Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm

Pull ARM updates from Russell King:

 - Print an un-hashed userspace PC on undefined instruction exception

 - Disable FDPIC ABI

 - Remove redundant vfp_flush/release_thread functions

 - Use raw_cpu_* rather than this_cpu_* in handle_bad_stack()

 - Avoid needlessly long backtraces when show_regs() is called

 - Fix an issue with stack traces through call_with_stack()

 - Avoid stack traces saving a duplicate exception PC value

 - Pass a void pointer to virt_to_page() in DMA mapping code

 - Fix kasan maps for modules when CONFIG_KASAN_VMALLOC=n

 - Show FDT region and page table level names in kernel page tables dump

* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm:
  ARM: 9246/1: dump: show page table level name
  ARM: 9245/1: dump: show FDT region
  ARM: 9242/1: kasan: Only map modules if CONFIG_KASAN_VMALLOC=n
  ARM: 9240/1: dma-mapping: Pass (void *) to virt_to_page()
  ARM: 9234/1: stacktrace: Avoid duplicate saving of exception PC value
  ARM: 9233/1: stacktrace: Skip frame pointer boundary check for call_with_stack()
  ARM: 9224/1: Dump the stack traces based on the parameter 'regs' of show_regs()
  ARM: 9232/1: Replace this_cpu_* with raw_cpu_* in handle_bad_stack()
  ARM: 9228/1: vfp: kill vfp_flush/release_thread()
  ARM: 9226/1: disable FDPIC ABI
  ARM: 9221/1: traps: print un-hashed user pc on undefined instruction

4 files changed, 72 insertions, 29 deletions

diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index 3d9cace63884..96f3fbd51764 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -201,7 +201,7 @@ void __show_regs(struct pt_regs *regs)
 void show_regs(struct pt_regs * regs)
 {
 	__show_regs(regs);
-	dump_stack();
+	dump_backtrace(regs, NULL, KERN_DEFAULT);
 }
 
 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
diff --git a/arch/arm/kernel/return_address.c b/arch/arm/kernel/return_address.c
index 8aac1e10b117..38f1ea9c724d 100644
--- a/arch/arm/kernel/return_address.c
+++ b/arch/arm/kernel/return_address.c
@@ -47,6 +47,7 @@ here:
 	frame.kr_cur = NULL;
 	frame.tsk = current;
 #endif
+	frame.ex_frame = false;
 
 	walk_stackframe(&frame, save_return_addr, &data);
 
diff --git a/arch/arm/kernel/stacktrace.c b/arch/arm/kernel/stacktrace.c
index d0fa2037460a..85443b5d1922 100644
--- a/arch/arm/kernel/stacktrace.c
+++ b/arch/arm/kernel/stacktrace.c
@@ -9,6 +9,8 @@
 #include <asm/stacktrace.h>
 #include <asm/traps.h>
 
+#include "reboot.h"
+
 #if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND)
 /*
  * Unwind the current stack frame and store the new register values in the
@@ -39,29 +41,74 @@
  * Note that with framepointer enabled, even the leaf functions have the same
  * prologue and epilogue, therefore we can ignore the LR value in this case.
  */
-int notrace unwind_frame(struct stackframe *frame)
+
+extern unsigned long call_with_stack_end;
+
+static int frame_pointer_check(struct stackframe *frame)
 {
 	unsigned long high, low;
 	unsigned long fp = frame->fp;
+	unsigned long pc = frame->pc;
+
+	/*
+	 * call_with_stack() is the only place we allow SP to jump from one
+	 * stack to another, with FP and SP pointing to different stacks,
+	 * skipping the FP boundary check at this point.
+	 */
+	if (pc >= (unsigned long)&call_with_stack &&
+			pc < (unsigned long)&call_with_stack_end)
+		return 0;
 
 	/* only go to a higher address on the stack */
 	low = frame->sp;
 	high = ALIGN(low, THREAD_SIZE);
 
-#ifdef CONFIG_CC_IS_CLANG
 	/* check current frame pointer is within bounds */
+#ifdef CONFIG_CC_IS_CLANG
 	if (fp < low + 4 || fp > high - 4)
 		return -EINVAL;
-
-	frame->sp = frame->fp;
-	frame->fp = READ_ONCE_NOCHECK(*(unsigned long *)(fp));
-	frame->pc = READ_ONCE_NOCHECK(*(unsigned long *)(fp + 4));
 #else
-	/* check current frame pointer is within bounds */
 	if (fp < low + 12 || fp > high - 4)
 		return -EINVAL;
+#endif
+
+	return 0;
+}
+
+int notrace unwind_frame(struct stackframe *frame)
+{
+	unsigned long fp = frame->fp;
+
+	if (frame_pointer_check(frame))
+		return -EINVAL;
+
+	/*
+	 * When we unwind through an exception stack, include the saved PC
+	 * value into the stack trace.
+	 */
+	if (frame->ex_frame) {
+		struct pt_regs *regs = (struct pt_regs *)frame->sp;
+
+		/*
+		 * We check that 'regs + sizeof(struct pt_regs)' (that is,
+		 * &regs[1]) does not exceed the bottom of the stack to avoid
+		 * accessing data outside the task's stack. This may happen
+		 * when frame->ex_frame is a false positive.
+		 */
+		if ((unsigned long)&regs[1] > ALIGN(frame->sp, THREAD_SIZE))
+			return -EINVAL;
+
+		frame->pc = regs->ARM_pc;
+		frame->ex_frame = false;
+		return 0;
+	}
 
