perf: RISC-V: Add support for SBI PMU and Sscofpmf

This series improves perf support for RISC-V based system using SBI PMU
and Sscofpmf extensions, by adding a new generic RISC-V perf framework
along with a pair of drivers: one that usese the new
performance-monitoring extensions and one that keeps support for the
existing systems that only have the legacy counters.
Tested-by: Nikita Shubin <n.shubin@yadro.com>

* palmer/riscv-pmu:
  MAINTAINERS: Add entry for RISC-V PMU drivers
  Documentation: riscv: Remove the old documentation
  RISC-V: Add sscofpmf extension support
  RISC-V: Add perf platform driver based on SBI PMU extension
  RISC-V: Add RISC-V SBI PMU extension definitions
  RISC-V: Add a simple platform driver for RISC-V legacy perf
  RISC-V: Add a perf core library for pmu drivers
  RISC-V: Add CSR encodings for all HPMCOUNTERS
  RISC-V: Remove the current perf implementation

Documentation/riscv/pmu.rst

-===================================
-Supporting PMUs on RISC-V platforms
-===================================
-
-Alan Kao <alankao@andestech.com>, Mar 2018
-
-Introduction
-------------
-
-As of this writing, perf_event-related features mentioned in The RISC-V ISA
-Privileged Version 1.10 are as follows:
-(please check the manual for more details)
-
-* [m|s]counteren
-* mcycle[h], cycle[h]
-* minstret[h], instret[h]
-* mhpeventx, mhpcounterx[h]
-
-With such function set only, porting perf would require a lot of work, due to
-the lack of the following general architectural performance monitoring features:
-
-* Enabling/Disabling counters
-  Counters are just free-running all the time in our case.
-* Interrupt caused by counter overflow
-  No such feature in the spec.
-* Interrupt indicator
-  It is not possible to have many interrupt ports for all counters, so an
-  interrupt indicator is required for software to tell which counter has
-  just overflowed.
-* Writing to counters
-  There will be an SBI to support this since the kernel cannot modify the
-  counters [1].  Alternatively, some vendor considers to implement
-  hardware-extension for M-S-U model machines to write counters directly.
-
-This document aims to provide developers a quick guide on supporting their
-PMUs in the kernel.  The following sections briefly explain perf' mechanism
-and todos.
-
-You may check previous discussions here [1][2].  Also, it might be helpful
-to check the appendix for related kernel structures.
-
-
-1. Initialization
------------------
-
-*riscv_pmu* is a global pointer of type *struct riscv_pmu*, which contains
-various methods according to perf's internal convention and PMU-specific
-parameters.  One should declare such instance to represent the PMU.  By default,
-*riscv_pmu* points to a constant structure *riscv_base_pmu*, which has very
-basic support to a baseline QEMU model.
-
-Then he/she can either assign the instance's pointer to *riscv_pmu* so that
-the minimal and already-implemented logic can be leveraged, or invent his/her
-own *riscv_init_platform_pmu* implementation.
-
-In other words, existing sources of *riscv_base_pmu* merely provide a
-reference implementation.  Developers can flexibly decide how many parts they
-can leverage, and in the most extreme case, they can customize every function
-according to their needs.
-
-
-2. Event Initialization
------------------------
-
-When a user launches a perf command to monitor some events, it is first
-interpreted by the userspace perf tool into multiple *perf_event_open*
-system calls, and then each of them calls to the body of *event_init*
-member function that was assigned in the previous step.  In *riscv_base_pmu*'s
-case, it is *riscv_event_init*.
-
-The main purpose of this function is to translate the event provided by user
-into bitmap, so that HW-related control registers or counters can directly be
-manipulated.  The translation is based on the mappings and methods provided in
-*riscv_pmu*.
-
-Note that some features can be done in this stage as well:
-
-(1) interrupt setting, which is stated in the next section;
-(2) privilege level setting (user space only, kernel space only, both);
-(3) destructor setting.  Normally it is sufficient to apply *riscv_destroy_event*;
-(4) tweaks for non-sampling events, which will be utilized by functions such as
-    *perf_adjust_period*, usually something like the follows::
-
-      if (!is_sampling_event(event)) {
-              hwc->sample_period = x86_pmu.max_period;
-              hwc->last_period = hwc->sample_period;
-              local64_set(&hwc->period_left, hwc->sample_period);
-      }
-
-In the case of *riscv_base_pmu*, only (3) is provided for now.
-
-
-3. Interrupt
-------------
-
-3.1. Interrupt Initialization
-
-This often occurs at the beginning of the *event_init* method. In common
-practice, this should be a code segment like::
-
-  int x86_reserve_hardware(void)
-  {
-        int err = 0;
-
-        if (!atomic_inc_not_zero(&pmc_refcount)) {
-                mutex_lock(&pmc_reserve_mutex);
-                if (atomic_read(&pmc_refcount) == 0) {
-                        if (!reserve_pmc_hardware())
-                                err = -EBUSY;
-                        else
-                                reserve_ds_buffers();
-                }
-                if (!err)
-                        atomic_inc(&pmc_refcount);
-                mutex_unlock(&pmc_reserve_mutex);
-        }
-
-        return err;
-  }
-
-And the magic is in *reserve_pmc_hardware*, which usually does atomic
-operations to make implemented IRQ accessible from some global function pointer.
-*release_pmc_hardware* serves the opposite purpose, and it is used in event
-destructors mentioned in previous section.
-
-(Note: From the implementations in all the architectures, the *reserve/release*
-pair are always IRQ settings, so the *pmc_hardware* seems somehow misleading.
-It does NOT deal with the binding between an event and a physical counter,
-which will be introduced in the next section.)
-
-3.2. IRQ Structure
-
-Basically, a IRQ runs the following pseudo code::
-
-  for each hardware counter that triggered this overflow
-
-      get the event of this counter
-
-      // following two steps are defined as *read()*,
-      // check the section Reading/Writing Counters for details.
-      count the delta value since previous interrupt
-      update the event->count (# event occurs) by adding delta, and
-                 event->hw.period_left by subtracting delta
-
-      if the event overflows
-          sample data
-          set the counter appropriately for the next overflow
-
-          if the event overflows again
-              too frequently, throttle this event
-          fi
-      fi
-
-  end for
-
-However as of this writing, none of the RISC-V implementations have designed an
-interrupt for perf, so the details are to be completed in the future.
-
-4. Reading/Writing Counters
----------------------------
-
-They seem symmetric but perf treats them quite differently.  For reading, there
-is a *read* interface in *struct pmu*, but it serves more than just reading.
-According to the context, the *read* function not only reads the content of the
-counter (event->count), but also updates the left period to the next interrupt
-(event->hw.period_left).
-
-But the core of perf does not need direct write to counters.  Writing counters
-is hidden behind the abstraction of 1) *pmu->start*, literally start counting so one
-has to set the counter to a good value for the next interrupt; 2) inside the IRQ
-it should set the counter to the same resonable value.
-
-Reading is not a problem in RISC-V but writing would need some effort, since
-counters are not allowed to be written by S-mode.
-
-
-5. add()/del()/start()/stop()
------------------------------
-
-Basic idea: add()/del() adds/deletes events to/from a PMU, and start()/stop()
-starts/stop the counter of some event in the PMU.  All of them take the same
-arguments: *struct perf_event *event* and *int flag*.
-
-Consider perf as a state machine, then you will find that these functions serve
-as the state transition process between those states.
-Three states (event->hw.state) are defined:
-
-* PERF_HES_STOPPED:	the counter is stopped
-* PERF_HES_UPTODATE:	the event->count is up-to-date
-* PERF_HES_ARCH:	arch-dependent usage ... we don't need this for now
-
-A normal flow of these state transitions are as follows:
-
-* A user launches a perf event, resulting in calling to *event_init*.
-* When being context-switched in, *add* is called by the perf core, with a flag
-  PERF_EF_START, which means that the event should be started after it is added.
-  At this stage, a general event is bound to a physical counter, if any.
-  The state changes to PERF_HES_STOPPED and PERF_HES_UPTODATE, because it is now
-  stopped, and the (software) event count does not need updating.
-
-  - *start* is then called, and the counter is enabled.
-    With flag PERF_EF_RELOAD, it writes an appropriate value to the counter (check
-    previous section for detail).
-    Nothing is written if the flag does not contain PERF_EF_RELOAD.
-    The state now is reset to none, because it is neither stopped nor updated
-    (the counting already started)
-
-* When being context-switched out, *del* is called.  It then checks out all the
-  events in the PMU and calls *stop* to update their counts.
-
-  - *stop* is called by *del*
-    and the perf core with flag PERF_EF_UPDATE, and it often shares the same
-    subroutine as *read* with the same logic.
-    The state changes to PERF_HES_STOPPED and PERF_HES_UPTODATE, again.
-
-  - Life cycle of these two pairs: *add* and *del* are called repeatedly as
-    tasks switch in-and-out; *start* and *stop* is also called when the perf core
-    needs a quick stop-and-start, for instance, when the interrupt period is being
-    adjusted.
-
-Current implementation is sufficient for now and can be easily extended to
-features in the future.
-
-A. Related Structures
----------------------
-
-* struct pmu: include/linux/perf_event.h
-* struct riscv_pmu: arch/riscv/include/asm/perf_event.h
-
-  Both structures are designed to be read-only.
-
-  *struct pmu* defines some function pointer interfaces, and most of them take
-  *struct perf_event* as a main argument, dealing with perf events according to
-  perf's internal state machine (check kernel/events/core.c for details).
-
-  *struct riscv_pmu* defines PMU-specific parameters.  The naming follows the
-  convention of all other architectures.
-
-* struct perf_event: include/linux/perf_event.h
-* struct hw_perf_event
-
-  The generic structure that represents perf events, and the hardware-related
-  details.
-
-* struct riscv_hw_events: arch/riscv/include/asm/perf_event.h
-
-  The structure that holds the status of events, has two fixed members:
-  the number of events and the array of the events.
-
-References
-----------
-
-[1] https://github.com/riscv/riscv-linux/pull/124
-
-[2] https://groups.google.com/a/groups.riscv.org/forum/#!topic/sw-dev/f19TmCNP6yA

