0000000000000000 0000007fcc474550
[   93.725573] 7fc0: 00000000004104bc 0000007fcc474430 0000007facc555f4 0000000080000000
[   93.733330] 7fe0: 000000002b424090 0000000000000069 0950020128000244 4104000008000004
[   93.741084] Call trace:

The above output makes a debugger life a lot more easier.

Signed-off-by: Rohit Thapliyal <r.thapliyal@xxxxxxxxxxx>
Signed-off-by: Maninder Singh <maninder1.s@xxxxxxxxxxx>
Reviewed-by: Akhilesh kumar <akhilesh.k@xxxxxxxxxxx>
---
 arch/arm64/kernel/traps.c |   44 +++++++++++++++++++++++++++++++++-----------
 1 file changed, 33 insertions(+), 11 deletions(-)

diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index 1ef2940..53d57db 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -51,8 +51,9 @@ int show_unhandled_signals = 1;
 /*
  * Dump out the contents of some memory nicely...
  */
+
 static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
-		     unsigned long top)
+		unsigned long top, unsigned int width)
 {
 	unsigned long first;
 	mm_segment_t fs;
@@ -70,18 +71,27 @@ static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
 
 	for (first = bottom & ~31; first < top; first += 32) {
 		unsigned long p;
-		char str[sizeof(" 12345678") * 8 + 1];
+		char str[sizeof(" 1234567812345678") * 8 + 1];
 
 		memset(str, ' ', sizeof(str));
 		str[sizeof(str) - 1] = '\0';
 
-		for (p = first, i = 0; i < 8 && p < top; i++, p += 4) {
+		for (p = first, i = 0; i < (width > 4 ? width-4 : width+4)
+					&& p < top; i++, p += width) {
 			if (p >= bottom && p < top) {
-				unsigned int val;
-				if (__get_user(val, (unsigned int *)p) == 0)
-					sprintf(str + i * 9, " %08x", val);
-				else
-					sprintf(str + i * 9, " ????????");
+				unsigned long val;
+
+				if (width == 8) {
+					if (__get_user(val, (unsigned long *)p) == 0)
+						sprintf(str + i * 17, " %016lx", val);
+					else
+						sprintf(str + i * 17, " ????????????????");
+				} else {
+					if (__get_user(val, (unsigned int *)p) == 0)
+						sprintf(str + i * 9, " %08x", (unsigned int)val);
+					else
+						sprintf(str + i * 9, " ????????");
+				}
 			}
 		}
 		printk("%s%04lx:%s\n", lvl, first & 0xffff, str);
@@ -95,7 +105,7 @@ static void dump_backtrace_entry(unsigned long where, unsigned long stack)
 	print_ip_sym(where);
 	if (in_exception_text(where))
 		dump_mem("", "Exception stack", stack,
-			 stack + sizeof(struct pt_regs));
+			 stack + sizeof(struct pt_regs), 8);
 }
 
 static void dump_instr(const char *lvl, struct pt_regs *regs)
@@ -191,6 +201,7 @@ static int __die(const char *str, int err, struct thread_info *thread,
 	struct task_struct *tsk = thread->task;
 	static int die_counter;
 	int ret;
+	unsigned int width = 8;
 
 	pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP "\n",
 		 str, err, ++die_counter);
@@ -206,8 +217,19 @@ static int __die(const char *str, int err, struct thread_info *thread,
 		 TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), thread + 1);
 
 	if (!user_mode(regs) || in_interrupt()) {
-		dump_mem(KERN_EMERG, "Stack: ", regs->sp,
-			 THREAD_SIZE + (unsigned long)task_stack_page(tsk));
+
+		if (regs->sp > (unsigned long)task_stack_page(tsk)) {
+			dump_mem(KERN_EMERG, "Stack: ", regs->sp,
+				THREAD_SIZE +
+				(unsigned long)task_stack_page(tsk), width);
+		} else {
+			if (compat_user_mode(regs))
+				width = 4;
+			dump_mem(KERN_EMERG, "Stack: ",
+				(unsigned long)task_stack_page(tsk),
+				THREAD_SIZE +
+				(unsigned long)task_stack_page(tsk), width);
+		}
 		dump_backtrace(regs, tsk);
 		dump_instr(KERN_EMERG, regs);
 	}
-- 
1.7.9.5

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