mm: show more information when in bad mode [1/1]

PD#154260

Problem:
When bad mode happens, no pfn/far information is printed.
It get's problems to debug.

Solution:
1. Add far as parameter for bad_mode handler
2. Show pfn of all registers for bad_mode

Verify:
Local verified.

Change-Id: I4b0b457eff44ee717094ee8056f96ff16f111139
Signed-off-by: tao zeng <tao.zeng@amlogic.com>

arch/arm64/kernel/entry.S

@@ -394,6 +394,9 @@ END(vectors)
 	mov	x0, sp
 	mov	x1, #\reason
 	mrs	x2, esr_el1
+#ifdef CONFIG_AMLOGIC_USER_FAULT
+	mrs	x3, far_el1
+#endif
 	b	bad_mode
 	.endm
 
@@ -516,6 +519,9 @@ el1_inv:
 	mov	x0, sp
 	mov	x2, x1
 	mov	x1, #BAD_SYNC
+#ifdef CONFIG_AMLOGIC_USER_FAULT
+	mrs	x3, far_el1
+#endif
 	b	bad_mode
 ENDPROC(el1_sync)
 

arch/arm64/kernel/traps.c

@@ -639,7 +639,12 @@ const char *esr_get_class_string(u32 esr)
  * bad_mode handles the impossible case in the exception vector. This is always
  * fatal.
  */
+#ifdef CONFIG_AMLOGIC_USER_FAULT
+asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr,
+			 unsigned long far)
+#else
 asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr)
+#endif
 {
 	console_verbose();
 
@@ -647,6 +652,11 @@ asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr)
 		handler[reason], smp_processor_id(), esr,
 		esr_get_class_string(esr));
 
+#ifdef CONFIG_AMLOGIC_USER_FAULT
+	regs->unused = far;
+	pr_crit("FAR:%lx\n", far);
+	show_all_pfn(current, regs);
+#endif /* CONFIG_AMLOGIC_USER_FAULT */
 	die("Oops - bad mode", regs, 0);
 	local_irq_disable();
 	panic("bad mode");

arch/arm64/mm/fault.c

@@ -275,6 +275,13 @@ void show_all_pfn(struct task_struct *task, struct pt_regs *regs)
 	else
 		sprintf(s1, "--------");
 	pr_info("sp :  %016llx  %s\n", regs->sp, s1);
+
+	pfn1 = get_user_pfn(task->mm, regs->unused);
+	if (pfn1 >= 0)
+		sprintf(s1, "%8lx", pfn1);
+	else
+		sprintf(s1, "--------");
+	pr_info("unused :  %016llx  %s\n", regs->unused, s1);
 }
 #endif /* CONFIG_AMLOGIC_USER_FAULT */