Commit 5fdf377d authored by Max Filippov's avatar Max Filippov
Browse files

xtensa: move oprofile stack tracing to stacktrace.c 



Old oprofile interface will share user stack tracing with new perf
interface. Move oprofile user/kernel stack tracing to stacktrace.c to
make it possible.

Signed-off-by: default avatarMax Filippov <jcmvbkbc@gmail.com>
parent b6569439

arch/xtensa/include/asm/stacktrace.h

+8 −0
Original line number Diff line number Diff line
@@ -33,4 +33,12 @@ void walk_stackframe(unsigned long *sp, 
		int (*fn)(struct stackframe *frame, void *data),

		void *data);



void xtensa_backtrace_kernel(struct pt_regs *regs, unsigned int depth,

			     int (*kfn)(struct stackframe *frame, void *data),

			     int (*ufn)(struct stackframe *frame, void *data),

			     void *data);

void xtensa_backtrace_user(struct pt_regs *regs, unsigned int depth,

			   int (*ufn)(struct stackframe *frame, void *data),

			   void *data);



#endif /* _XTENSA_STACKTRACE_H */

arch/xtensa/kernel/stacktrace.c

+166 −1
Original line number Diff line number Diff line 
/*

 * arch/xtensa/kernel/stacktrace.c

 * Kernel and userspace stack tracing.

 *

 * This file is subject to the terms and conditions of the GNU General Public

 * License.  See the file "COPYING" in the main directory of this archive

 * for more details.

 *

 * Copyright (C) 2001 - 2013 Tensilica Inc.

 * Copyright (C) 2015 Cadence Design Systems Inc.

 */

#include <linux/export.h>

#include <linux/sched.h>
@@ -13,6 +14,170 @@ 


#include <asm/stacktrace.h>

#include <asm/traps.h>

#include <asm/uaccess.h>



#if IS_ENABLED(CONFIG_OPROFILE) || IS_ENABLED(CONFIG_PERF_EVENTS)



/* Address of common_exception_return, used to check the

 * transition from kernel to user space.

 */

extern int common_exception_return;



/* A struct that maps to the part of the frame containing the a0 and

 * a1 registers.

 */

struct frame_start {

	unsigned long a0;

	unsigned long a1;

};



void xtensa_backtrace_user(struct pt_regs *regs, unsigned int depth,

			   int (*ufn)(struct stackframe *frame, void *data),

			   void *data)

{

	unsigned long windowstart = regs->windowstart;

	unsigned long windowbase = regs->windowbase;

	unsigned long a0 = regs->areg[0];

	unsigned long a1 = regs->areg[1];

	unsigned long pc = regs->pc;

	struct stackframe frame;

	int index;



	if (!depth--)

		return;



	frame.pc = pc;

	frame.sp = a1;



	if (pc == 0 || pc >= TASK_SIZE || ufn(&frame, data))

		return;



	/* Two steps:

	 *

	 * 1. Look through the register window for the

	 * previous PCs in the call trace.

	 *

	 * 2. Look on the stack.

	 */



	/* Step 1.  */

	/* Rotate WINDOWSTART to move the bit corresponding to

	 * the current window to the bit #0.

	 */

	windowstart = (windowstart << WSBITS | windowstart) >> windowbase;



	/* Look for bits that are set, they correspond to

	 * valid windows.

	 */

	for (index = WSBITS - 1; (index > 0) && depth; depth--, index--)

		if (windowstart & (1 << index)) {

			/* Get the PC from a0 and a1. */

			pc = MAKE_PC_FROM_RA(a0, pc);

			/* Read a0 and a1 from the

			 * corresponding position in AREGs.

			 */

			a0 = regs->areg[index * 4];

			a1 = regs->areg[index * 4 + 1];



			frame.pc = pc;

			frame.sp = a1;



			if (pc == 0 || pc >= TASK_SIZE || ufn(&frame, data))

				return;

		}



	/* Step 2. */

	/* We are done with the register window, we need to

	 * look through the stack.

