linux/arch/s390/include/asm/perf_event.h
Ilya Leoshkevich 914d52e464 s390: implement perf_arch_fetch_caller_regs
On s390 bpf_get_stack_raw_tp() returns 0 entries for both kernel and
user stacks. While there is no practical unwinding solution for userspace
on s390 at this moment, there certainly is a kernel unwinder. However,
it is not properly integrated with BPF.

In order to start unwinding, bpf_get_stack_raw_tp() obtains the current
kernel register values using perf_fetch_caller_regs(), which is not
implemented for s390. The actual unwinding then happens by passing those
registers to perf_callchain_kernel().

Implement perf_arch_fetch_caller_regs() for s390, where
__builtin_frame_address(0) points to back_chain.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2019-11-30 10:52:44 +01:00

84 lines
3.1 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* Performance event support - s390 specific definitions.
*
* Copyright IBM Corp. 2009, 2017
* Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
* Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
*/
#ifndef _ASM_S390_PERF_EVENT_H
#define _ASM_S390_PERF_EVENT_H
#include <linux/perf_event.h>
#include <linux/device.h>
#include <asm/stacktrace.h>
/* Per-CPU flags for PMU states */
#define PMU_F_RESERVED 0x1000
#define PMU_F_ENABLED 0x2000
#define PMU_F_IN_USE 0x4000
#define PMU_F_ERR_IBE 0x0100
#define PMU_F_ERR_LSDA 0x0200
#define PMU_F_ERR_MASK (PMU_F_ERR_IBE|PMU_F_ERR_LSDA)
/* Perf definitions for PMU event attributes in sysfs */
extern __init const struct attribute_group **cpumf_cf_event_group(void);
extern ssize_t cpumf_events_sysfs_show(struct device *dev,
struct device_attribute *attr,
char *page);
#define EVENT_VAR(_cat, _name) event_attr_##_cat##_##_name
#define EVENT_PTR(_cat, _name) (&EVENT_VAR(_cat, _name).attr.attr)
#define CPUMF_EVENT_ATTR(cat, name, id) \
PMU_EVENT_ATTR(name, EVENT_VAR(cat, name), id, cpumf_events_sysfs_show)
#define CPUMF_EVENT_PTR(cat, name) EVENT_PTR(cat, name)
/* Perf callbacks */
struct pt_regs;
extern unsigned long perf_instruction_pointer(struct pt_regs *regs);
extern unsigned long perf_misc_flags(struct pt_regs *regs);
#define perf_misc_flags(regs) perf_misc_flags(regs)
#define perf_arch_bpf_user_pt_regs(regs) &regs->user_regs
/* Perf pt_regs extension for sample-data-entry indicators */
struct perf_sf_sde_regs {
unsigned char in_guest:1; /* guest sample */
unsigned long reserved:63; /* reserved */
};
/* Perf PMU definitions for the counter facility */
#define PERF_CPUM_CF_MAX_CTR 0xffffUL /* Max ctr for ECCTR */
/* Perf PMU definitions for the sampling facility */
#define PERF_CPUM_SF_MAX_CTR 2
#define PERF_EVENT_CPUM_SF 0xB0000UL /* Event: Basic-sampling */
#define PERF_EVENT_CPUM_SF_DIAG 0xBD000UL /* Event: Combined-sampling */
#define PERF_EVENT_CPUM_CF_DIAG 0xBC000UL /* Event: Counter sets */
#define PERF_CPUM_SF_BASIC_MODE 0x0001 /* Basic-sampling flag */
#define PERF_CPUM_SF_DIAG_MODE 0x0002 /* Diagnostic-sampling flag */
#define PERF_CPUM_SF_MODE_MASK (PERF_CPUM_SF_BASIC_MODE| \
PERF_CPUM_SF_DIAG_MODE)
#define PERF_CPUM_SF_FULL_BLOCKS 0x0004 /* Process full SDBs only */
#define PERF_CPUM_SF_FREQ_MODE 0x0008 /* Sampling with frequency */
#define REG_NONE 0
#define REG_OVERFLOW 1
#define OVERFLOW_REG(hwc) ((hwc)->extra_reg.config)
#define SFB_ALLOC_REG(hwc) ((hwc)->extra_reg.alloc)
#define TEAR_REG(hwc) ((hwc)->last_tag)
#define SAMPL_RATE(hwc) ((hwc)->event_base)
#define SAMPL_FLAGS(hwc) ((hwc)->config_base)
#define SAMPL_DIAG_MODE(hwc) (SAMPL_FLAGS(hwc) & PERF_CPUM_SF_DIAG_MODE)
#define SDB_FULL_BLOCKS(hwc) (SAMPL_FLAGS(hwc) & PERF_CPUM_SF_FULL_BLOCKS)
#define SAMPLE_FREQ_MODE(hwc) (SAMPL_FLAGS(hwc) & PERF_CPUM_SF_FREQ_MODE)
#define perf_arch_fetch_caller_regs(regs, __ip) do { \
(regs)->psw.addr = (__ip); \
(regs)->gprs[15] = (unsigned long)__builtin_frame_address(0) - \
offsetof(struct stack_frame, back_chain); \
} while (0)
#endif /* _ASM_S390_PERF_EVENT_H */