[PATCH v2] powerpc/kernel/sysfs: Add PMU_SYSFS config option to enable PMU SPRs sysfs file creation

[maddy]

On 11/13/19 9:40 PM, Kajol Jain wrote:
> Many of the performance moniroting unit (PMU) SPRs are
> exposed in the sysfs. "perf" API is the primary interface to program
> PMU and collect counter data in the system. So expose these
> PMU SPRs in the absence of CONFIG_PERF_EVENTS.
>
> Patch adds a new CONFIG option 'CONFIG_PMU_SYSFS'. The new config
> option used in kernel/sysfs.c for PMU SPRs sysfs file creation and
> this new option is enabled only if 'CONFIG_PERF_EVENTS' option is
> disabled.
>
> Tested this patch with enable/disable CONFIG_PERF_EVENTS option
> in powernv and pseries machines.
> Also did compilation testing for different architecture include:
> x86, mips, mips64, alpha, arm. And with book3s_32.config option.

Reviewed-By: Madhavan Srinivasan <maddy at linux.vnet.ibm.com>

>
> Signed-off-by: Kajol Jain <kjain at linux.ibm.com>
> ---
>   arch/powerpc/kernel/sysfs.c            | 21 +++++++++++++++++++++
>   arch/powerpc/platforms/Kconfig.cputype |  8 ++++++++
>   2 files changed, 29 insertions(+)
>
> ---
> Changelog:
> v1 -> v2
> - Added new config option 'PMU_SYSFS' for PMU SPR's creation
>    rather than using PERF_EVENTS config option directly and make
>    sure SPR's file creation only if 'CONFIG_PERF_EVENTS' disabled.
> ---
> diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c
> index 80a676da11cb..b7c01f1ef236 100644
> --- a/arch/powerpc/kernel/sysfs.c
> +++ b/arch/powerpc/kernel/sysfs.c
> @@ -457,16 +457,21 @@ static ssize_t __used \
>
>   #if defined(CONFIG_PPC64)
>   #define HAS_PPC_PMC_CLASSIC	1
> +#ifdef CONFIG_PMU_SYSFS
>   #define HAS_PPC_PMC_IBM		1
> +#endif
>   #define HAS_PPC_PMC_PA6T	1
>   #elif defined(CONFIG_PPC_BOOK3S_32)
>   #define HAS_PPC_PMC_CLASSIC	1
> +#ifdef CONFIG_PMU_SYSFS
>   #define HAS_PPC_PMC_IBM		1
>   #define HAS_PPC_PMC_G4		1
>   #endif
> +#endif
>
>
>   #ifdef HAS_PPC_PMC_CLASSIC
> +#ifdef CONFIG_PMU_SYSFS
>   SYSFS_PMCSETUP(mmcr0, SPRN_MMCR0);
>   SYSFS_PMCSETUP(mmcr1, SPRN_MMCR1);
>   SYSFS_PMCSETUP(pmc1, SPRN_PMC1);
> @@ -485,6 +490,10 @@ SYSFS_PMCSETUP(pmc7, SPRN_PMC7);
>   SYSFS_PMCSETUP(pmc8, SPRN_PMC8);
>
>   SYSFS_PMCSETUP(mmcra, SPRN_MMCRA);
> +#endif /* CONFIG_PPC64 */
> +#endif /* CONFIG_PMU_SYSFS */
> +
> +#ifdef CONFIG_PPC64
>   SYSFS_SPRSETUP(purr, SPRN_PURR);
>   SYSFS_SPRSETUP(spurr, SPRN_SPURR);
>   SYSFS_SPRSETUP(pir, SPRN_PIR);
> @@ -495,7 +504,9 @@ SYSFS_SPRSETUP(tscr, SPRN_TSCR);
>     enable write when needed with a separate function.
>     Lets be conservative and default to pseries.
>   */
> +#ifdef CONFIG_PMU_SYSFS
>   static DEVICE_ATTR(mmcra, 0600, show_mmcra, store_mmcra);
> +#endif /* CONFIG_PMU_SYSFS */
>   static DEVICE_ATTR(spurr, 0400, show_spurr, NULL);
>   static DEVICE_ATTR(purr, 0400, show_purr, store_purr);
>   static DEVICE_ATTR(pir, 0400, show_pir, NULL);
> @@ -606,12 +617,14 @@ static void sysfs_create_dscr_default(void)
>   #endif /* CONFIG_PPC64 */
>
>   #ifdef HAS_PPC_PMC_PA6T
