1 files changed, 33 insertions, 20 deletions

diff --git a/arch/parisc/kernel/unwind.c b/arch/parisc/kernel/unwind.c
index 2d14f17838d2..7ac88ff13d3c 100644
--- a/arch/parisc/kernel/unwind.c
+++ b/arch/parisc/kernel/unwind.c
@@ -14,6 +14,7 @@
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/sort.h>
+#include <linux/sched/task_stack.h>
 
 #include <linux/uaccess.h>
 #include <asm/assembly.h>
@@ -21,16 +22,21 @@
 #include <asm/ptrace.h>
 
 #include <asm/unwind.h>
+#include <asm/switch_to.h>
+#include <asm/sections.h>
+#include <asm/ftrace.h>
 
 /* #define DEBUG 1 */
 #ifdef DEBUG
 #define dbg(x...) pr_debug(x)
 #else
-#define dbg(x...)
+#define dbg(x...) do { } while (0)
 #endif
 
 #define KERNEL_START (KERNEL_BINARY_TEXT_START)
 
+#define ALIGNMENT_OK(ptr, type) (((ptr) & (sizeof(type) - 1)) == 0)
+
 extern struct unwind_table_entry __start___unwind[];
 extern struct unwind_table_entry __stop___unwind[];
 
@@ -40,7 +46,7 @@ static DEFINE_SPINLOCK(unwind_lock);
  * we can call unwind_init as early in the bootup process as 
  * possible (before the slab allocator is initialized)
  */
-static struct unwind_table kernel_unwind_table __read_mostly;
+static struct unwind_table kernel_unwind_table __ro_after_init;
 static LIST_HEAD(unwind_tables);
 
 static inline const struct unwind_table_entry *
@@ -176,7 +182,7 @@ void unwind_table_remove(struct unwind_table *table)
 /* Called from setup_arch to import the kernel unwind info */
 int __init unwind_init(void)
 {
-	long start, stop;
+	long start __maybe_unused, stop __maybe_unused;
 	register unsigned long gp __asm__ ("r27");
 
 	start = (long)&__start___unwind[0];
@@ -203,6 +209,11 @@ int __init unwind_init(void)
 	return 0;
 }
 
+static bool pc_is_kernel_fn(unsigned long pc, void *fn)
+{
+	return (unsigned long)dereference_kernel_function_descriptor(fn) == pc;
+}
+
 static int unwind_special(struct unwind_frame_info *info, unsigned long pc, int frame_size)
 {
 	/*
@@ -212,7 +223,6 @@ static int unwind_special(struct unwind_frame_info *info, unsigned long pc, int
 	 * Note: We could use dereference_kernel_function_descriptor()
 	 * instead but we want to keep it simple here.
 	 */
-	extern void * const handle_interruption;
 	extern void * const ret_from_kernel_thread;
 	extern void * const syscall_exit;
 	extern void * const intr_return;
@@ -221,7 +231,7 @@ static int unwind_special(struct unwind_frame_info *info, unsigned long pc, int
 	extern void * const _call_on_stack;
 #endif /* CONFIG_IRQSTACKS */
 
-	if (pc == (unsigned long) &handle_interruption) {
+	if (pc_is_kernel_fn(pc, handle_interruption)) {
 		struct pt_regs *regs = (struct pt_regs *)(info->sp - frame_size - PT_SZ_ALGN);
 		dbg("Unwinding through handle_interruption()\n");
 		info->prev_sp = regs->gr[30];
@@ -229,13 +239,13 @@ static int unwind_special(struct unwind_frame_info *info, unsigned long pc, int
 		return 1;
 	}
 
-	if (pc == (unsigned long) &ret_from_kernel_thread ||
-	    pc == (unsigned long) &syscall_exit) {
+	if (pc == (unsigned long)&ret_from_kernel_thread ||
+	    pc == (unsigned long)&syscall_exit) {
 		info->prev_sp = info->prev_ip = 0;
 		return 1;
 	}
 
-	if (pc == (unsigned long) &intr_return) {
+	if (pc == (unsigned long)&intr_return) {
 		struct pt_regs *regs;
 
 		dbg("Found intr_return()\n");
@@ -246,20 +256,23 @@ static int unwind_special(struct unwind_frame_info *info, unsigned long pc, int
 		return 1;
 	}
 
-	if (pc == (unsigned long) &_switch_to_ret) {
+	if (pc_is_kernel_fn(pc, _switch_to) ||
+	    pc == (unsigned long)&_switch_to_ret) {
 		info->prev_sp = info->sp - CALLEE_SAVE_FRAME_SIZE;
-		info->prev_ip = *(unsigned long *)(info->prev_sp - RP_OFFSET);
+		if (ALIGNMENT_OK(info->prev_sp, long))
+			info->prev_ip = *(unsigned long *)(info->prev_sp - RP_OFFSET);
+		else
+			info->prev_ip = info->prev_sp = 0;
 		return 1;
 	}
 
 #ifdef CONFIG_IRQSTACKS
-	if (pc == (unsigned long) &_call_on_stack) {
+	if (pc == (unsigned long)&_call_on_stack && ALIGNMENT_OK(info->sp, long)) {
 		info->prev_sp = *(unsigned long *)(info->sp - FRAME_SIZE - REG_SZ);
 		info->prev_ip = *(unsigned long *)(info->sp - FRAME_SIZE - RP_OFFSET);
 		return 1;
 	}
 #endif
-
 	return 0;
 }
 
@@ -292,17 +305,15 @@ static void unwind_frame_regs(struct unwind_frame_info *info)
 			info->prev_sp = sp - 64;
 			info->prev_ip = 0;
 
-			/* The stack is at the end inside the thread_union
-			 * struct. If we reach data, we have reached the
-			 * beginning of the stack and should stop unwinding. */
-			if (info->prev_sp >= (unsigned long) task_thread_info(info->t) &&
-			    info->prev_sp < ((unsigned long) task_thread_info(info->t)
-						+ THREAD_SZ_ALGN)) {
+			/* Check if stack is inside kernel stack area */
+			if ((info->prev_sp - (unsigned long) task_stack_page(info->t))
+					>= THREAD_SIZE) {
 				info->prev_sp = 0;
 				break;
 			}
 
-			if (get_user(tmp, (unsigned long *)(info->prev_sp - RP_OFFSET))) 
+			if (copy_from_kernel_nofault(&tmp,
+			    (void *)info->prev_sp - RP_OFFSET, sizeof(tmp)))
 				break;
 			info->prev_ip = tmp;
 			sp = info->prev_sp;
@@ -364,8 +375,10 @@ static void unwind_frame_regs(struct unwind_frame_info *info)
 			info->prev_sp = info->sp - frame_size;
 			if (e->Millicode)
 				info->rp = info->r31;
-			else if (rpoffset)
+			else if (rpoffset && ALIGNMENT_OK(info->prev_sp, long))
 				info->rp = *(unsigned long *)(info->prev_sp - rpoffset);
+			else
+				info->rp = 0;
 			info->prev_ip = info->rp;
 			info->rp = 0;
 		}