Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [PATCH] x86/perf: Add hardware performance events support for
 Zhaoxin CPU.
To:     Peter Zijlstra <peterz@infradead.org>
CC:     <mingo@redhat.com>, <acme@kernel.org>, <mark.rutland@arm.com>,
        <alexander.shishkin@linux.intel.com>, <jolsa@redhat.com>,
        <namhyung@kernel.org>, <tglx@linutronix.de>, <bp@alien8.de>,
        <x86@kernel.org>, <hpa@zytor.com>, <linux-kernel@vger.kernel.org>,
        <cooperyan@zhaoxin.com>, <codyyao@zhaoxin.com>
References: <1586747669-4827-1-git-send-email-CodyYao-oc@zhaoxin.com>
 <20200415102340.GB20730@hirez.programming.kicks-ass.net>
 <20200415103141.GS20760@hirez.programming.kicks-ass.net>
From:   CodyYao-oc <CodyYao-oc@zhaoxin.com>
Message-ID: <714558bb-077a-4625-18c3-57c20c1e3db5@zhaoxin.com>
Date:   Wed, 6 May 2020 20:55:54 +0800
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101
 Thunderbird/68.8.0
MIME-Version: 1.0
In-Reply-To: <20200415103141.GS20760@hirez.programming.kicks-ass.net>
Content-Type: text/plain; charset="utf-8"; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 2020/4/15 下午6:31, Peter Zijlstra wrote:
> On Wed, Apr 15, 2020 at 12:23:40PM +0200, Peter Zijlstra wrote:
>> On Mon, Apr 13, 2020 at 11:14:29AM +0800, CodyYao-oc wrote:
>>> Zhaoxin CPU has provided facilities for monitoring performance
>>> via PMU(Performance Monitor Unit), but the functionality is unused so far.
>>> Therefore, add support for zhaoxin pmu to make performance related
>>> hardware events available.
>>>
>>> Signed-off-by: CodyYao-oc <CodyYao-oc@zhaoxin.com>
>>> Reported-by: kbuild test robot <lkp@intel.com>
>>
>> What's that reported-by thing? Did the robot complain you didn't have a
>> PMU implementation?
>>
>> Anyway, I've made the below changes to the patch.
> 
> In whole, the patch now looks like this. I've also added that event
> table you provided last time to the Changelog.
> 
> ---
> Subject: x86/perf: Add hardware performance events support for Zhaoxin CPU.
> From: CodyYao-oc <CodyYao-oc@zhaoxin.com>
> Date: Mon, 13 Apr 2020 11:14:29 +0800
> 
> From: CodyYao-oc <CodyYao-oc@zhaoxin.com>
> 
> Zhaoxin CPU has provided facilities for monitoring performance
> via PMU (Performance Monitor Unit), but the functionality is unused so far.
> Therefore, add support for zhaoxin pmu to make performance related
> hardware events available.
> 
> The PMU is mostly an Intel Architectural PerfMon-v2 with a novel
> errata for the ZXC line. It supports the following events:
> 
>    -----------------------------------------------------------------------------------------------------------------------------------
>    Event                      | Event  | Umask |          Description
> 			     | Select |       |
>    -----------------------------------------------------------------------------------------------------------------------------------
>    cpu-cycles                 |  82h   |  00h  | unhalt core clock
>    instructions               |  00h   |  00h  | number of instructions at retirement.
>    cache-references           |  15h   |  05h  | number of fillq pushs at the current cycle.
>    cache-misses               |  1ah   |  05h  | number of l2 miss pushed by fillq.
>    branch-instructions        |  28h   |  00h  | counts the number of branch instructions retired.
>    branch-misses              |  29h   |  00h  | mispredicted branch instructions at retirement.
>    bus-cycles                 |  83h   |  00h  | unhalt bus clock
>    stalled-cycles-frontend    |  01h   |  01h  | Increments each cycle the # of Uops issued by the RAT to RS.
>    stalled-cycles-backend     |  0fh   |  04h  | RS0/1/2/3/45 empty
>    L1-dcache-loads            |  68h   |  05h  | number of retire/commit load.
>    L1-dcache-load-misses      |  4bh   |  05h  | retired load uops whose data source followed an L1 miss.
>    L1-dcache-stores           |  69h   |  06h  | number of retire/commit Store,no LEA
>    L1-dcache-store-misses     |  62h   |  05h  | cache lines in M state evicted out of L1D due to Snoop HitM or dirty line replacement.