	 */

	if (!depth)

		return;



	/* Start from the a1 register. */

	/* a1 = regs->areg[1]; */

	while (a0 != 0 && depth--) {

		struct frame_start frame_start;

		/* Get the location for a1, a0 for the

		 * previous frame from the current a1.

		 */

		unsigned long *psp = (unsigned long *)a1;



		psp -= 4;



		/* Check if the region is OK to access. */

		if (!access_ok(VERIFY_READ, psp, sizeof(frame_start)))

			return;

		/* Copy a1, a0 from user space stack frame. */

		if (__copy_from_user_inatomic(&frame_start, psp,

					      sizeof(frame_start)))

			return;



		pc = MAKE_PC_FROM_RA(a0, pc);

		a0 = frame_start.a0;

		a1 = frame_start.a1;



		frame.pc = pc;

		frame.sp = a1;



		if (pc == 0 || pc >= TASK_SIZE || ufn(&frame, data))

			return;

	}

}

EXPORT_SYMBOL(xtensa_backtrace_user);



void xtensa_backtrace_kernel(struct pt_regs *regs, unsigned int depth,

			     int (*kfn)(struct stackframe *frame, void *data),

			     int (*ufn)(struct stackframe *frame, void *data),

			     void *data)

{

	unsigned long pc = regs->depc > VALID_DOUBLE_EXCEPTION_ADDRESS ?

		regs->depc : regs->pc;

	unsigned long sp_start, sp_end;

	unsigned long a0 = regs->areg[0];

	unsigned long a1 = regs->areg[1];



	sp_start = a1 & ~(THREAD_SIZE - 1);

	sp_end = sp_start + THREAD_SIZE;



	/* Spill the register window to the stack first. */

	spill_registers();



	/* Read the stack frames one by one and create the PC

	 * from the a0 and a1 registers saved there.

	 */

	while (a1 > sp_start && a1 < sp_end && depth--) {

		struct stackframe frame;

		unsigned long *psp = (unsigned long *)a1;



		frame.pc = pc;

		frame.sp = a1;



		if (kernel_text_address(pc) && kfn(&frame, data))

			return;



		if (pc == (unsigned long)&common_exception_return) {

			regs = (struct pt_regs *)a1;

			if (user_mode(regs)) {

				if (ufn == NULL)

					return;

				xtensa_backtrace_user(regs, depth, ufn, data);

				return;

			}

			a0 = regs->areg[0];

			a1 = regs->areg[1];

			continue;

		}



		sp_start = a1;



		pc = MAKE_PC_FROM_RA(a0, pc);

		a0 = *(psp - 4);

		a1 = *(psp - 3);

	}

}

EXPORT_SYMBOL(xtensa_backtrace_kernel);



#endif



void walk_stackframe(unsigned long *sp,

		int (*fn)(struct stackframe *frame, void *data),

arch/xtensa/oprofile/backtrace.c

+8 −150
Original line number Diff line number Diff line
@@ -2,168 +2,26 @@ 
 * @file backtrace.c

 *

 * @remark Copyright 2008 Tensilica Inc.

 * Copyright (C) 2015 Cadence Design Systems Inc.

 * @remark Read the file COPYING

 *

 */



#include <linux/oprofile.h>

#include <linux/sched.h>

#include <linux/mm.h>

#include <asm/ptrace.h>

#include <asm/uaccess.h>

#include <asm/traps.h>

#include <asm/stacktrace.h>



/* Address of common_exception_return, used to check the

 * transition from kernel to user space.

 */

extern int common_exception_return;



/* A struct that maps to the part of the frame containing the a0 and

 * a1 registers.

 */

struct frame_start {

	unsigned long a0;

	unsigned long a1;

};



static void xtensa_backtrace_user(struct pt_regs *regs, unsigned int depth)

{

	unsigned long windowstart = regs->windowstart;

	unsigned long windowbase = regs->windowbase;

	unsigned long a0 = regs->areg[0];

	unsigned long a1 = regs->areg[1];

	unsigned long pc = MAKE_PC_FROM_RA(a0, regs->pc);

	int index;



	/* First add the current PC to the trace. */

	if (pc != 0 && pc <= TASK_SIZE)

		oprofile_add_trace(pc);

	else

		return;



	/* Two steps:

	 *

	 * 1. Look through the register window for the

	 * previous PCs in the call trace.

