Commit 1ddc96bd authored by Tiezhu Yang's avatar Tiezhu Yang Committed by Thomas Bogendoerfer
Browse files

MIPS: kernel: Support extracting off-line stack traces from user-space with perf 

Add perf_event_mips_regs/perf_reg_value/perf_reg_validate to support
features HAVE_PERF_REGS/HAVE_PERF_USER_STACK_DUMP in kernel.

[ayan@wavecomp.com: Repick this patch for unwinding userstack backtrace
 by perf and libunwind on MIPS based CPU.]

[ralf@linux-mips.org: Add perf_get_regs_user() which is required after
'commit 88a7c26a ("perf: Move task_pt_regs sampling into arch code")'.]

[yangtiezhu@loongson.cn: Fix build error about perf_get_regs_user() after
commit 76a4efa8 ("perf/arch: Remove perf_sample_data::regs_user_copy"),
and also separate the original patches into two parts (MIPS kernel and perf
tools) to merge easily.]

The original patches:
https://lore.kernel.org/patchwork/patch/1126521/
https://lore.kernel.org/patchwork/patch/1126520/



Signed-off-by: default avatarDavid Daney <david.daney@cavium.com>
Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
Signed-off-by: default avatarArcher Yan <ayan@wavecomp.com>
Signed-off-by: default avatarTiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: default avatarThomas Bogendoerfer <tsbogend@alpha.franken.de>
parent c87bc737

arch/mips/Kconfig

+2 −0
Original line number Diff line number Diff line
@@ -77,6 +77,8 @@ config MIPS 
	select HAVE_NMI

	select HAVE_OPROFILE

	select HAVE_PERF_EVENTS

	select HAVE_PERF_REGS

	select HAVE_PERF_USER_STACK_DUMP

	select HAVE_REGS_AND_STACK_ACCESS_API

	select HAVE_RSEQ

	select HAVE_SPARSE_SYSCALL_NR

arch/mips/include/uapi/asm/perf_regs.h

0 → 100644
+40 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */

#ifndef _ASM_MIPS_PERF_REGS_H

#define _ASM_MIPS_PERF_REGS_H



enum perf_event_mips_regs {

	PERF_REG_MIPS_PC,

	PERF_REG_MIPS_R1,

	PERF_REG_MIPS_R2,

	PERF_REG_MIPS_R3,

	PERF_REG_MIPS_R4,

	PERF_REG_MIPS_R5,

	PERF_REG_MIPS_R6,

	PERF_REG_MIPS_R7,

	PERF_REG_MIPS_R8,

	PERF_REG_MIPS_R9,

	PERF_REG_MIPS_R10,

	PERF_REG_MIPS_R11,

	PERF_REG_MIPS_R12,

	PERF_REG_MIPS_R13,

	PERF_REG_MIPS_R14,

	PERF_REG_MIPS_R15,

	PERF_REG_MIPS_R16,

	PERF_REG_MIPS_R17,

	PERF_REG_MIPS_R18,

	PERF_REG_MIPS_R19,

	PERF_REG_MIPS_R20,

	PERF_REG_MIPS_R21,

	PERF_REG_MIPS_R22,

	PERF_REG_MIPS_R23,

	PERF_REG_MIPS_R24,

	PERF_REG_MIPS_R25,

	PERF_REG_MIPS_R26,

	PERF_REG_MIPS_R27,

	PERF_REG_MIPS_R28,

	PERF_REG_MIPS_R29,

	PERF_REG_MIPS_R30,

	PERF_REG_MIPS_R31,

	PERF_REG_MIPS_MAX = PERF_REG_MIPS_R31 + 1,

};

#endif /* _ASM_MIPS_PERF_REGS_H */

arch/mips/kernel/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -103,7 +103,7 @@ obj-$(CONFIG_MIPSR2_TO_R6_EMULATOR) += mips-r2-to-r6-emul.o 


CFLAGS_cpu-bugs64.o	= $(shell if $(CC) $(KBUILD_CFLAGS) -Wa,-mdaddi -c -o /dev/null -x c /dev/null >/dev/null 2>&1; then echo "-DHAVE_AS_SET_DADDI"; fi)



obj-$(CONFIG_PERF_EVENTS)	+= perf_event.o

obj-$(CONFIG_PERF_EVENTS)	+= perf_event.o perf_regs.o

obj-$(CONFIG_HW_PERF_EVENTS)	+= perf_event_mipsxx.o



obj-$(CONFIG_JUMP_LABEL)	+= jump_label.o

arch/mips/kernel/perf_regs.c

0 → 100644
+68 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/*

 * 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.

 *

 * Some parts derived from x86 version of this file.

 *

 * Copyright (C) 2013 Cavium, Inc.

 */



#include <linux/perf_event.h>



#include <asm/ptrace.h>



#ifdef CONFIG_32BIT

u64 perf_reg_abi(struct task_struct *tsk)

{

	return PERF_SAMPLE_REGS_ABI_32;

}

#else /* Must be CONFIG_64BIT */

u64 perf_reg_abi(struct task_struct *tsk)

{

	if (test_tsk_thread_flag(tsk, TIF_32BIT_REGS))

		return PERF_SAMPLE_REGS_ABI_32;

	else

		return PERF_SAMPLE_REGS_ABI_64;

}

#endif /* CONFIG_32BIT */



int perf_reg_validate(u64 mask)

{

	if (!mask)

		return -EINVAL;

	if (mask & ~((1ull << PERF_REG_MIPS_MAX) - 1))

		return -EINVAL;

	return 0;

}



u64 perf_reg_value(struct pt_regs *regs, int idx)

{

	long v;



	switch (idx) {

	case PERF_REG_MIPS_PC:

		v = regs->cp0_epc;

		break;

	case PERF_REG_MIPS_R1 ... PERF_REG_MIPS_R25:

		v = regs->regs[idx - PERF_REG_MIPS_R1 + 1];

		break;

	case PERF_REG_MIPS_R28 ... PERF_REG_MIPS_R31:

		v = regs->regs[idx - PERF_REG_MIPS_R28 + 28];

		break;



	default:

		WARN_ON_ONCE(1);

		return 0;

	}



	return (s64)v; /* Sign extend if 32-bit. */

}



void perf_get_regs_user(struct perf_regs *regs_user,

			struct pt_regs *regs)

{

	regs_user->regs = task_pt_regs(current);

	regs_user->abi = perf_reg_abi(current);

}