MAINTAINERS

@@ -16561,6 +16561,15 @@ S:	Maintained
 F:	drivers/mtd/nand/raw/r852.c
 F:	drivers/mtd/nand/raw/r852.h
 
+RISC-V PMU DRIVERS
+M:	Atish Patra <atishp@atishpatra.org>
+R:	Anup Patel <anup@brainfault.org>
+L:	linux-riscv@lists.infradead.org
+S:	Supported
+F:	drivers/perf/riscv_pmu.c
+F:	drivers/perf/riscv_pmu_legacy.c
+F:	drivers/perf/riscv_pmu_sbi.c
+
 RISC-V ARCHITECTURE
 M:	Paul Walmsley <paul.walmsley@sifive.com>
 M:	Palmer Dabbelt <palmer@dabbelt.com>

arch/riscv/Kconfig

@@ -333,19 +333,6 @@ config RISCV_ISA_C
 
 	   If you don't know what to do here, say Y.
 
-menu "supported PMU type"
-	depends on PERF_EVENTS
-
-config RISCV_BASE_PMU
-	bool "Base Performance Monitoring Unit"
-	def_bool y
-	help
-	  A base PMU that serves as a reference implementation and has limited
-	  feature of perf.  It can run on any RISC-V machines so serves as the
-	  fallback, but this option can also be disable to reduce kernel size.
-
-endmenu
-
 config FPU
 	bool "FPU support"
 	default y

arch/riscv/include/asm/csr.h

@@ -66,6 +66,7 @@
 #define IRQ_S_EXT		9
 #define IRQ_VS_EXT		10
 #define IRQ_M_EXT		11
+#define IRQ_PMU_OVF		13
 