>    L1-icache-loads            |  00h   |  03h  | number of l1i cache access for valid normal fetch,including un-cacheable access.
>    L1-icache-load-misses      |  01h   |  03h  | number of l1i cache miss for valid normal fetch,including un-cacheable miss.
>    L1-icache-prefetches       |  0ah   |  03h  | number of prefetch.
>    L1-icache-prefetch-misses  |  0bh   |  03h  | number of prefetch miss.
>    dTLB-loads                 |  68h   |  05h  | number of retire/commit load
>    dTLB-load-misses           |  2ch   |  05h  | number of load operations miss all level tlbs and cause a tablewalk.
>    dTLB-stores                |  69h   |  06h  | number of retire/commit Store,no LEA
>    dTLB-store-misses          |  30h   |  05h  | number of store operations miss all level tlbs and cause a tablewalk.
>    dTLB-prefetches            |  64h   |  05h  | number of hardware pte prefetch requests dispatched out of the prefetch FIFO.
>    dTLB-prefetch-misses       |  65h   |  05h  | number of hardware pte prefetch requests miss the l1d data cache.
>    iTLB-load                  |  00h   |  00h  | actually counter instructions.
>    iTLB-load-misses           |  34h   |  05h  | number of code operations miss all level tlbs and cause a tablewalk.
>    -----------------------------------------------------------------------------------------------------------------------------------
> 
> Reported-by: kbuild test robot <lkp@intel.com>
> Signed-off-by: CodyYao-oc <CodyYao-oc@zhaoxin.com>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> Link: https://lkml.kernel.org/r/1586747669-4827-1-git-send-email-CodyYao-oc@zhaoxin.com
> ---
>   arch/x86/events/Makefile               |    2
>   arch/x86/events/core.c                 |    4
>   arch/x86/events/perf_event.h           |   10
>   arch/x86/events/zhaoxin/Makefile       |    2
>   arch/x86/events/zhaoxin/core.c         |  613 +++++++++++++++++++++++++++++++++
>   arch/x86/kernel/cpu/perfctr-watchdog.c |    8
>   6 files changed, 639 insertions(+)
>   create mode 100644 arch/x86/events/zhaoxin/Makefile
>   create mode 100644 arch/x86/events/zhaoxin/core.c
> 
> --- a/arch/x86/events/Makefile
> +++ b/arch/x86/events/Makefile
> @@ -3,3 +3,5 @@ obj-y					+= core.o probe.o
>   obj-y					+= amd/
>   obj-$(CONFIG_X86_LOCAL_APIC)            += msr.o
>   obj-$(CONFIG_CPU_SUP_INTEL)		+= intel/
> +obj-$(CONFIG_CPU_SUP_CENTAUR)		+= zhaoxin/
> +obj-$(CONFIG_CPU_SUP_ZHAOXIN)		+= zhaoxin/
> --- a/arch/x86/events/core.c
> +++ b/arch/x86/events/core.c
> @@ -1839,6 +1839,10 @@ static int __init init_hw_perf_events(vo
>   		err = amd_pmu_init();
>   		x86_pmu.name = "HYGON";
>   		break;
> +	case X86_VENDOR_ZHAOXIN:
> +	case X86_VENDOR_CENTAUR:
> +		err = zhaoxin_pmu_init();
> +		break;
>   	default:
>   		err = -ENOTSUPP;
>   	}
> --- a/arch/x86/events/perf_event.h
> +++ b/arch/x86/events/perf_event.h
> @@ -618,6 +618,7 @@ struct x86_pmu {
>   
>   	/* PMI handler bits */
>   	unsigned int	late_ack		:1,
> +			enabled_ack		:1,
>   			counter_freezing	:1;
>   	/*
>   	 * sysfs attrs
> @@ -1133,3 +1134,12 @@ static inline int is_ht_workaround_enabl
>   	return 0;
>   }
>   #endif /* CONFIG_CPU_SUP_INTEL */
> +
> +#if ((defined CONFIG_CPU_SUP_CENTAUR) || (defined CONFIG_CPU_SUP_ZHAOXIN))
> +int zhaoxin_pmu_init(void);
> +#else
> +static inline int zhaoxin_pmu_init(void)
> +{
> +	return 0;
> +}
> +#endif /*CONFIG_CPU_SUP_CENTAUR or CONFIG_CPU_SUP_ZHAOXIN*/
> --- /dev/null
> +++ b/arch/x86/events/zhaoxin/Makefile
> @@ -0,0 +1,2 @@
> +# SPDX-License-Identifier: GPL-2.0
> +obj-y	+= core.o
> --- /dev/null
> +++ b/arch/x86/events/zhaoxin/core.c
> @@ -0,0 +1,613 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Zhoaxin PMU; like Intel Architectural PerfMon-v2
> + */
> +
> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> +
> +#include <linux/stddef.h>
> +#include <linux/types.h>
> +#include <linux/init.h>
> +#include <linux/slab.h>
> +#include <linux/export.h>
> +#include <linux/nmi.h>
> +
> +#include <asm/cpufeature.h>
> +#include <asm/hardirq.h>
> +#include <asm/apic.h>
> +
> +#include "../perf_event.h"
> +
> +/*
> + * Zhaoxin PerfMon, used on zxc and later.