	 *

	 * 2. Look on the stack.

	 */



	/* Step 1.  */

	/* Rotate WINDOWSTART to move the bit corresponding to

	 * the current window to the bit #0.

	 */

	windowstart = (windowstart << WSBITS | windowstart) >> windowbase;



	/* Look for bits that are set, they correspond to

	 * valid windows.

	 */

	for (index = WSBITS - 1; (index > 0) && depth; depth--, index--)

		if (windowstart & (1 << index)) {

			/* Read a0 and a1 from the

			 * corresponding position in AREGs.

			 */

			a0 = regs->areg[index * 4];

			a1 = regs->areg[index * 4 + 1];

			/* Get the PC from a0 and a1. */

			pc = MAKE_PC_FROM_RA(a0, pc);



			/* Add the PC to the trace. */

			if (pc != 0 && pc <= TASK_SIZE)

				oprofile_add_trace(pc);

			else

				return;

		}



	/* Step 2. */

	/* We are done with the register window, we need to

	 * look through the stack.

	 */

	if (depth > 0) {

		/* Start from the a1 register. */

		/* a1 = regs->areg[1]; */

		while (a0 != 0 && depth--) {



			struct frame_start frame_start;

			/* Get the location for a1, a0 for the

			 * previous frame from the current a1.

			 */

			unsigned long *psp = (unsigned long *)a1;

			psp -= 4;



			/* Check if the region is OK to access. */

			if (!access_ok(VERIFY_READ, psp, sizeof(frame_start)))

				return;

			/* Copy a1, a0 from user space stack frame. */

			if (__copy_from_user_inatomic(&frame_start, psp,

						sizeof(frame_start)))

				return;



			a0 = frame_start.a0;

			a1 = frame_start.a1;

			pc = MAKE_PC_FROM_RA(a0, pc);



			if (pc != 0 && pc <= TASK_SIZE)

				oprofile_add_trace(pc);

			else

				return;

		}

	}

}



static void xtensa_backtrace_kernel(struct pt_regs *regs, unsigned int depth)

static int xtensa_backtrace_cb(struct stackframe *frame, void *data)

{

	unsigned long pc = regs->pc;

	unsigned long *psp;

	unsigned long sp_start, sp_end;

	unsigned long a0 = regs->areg[0];

	unsigned long a1 = regs->areg[1];



	sp_start = a1 & ~(THREAD_SIZE-1);

	sp_end = sp_start + THREAD_SIZE;



	/* Spill the register window to the stack first. */

	spill_registers();



	/* Read the stack frames one by one and create the PC

	 * from the a0 and a1 registers saved there.

	 */

	while (a1 > sp_start && a1 < sp_end && depth--) {

		pc = MAKE_PC_FROM_RA(a0, pc);



		/* Add the PC to the trace. */

		oprofile_add_trace(pc);

		if (pc == (unsigned long) &common_exception_return) {

			regs = (struct pt_regs *)a1;

			if (user_mode(regs)) {

				pc = regs->pc;

				if (pc != 0 && pc <= TASK_SIZE)

					oprofile_add_trace(pc);

				else

					return;

				return xtensa_backtrace_user(regs, depth);

			}

			a0 = regs->areg[0];

			a1 = regs->areg[1];

			continue;

		}



		psp = (unsigned long *)a1;



		a0 = *(psp - 4);

		a1 = *(psp - 3);



		if (a1 <= (unsigned long)psp)

			return;



	}

	return;

	oprofile_add_trace(frame->pc);

	return 0;

}



void xtensa_backtrace(struct pt_regs * const regs, unsigned int depth)

{

	if (user_mode(regs))

		xtensa_backtrace_user(regs, depth);

		xtensa_backtrace_user(regs, depth, xtensa_backtrace_cb, NULL);

	else

		xtensa_backtrace_kernel(regs, depth);

		xtensa_backtrace_kernel(regs, depth, xtensa_backtrace_cb,

					xtensa_backtrace_cb, NULL);

}

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