 /* Exception causes */
 #define EXC_INST_MISALIGNED	0
@@ -151,9 +152,69 @@
 #define CSR_CYCLE		0xc00
 #define CSR_TIME		0xc01
 #define CSR_INSTRET		0xc02
+#define CSR_HPMCOUNTER3		0xc03
+#define CSR_HPMCOUNTER4		0xc04
+#define CSR_HPMCOUNTER5		0xc05
+#define CSR_HPMCOUNTER6		0xc06
+#define CSR_HPMCOUNTER7		0xc07
+#define CSR_HPMCOUNTER8		0xc08
+#define CSR_HPMCOUNTER9		0xc09
+#define CSR_HPMCOUNTER10	0xc0a
+#define CSR_HPMCOUNTER11	0xc0b
+#define CSR_HPMCOUNTER12	0xc0c
+#define CSR_HPMCOUNTER13	0xc0d
+#define CSR_HPMCOUNTER14	0xc0e
+#define CSR_HPMCOUNTER15	0xc0f
+#define CSR_HPMCOUNTER16	0xc10
+#define CSR_HPMCOUNTER17	0xc11
+#define CSR_HPMCOUNTER18	0xc12
+#define CSR_HPMCOUNTER19	0xc13
+#define CSR_HPMCOUNTER20	0xc14
+#define CSR_HPMCOUNTER21	0xc15
+#define CSR_HPMCOUNTER22	0xc16
+#define CSR_HPMCOUNTER23	0xc17
+#define CSR_HPMCOUNTER24	0xc18
+#define CSR_HPMCOUNTER25	0xc19
+#define CSR_HPMCOUNTER26	0xc1a
+#define CSR_HPMCOUNTER27	0xc1b
+#define CSR_HPMCOUNTER28	0xc1c
+#define CSR_HPMCOUNTER29	0xc1d
+#define CSR_HPMCOUNTER30	0xc1e
+#define CSR_HPMCOUNTER31	0xc1f
 #define CSR_CYCLEH		0xc80
 #define CSR_TIMEH		0xc81
 #define CSR_INSTRETH		0xc82
+#define CSR_HPMCOUNTER3H	0xc83
+#define CSR_HPMCOUNTER4H	0xc84
+#define CSR_HPMCOUNTER5H	0xc85
+#define CSR_HPMCOUNTER6H	0xc86
+#define CSR_HPMCOUNTER7H	0xc87
+#define CSR_HPMCOUNTER8H	0xc88
+#define CSR_HPMCOUNTER9H	0xc89
+#define CSR_HPMCOUNTER10H	0xc8a
+#define CSR_HPMCOUNTER11H	0xc8b
+#define CSR_HPMCOUNTER12H	0xc8c
+#define CSR_HPMCOUNTER13H	0xc8d
+#define CSR_HPMCOUNTER14H	0xc8e
+#define CSR_HPMCOUNTER15H	0xc8f
+#define CSR_HPMCOUNTER16H	0xc90
+#define CSR_HPMCOUNTER17H	0xc91
+#define CSR_HPMCOUNTER18H	0xc92
+#define CSR_HPMCOUNTER19H	0xc93
+#define CSR_HPMCOUNTER20H	0xc94
+#define CSR_HPMCOUNTER21H	0xc95
+#define CSR_HPMCOUNTER22H	0xc96
+#define CSR_HPMCOUNTER23H	0xc97
+#define CSR_HPMCOUNTER24H	0xc98
+#define CSR_HPMCOUNTER25H	0xc99
+#define CSR_HPMCOUNTER26H	0xc9a
+#define CSR_HPMCOUNTER27H	0xc9b
+#define CSR_HPMCOUNTER28H	0xc9c
+#define CSR_HPMCOUNTER29H	0xc9d
+#define CSR_HPMCOUNTER30H	0xc9e
+#define CSR_HPMCOUNTER31H	0xc9f
+
+#define CSR_SSCOUNTOVF		0xda0
 
 #define CSR_SSTATUS		0x100
 #define CSR_SIE			0x104
@@ -241,7 +302,10 @@
 # define RV_IRQ_SOFT		IRQ_S_SOFT
 # define RV_IRQ_TIMER	IRQ_S_TIMER
 # define RV_IRQ_EXT		IRQ_S_EXT
-#endif /* CONFIG_RISCV_M_MODE */
+# define RV_IRQ_PMU	IRQ_PMU_OVF
+# define SIP_LCOFIP     (_AC(0x1, UL) << IRQ_PMU_OVF)
+
+#endif /* !CONFIG_RISCV_M_MODE */
 
 /* IE/IP (Supervisor/Machine Interrupt Enable/Pending) flags */
 #define IE_SIE		(_AC(0x1, UL) << RV_IRQ_SOFT)

arch/riscv/include/asm/hwcap.h

@@ -51,6 +51,7 @@ extern unsigned long elf_hwcap;
  * available logical extension id.
  */
 enum riscv_isa_ext_id {
+	RISCV_ISA_EXT_SSCOFPMF = RISCV_ISA_EXT_BASE,
 	RISCV_ISA_EXT_ID_MAX = RISCV_ISA_EXT_MAX,
 };
 

arch/riscv/include/asm/perf_event.h

@@ -9,77 +9,5 @@
 #define _ASM_RISCV_PERF_EVENT_H
 
 #include <linux/perf_event.h>
-#include <linux/ptrace.h>
-#include <linux/interrupt.h>
-
-#ifdef CONFIG_RISCV_BASE_PMU
-#define RISCV_BASE_COUNTERS	2
-
-/*
- * The RISCV_MAX_COUNTERS parameter should be specified.
- */
-
-#define RISCV_MAX_COUNTERS	2
-
-/*
- * These are the indexes of bits in counteren register *minus* 1,
- * except for cycle.  It would be coherent if it can directly mapped
- * to counteren bit definition, but there is a *time* register at
- * counteren[1].  Per-cpu structure is scarce resource here.
- *
- * According to the spec, an implementation can support counter up to
- * mhpmcounter31, but many high-end processors has at most 6 general
- * PMCs, we give the definition to MHPMCOUNTER8 here.
- */
-#define RISCV_PMU_CYCLE		0
-#define RISCV_PMU_INSTRET	1
-#define RISCV_PMU_MHPMCOUNTER3	2
-#define RISCV_PMU_MHPMCOUNTER4	3
-#define RISCV_PMU_MHPMCOUNTER5	4
-#define RISCV_PMU_MHPMCOUNTER6	5
-#define RISCV_PMU_MHPMCOUNTER7	6
-#define RISCV_PMU_MHPMCOUNTER8	7
-
-#define RISCV_OP_UNSUPP		(-EOPNOTSUPP)
-
-struct cpu_hw_events {
-	/* # currently enabled events*/
-	int			n_events;
-	/* currently enabled events */
-	struct perf_event	*events[RISCV_MAX_COUNTERS];
-	/* vendor-defined PMU data */
-	void			*platform;
-};
-
-struct riscv_pmu {
-	struct pmu	*pmu;
-
-	/* generic hw/cache events table */
-	const int	*hw_events;
-	const int	(*cache_events)[PERF_COUNT_HW_CACHE_MAX]
-				       [PERF_COUNT_HW_CACHE_OP_MAX]
-				       [PERF_COUNT_HW_CACHE_RESULT_MAX];
-	/* method used to map hw/cache events */
-	int		(*map_hw_event)(u64 config);
-	int		(*map_cache_event)(u64 config);
-
-	/* max generic hw events in map */
-	int		max_events;
-	/* number total counters, 2(base) + x(general) */
-	int		num_counters;
-	/* the width of the counter */
-	int		counter_width;
-
-	/* vendor-defined PMU features */
-	void		*platform;
-
-	irqreturn_t	(*handle_irq)(int irq_num, void *dev);
-	int		irq;
-};
-
-#endif
-#ifdef CONFIG_PERF_EVENTS
 #define perf_arch_bpf_user_pt_regs(regs) (struct user_regs_struct *)regs
-#endif
-
 #endif /* _ASM_RISCV_PERF_EVENT_H */

arch/riscv/include/asm/sbi.h

@@ -29,6 +29,7 @@ enum sbi_ext_id {
 	SBI_EXT_RFENCE = 0x52464E43,
 	SBI_EXT_HSM = 0x48534D,
 	SBI_EXT_SRST = 0x53525354,
+	SBI_EXT_PMU = 0x504D55,
 
