From 1ddc96bd42daeeb58f66c9515e506f245ccb00c6 Mon Sep 17 00:00:00 2001 From: Tiezhu Yang Date: Thu, 4 Feb 2021 11:35:22 +0800 Subject: [PATCH] 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 88a7c26af8da ("perf: Move task_pt_regs sampling into arch code")'.] [yangtiezhu@loongson.cn: Fix build error about perf_get_regs_user() after commit 76a4efa80900 ("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 Signed-off-by: Ralf Baechle Signed-off-by: Archer Yan Signed-off-by: Tiezhu Yang Signed-off-by: Thomas Bogendoerfer --- arch/mips/Kconfig | 2 + arch/mips/include/uapi/asm/perf_regs.h | 40 +++++++++++++++ arch/mips/kernel/Makefile | 2 +- arch/mips/kernel/perf_regs.c | 68 ++++++++++++++++++++++++++ 4 files changed, 111 insertions(+), 1 deletion(-) create mode 100644 arch/mips/include/uapi/asm/perf_regs.h create mode 100644 arch/mips/kernel/perf_regs.c diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig index 71df230d9c54..57b06798706c 100644 --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -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 diff --git a/arch/mips/include/uapi/asm/perf_regs.h b/arch/mips/include/uapi/asm/perf_regs.h new file mode 100644 index 000000000000..d0f4ecd616cf --- /dev/null +++ b/arch/mips/include/uapi/asm/perf_regs.h @@ -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 */ diff --git a/arch/mips/kernel/Makefile b/arch/mips/kernel/Makefile index 2303a5868c14..a893ea041ef5 100644 --- a/arch/mips/kernel/Makefile +++ b/arch/mips/kernel/Makefile @@ -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 diff --git a/arch/mips/kernel/perf_regs.c b/arch/mips/kernel/perf_regs.c new file mode 100644 index 000000000000..e686780d1647 --- /dev/null +++ b/arch/mips/kernel/perf_regs.c @@ -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 + +#include + +#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); +}