xtensa: add support for oprofile (e6ffe17e) · Commits · 戴 / test

arch/xtensa/Kconfig

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		@@ -17,6 +17,7 @@ config XTENSA
		select ARCH_WANT_OPTIONAL_GPIOLIB
		select CLONE_BACKWARDS
		select IRQ_DOMAIN
		select HAVE_OPROFILE
		help
		Xtensa processors are 32-bit RISC machines designed by Tensilica
		primarily for embedded systems. These processors are both

arch/xtensa/Makefile

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		@@ -87,6 +87,7 @@ core-y += arch/xtensa/kernel/ arch/xtensa/mm/
		core-y += $(buildvar) $(buildplf)

		libs-y += arch/xtensa/lib/ $(LIBGCC)
		drivers-$(CONFIG_OPROFILE) += arch/xtensa/oprofile/

		ifneq ($(CONFIG_BUILTIN_DTB),"")
		core-$(CONFIG_OF) += arch/xtensa/boot/dts/

arch/xtensa/kernel/entry.S

+1 −1

Original line number	Diff line number	Diff line
		@@ -399,7 +399,7 @@ common_exception:
		callx4 a4

		/* Jump here for exception exit */

		.global common_exception_return
		common_exception_return:

		/* Jump if we are returning from kernel exceptions. */

arch/xtensa/oprofile/Makefile

0 → 100644

+9 −0

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		obj-$(CONFIG_OPROFILE) += oprofile.o

		DRIVER_OBJS = $(addprefix ../../../drivers/oprofile/, \
		oprof.o cpu_buffer.o buffer_sync.o \
		event_buffer.o oprofile_files.o \
		oprofilefs.o oprofile_stats.o \
		timer_int.o )

		oprofile-y := $(DRIVER_OBJS) init.o backtrace.o

arch/xtensa/oprofile/backtrace.c

0 → 100644

+171 −0

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		/**
		* @file backtrace.c
		*
		* @remark Copyright 2008 Tensilica 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>

		/* 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)
		{
		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. */
		if (kernel_text_address(pc))
		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;
		}

		void xtensa_backtrace(struct pt_regs * const regs, unsigned int depth)
		{
		if (user_mode(regs))
		xtensa_backtrace_user(regs, depth);
		else
		xtensa_backtrace_kernel(regs, depth);
		}

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