 	/* Experimentals extensions must lie within this range */
 	SBI_EXT_EXPERIMENTAL_START = 0x08000000,
@@ -95,6 +96,98 @@ enum sbi_srst_reset_reason {
 	SBI_SRST_RESET_REASON_SYS_FAILURE,
 };
 
+enum sbi_ext_pmu_fid {
+	SBI_EXT_PMU_NUM_COUNTERS = 0,
+	SBI_EXT_PMU_COUNTER_GET_INFO,
+	SBI_EXT_PMU_COUNTER_CFG_MATCH,
+	SBI_EXT_PMU_COUNTER_START,
+	SBI_EXT_PMU_COUNTER_STOP,
+	SBI_EXT_PMU_COUNTER_FW_READ,
+};
+
+#define RISCV_PMU_RAW_EVENT_MASK GENMASK_ULL(55, 0)
+#define RISCV_PMU_RAW_EVENT_IDX 0x20000
+
+/** General pmu event codes specified in SBI PMU extension */
+enum sbi_pmu_hw_generic_events_t {
+	SBI_PMU_HW_NO_EVENT			= 0,
+	SBI_PMU_HW_CPU_CYCLES			= 1,
+	SBI_PMU_HW_INSTRUCTIONS			= 2,
+	SBI_PMU_HW_CACHE_REFERENCES		= 3,
+	SBI_PMU_HW_CACHE_MISSES			= 4,
+	SBI_PMU_HW_BRANCH_INSTRUCTIONS		= 5,
+	SBI_PMU_HW_BRANCH_MISSES		= 6,
+	SBI_PMU_HW_BUS_CYCLES			= 7,
+	SBI_PMU_HW_STALLED_CYCLES_FRONTEND	= 8,
+	SBI_PMU_HW_STALLED_CYCLES_BACKEND	= 9,
+	SBI_PMU_HW_REF_CPU_CYCLES		= 10,
+
+	SBI_PMU_HW_GENERAL_MAX,
+};
+
+/**
+ * Special "firmware" events provided by the firmware, even if the hardware
+ * does not support performance events. These events are encoded as a raw
+ * event type in Linux kernel perf framework.
+ */
+enum sbi_pmu_fw_generic_events_t {
+	SBI_PMU_FW_MISALIGNED_LOAD	= 0,
+	SBI_PMU_FW_MISALIGNED_STORE	= 1,
+	SBI_PMU_FW_ACCESS_LOAD		= 2,
+	SBI_PMU_FW_ACCESS_STORE		= 3,
+	SBI_PMU_FW_ILLEGAL_INSN		= 4,
+	SBI_PMU_FW_SET_TIMER		= 5,
+	SBI_PMU_FW_IPI_SENT		= 6,
+	SBI_PMU_FW_IPI_RECVD		= 7,
+	SBI_PMU_FW_FENCE_I_SENT		= 8,
+	SBI_PMU_FW_FENCE_I_RECVD	= 9,
+	SBI_PMU_FW_SFENCE_VMA_SENT	= 10,
+	SBI_PMU_FW_SFENCE_VMA_RCVD	= 11,
+	SBI_PMU_FW_SFENCE_VMA_ASID_SENT	= 12,
+	SBI_PMU_FW_SFENCE_VMA_ASID_RCVD	= 13,
+
+	SBI_PMU_FW_HFENCE_GVMA_SENT	= 14,
+	SBI_PMU_FW_HFENCE_GVMA_RCVD	= 15,
+	SBI_PMU_FW_HFENCE_GVMA_VMID_SENT = 16,
+	SBI_PMU_FW_HFENCE_GVMA_VMID_RCVD = 17,
+
+	SBI_PMU_FW_HFENCE_VVMA_SENT	= 18,
+	SBI_PMU_FW_HFENCE_VVMA_RCVD	= 19,
+	SBI_PMU_FW_HFENCE_VVMA_ASID_SENT = 20,
+	SBI_PMU_FW_HFENCE_VVMA_ASID_RCVD = 21,
+	SBI_PMU_FW_MAX,
+};
+
+/* SBI PMU event types */
+enum sbi_pmu_event_type {
+	SBI_PMU_EVENT_TYPE_HW = 0x0,
+	SBI_PMU_EVENT_TYPE_CACHE = 0x1,
+	SBI_PMU_EVENT_TYPE_RAW = 0x2,
+	SBI_PMU_EVENT_TYPE_FW = 0xf,
+};
+
+/* SBI PMU event types */
+enum sbi_pmu_ctr_type {
+	SBI_PMU_CTR_TYPE_HW = 0x0,
+	SBI_PMU_CTR_TYPE_FW,
+};
+
+/* Flags defined for config matching function */
+#define SBI_PMU_CFG_FLAG_SKIP_MATCH	(1 << 0)
+#define SBI_PMU_CFG_FLAG_CLEAR_VALUE	(1 << 1)
+#define SBI_PMU_CFG_FLAG_AUTO_START	(1 << 2)
+#define SBI_PMU_CFG_FLAG_SET_VUINH	(1 << 3)
+#define SBI_PMU_CFG_FLAG_SET_VSNH	(1 << 4)
+#define SBI_PMU_CFG_FLAG_SET_UINH	(1 << 5)
+#define SBI_PMU_CFG_FLAG_SET_SINH	(1 << 6)
+#define SBI_PMU_CFG_FLAG_SET_MINH	(1 << 7)
+
+/* Flags defined for counter start function */
+#define SBI_PMU_START_FLAG_SET_INIT_VALUE (1 << 0)
+
+/* Flags defined for counter stop function */
+#define SBI_PMU_STOP_FLAG_RESET (1 << 0)
+
 #define SBI_SPEC_VERSION_DEFAULT	0x1
 #define SBI_SPEC_VERSION_MAJOR_SHIFT	24
 #define SBI_SPEC_VERSION_MAJOR_MASK	0x7f
@@ -108,6 +201,8 @@ enum sbi_srst_reset_reason {
 #define SBI_ERR_DENIED		-4
 #define SBI_ERR_INVALID_ADDRESS	-5
 #define SBI_ERR_ALREADY_AVAILABLE -6
+#define SBI_ERR_ALREADY_STARTED -7
+#define SBI_ERR_ALREADY_STOPPED -8
 