> +#ifdef CONFIG_PMU_SYSFS
>   SYSFS_PMCSETUP(pa6t_pmc0, SPRN_PA6T_PMC0);
>   SYSFS_PMCSETUP(pa6t_pmc1, SPRN_PA6T_PMC1);
>   SYSFS_PMCSETUP(pa6t_pmc2, SPRN_PA6T_PMC2);
>   SYSFS_PMCSETUP(pa6t_pmc3, SPRN_PA6T_PMC3);
>   SYSFS_PMCSETUP(pa6t_pmc4, SPRN_PA6T_PMC4);
>   SYSFS_PMCSETUP(pa6t_pmc5, SPRN_PA6T_PMC5);
> +#endif /* CONFIG_PMU_SYSFS */
>   #ifdef CONFIG_DEBUG_MISC
>   SYSFS_SPRSETUP(hid0, SPRN_HID0);
>   SYSFS_SPRSETUP(hid1, SPRN_HID1);
> @@ -644,6 +657,7 @@ SYSFS_SPRSETUP(tsr3, SPRN_PA6T_TSR3);
>   #endif /* CONFIG_DEBUG_MISC */
>   #endif /* HAS_PPC_PMC_PA6T */
>
> +#ifdef CONFIG_PMU_SYSFS
>   #ifdef HAS_PPC_PMC_IBM
>   static struct device_attribute ibm_common_attrs[] = {
>   	__ATTR(mmcr0, 0600, show_mmcr0, store_mmcr0),
> @@ -671,9 +685,11 @@ static struct device_attribute classic_pmc_attrs[] = {
>   	__ATTR(pmc8, 0600, show_pmc8, store_pmc8),
>   #endif
>   };
> +#endif /* CONFIG_PMU_SYSFS */
>
>   #ifdef HAS_PPC_PMC_PA6T
>   static struct device_attribute pa6t_attrs[] = {
> +#ifdef CONFIG_PMU_SYSFS
>   	__ATTR(mmcr0, 0600, show_mmcr0, store_mmcr0),
>   	__ATTR(mmcr1, 0600, show_mmcr1, store_mmcr1),
>   	__ATTR(pmc0, 0600, show_pa6t_pmc0, store_pa6t_pmc0),
> @@ -682,6 +698,7 @@ static struct device_attribute pa6t_attrs[] = {
>   	__ATTR(pmc3, 0600, show_pa6t_pmc3, store_pa6t_pmc3),
>   	__ATTR(pmc4, 0600, show_pa6t_pmc4, store_pa6t_pmc4),
>   	__ATTR(pmc5, 0600, show_pa6t_pmc5, store_pa6t_pmc5),
> +#endif /* CONFIG_PMU_SYSFS */
>   #ifdef CONFIG_DEBUG_MISC
>   	__ATTR(hid0, 0600, show_hid0, store_hid0),
>   	__ATTR(hid1, 0600, show_hid1, store_hid1),
> @@ -787,8 +804,10 @@ static int register_cpu_online(unsigned int cpu)
>   			device_create_file(s, &pmc_attrs[i]);
>
>   #ifdef CONFIG_PPC64
> +#ifdef CONFIG_PMU_SYSFS
>   	if (cpu_has_feature(CPU_FTR_MMCRA))
>   		device_create_file(s, &dev_attr_mmcra);
> +#endif /* CONFIG_PMU_SYSFS */
>
>   	if (cpu_has_feature(CPU_FTR_PURR)) {
>   		if (!firmware_has_feature(FW_FEATURE_LPAR))
> @@ -876,8 +895,10 @@ static int unregister_cpu_online(unsigned int cpu)
>   			device_remove_file(s, &pmc_attrs[i]);
>
>   #ifdef CONFIG_PPC64
> +#ifdef CONFIG_PMU_SYSFS
>   	if (cpu_has_feature(CPU_FTR_MMCRA))
>   		device_remove_file(s, &dev_attr_mmcra);
> +#endif /* CONFIG_PMU_SYSFS */
>
>   	if (cpu_has_feature(CPU_FTR_PURR))
>   		device_remove_file(s, &dev_attr_purr);
> diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype
> index 12543e53fa96..f3ad579c559f 100644
> --- a/arch/powerpc/platforms/Kconfig.cputype
> +++ b/arch/powerpc/platforms/Kconfig.cputype
> @@ -417,6 +417,14 @@ config PPC_MM_SLICES
>   config PPC_HAVE_PMU_SUPPORT
>          bool
>
> +config PMU_SYSFS
> +	bool
> +	default y if !PERF_EVENTS
> +	help
> +	  This option enables PMU SPR sysfs file creation. Since PMU SPRs are
> +	  intended to be used via "perf" interface, config option is enabled
> +	  only when CONFIG_PERF_EVENTS is disabled.
> +
>   config PPC_PERF_CTRS
>          def_bool y
>          depends on PERF_EVENTS && PPC_HAVE_PMU_SUPPORT