> + */
> +static u64 zx_pmon_event_map[PERF_COUNT_HW_MAX] __read_mostly = {
> +
> +	[PERF_COUNT_HW_CPU_CYCLES]        = 0x0082,
> +	[PERF_COUNT_HW_INSTRUCTIONS]      = 0x00c0,
> +	[PERF_COUNT_HW_CACHE_REFERENCES]  = 0x0515,
> +	[PERF_COUNT_HW_CACHE_MISSES]      = 0x051a,
> +	[PERF_COUNT_HW_BUS_CYCLES]        = 0x0083,
> +};
> +
> +static struct event_constraint zxc_event_constraints[] __read_mostly = {
> +
> +	FIXED_EVENT_CONSTRAINT(0x0082, 1), /* unhalted core clock cycles */
> +	EVENT_CONSTRAINT_END
> +};
> +
> +static struct event_constraint zxd_event_constraints[] __read_mostly = {
> +
> +	FIXED_EVENT_CONSTRAINT(0x00c0, 0), /* retired instructions */
> +	FIXED_EVENT_CONSTRAINT(0x0082, 1), /* unhalted core clock cycles */
> +	FIXED_EVENT_CONSTRAINT(0x0083, 2), /* unhalted bus clock cycles */
> +	EVENT_CONSTRAINT_END
> +};
> +
> +static __initconst const u64 zxd_hw_cache_event_ids
> +				[PERF_COUNT_HW_CACHE_MAX]
> +				[PERF_COUNT_HW_CACHE_OP_MAX]
> +				[PERF_COUNT_HW_CACHE_RESULT_MAX] = {
> +[C(L1D)] = {
> +	[C(OP_READ)] = {
> +		[C(RESULT_ACCESS)] = 0x0042,
> +		[C(RESULT_MISS)] = 0x0538,
> +	},
> +	[C(OP_WRITE)] = {
> +		[C(RESULT_ACCESS)] = 0x0043,
> +		[C(RESULT_MISS)] = 0x0562,
> +	},
> +	[C(OP_PREFETCH)] = {
> +		[C(RESULT_ACCESS)] = -1,
> +		[C(RESULT_MISS)] = -1,
> +	},
> +},
> +[C(L1I)] = {
> +	[C(OP_READ)] = {
> +		[C(RESULT_ACCESS)] = 0x0300,
> +		[C(RESULT_MISS)] = 0x0301,
> +	},
> +	[C(OP_WRITE)] = {
> +		[C(RESULT_ACCESS)] = -1,
> +		[C(RESULT_MISS)] = -1,
> +	},
> +	[C(OP_PREFETCH)] = {
> +		[C(RESULT_ACCESS)] = 0x030a,
> +		[C(RESULT_MISS)] = 0x030b,
> +	},
> +},
> +[C(LL)] = {
> +	[C(OP_READ)] = {
> +		[C(RESULT_ACCESS)] = -1,
> +		[C(RESULT_MISS)] = -1,
> +	},
> +	[C(OP_WRITE)] = {
> +		[C(RESULT_ACCESS)] = -1,
> +		[C(RESULT_MISS)] = -1,
> +	},
> +	[C(OP_PREFETCH)] = {
> +		[C(RESULT_ACCESS)] = -1,
> +		[C(RESULT_MISS)] = -1,
> +	},
> +},
> +[C(DTLB)] = {
> +	[C(OP_READ)] = {
> +		[C(RESULT_ACCESS)] = 0x0042,
> +		[C(RESULT_MISS)] = 0x052c,
> +	},
> +	[C(OP_WRITE)] = {
> +		[C(RESULT_ACCESS)] = 0x0043,
> +		[C(RESULT_MISS)] = 0x0530,
> +	},
> +	[C(OP_PREFETCH)] = {
> +		[C(RESULT_ACCESS)] = 0x0564,
> +		[C(RESULT_MISS)] = 0x0565,
> +	},
> +},
> +[C(ITLB)] = {
> +	[C(OP_READ)] = {
> +		[C(RESULT_ACCESS)] = 0x00c0,
> +		[C(RESULT_MISS)] = 0x0534,
> +	},
> +	[C(OP_WRITE)] = {
> +		[C(RESULT_ACCESS)] = -1,
> +		[C(RESULT_MISS)] = -1,
> +	},
> +	[C(OP_PREFETCH)] = {
> +		[C(RESULT_ACCESS)] = -1,
> +		[C(RESULT_MISS)] = -1,
> +	},
> +},
> +[C(BPU)] = {
> +	[C(OP_READ)] = {
> +		[C(RESULT_ACCESS)] = 0x0700,
> +		[C(RESULT_MISS)] = 0x0709,
> +	},
> +	[C(OP_WRITE)] = {
> +		[C(RESULT_ACCESS)] = -1,
> +		[C(RESULT_MISS)] = -1,
> +	},
> +	[C(OP_PREFETCH)] = {
> +		[C(RESULT_ACCESS)] = -1,