 extern unsigned long sbi_spec_version;
 struct sbiret {

arch/riscv/kernel/Makefile

@@ -51,7 +51,6 @@ obj-$(CONFIG_MODULE_SECTIONS)	+= module-sections.o
 obj-$(CONFIG_FUNCTION_TRACER)	+= mcount.o ftrace.o
 obj-$(CONFIG_DYNAMIC_FTRACE)	+= mcount-dyn.o
 
-obj-$(CONFIG_RISCV_BASE_PMU)	+= perf_event.o
 obj-$(CONFIG_PERF_EVENTS)	+= perf_callchain.o
 obj-$(CONFIG_HAVE_PERF_REGS)	+= perf_regs.o
 obj-$(CONFIG_RISCV_SBI)		+= sbi.o

arch/riscv/kernel/cpu.c

@@ -87,6 +87,7 @@ int riscv_of_parent_hartid(struct device_node *node)
  *    extensions by an underscore.
  */
 static struct riscv_isa_ext_data isa_ext_arr[] = {
+	__RISCV_ISA_EXT_DATA(sscofpmf, RISCV_ISA_EXT_SSCOFPMF),
 	__RISCV_ISA_EXT_DATA("", RISCV_ISA_EXT_MAX),
 };
 

arch/riscv/kernel/cpufeature.c

@@ -190,6 +190,8 @@ void __init riscv_fill_hwcap(void)
 			if (!ext_long) {
 				this_hwcap |= isa2hwcap[(unsigned char)(*ext)];
 				set_bit(*ext - 'a', this_isa);
+			} else {
+				SET_ISA_EXT_MAP("sscofpmf", RISCV_ISA_EXT_SSCOFPMF);
 			}
 #undef SET_ISA_EXT_MAP
 		}

drivers/perf/Kconfig

@@ -56,6 +56,36 @@ config ARM_PMU
 	  Say y if you want to use CPU performance monitors on ARM-based
 	  systems.
 
+config RISCV_PMU
+	depends on RISCV
+	bool "RISC-V PMU framework"
+	default y
+	help
+	  Say y if you want to use CPU performance monitors on RISCV-based
+	  systems. This provides the core PMU framework that abstracts common
+	  PMU functionalities in a core library so that different PMU drivers
+	  can reuse it.
+
+config RISCV_PMU_LEGACY
+	depends on RISCV_PMU
+	bool "RISC-V legacy PMU implementation"
+	default y
+	help
+	  Say y if you want to use the legacy CPU performance monitor
+	  implementation on RISC-V based systems. This only allows counting
+	  of cycle/instruction counter and doesn't support counter overflow,
+	  or programmable counters. It will be removed in future.
+
+config RISCV_PMU_SBI
+	depends on RISCV_PMU && RISCV_SBI
+	bool "RISC-V PMU based on SBI PMU extension"
+	default y
+	help
+	  Say y if you want to use the CPU performance monitor
+	  using SBI PMU extension on RISC-V based systems. This option provides
+	  full perf feature support i.e. counter overflow, privilege mode
+	  filtering, counter configuration.
+
 config ARM_PMU_ACPI
 	depends on ARM_PMU && ACPI
 	def_bool y

drivers/perf/Makefile

@@ -10,6 +10,9 @@ obj-$(CONFIG_FSL_IMX8_DDR_PMU) += fsl_imx8_ddr_perf.o
 obj-$(CONFIG_HISI_PMU) += hisilicon/
 obj-$(CONFIG_QCOM_L2_PMU)	+= qcom_l2_pmu.o
 obj-$(CONFIG_QCOM_L3_PMU) += qcom_l3_pmu.o
+obj-$(CONFIG_RISCV_PMU) += riscv_pmu.o
+obj-$(CONFIG_RISCV_PMU_LEGACY) += riscv_pmu_legacy.o
+obj-$(CONFIG_RISCV_PMU_SBI) += riscv_pmu_sbi.o
 obj-$(CONFIG_THUNDERX2_PMU) += thunderx2_pmu.o
 obj-$(CONFIG_XGENE_PMU) += xgene_pmu.o
 obj-$(CONFIG_ARM_SPE_PMU) += arm_spe_pmu.o

