arch/s390/kernel/perf_event.c

Source file repositories/reference/linux-study-clean/arch/s390/kernel/perf_event.c

File Facts

System
Linux kernel
Corpus path
arch/s390/kernel/perf_event.c
Extension
.c
Size
5801 bytes
Lines
230
Domain
Architecture Layer
Bucket
arch/s390
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0
/*
 * Performance event support for s390x
 *
 *  Copyright IBM Corp. 2012, 2013
 *  Author(s): Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
 */
#define pr_fmt(fmt) "perf: " fmt

#include <linux/kernel.h>
#include <linux/perf_event.h>
#include <linux/kvm_host.h>
#include <linux/percpu.h>
#include <linux/seq_file.h>
#include <linux/spinlock.h>
#include <linux/uaccess.h>
#include <linux/sysfs.h>
#include <asm/stacktrace.h>
#include <asm/irq.h>
#include <asm/cpu_mf.h>
#include <asm/lowcore.h>
#include <asm/processor.h>
#include <asm/sysinfo.h>
#include <asm/unwind.h>

static struct kvm_s390_sie_block *sie_block(struct pt_regs *regs)
{
	struct stack_frame *stack = (struct stack_frame *) regs->gprs[15];

	if (!stack)
		return NULL;

	return (struct kvm_s390_sie_block *)stack->sie_control_block;
}

static bool is_in_guest(struct pt_regs *regs)
{
	if (user_mode(regs))
		return false;
#if IS_ENABLED(CONFIG_KVM)
	return instruction_pointer(regs) == (unsigned long) &sie_exit;
#else
	return false;
#endif
}

static unsigned long guest_is_user_mode(struct pt_regs *regs)
{
	return sie_block(regs)->gpsw.mask & PSW_MASK_PSTATE;
}

static unsigned long instruction_pointer_guest(struct pt_regs *regs)
{
	return sie_block(regs)->gpsw.addr;
}

unsigned long perf_arch_instruction_pointer(struct pt_regs *regs)
{
	return is_in_guest(regs) ? instruction_pointer_guest(regs)
				 : instruction_pointer(regs);
}

static unsigned long perf_misc_guest_flags(struct pt_regs *regs)
{
	return guest_is_user_mode(regs) ? PERF_RECORD_MISC_GUEST_USER
					: PERF_RECORD_MISC_GUEST_KERNEL;
}

static unsigned long perf_misc_flags_sf(struct pt_regs *regs)
{
	struct perf_sf_sde_regs *sde_regs;
	unsigned long flags;

	sde_regs = (struct perf_sf_sde_regs *) &regs->int_parm_long;
	if (sde_regs->in_guest)
		flags = user_mode(regs) ? PERF_RECORD_MISC_GUEST_USER
					: PERF_RECORD_MISC_GUEST_KERNEL;
	else
		flags = user_mode(regs) ? PERF_RECORD_MISC_USER
					: PERF_RECORD_MISC_KERNEL;
	return flags;
}

unsigned long perf_arch_misc_flags(struct pt_regs *regs)
{
	/* Check if the cpum_sf PMU has created the pt_regs structure.
	 * In this case, perf misc flags can be easily extracted.  Otherwise,
	 * do regular checks on the pt_regs content.
	 */
	if (regs->int_code == 0x1407 && regs->int_parm == CPU_MF_INT_SF_PRA)

Annotation

Implementation Notes