> +		[C(RESULT_MISS)] = -1,
> +	},
> +},
> +[C(NODE)] = {
> +	[C(OP_READ)] = {
> +		[C(RESULT_ACCESS)] = -1,
> +		[C(RESULT_MISS)] = -1,
> +	},
> +	[C(OP_WRITE)] = {
> +		[C(RESULT_ACCESS)] = -1,
> +		[C(RESULT_MISS)] = -1,
> +	},
> +	[C(OP_PREFETCH)] = {
> +		[C(RESULT_ACCESS)] = -1,
> +		[C(RESULT_MISS)] = -1,
> +	},
> +},
> +};
> +
> +static __initconst const u64 zxe_hw_cache_event_ids
> +				[PERF_COUNT_HW_CACHE_MAX]
> +				[PERF_COUNT_HW_CACHE_OP_MAX]
> +				[PERF_COUNT_HW_CACHE_RESULT_MAX] = {
> +[C(L1D)] = {
> +	[C(OP_READ)] = {
> +		[C(RESULT_ACCESS)] = 0x0568,
> +		[C(RESULT_MISS)] = 0x054b,
> +	},
> +	[C(OP_WRITE)] = {
> +		[C(RESULT_ACCESS)] = 0x0669,
> +		[C(RESULT_MISS)] = 0x0562,
> +	},
> +	[C(OP_PREFETCH)] = {
> +		[C(RESULT_ACCESS)] = -1,
> +		[C(RESULT_MISS)] = -1,
> +	},
> +},
> +[C(L1I)] = {
> +	[C(OP_READ)] = {
> +		[C(RESULT_ACCESS)] = 0x0300,
> +		[C(RESULT_MISS)] = 0x0301,
> +	},
> +	[C(OP_WRITE)] = {
> +		[C(RESULT_ACCESS)] = -1,
> +		[C(RESULT_MISS)] = -1,
> +	},
> +	[C(OP_PREFETCH)] = {
> +		[C(RESULT_ACCESS)] = 0x030a,
> +		[C(RESULT_MISS)] = 0x030b,
> +	},
> +},
> +[C(LL)] = {
> +	[C(OP_READ)] = {
> +		[C(RESULT_ACCESS)] = 0x0,
> +		[C(RESULT_MISS)] = 0x0,
> +	},
> +	[C(OP_WRITE)] = {
> +		[C(RESULT_ACCESS)] = 0x0,
> +		[C(RESULT_MISS)] = 0x0,
> +	},
> +	[C(OP_PREFETCH)] = {
> +		[C(RESULT_ACCESS)] = 0x0,
> +		[C(RESULT_MISS)] = 0x0,
> +	},
> +},
> +[C(DTLB)] = {
> +	[C(OP_READ)] = {
> +		[C(RESULT_ACCESS)] = 0x0568,
> +		[C(RESULT_MISS)] = 0x052c,
> +	},
> +	[C(OP_WRITE)] = {
> +		[C(RESULT_ACCESS)] = 0x0669,
> +		[C(RESULT_MISS)] = 0x0530,
> +	},
> +	[C(OP_PREFETCH)] = {
> +		[C(RESULT_ACCESS)] = 0x0564,
> +		[C(RESULT_MISS)] = 0x0565,
> +	},
> +},
> +[C(ITLB)] = {
> +	[C(OP_READ)] = {
> +		[C(RESULT_ACCESS)] = 0x00c0,
> +		[C(RESULT_MISS)] = 0x0534,
> +	},
> +	[C(OP_WRITE)] = {
> +		[C(RESULT_ACCESS)] = -1,
> +		[C(RESULT_MISS)] = -1,
> +	},
> +	[C(OP_PREFETCH)] = {
> +		[C(RESULT_ACCESS)] = -1,
> +		[C(RESULT_MISS)] = -1,
> +	},
> +},
> +[C(BPU)] = {
> +	[C(OP_READ)] = {
> +		[C(RESULT_ACCESS)] = 0x0028,
> +		[C(RESULT_MISS)] = 0x0029,
> +	},
> +	[C(OP_WRITE)] = {
> +		[C(RESULT_ACCESS)] = -1,
> +		[C(RESULT_MISS)] = -1,
> +	},
> +	[C(OP_PREFETCH)] = {
> +		[C(RESULT_ACCESS)] = -1,
> +		[C(RESULT_MISS)] = -1,
> +	},
> +},
> +[C(NODE)] = {
> +	[C(OP_READ)] = {
> +		[C(RESULT_ACCESS)] = -1,
> +		[C(RESULT_MISS)] = -1,
> +	},
> +	[C(OP_WRITE)] = {
> +		[C(RESULT_ACCESS)] = -1,
> +		[C(RESULT_MISS)] = -1,
> +	},
> +	[C(OP_PREFETCH)] = {
> +		[C(RESULT_ACCESS)] = -1,
> +		[C(RESULT_MISS)] = -1,
> +	},
> +},
> +};
> +
> +static void zhaoxin_pmu_disable_all(void)
> +{
> +	wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, 0);
> +}
> +
> +static void zhaoxin_pmu_enable_all(int added)