drivers/perf/riscv_pmu.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * RISC-V performance counter support.
+ *
+ * Copyright (C) 2021 Western Digital Corporation or its affiliates.
+ *
+ * This implementation is based on old RISC-V perf and ARM perf event code
+ * which are in turn based on sparc64 and x86 code.
+ */
+
+#include <linux/cpumask.h>
+#include <linux/irq.h>
+#include <linux/irqdesc.h>
+#include <linux/perf/riscv_pmu.h>
+#include <linux/printk.h>
+#include <linux/smp.h>
+
+#include <asm/sbi.h>
+
+static unsigned long csr_read_num(int csr_num)
+{
+#define switchcase_csr_read(__csr_num, __val)		{\
+	case __csr_num:					\
+		__val = csr_read(__csr_num);		\
+		break; }
+#define switchcase_csr_read_2(__csr_num, __val)		{\
+	switchcase_csr_read(__csr_num + 0, __val)	 \
+	switchcase_csr_read(__csr_num + 1, __val)}
+#define switchcase_csr_read_4(__csr_num, __val)		{\
+	switchcase_csr_read_2(__csr_num + 0, __val)	 \
+	switchcase_csr_read_2(__csr_num + 2, __val)}
+#define switchcase_csr_read_8(__csr_num, __val)		{\
+	switchcase_csr_read_4(__csr_num + 0, __val)	 \
+	switchcase_csr_read_4(__csr_num + 4, __val)}
+#define switchcase_csr_read_16(__csr_num, __val)	{\
+	switchcase_csr_read_8(__csr_num + 0, __val)	 \
+	switchcase_csr_read_8(__csr_num + 8, __val)}
+#define switchcase_csr_read_32(__csr_num, __val)	{\
+	switchcase_csr_read_16(__csr_num + 0, __val)	 \
+	switchcase_csr_read_16(__csr_num + 16, __val)}
+
+	unsigned long ret = 0;
+
+	switch (csr_num) {
+	switchcase_csr_read_32(CSR_CYCLE, ret)
+	switchcase_csr_read_32(CSR_CYCLEH, ret)
+	default :
+		break;
+	}
+
+	return ret;
+#undef switchcase_csr_read_32
+#undef switchcase_csr_read_16
+#undef switchcase_csr_read_8
+#undef switchcase_csr_read_4
+#undef switchcase_csr_read_2
+#undef switchcase_csr_read
+}
+
+/*
+ * Read the CSR of a corresponding counter.
+ */
+unsigned long riscv_pmu_ctr_read_csr(unsigned long csr)
+{
+	if (csr < CSR_CYCLE || csr > CSR_HPMCOUNTER31H ||
+	   (csr > CSR_HPMCOUNTER31 && csr < CSR_CYCLEH)) {
+		pr_err("Invalid performance counter csr %lx\n", csr);
+		return -EINVAL;
+	}
+
+	return csr_read_num(csr);
+}
+
+u64 riscv_pmu_ctr_get_width_mask(struct perf_event *event)
+{
+	int cwidth;
+	struct riscv_pmu *rvpmu = to_riscv_pmu(event->pmu);
+	struct hw_perf_event *hwc = &event->hw;
+
+	if (!rvpmu->ctr_get_width)
+	/**
+	 * If the pmu driver doesn't support counter width, set it to default
+	 * maximum allowed by the specification.
+	 */
+		cwidth = 63;
+	else {
+		if (hwc->idx == -1)
+			/* Handle init case where idx is not initialized yet */
+			cwidth = rvpmu->ctr_get_width(0);
+		else
+			cwidth = rvpmu->ctr_get_width(hwc->idx);
+	}
+
+	return GENMASK_ULL(cwidth, 0);
+}
+
+u64 riscv_pmu_event_update(struct perf_event *event)
+{
+	struct riscv_pmu *rvpmu = to_riscv_pmu(event->pmu);
+	struct hw_perf_event *hwc = &event->hw;
+	u64 prev_raw_count, new_raw_count;
+	unsigned long cmask;
+	u64 oldval, delta;
+
+	if (!rvpmu->ctr_read)
+		return 0;
+
+	cmask = riscv_pmu_ctr_get_width_mask(event);
+
+	do {
+		prev_raw_count = local64_read(&hwc->prev_count);
+		new_raw_count = rvpmu->ctr_read(event);
+		oldval = local64_cmpxchg(&hwc->prev_count, prev_raw_count,
+					 new_raw_count);
+	} while (oldval != prev_raw_count);
+
+	delta = (new_raw_count - prev_raw_count) & cmask;
+	local64_add(delta, &event->count);
+	local64_sub(delta, &hwc->period_left);
+
+	return delta;
+}
+
+static void riscv_pmu_stop(struct perf_event *event, int flags)
+{
+	struct hw_perf_event *hwc = &event->hw;
+	struct riscv_pmu *rvpmu = to_riscv_pmu(event->pmu);
+
+	WARN_ON_ONCE(hwc->state & PERF_HES_STOPPED);
+
+	if (!(hwc->state & PERF_HES_STOPPED)) {
+		if (rvpmu->ctr_stop) {
+			rvpmu->ctr_stop(event, 0);
+			hwc->state |= PERF_HES_STOPPED;
+		}
+		riscv_pmu_event_update(event);
+		hwc->state |= PERF_HES_UPTODATE;
+	}
+}
+
+int riscv_pmu_event_set_period(struct perf_event *event)
+{
+	struct hw_perf_event *hwc = &event->hw;
+	s64 left = local64_read(&hwc->period_left);
+	s64 period = hwc->sample_period;
+	int overflow = 0;
+	uint64_t max_period = riscv_pmu_ctr_get_width_mask(event);
+
+	if (unlikely(left <= -period)) {
+		left = period;
+		local64_set(&hwc->period_left, left);
+		hwc->last_period = period;
+		overflow = 1;
+	}
+
+	if (unlikely(left <= 0)) {
+		left += period;
+		local64_set(&hwc->period_left, left);
+		hwc->last_period = period;
+		overflow = 1;
+	}
+
+	/*
+	 * Limit the maximum period to prevent the counter value
+	 * from overtaking the one we are about to program. In
+	 * effect we are reducing max_period to account for
+	 * interrupt latency (and we are being very conservative).
+	 */
+	if (left > (max_period >> 1))
+		left = (max_period >> 1);
+
+	local64_set(&hwc->prev_count, (u64)-left);
+	perf_event_update_userpage(event);
+
+	return overflow;
+}
+
+static void riscv_pmu_start(struct perf_event *event, int flags)
+{
+	struct hw_perf_event *hwc = &event->hw;
+	struct riscv_pmu *rvpmu = to_riscv_pmu(event->pmu);
+	uint64_t max_period = riscv_pmu_ctr_get_width_mask(event);
+	u64 init_val;
+
+	if (WARN_ON_ONCE(!(event->hw.state & PERF_HES_STOPPED)))
+		return;
+
+	if (flags & PERF_EF_RELOAD)
+		WARN_ON_ONCE(!(event->hw.state & PERF_HES_UPTODATE));
+
+	hwc->state = 0;
+	riscv_pmu_event_set_period(event);
+	init_val = local64_read(&hwc->prev_count) & max_period;
+	rvpmu->ctr_start(event, init_val);
+	perf_event_update_userpage(event);
+}
+
+static int riscv_pmu_add(struct perf_event *event, int flags)
+{
+	struct riscv_pmu *rvpmu = to_riscv_pmu(event->pmu);
+	struct cpu_hw_events *cpuc = this_cpu_ptr(rvpmu->hw_events);
+	struct hw_perf_event *hwc = &event->hw;
+	int idx;
+
+	idx = rvpmu->ctr_get_idx(event);
+	if (idx < 0)
+		return idx;
+
+	hwc->idx = idx;
+	cpuc->events[idx] = event;
+	cpuc->n_events++;
+	hwc->state = PERF_HES_UPTODATE | PERF_HES_STOPPED;
+	if (flags & PERF_EF_START)
+		riscv_pmu_start(event, PERF_EF_RELOAD);
+
+	/* Propagate our changes to the userspace mapping. */
+	perf_event_update_userpage(event);
+
+	return 0;
+}
+
+static void riscv_pmu_del(struct perf_event *event, int flags)
+{
+	struct riscv_pmu *rvpmu = to_riscv_pmu(event->pmu);
+	struct cpu_hw_events *cpuc = this_cpu_ptr(rvpmu->hw_events);
+	struct hw_perf_event *hwc = &event->hw;
+
+	riscv_pmu_stop(event, PERF_EF_UPDATE);
+	cpuc->events[hwc->idx] = NULL;
+	/* The firmware need to reset the counter mapping */
+	if (rvpmu->ctr_stop)
+		rvpmu->ctr_stop(event, RISCV_PMU_STOP_FLAG_RESET);
+	cpuc->n_events--;
+	if (rvpmu->ctr_clear_idx)
+		rvpmu->ctr_clear_idx(event);
+	perf_event_update_userpage(event);
+	hwc->idx = -1;
+}
+
+static void riscv_pmu_read(struct perf_event *event)
+{
+	riscv_pmu_event_update(event);
+}
+
+static int riscv_pmu_event_init(struct perf_event *event)
+{
+	struct hw_perf_event *hwc = &event->hw;
+	struct riscv_pmu *rvpmu = to_riscv_pmu(event->pmu);
+	int mapped_event;
+	u64 event_config = 0;
+	uint64_t cmask;
+
+	hwc->flags = 0;
+	mapped_event = rvpmu->event_map(event, &event_config);
+	if (mapped_event < 0) {
+		pr_debug("event %x:%llx not supported\n", event->attr.type,
+			 event->attr.config);
+		return mapped_event;
+	}
+
+	/*
+	 * idx is set to -1 because the index of a general event should not be
+	 * decided until binding to some counter in pmu->add().
+	 * config will contain the information about counter CSR
+	 * the idx will contain the counter index
+	 */
+	hwc->config = event_config;
+	hwc->idx = -1;
+	hwc->event_base = mapped_event;
+
+	if (!is_sampling_event(event)) {
+		/*
+		 * For non-sampling runs, limit the sample_period to half
+		 * of the counter width. That way, the new counter value
+		 * is far less likely to overtake the previous one unless
+		 * you have some serious IRQ latency issues.
+		 */
+		cmask = riscv_pmu_ctr_get_width_mask(event);
+		hwc->sample_period  =  cmask >> 1;
+		hwc->last_period    = hwc->sample_period;
+		local64_set(&hwc->period_left, hwc->sample_period);
+	}
+
+	return 0;
+}
+
+struct riscv_pmu *riscv_pmu_alloc(void)
+{
+	struct riscv_pmu *pmu;
+	int cpuid, i;
+	struct cpu_hw_events *cpuc;
+
+	pmu = kzalloc(sizeof(*pmu), GFP_KERNEL);
+	if (!pmu)
+		goto out;
+
+	pmu->hw_events = alloc_percpu_gfp(struct cpu_hw_events, GFP_KERNEL);
+	if (!pmu->hw_events) {
+		pr_info("failed to allocate per-cpu PMU data.\n");
+		goto out_free_pmu;
+	}
+
+	for_each_possible_cpu(cpuid) {
+		cpuc = per_cpu_ptr(pmu->hw_events, cpuid);
+		cpuc->n_events = 0;
+		for (i = 0; i < RISCV_MAX_COUNTERS; i++)
+			cpuc->events[i] = NULL;
+	}
+	pmu->pmu = (struct pmu) {
+		.event_init	= riscv_pmu_event_init,
+		.add		= riscv_pmu_add,
+		.del		= riscv_pmu_del,
+		.start		= riscv_pmu_start,
+		.stop		= riscv_pmu_stop,
+		.read		= riscv_pmu_read,
+	};
+
+	return pmu;
+
+out_free_pmu:
+	kfree(pmu);
+out:
+	return NULL;
+}

