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 88a7c26af8 ("perf: Move task_pt_regs sampling into arch code")'.]

[yangtiezhu@loongson.cn: Fix build error about perf_get_regs_user() after
commit 76a4efa809 ("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: David Daney <david.daney@cavium.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Archer Yan <ayan@wavecomp.com>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
This commit is contained in:
Tiezhu Yang 2021-02-04 11:35:22 +08:00 committed by Thomas Bogendoerfer
parent c87bc73722
commit 1ddc96bd42
4 changed files with 111 additions and 1 deletions

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@ -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

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@ -0,0 +1,40 @@
/* 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 */

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@ -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

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@ -0,0 +1,68 @@
// 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);
}