 	/* restore the registers from the stack frame */
+#ifdef CONFIG_CC_IS_CLANG
+	frame->sp = frame->fp;
+	frame->fp = READ_ONCE_NOCHECK(*(unsigned long *)(fp));
+	frame->pc = READ_ONCE_NOCHECK(*(unsigned long *)(fp + 4));
+#else
 	frame->fp = READ_ONCE_NOCHECK(*(unsigned long *)(fp - 12));
 	frame->sp = READ_ONCE_NOCHECK(*(unsigned long *)(fp - 8));
 	frame->pc = READ_ONCE_NOCHECK(*(unsigned long *)(fp - 4));
@@ -72,6 +119,9 @@ int notrace unwind_frame(struct stackframe *frame)
 					(void *)frame->fp, &frame->kr_cur);
 #endif
 
+	if (in_entry_text(frame->pc))
+		frame->ex_frame = true;
+
 	return 0;
 }
 #endif
@@ -102,7 +152,6 @@ static int save_trace(struct stackframe *frame, void *d)
 {
 	struct stack_trace_data *data = d;
 	struct stack_trace *trace = data->trace;
-	struct pt_regs *regs;
 	unsigned long addr = frame->pc;
 
 	if (data->no_sched_functions && in_sched_functions(addr))
@@ -113,19 +162,6 @@ static int save_trace(struct stackframe *frame, void *d)
 	}
 
 	trace->entries[trace->nr_entries++] = addr;
-
-	if (trace->nr_entries >= trace->max_entries)
-		return 1;
-
-	if (!in_entry_text(frame->pc))
-		return 0;
-
-	regs = (struct pt_regs *)frame->sp;
-	if ((unsigned long)&regs[1] > ALIGN(frame->sp, THREAD_SIZE))
-		return 0;
-
-	trace->entries[trace->nr_entries++] = regs->ARM_pc;
-
 	return trace->nr_entries >= trace->max_entries;
 }
 
@@ -167,6 +203,9 @@ here:
 	frame.kr_cur = NULL;
 	frame.tsk = tsk;
 #endif
+#ifdef CONFIG_UNWINDER_FRAME_POINTER
+	frame.ex_frame = false;
+#endif
 
 	walk_stackframe(&frame, save_trace, &data);
 }
@@ -188,6 +227,9 @@ void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
 	frame.kr_cur = NULL;
 	frame.tsk = current;
 #endif
+#ifdef CONFIG_UNWINDER_FRAME_POINTER
+	frame.ex_frame = in_entry_text(frame.pc);
+#endif
 
 	walk_stackframe(&frame, save_trace, &data);
 }
diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index 9283dc65be31..20b2db6dcd1c 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -205,14 +205,14 @@ static void dump_instr(const char *lvl, struct pt_regs *regs)
 }
 
 #ifdef CONFIG_ARM_UNWIND
-static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
-				  const char *loglvl)
+void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
+		    const char *loglvl)
 {
 	unwind_backtrace(regs, tsk, loglvl);
 }
 #else
-static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
-			   const char *loglvl)
+void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
+		    const char *loglvl)
 {
 	unsigned int fp, mode;
 	int ok = 1;
@@ -487,7 +487,7 @@ asmlinkage void do_undefinstr(struct pt_regs *regs)
 die_sig:
 #ifdef CONFIG_DEBUG_USER
 	if (user_debug & UDBG_UNDEFINED) {
-		pr_info("%s (%d): undefined instruction: pc=%p\n",
+		pr_info("%s (%d): undefined instruction: pc=%px\n",
 			current->comm, task_pid_nr(current), pc);
 		__show_regs(regs);
 		dump_instr(KERN_INFO, regs);
@@ -920,9 +920,9 @@ asmlinkage void handle_bad_stack(struct pt_regs *regs)
 {
 	unsigned long tsk_stk = (unsigned long)current->stack;
 #ifdef CONFIG_IRQSTACKS
-	unsigned long irq_stk = (unsigned long)this_cpu_read(irq_stack_ptr);
+	unsigned long irq_stk = (unsigned long)raw_cpu_read(irq_stack_ptr);
 #endif
-	unsigned long ovf_stk = (unsigned long)this_cpu_read(overflow_stack_ptr);
+	unsigned long ovf_stk = (unsigned long)raw_cpu_read(overflow_stack_ptr);
 
 	console_verbose();
 	pr_emerg("Insufficient stack space to handle exception!");