drivers/perf/riscv_pmu_legacy.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * RISC-V performance counter support.
+ *
+ * Copyright (C) 2021 Western Digital Corporation or its affiliates.
+ *
+ * This implementation is based on old RISC-V perf and ARM perf event code
+ * which are in turn based on sparc64 and x86 code.
+ */
+
+#include <linux/mod_devicetable.h>
+#include <linux/perf/riscv_pmu.h>
+#include <linux/platform_device.h>
+
+#define RISCV_PMU_LEGACY_CYCLE		0
+#define RISCV_PMU_LEGACY_INSTRET	1
+#define RISCV_PMU_LEGACY_NUM_CTR	2
+
+static bool pmu_init_done;
+
+static int pmu_legacy_ctr_get_idx(struct perf_event *event)
+{
+	struct perf_event_attr *attr = &event->attr;
+
+	if (event->attr.type != PERF_TYPE_HARDWARE)
+		return -EOPNOTSUPP;
+	if (attr->config == PERF_COUNT_HW_CPU_CYCLES)
+		return RISCV_PMU_LEGACY_CYCLE;
+	else if (attr->config == PERF_COUNT_HW_INSTRUCTIONS)
+		return RISCV_PMU_LEGACY_INSTRET;
+	else
+		return -EOPNOTSUPP;
+}
+
+/* For legacy config & counter index are same */
+static int pmu_legacy_event_map(struct perf_event *event, u64 *config)
+{
+	return pmu_legacy_ctr_get_idx(event);
+}
+
+static u64 pmu_legacy_read_ctr(struct perf_event *event)
+{
+	struct hw_perf_event *hwc = &event->hw;
+	int idx = hwc->idx;
+	u64 val;
+
+	if (idx == RISCV_PMU_LEGACY_CYCLE) {
+		val = riscv_pmu_ctr_read_csr(CSR_CYCLE);
+		if (IS_ENABLED(CONFIG_32BIT))
+			val = (u64)riscv_pmu_ctr_read_csr(CSR_CYCLEH) << 32 | val;
+	} else if (idx == RISCV_PMU_LEGACY_INSTRET) {
+		val = riscv_pmu_ctr_read_csr(CSR_INSTRET);
+		if (IS_ENABLED(CONFIG_32BIT))
+			val = ((u64)riscv_pmu_ctr_read_csr(CSR_INSTRETH)) << 32 | val;
+	} else
+		return 0;
+
+	return val;
+}
+
+static void pmu_legacy_ctr_start(struct perf_event *event, u64 ival)
+{
+	struct hw_perf_event *hwc = &event->hw;
+	u64 initial_val = pmu_legacy_read_ctr(event);
+
+	/**
+	 * The legacy method doesn't really have a start/stop method.
+	 * It also can not update the counter with a initial value.
+	 * But we still need to set the prev_count so that read() can compute
+	 * the delta. Just use the current counter value to set the prev_count.
+	 */
+	local64_set(&hwc->prev_count, initial_val);
+}
+
+/**
+ * This is just a simple implementation to allow legacy implementations
+ * compatible with new RISC-V PMU driver framework.
+ * This driver only allows reading two counters i.e CYCLE & INSTRET.
+ * However, it can not start or stop the counter. Thus, it is not very useful
+ * will be removed in future.
+ */
+static void pmu_legacy_init(struct riscv_pmu *pmu)
+{
+	pr_info("Legacy PMU implementation is available\n");
+
+	pmu->num_counters = RISCV_PMU_LEGACY_NUM_CTR;
+	pmu->ctr_start = pmu_legacy_ctr_start;
+	pmu->ctr_stop = NULL;
+	pmu->event_map = pmu_legacy_event_map;
+	pmu->ctr_get_idx = pmu_legacy_ctr_get_idx;
+	pmu->ctr_get_width = NULL;
+	pmu->ctr_clear_idx = NULL;
+	pmu->ctr_read = pmu_legacy_read_ctr;
+
+	perf_pmu_register(&pmu->pmu, "cpu", PERF_TYPE_RAW);
+}
+
+static int pmu_legacy_device_probe(struct platform_device *pdev)
+{
+	struct riscv_pmu *pmu = NULL;
+
+	pmu = riscv_pmu_alloc();
+	if (!pmu)
+		return -ENOMEM;
+	pmu_legacy_init(pmu);
+
+	return 0;
+}
+
+static struct platform_driver pmu_legacy_driver = {
+	.probe		= pmu_legacy_device_probe,
+	.driver		= {
+		.name	= RISCV_PMU_LEGACY_PDEV_NAME,
+	},
+};
+
+static int __init riscv_pmu_legacy_devinit(void)
+{
+	int ret;
+	struct platform_device *pdev;
+
+	if (likely(pmu_init_done))
+		return 0;
+
+	ret = platform_driver_register(&pmu_legacy_driver);
+	if (ret)
+		return ret;
+
+	pdev = platform_device_register_simple(RISCV_PMU_LEGACY_PDEV_NAME, -1, NULL, 0);
+	if (IS_ERR(pdev)) {
+		platform_driver_unregister(&pmu_legacy_driver);
+		return PTR_ERR(pdev);
+	}
+
+	return ret;
+}
+late_initcall(riscv_pmu_legacy_devinit);
+
+void riscv_pmu_legacy_skip_init(void)
+{
+	pmu_init_done = true;
+}