> +{
> +	wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, x86_pmu.intel_ctrl);
> +}
> +
> +static inline u64 zhaoxin_pmu_get_status(void)
> +{
> +	u64 status;
> +
> +	rdmsrl(MSR_CORE_PERF_GLOBAL_STATUS, status);
> +
> +	return status;
> +}
> +
> +static inline void zhaoxin_pmu_ack_status(u64 ack)
> +{
> +	wrmsrl(MSR_CORE_PERF_GLOBAL_OVF_CTRL, ack);
> +}
> +
> +static inline void zxc_pmu_ack_status(u64 ack)
> +{
> +	/*
> +	 * ZXC needs global control enabled in order to clear status bits.
> +	 */
> +	zhaoxin_pmu_enable_all(0);
> +	zhaoxin_pmu_ack_status(ack);
> +	zhaoxin_pmu_disable_all();
> +}
> +
> +static void zhaoxin_pmu_disable_fixed(struct hw_perf_event *hwc)
> +{
> +	int idx = hwc->idx - INTEL_PMC_IDX_FIXED;
> +	u64 ctrl_val, mask;
> +
> +	mask = 0xfULL << (idx * 4);
> +
> +	rdmsrl(hwc->config_base, ctrl_val);
> +	ctrl_val &= ~mask;
> +	wrmsrl(hwc->config_base, ctrl_val);
> +}
> +
> +static void zhaoxin_pmu_disable_event(struct perf_event *event)
> +{
> +	struct hw_perf_event *hwc = &event->hw;
> +
> +	if (unlikely(hwc->config_base == MSR_ARCH_PERFMON_FIXED_CTR_CTRL)) {
> +		zhaoxin_pmu_disable_fixed(hwc);
> +		return;
> +	}
> +
> +	x86_pmu_disable_event(event);
> +}
> +
> +static void zhaoxin_pmu_enable_fixed(struct hw_perf_event *hwc)
> +{
> +	int idx = hwc->idx - INTEL_PMC_IDX_FIXED;
> +	u64 ctrl_val, bits, mask;
> +
> +	/*
> +	 * Enable IRQ generation (0x8),
> +	 * and enable ring-3 counting (0x2) and ring-0 counting (0x1)
> +	 * if requested:
> +	 */
> +	bits = 0x8ULL;
> +	if (hwc->config & ARCH_PERFMON_EVENTSEL_USR)
> +		bits |= 0x2;
> +	if (hwc->config & ARCH_PERFMON_EVENTSEL_OS)
> +		bits |= 0x1;
> +
> +	bits <<= (idx * 4);
> +	mask = 0xfULL << (idx * 4);
> +
> +	rdmsrl(hwc->config_base, ctrl_val);
> +	ctrl_val &= ~mask;
> +	ctrl_val |= bits;
> +	wrmsrl(hwc->config_base, ctrl_val);
> +}
> +
> +static void zhaoxin_pmu_enable_event(struct perf_event *event)
> +{
> +	struct hw_perf_event *hwc = &event->hw;
> +
> +	if (unlikely(hwc->config_base == MSR_ARCH_PERFMON_FIXED_CTR_CTRL)) {
> +		zhaoxin_pmu_enable_fixed(hwc);
> +		return;
> +	}
> +
> +	__x86_pmu_enable_event(hwc, ARCH_PERFMON_EVENTSEL_ENABLE);
> +}
> +
> +/*
> + * This handler is triggered by the local APIC, so the APIC IRQ handling
> + * rules apply:
> + */
> +static int zhaoxin_pmu_handle_irq(struct pt_regs *regs)
> +{
> +	struct perf_sample_data data;
> +	struct cpu_hw_events *cpuc;
> +	int handled = 0;
> +	u64 status;
> +	int bit;
> +
> +	cpuc = this_cpu_ptr(&cpu_hw_events);
> +	apic_write(APIC_LVTPC, APIC_DM_NMI);
> +	zhaoxin_pmu_disable_all();
> +	status = zhaoxin_pmu_get_status();
> +	if (!status)
> +		goto done;
> +
> +again:
> +	if (x86_pmu.enabled_ack)
> +		zxc_pmu_ack_status(status);
