Commit 6bf212c8 authored by Kalesh Singh's avatar Kalesh Singh Committed by Marc Zyngier
Browse files

arm64: stacktrace: Add shared header for common stack unwinding code 



In order to reuse the arm64 stack unwinding logic for the nVHE
hypervisor stack, move the common code to a shared header
(arch/arm64/include/asm/stacktrace/common.h).

The nVHE hypervisor cannot safely link against kernel code, so we
make use of the shared header to avoid duplicated logic later in
this series.

Signed-off-by: default avatarKalesh Singh <kaleshsingh@google.com>
Reviewed-by: default avatarMark Brown <broonie@kernel.org>
Reviewed-by: default avatarFuad Tabba <tabba@google.com>
Tested-by: default avatarFuad Tabba <tabba@google.com>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220726073750.3219117-2-kaleshsingh@google.com
parent 82a592c1

arch/arm64/include/asm/stacktrace.h

+1 −34
Original line number Diff line number Diff line
@@ -8,52 +8,19 @@ 
#include <linux/percpu.h>

#include <linux/sched.h>

#include <linux/sched/task_stack.h>

#include <linux/types.h>

#include <linux/llist.h>



#include <asm/memory.h>

#include <asm/ptrace.h>

#include <asm/sdei.h>



enum stack_type {

	STACK_TYPE_UNKNOWN,

	STACK_TYPE_TASK,

	STACK_TYPE_IRQ,

	STACK_TYPE_OVERFLOW,

	STACK_TYPE_SDEI_NORMAL,

	STACK_TYPE_SDEI_CRITICAL,

	__NR_STACK_TYPES

};



struct stack_info {

	unsigned long low;

	unsigned long high;

	enum stack_type type;

};

#include <asm/stacktrace/common.h>



extern void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,

			   const char *loglvl);



DECLARE_PER_CPU(unsigned long *, irq_stack_ptr);



static inline bool on_stack(unsigned long sp, unsigned long size,

			    unsigned long low, unsigned long high,

			    enum stack_type type, struct stack_info *info)

{

	if (!low)

		return false;



	if (sp < low || sp + size < sp || sp + size > high)

		return false;



	if (info) {

		info->low = low;

		info->high = high;

		info->type = type;

	}

	return true;

}



static inline bool on_irq_stack(unsigned long sp, unsigned long size,

				struct stack_info *info)

{

arch/arm64/include/asm/stacktrace/common.h

0 → 100644
+105 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0-only */

/*

 * Common arm64 stack unwinder code.

 *

 * Copyright (C) 2012 ARM Ltd.

 */

#ifndef __ASM_STACKTRACE_COMMON_H

#define __ASM_STACKTRACE_COMMON_H



#include <linux/bitmap.h>

#include <linux/bitops.h>

#include <linux/types.h>



enum stack_type {

	STACK_TYPE_UNKNOWN,

	STACK_TYPE_TASK,

	STACK_TYPE_IRQ,

	STACK_TYPE_OVERFLOW,

	STACK_TYPE_SDEI_NORMAL,

	STACK_TYPE_SDEI_CRITICAL,

	__NR_STACK_TYPES

};



struct stack_info {

	unsigned long low;

	unsigned long high;

	enum stack_type type;

};



/*

 * A snapshot of a frame record or fp/lr register values, along with some

 * accounting information necessary for robust unwinding.

 *

 * @fp:          The fp value in the frame record (or the real fp)

 * @pc:          The lr value in the frame record (or the real lr)

 *

 * @stacks_done: Stacks which have been entirely unwound, for which it is no

 *               longer valid to unwind to.

 *

 * @prev_fp:     The fp that pointed to this frame record, or a synthetic value

 *               of 0. This is used to ensure that within a stack, each

 *               subsequent frame record is at an increasing address.

 * @prev_type:   The type of stack this frame record was on, or a synthetic

 *               value of STACK_TYPE_UNKNOWN. This is used to detect a

 *               transition from one stack to another.