include/linux/cpuhotplug.h

@@ -165,6 +165,7 @@ enum cpuhp_state {
 	CPUHP_AP_PERF_ARM_HW_BREAKPOINT_STARTING,
 	CPUHP_AP_PERF_ARM_ACPI_STARTING,
 	CPUHP_AP_PERF_ARM_STARTING,
+	CPUHP_AP_PERF_RISCV_STARTING,
 	CPUHP_AP_ARM_L2X0_STARTING,
 	CPUHP_AP_EXYNOS4_MCT_TIMER_STARTING,
 	CPUHP_AP_ARM_ARCH_TIMER_STARTING,

include/linux/perf/riscv_pmu.h

+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2018 SiFive
+ * Copyright (C) 2018 Andes Technology Corporation
+ * Copyright (C) 2021 Western Digital Corporation or its affiliates.
+ *
+ */
+
+#ifndef _ASM_RISCV_PERF_EVENT_H
+#define _ASM_RISCV_PERF_EVENT_H
+
+#include <linux/perf_event.h>
+#include <linux/ptrace.h>
+#include <linux/interrupt.h>
+
+#ifdef CONFIG_RISCV_PMU
+
+/*
+ * The RISCV_MAX_COUNTERS parameter should be specified.
+ */
+
+#define RISCV_MAX_COUNTERS	64
+#define RISCV_OP_UNSUPP		(-EOPNOTSUPP)
+#define RISCV_PMU_PDEV_NAME	"riscv-pmu"
+#define RISCV_PMU_LEGACY_PDEV_NAME	"riscv-pmu-legacy"
+
+#define RISCV_PMU_STOP_FLAG_RESET 1
+
+struct cpu_hw_events {
+	/* currently enabled events */
+	int			n_events;
+	/* Counter overflow interrupt */
+	int		irq;
+	/* currently enabled events */
+	struct perf_event	*events[RISCV_MAX_COUNTERS];
+	/* currently enabled hardware counters */
+	DECLARE_BITMAP(used_hw_ctrs, RISCV_MAX_COUNTERS);
+	/* currently enabled firmware counters */
+	DECLARE_BITMAP(used_fw_ctrs, RISCV_MAX_COUNTERS);
+};
+
+struct riscv_pmu {
+	struct pmu	pmu;
+	char		*name;
+
+	irqreturn_t	(*handle_irq)(int irq_num, void *dev);
+
+	int		num_counters;
+	u64		(*ctr_read)(struct perf_event *event);
+	int		(*ctr_get_idx)(struct perf_event *event);
+	int		(*ctr_get_width)(int idx);
+	void		(*ctr_clear_idx)(struct perf_event *event);
+	void		(*ctr_start)(struct perf_event *event, u64 init_val);
+	void		(*ctr_stop)(struct perf_event *event, unsigned long flag);
+	int		(*event_map)(struct perf_event *event, u64 *config);
+
+	struct cpu_hw_events	__percpu *hw_events;
+	struct hlist_node	node;
+};
+
+#define to_riscv_pmu(p) (container_of(p, struct riscv_pmu, pmu))
+unsigned long riscv_pmu_ctr_read_csr(unsigned long csr);
+int riscv_pmu_event_set_period(struct perf_event *event);
+uint64_t riscv_pmu_ctr_get_width_mask(struct perf_event *event);
+u64 riscv_pmu_event_update(struct perf_event *event);
+#ifdef CONFIG_RISCV_PMU_LEGACY
+void riscv_pmu_legacy_skip_init(void);
+#else
+static inline void riscv_pmu_legacy_skip_init(void) {};
+#endif
+struct riscv_pmu *riscv_pmu_alloc(void);
+
+#endif /* CONFIG_RISCV_PMU */
+
+#endif /* _ASM_RISCV_PERF_EVENT_H */