> +	else
> +		zhaoxin_pmu_ack_status(status);
> +
> +	inc_irq_stat(apic_perf_irqs);
> +
> +	/*
> +	 * CondChgd bit 63 doesn't mean any overflow status. Ignore
> +	 * and clear the bit.
> +	 */
> +	if (__test_and_clear_bit(63, (unsigned long *)&status)) {
> +		if (!status)
> +			goto done;
> +	}
> +
> +	for_each_set_bit(bit, (unsigned long *)&status, X86_PMC_IDX_MAX) {
> +		struct perf_event *event = cpuc->events[bit];
> +
> +		handled++;
> +
> +		if (!test_bit(bit, cpuc->active_mask))
> +			continue;
> +
> +		x86_perf_event_update(event);
> +		perf_sample_data_init(&data, 0, event->hw.last_period);
> +
> +		if (!x86_perf_event_set_period(event))
> +			continue;
> +
> +		if (perf_event_overflow(event, &data, regs))
> +			x86_pmu_stop(event, 0);
> +	}
> +
> +	/*
> +	 * Repeat if there is more work to be done:
> +	 */
> +	status = zhaoxin_pmu_get_status();
> +	if (status)
> +		goto again;
> +
> +done:
> +	zhaoxin_pmu_enable_all(0);
> +	return handled;
> +}
> +
> +static u64 zhaoxin_pmu_event_map(int hw_event)
> +{
> +	return zx_pmon_event_map[hw_event];
> +}
> +
> +static struct event_constraint *
> +zhaoxin_get_event_constraints(struct cpu_hw_events *cpuc, int idx,
> +			struct perf_event *event)
> +{
> +	struct event_constraint *c;
> +
> +	if (x86_pmu.event_constraints) {
> +		for_each_event_constraint(c, x86_pmu.event_constraints) {
> +			if ((event->hw.config & c->cmask) == c->code)
> +				return c;
> +		}
> +	}
> +
> +	return &unconstrained;
> +}
> +
> +PMU_FORMAT_ATTR(event,	"config:0-7");
> +PMU_FORMAT_ATTR(umask,	"config:8-15");
> +PMU_FORMAT_ATTR(edge,	"config:18");
> +PMU_FORMAT_ATTR(inv,	"config:23");
> +PMU_FORMAT_ATTR(cmask,	"config:24-31");
> +
> +static struct attribute *zx_arch_formats_attr[] = {
> +	&format_attr_event.attr,
> +	&format_attr_umask.attr,
> +	&format_attr_edge.attr,
> +	&format_attr_inv.attr,
> +	&format_attr_cmask.attr,
> +	NULL,
> +};
> +
> +static ssize_t zhaoxin_event_sysfs_show(char *page, u64 config)
> +{
> +	u64 event = (config & ARCH_PERFMON_EVENTSEL_EVENT);
> +
> +	return x86_event_sysfs_show(page, config, event);
> +}
> +
> +static const struct x86_pmu zhaoxin_pmu __initconst = {
> +	.name			= "zhaoxin",
> +	.handle_irq		= zhaoxin_pmu_handle_irq,
> +	.disable_all		= zhaoxin_pmu_disable_all,
> +	.enable_all		= zhaoxin_pmu_enable_all,
> +	.enable			= zhaoxin_pmu_enable_event,
> +	.disable		= zhaoxin_pmu_disable_event,
> +	.hw_config		= x86_pmu_hw_config,
> +	.schedule_events	= x86_schedule_events,
> +	.eventsel		= MSR_ARCH_PERFMON_EVENTSEL0,
> +	.perfctr		= MSR_ARCH_PERFMON_PERFCTR0,
> +	.event_map		= zhaoxin_pmu_event_map,
> +	.max_events		= ARRAY_SIZE(zx_pmon_event_map),
> +	.apic			= 1,
> +	/*
> +	 * For zxd/zxe, read/write operation for PMCx MSR is 48 bits.