 *

 * @kr_cur:      When KRETPROBES is selected, holds the kretprobe instance

 *               associated with the most recently encountered replacement lr

 *               value.

 *

 * @task:        The task being unwound.

 */

struct unwind_state {

	unsigned long fp;

	unsigned long pc;

	DECLARE_BITMAP(stacks_done, __NR_STACK_TYPES);

	unsigned long prev_fp;

	enum stack_type prev_type;

#ifdef CONFIG_KRETPROBES

	struct llist_node *kr_cur;

#endif

	struct task_struct *task;

};



static inline bool on_stack(unsigned long sp, unsigned long size,

			    unsigned long low, unsigned long high,

			    enum stack_type type, struct stack_info *info)

{

	if (!low)

		return false;



	if (sp < low || sp + size < sp || sp + size > high)

		return false;



	if (info) {

		info->low = low;

		info->high = high;

		info->type = type;

	}

	return true;

}



static inline void unwind_init_common(struct unwind_state *state,

				      struct task_struct *task)

{

	state->task = task;

#ifdef CONFIG_KRETPROBES

	state->kr_cur = NULL;

#endif



	/*

	 * Prime the first unwind.

	 *

	 * In unwind_next() we'll check that the FP points to a valid stack,

	 * which can't be STACK_TYPE_UNKNOWN, and the first unwind will be

	 * treated as a transition to whichever stack that happens to be. The

	 * prev_fp value won't be used, but we set it to 0 such that it is

	 * definitely not an accessible stack address.

	 */

	bitmap_zero(state->stacks_done, __NR_STACK_TYPES);

	state->prev_fp = 0;

	state->prev_type = STACK_TYPE_UNKNOWN;

}



#endif	/* __ASM_STACKTRACE_COMMON_H */

arch/arm64/kernel/stacktrace.c

+0 −57
Original line number Diff line number Diff line
@@ -18,63 +18,6 @@ 
#include <asm/stack_pointer.h>

#include <asm/stacktrace.h>



/*

 * A snapshot of a frame record or fp/lr register values, along with some

 * accounting information necessary for robust unwinding.

 *

 * @fp:          The fp value in the frame record (or the real fp)

 * @pc:          The lr value in the frame record (or the real lr)

 *

 * @stacks_done: Stacks which have been entirely unwound, for which it is no

 *               longer valid to unwind to.

 *

 * @prev_fp:     The fp that pointed to this frame record, or a synthetic value

 *               of 0. This is used to ensure that within a stack, each

 *               subsequent frame record is at an increasing address.

 * @prev_type:   The type of stack this frame record was on, or a synthetic

 *               value of STACK_TYPE_UNKNOWN. This is used to detect a

 *               transition from one stack to another.

 *

 * @kr_cur:      When KRETPROBES is selected, holds the kretprobe instance

 *               associated with the most recently encountered replacement lr

 *               value.

 *

 * @task:        The task being unwound.

 */

struct unwind_state {

	unsigned long fp;

	unsigned long pc;

	DECLARE_BITMAP(stacks_done, __NR_STACK_TYPES);

	unsigned long prev_fp;

	enum stack_type prev_type;

#ifdef CONFIG_KRETPROBES

	struct llist_node *kr_cur;

#endif

	struct task_struct *task;

};



static void unwind_init_common(struct unwind_state *state,

			       struct task_struct *task)

{

	state->task = task;

#ifdef CONFIG_KRETPROBES

	state->kr_cur = NULL;

#endif



	/*

	 * Prime the first unwind.

	 *

	 * In unwind_next() we'll check that the FP points to a valid stack,

	 * which can't be STACK_TYPE_UNKNOWN, and the first unwind will be

	 * treated as a transition to whichever stack that happens to be. The

	 * prev_fp value won't be used, but we set it to 0 such that it is

	 * definitely not an accessible stack address.

	 */

	bitmap_zero(state->stacks_done, __NR_STACK_TYPES);

	state->prev_fp = 0;

	state->prev_type = STACK_TYPE_UNKNOWN;

}



/*

 * Start an unwind from a pt_regs.

 *