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From: Peter Zijlstra <peterz@infradead.org>
To: kan.liang@linux.intel.com
Cc: mingo@redhat.com, acme@kernel.org, tglx@linutronix.de,
	bp@alien8.de, x86@kernel.org, linux-kernel@vger.kernel.org,
	mark.rutland@arm.com, alexander.shishkin@linux.intel.com,
	jolsa@redhat.com, namhyung@kernel.org, dave.hansen@intel.com,
	yu-cheng.yu@intel.com, bigeasy@linutronix.de, gorcunov@gmail.com,
	hpa@zytor.com, alexey.budankov@linux.intel.com,
	eranian@google.com, ak@linux.intel.com, like.xu@linux.intel.com,
	yao.jin@linux.intel.com, wei.w.wang@intel.com
Subject: Re: [PATCH V2 14/23] perf/x86/intel/lbr: Support Architectural LBR
Date: Tue, 30 Jun 2020 17:49:54 +0200	[thread overview]
Message-ID: <20200630154954.GU4781@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <1593195620-116988-15-git-send-email-kan.liang@linux.intel.com>

On Fri, Jun 26, 2020 at 11:20:11AM -0700, kan.liang@linux.intel.com wrote:

> +	if (boot_cpu_has(X86_FEATURE_ARCH_LBR))
> +		intel_pmu_arch_lbr_init();

> +static inline bool is_lbr_call_stack_bit_set(u64 config)
> +{
> +	if (x86_pmu.arch_lbr)
> +		return !!(config & ARCH_LBR_CALL_STACK);
> +
> +	return !!(config & LBR_CALL_STACK);
> +}

> +	if (!x86_pmu.arch_lbr && !pmi && cpuc->lbr_sel)
>  		wrmsrl(MSR_LBR_SELECT, lbr_select);

> +	if (!x86_pmu.arch_lbr)
> +		debugctl |= DEBUGCTLMSR_LBR;

> +	if (x86_pmu.arch_lbr)
> +		wrmsrl(MSR_ARCH_LBR_CTL, lbr_select | ARCH_LBR_CTL_LBREN);
>  }

etc...

> +void __init intel_pmu_arch_lbr_init(void)
> +{
> +	unsigned int unused_edx;
> +	u64 lbr_nr;
> +
> +	/* Arch LBR Capabilities */
> +	cpuid(28, &x86_pmu.lbr_eax.full, &x86_pmu.lbr_ebx.full,
> +		  &x86_pmu.lbr_ecx.full, &unused_edx);
> +
> +	lbr_nr = x86_pmu_get_max_arch_lbr_nr();
> +	if (!lbr_nr)
> +		return;
> +
> +	/* Apply the max depth of Arch LBR */
> +	if (wrmsrl_safe(MSR_ARCH_LBR_DEPTH, lbr_nr))
> +		return;
> +
> +	x86_pmu.lbr_nr = lbr_nr;
> +	x86_get_pmu()->task_ctx_size = sizeof(struct x86_perf_task_context_arch_lbr) +
> +				       lbr_nr * sizeof(struct lbr_entry);
> +
> +	x86_pmu.lbr_from = MSR_ARCH_LBR_FROM_0;
> +	x86_pmu.lbr_to = MSR_ARCH_LBR_TO_0;
> +	x86_pmu.lbr_info = MSR_ARCH_LBR_INFO_0;
> +
> +	/* LBR callstack requires both CPL and Branch Filtering support */
> +	if (!x86_pmu.lbr_ebx.split.lbr_cpl ||
> +	    !x86_pmu.lbr_ebx.split.lbr_filter ||
> +	    !x86_pmu.lbr_ebx.split.lbr_call_stack)
> +		arch_lbr_ctl_map[PERF_SAMPLE_BRANCH_CALL_STACK_SHIFT] = LBR_NOT_SUPP;
> +
> +	if (!x86_pmu.lbr_ebx.split.lbr_cpl) {
> +		arch_lbr_ctl_map[PERF_SAMPLE_BRANCH_USER_SHIFT] = LBR_NOT_SUPP;
> +		arch_lbr_ctl_map[PERF_SAMPLE_BRANCH_KERNEL_SHIFT] = LBR_NOT_SUPP;
> +	} else if (!x86_pmu.lbr_ebx.split.lbr_filter) {
> +		arch_lbr_ctl_map[PERF_SAMPLE_BRANCH_ANY_SHIFT] = LBR_NOT_SUPP;
> +		arch_lbr_ctl_map[PERF_SAMPLE_BRANCH_ANY_RETURN_SHIFT] = LBR_NOT_SUPP;
> +		arch_lbr_ctl_map[PERF_SAMPLE_BRANCH_ANY_CALL_SHIFT] = LBR_NOT_SUPP;
> +		arch_lbr_ctl_map[PERF_SAMPLE_BRANCH_IND_CALL_SHIFT] = LBR_NOT_SUPP;
> +		arch_lbr_ctl_map[PERF_SAMPLE_BRANCH_COND_SHIFT] = LBR_NOT_SUPP;
> +		arch_lbr_ctl_map[PERF_SAMPLE_BRANCH_IND_JUMP_SHIFT] = LBR_NOT_SUPP;
> +		arch_lbr_ctl_map[PERF_SAMPLE_BRANCH_CALL_SHIFT] = LBR_NOT_SUPP;
> +	}
> +
> +	x86_pmu.lbr_ctl_mask = ARCH_LBR_CTL_MASK;
> +	x86_pmu.lbr_ctl_map  = arch_lbr_ctl_map;
> +
> +	if (!x86_pmu.lbr_ebx.split.lbr_cpl && !x86_pmu.lbr_ebx.split.lbr_filter)
> +		x86_pmu.lbr_ctl_map = NULL;
> +
> +	x86_pmu.lbr_reset = intel_pmu_arch_lbr_reset;
> +	x86_pmu.lbr_read = intel_pmu_arch_lbr_read;
> +	x86_pmu.lbr_save = intel_pmu_arch_lbr_save;
> +	x86_pmu.lbr_restore = intel_pmu_arch_lbr_restore;
> +
> +	x86_pmu.arch_lbr = true;
> +	pr_cont("Architectural LBR, ");
> +}