> +	 */
> +	.max_period		= (1ULL << 47) - 1,
> +	.get_event_constraints	= zhaoxin_get_event_constraints,
> +
> +	.format_attrs		= zx_arch_formats_attr,
> +	.events_sysfs_show	= zhaoxin_event_sysfs_show,
> +};
> +
> +static const struct { int id; char *name; } zx_arch_events_map[] __initconst = {
> +	{ PERF_COUNT_HW_CPU_CYCLES, "cpu cycles" },
> +	{ PERF_COUNT_HW_INSTRUCTIONS, "instructions" },
> +	{ PERF_COUNT_HW_BUS_CYCLES, "bus cycles" },
> +	{ PERF_COUNT_HW_CACHE_REFERENCES, "cache references" },
> +	{ PERF_COUNT_HW_CACHE_MISSES, "cache misses" },
> +	{ PERF_COUNT_HW_BRANCH_INSTRUCTIONS, "branch instructions" },
> +	{ PERF_COUNT_HW_BRANCH_MISSES, "branch misses" },
> +};
> +
> +static __init void zhaoxin_arch_events_quirk(void)
> +{
> +	int bit;
> +
> +	/* disable event that reported as not presend by cpuid */
> +	for_each_set_bit(bit, x86_pmu.events_mask, ARRAY_SIZE(zx_arch_events_map)) {
> +		zx_pmon_event_map[zx_arch_events_map[bit].id] = 0;
> +		pr_warn("CPUID marked event: \'%s\' unavailable\n",
> +			zx_arch_events_map[bit].name);
> +	}
> +}
> +
> +__init int zhaoxin_pmu_init(void)
> +{
> +	union cpuid10_edx edx;
> +	union cpuid10_eax eax;
> +	union cpuid10_ebx ebx;
> +	struct event_constraint *c;
> +	unsigned int unused;
> +	int version;
> +
> +	pr_info("Welcome to zhaoxin pmu!\n");
> +
> +	/*
> +	 * Check whether the Architectural PerfMon supports
> +	 * hw_event or not.
> +	 */
> +	cpuid(10, &eax.full, &ebx.full, &unused, &edx.full);
> +
> +	if (eax.split.mask_length < ARCH_PERFMON_EVENTS_COUNT - 1)
> +		return -ENODEV;
> +
> +	version = eax.split.version_id;
> +	if (version != 2)
> +		return -ENODEV;
> +
> +	x86_pmu = zhaoxin_pmu;
> +	pr_info("Version check pass!\n");
> +
> +	x86_pmu.version			= version;
> +	x86_pmu.num_counters		= eax.split.num_counters;
> +	x86_pmu.cntval_bits		= eax.split.bit_width;
> +	x86_pmu.cntval_mask		= (1ULL << eax.split.bit_width) - 1;
> +	x86_pmu.events_maskl		= ebx.full;
> +	x86_pmu.events_mask_len		= eax.split.mask_length;
> +
> +	x86_pmu.num_counters_fixed = edx.split.num_counters_fixed;
> +	x86_add_quirk(zhaoxin_arch_events_quirk);
> +
> +	switch (boot_cpu_data.x86) {
> +	case 0x06:
> +		if (boot_cpu_data.x86_model == 0x0f || boot_cpu_data.x86_model == 0x19) {
> +
> +			x86_pmu.max_period = x86_pmu.cntval_mask >> 1;
> +
> +			/* Clearing status works only if the global control is enable on zxc. */
> +			x86_pmu.enabled_ack = 1;
> +
> +			x86_pmu.event_constraints = zxc_event_constraints;
> +			zx_pmon_event_map[PERF_COUNT_HW_INSTRUCTIONS] = 0;
> +			zx_pmon_event_map[PERF_COUNT_HW_CACHE_REFERENCES] = 0;
> +			zx_pmon_event_map[PERF_COUNT_HW_CACHE_MISSES] = 0;
> +			zx_pmon_event_map[PERF_COUNT_HW_BUS_CYCLES] = 0;
> +
> +			pr_cont("ZXC events, ");
> +			break;
> +		}
> +		return -ENODEV;
> +