How about we make this here clear FEATURE_ARCH_LBR if it fails and then
do away with x86_pmu.arch_lbr and use
static_cpu_has(X86_FEATURE_ARCH_LBR) a lot more?

  reply	other threads:[~2020-06-30 15:50 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-26 18:19 [PATCH V2 00/23] Support Architectural LBR kan.liang
2020-06-26 18:19 ` [PATCH V2 01/23] x86/cpufeatures: Add Architectural LBRs feature bit kan.liang
2020-06-29 18:35   ` Liang, Kan
2020-06-26 18:19 ` [PATCH V2 02/23] perf/x86/intel/lbr: Add a function pointer for LBR reset kan.liang
2020-06-26 18:20 ` [PATCH V2 03/23] perf/x86/intel/lbr: Add a function pointer for LBR read kan.liang
2020-06-26 18:20 ` [PATCH V2 04/23] perf/x86/intel/lbr: Add the function pointers for LBR save and restore kan.liang
2020-06-26 18:20 ` [PATCH V2 05/23] perf/x86/intel/lbr: Factor out a new struct for generic optimization kan.liang
2020-06-26 18:20 ` [PATCH V2 06/23] perf/x86/intel/lbr: Use dynamic data structure for task_ctx kan.liang
2020-06-26 18:20 ` [PATCH V2 07/23] x86/msr-index: Add bunch of MSRs for Arch LBR kan.liang
2020-06-26 18:20 ` [PATCH V2 08/23] perf/x86: Expose CPUID enumeration bits for arch LBR kan.liang
2020-06-30 15:01   ` Peter Zijlstra
2020-06-30 15:36     ` Liang, Kan
2020-06-30 16:39       ` Peter Zijlstra
2020-06-26 18:20 ` [PATCH V2 09/23] perf/x86/intel: Check Arch LBR MSRs kan.liang
2020-06-30 14:57   ` Peter Zijlstra
2020-06-30 15:29     ` Liang, Kan
2020-06-26 18:20 ` [PATCH V2 10/23] perf/x86/intel/lbr: Support LBR_CTL kan.liang
2020-06-26 18:20 ` [PATCH V2 11/23] perf/x86/intel/lbr: Unify the stored format of LBR information kan.liang
2020-06-26 18:20 ` [PATCH V2 12/23] perf/x86/intel/lbr: Factor out rdlbr_all() and wrlbr_all() kan.liang
2020-06-26 18:20 ` [PATCH V2 13/23] perf/x86/intel/lbr: Factor out intel_pmu_store_lbr kan.liang
2020-06-30 15:43   ` Peter Zijlstra
2020-06-26 18:20 ` [PATCH V2 14/23] perf/x86/intel/lbr: Support Architectural LBR kan.liang
2020-06-30 15:49   ` Peter Zijlstra [this message]
2020-06-30 16:17     ` Liang, Kan
2020-06-30 16:42       ` Peter Zijlstra
2020-06-26 18:20 ` [PATCH V2 15/23] perf/core: Factor out functions to allocate/free the task_ctx_data kan.liang
2020-06-26 18:20 ` [PATCH V2 16/23] perf/core: Use kmem_cache to allocate the PMU specific data kan.liang
2020-06-26 18:20 ` [PATCH V2 17/23] perf/x86/intel/lbr: Create kmem_cache for the LBR context data kan.liang
2020-06-26 18:20 ` [PATCH V2 18/23] perf/x86: Remove task_ctx_size kan.liang
2020-06-26 18:20 ` [PATCH V2 19/23] x86/fpu: Use proper mask to replace full instruction mask kan.liang
2020-06-26 18:20 ` [PATCH V2 20/23] x86/fpu/xstate: Support dynamic supervisor feature for LBR kan.liang
2020-06-26 18:20 ` [PATCH V2 21/23] x86/fpu/xstate: Add helpers for LBR dynamic supervisor feature kan.liang
2020-06-26 18:20 ` [PATCH V2 22/23] perf/x86/intel/lbr: Support XSAVES/XRSTORS for LBR context switch kan.liang
2020-06-26 18:20 ` [PATCH V2 23/23] perf/x86/intel/lbr: Support XSAVES for arch LBR read kan.liang

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