> +	case 0x07:
> +		zx_pmon_event_map[PERF_COUNT_HW_STALLED_CYCLES_FRONTEND] =
> +			X86_CONFIG(.event = 0x01, .umask = 0x01, .inv = 0x01, .cmask = 0x01);
> +
> +		zx_pmon_event_map[PERF_COUNT_HW_STALLED_CYCLES_BACKEND] =
> +			X86_CONFIG(.event = 0x0f, .umask = 0x04, .inv = 0, .cmask = 0);
> +
> +		switch (boot_cpu_data.x86_model) {
> +		case 0x1b:
> +			memcpy(hw_cache_event_ids, zxd_hw_cache_event_ids,
> +			       sizeof(hw_cache_event_ids));
> +
> +			x86_pmu.event_constraints = zxd_event_constraints;
> +
> +			zx_pmon_event_map[PERF_COUNT_HW_BRANCH_INSTRUCTIONS] = 0x0700;
> +			zx_pmon_event_map[PERF_COUNT_HW_BRANCH_MISSES] = 0x0709;
> +
> +			pr_cont("ZXD events, ");
> +			break;
> +		case 0x3b:
> +			memcpy(hw_cache_event_ids, zxe_hw_cache_event_ids,
> +			       sizeof(hw_cache_event_ids));
> +
> +			x86_pmu.event_constraints = zxd_event_constraints;
> +
> +			zx_pmon_event_map[PERF_COUNT_HW_BRANCH_INSTRUCTIONS] = 0x0028;
> +			zx_pmon_event_map[PERF_COUNT_HW_BRANCH_MISSES] = 0x0029;
> +
> +			pr_cont("ZXE events, ");
> +			break;
> +		default:
> +			return -ENODEV;
> +		}
> +		break;
> +
> +	default:
> +		return -ENODEV;
> +	}
> +
> +	x86_pmu.intel_ctrl = (1 << (x86_pmu.num_counters)) - 1;
> +	x86_pmu.intel_ctrl |= ((1LL << x86_pmu.num_counters_fixed)-1) << INTEL_PMC_IDX_FIXED;
> +
> +	if (x86_pmu.event_constraints) {
> +		for_each_event_constraint(c, x86_pmu.event_constraints) {
> +			c->idxmsk64 |= (1ULL << x86_pmu.num_counters) - 1;
> +			c->weight += x86_pmu.num_counters;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> --- a/arch/x86/kernel/cpu/perfctr-watchdog.c
> +++ b/arch/x86/kernel/cpu/perfctr-watchdog.c
> @@ -63,6 +63,10 @@ static inline unsigned int nmi_perfctr_m
>   		case 15:
>   			return msr - MSR_P4_BPU_PERFCTR0;
>   		}
> +		fallthrough;
> +	case X86_VENDOR_ZHAOXIN:
> +	case X86_VENDOR_CENTAUR:
> +		return msr - MSR_ARCH_PERFMON_PERFCTR0;
>   	}
>   	return 0;
>   }
> @@ -92,6 +96,10 @@ static inline unsigned int nmi_evntsel_m
>   		case 15:
>   			return msr - MSR_P4_BSU_ESCR0;
>   		}
> +		fallthrough;
> +	case X86_VENDOR_ZHAOXIN:
> +	case X86_VENDOR_CENTAUR:
> +		return msr - MSR_ARCH_PERFMON_EVENTSEL0;
>   	}
>   	return 0;
>   
> .
> 
Dear Peter,

I'm so sorry that my coding errors have caused a misunderstanding. The 
above 'fallthrough' should be 'break' in perfctr-watchdog.c, I changed 
it when I resend the patch. But it looks like that there is no need to 
resend the patch, becasue I got an email on May 2nd from tip-bot2, which 
tells me this commit has been merged into the perf/core branch of tip.

Is there any way to change 'fallthrough' to 'break'? I guess I have no 
permission to change the perf/core branch of tip, if you can, please help.

Thank you very much for your patience and kind help.

Cody.