Messages in this thread | | | Date | Wed, 18 May 2022 09:10:15 +0200 | From | Greg KH <> | Subject | Re: [PATCH v4 3/8] soc: fujitsu: Add hardware prefetch control support for A64FX |
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On Wed, May 18, 2022 at 03:30:27PM +0900, Kohei Tarumizu wrote: > Adds module init/exit code to create sysfs attributes for A64FX with > "stream_detect_prefetcher_enable", "stream_detect_prefetcher_strong" > and "stream_detect_prefetcher_dist". > > This driver works only if part number is FUJITSU_CPU_PART_A64FX. The > details of the registers to be read and written in this patch are > described below. > > "https://github.com/fujitsu/A64FX/tree/master/doc/" > A64FX_Specification_HPC_Extension_v1_EN.pdf > > Signed-off-by: Kohei Tarumizu <tarumizu.kohei@fujitsu.com> > --- > drivers/soc/fujitsu/a64fx-pfctl.c | 373 ++++++++++++++++++++++++++++++ > 1 file changed, 373 insertions(+) > create mode 100644 drivers/soc/fujitsu/a64fx-pfctl.c > > diff --git a/drivers/soc/fujitsu/a64fx-pfctl.c b/drivers/soc/fujitsu/a64fx-pfctl.c > new file mode 100644 > index 000000000000..f765f53987d4 > --- /dev/null > +++ b/drivers/soc/fujitsu/a64fx-pfctl.c > @@ -0,0 +1,373 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright 2022 FUJITSU LIMITED > + * > + * A64FX Hardware Prefetch Control support > + */ > + > +#include <asm/cputype.h> > +#include <linux/cacheinfo.h> > +#include <linux/device.h> > +#include <linux/module.h> > +#include <linux/pfctl.h> > +#include <linux/smp.h> > +#include <linux/sysfs.h> > + > +/* > + * Constants for these add the "A64FX_SDPF" prefix to the name described in > + * section "1.3.4.2. IMP_PF_STREAM_DETECT_CTRL_EL0" of "A64FX specification". > + * (https://github.com/fujitsu/A64FX/tree/master/doc/A64FX_Specification_HPC_Extension_v1_EN.pdf") > + * See this document for register specification details. > + */ > +#define A64FX_SDPF_IMP_PF_STREAM_DETECT_CTRL_EL0 sys_reg(3, 3, 11, 4, 0) > +#define A64FX_SDPF_V BIT_ULL(63) > +#define A64FX_SDPF_L1PF_DIS BIT_ULL(59) > +#define A64FX_SDPF_L2PF_DIS BIT_ULL(58) > +#define A64FX_SDPF_L1W BIT_ULL(55) > +#define A64FX_SDPF_L2W BIT_ULL(54) > +#define A64FX_SDPF_L1_DIST GENMASK_ULL(27, 24) > +#define A64FX_SDPF_L2_DIST GENMASK_ULL(19, 16) > + > +#define PFCTL_MIN_L1_DIST 256 > +#define PFCTL_MIN_L2_DIST 1024 > +#define PFCTL_DIST_AUTO_VAL 0 > +#define PFCTL_STRONG_VAL 0 > +#define PFCTL_WEAK_VAL 1 > + > +/* > + * Define bitfield access macros for non-constant mask, because macros such as > + * FIELD_FIT defined in include/linux/bitfield.h require constant mask. > + */ > +#define NC_FIELD_FIT(_mask, _val) \ > + !((((typeof(_mask))_val) << __bf_shf(_mask)) & ~(_mask)) > + > +#define NC_FIELD_PREP(_mask, _val) \ > + (((typeof(_mask))(_val) << __bf_shf(_mask)) & (_mask)) > + > +#define NC_FIELD_GET(_mask, _reg) \ > + ((typeof(_mask))(((_reg) & (_mask)) >> __bf_shf(_mask))) > + > +struct a64fx_pfctl_attr { > + struct device_attribute attr; > + u64 mask; > + void *data; > +}; > + > +static const char strength_strong_string[] = "strong"; > +static const char strength_weak_string[] = "weak"; > +static const char dist_auto_string[] = "auto"; > + > +/* > + * Returns the cpu number of the cpu_device(/sys/devices/system/cpu/cpuX) > + * in the ancestor directory of prefetch_control. > + * > + * When initializing this driver, it is verified that the cache directory exists > + * under cpuX device. Therefore, the third level up from prefetch_control is > + * cpuX device as shown below. > + * > + * /sys/devices/system/cpu/cpuX/cache/indexX/prefetch_control > + */ > +static inline unsigned int pfctl_dev_get_cpu(struct device *pfctl_dev) > +{ > + return pfctl_dev->parent->parent->parent->id; > +} > + > +/* Enable the value written to the A64FX_SDPF_IMP_PF_STREAM_DETECT_CTRL_EL0 */ > +static inline void enable_verify(u64 *reg) > +{ > + *reg |= NC_FIELD_PREP(A64FX_SDPF_V, 1); > +} > + > +static void _pfctl_read_mask(void *_reg) > +{ > + u64 *reg = (u64 *)_reg; > + > + *reg = read_sysreg_s(A64FX_SDPF_IMP_PF_STREAM_DETECT_CTRL_EL0); > +} > + > +static u64 pfctl_read_mask(unsigned int cpu, u64 mask) > +{ > + u64 reg; > + > + smp_call_function_single(cpu, _pfctl_read_mask, ®, true); > + > + return NC_FIELD_GET(mask, reg); > +} > + > +struct write_info { > + u64 mask; > + u64 val; > +}; > + > +static void _pfctl_write_mask(void *info) > +{ > + struct write_info *winfo = info; > + u64 reg; > + > + reg = read_sysreg_s(A64FX_SDPF_IMP_PF_STREAM_DETECT_CTRL_EL0); > + > + reg &= ~winfo->mask; > + reg |= NC_FIELD_PREP(winfo->mask, winfo->val); > + > + enable_verify(®); > + > + write_sysreg_s(reg, A64FX_SDPF_IMP_PF_STREAM_DETECT_CTRL_EL0); > +} > + > +static int pfctl_write_mask(unsigned int cpu, u64 mask, u64 val) > +{ > + struct write_info info = { > + .mask = mask, > + .val = val, > + }; > + > + if (!NC_FIELD_FIT(mask, val)) > + return -EINVAL; > + > + smp_call_function_single(cpu, _pfctl_write_mask, &info, true); > + > + return 0; > +} > + > +static ssize_t > +pfctl_enable_show(struct device *pfctl_dev, struct device_attribute *attr, > + char *buf) > +{ > + unsigned int cpu = pfctl_dev_get_cpu(pfctl_dev); > + struct a64fx_pfctl_attr *aa; > + bool val; > + > + aa = container_of(attr, struct a64fx_pfctl_attr, attr); > + > + val = (bool)pfctl_read_mask(cpu, aa->mask); > + > + return sysfs_emit(buf, "%d\n", val ? 0 : 1); > +} > + > +static ssize_t > +pfctl_enable_store(struct device *pfctl_dev, struct device_attribute *attr, > + const char *buf, size_t size) > +{ > + unsigned int cpu = pfctl_dev_get_cpu(pfctl_dev); > + struct a64fx_pfctl_attr *aa; > + bool val; > + int ret; > + > + aa = container_of(attr, struct a64fx_pfctl_attr, attr); > + > + if (strtobool(buf, &val) < 0) > + return -EINVAL; > + > + ret = pfctl_write_mask(cpu, aa->mask, val ? 0 : 1); > + if (ret < 0) > + return ret; > + > + return size; > +} > + > +#define A64FX_PFCTL_ENABLE_ATTR(_level, _mask) \ > + struct a64fx_pfctl_attr attr_l##_level##_enable = { \ > + .attr = __ATTR(stream_detect_prefetcher_enable, 0600, \ > + pfctl_enable_show, pfctl_enable_store), \ > + .mask = _mask, } > + > + > +static A64FX_PFCTL_ENABLE_ATTR(1, A64FX_SDPF_L1PF_DIS); > +static A64FX_PFCTL_ENABLE_ATTR(2, A64FX_SDPF_L2PF_DIS); > + > +static ssize_t > +pfctl_dist_show(struct device *pfctl_dev, struct device_attribute *attr, > + char *buf) > +{ > + unsigned int cpu = pfctl_dev_get_cpu(pfctl_dev); > + struct a64fx_pfctl_attr *aa; > + u64 val, min_dist; > + > + aa = container_of(attr, struct a64fx_pfctl_attr, attr); > + min_dist = (u64)aa->data; > + > + val = pfctl_read_mask(cpu, aa->mask); > + > + if (val == PFCTL_DIST_AUTO_VAL) > + return sysfs_emit(buf, "%s\n", dist_auto_string); > + else > + return sysfs_emit(buf, "%llu\n", val * min_dist); > +} > + > +static ssize_t > +pfctl_dist_store(struct device *pfctl_dev, struct device_attribute *attr, > + const char *buf, size_t size) > +{ > + unsigned int cpu = pfctl_dev_get_cpu(pfctl_dev); > + struct a64fx_pfctl_attr *aa; > + u64 min_dist, val; > + int ret; > + > + aa = container_of(attr, struct a64fx_pfctl_attr, attr); > + min_dist = (u64)aa->data; > + > + if (sysfs_streq(buf, dist_auto_string)) { > + val = PFCTL_DIST_AUTO_VAL; > + } else { > + ret = kstrtoull(buf, 10, &val); > + if (ret < 0 || val < 1) > + return -EINVAL; > + } > + > + val = roundup(val, min_dist) / min_dist; > + > + if (!NC_FIELD_FIT(aa->mask, val)) > + return -EINVAL; > + > + ret = pfctl_write_mask(cpu, aa->mask, val); > + if (ret < 0) > + return ret; > + > + return size; > +} > + > +#define PFCTL_DIST_ATTR(_level, _mask, _min_dist) \ > + struct a64fx_pfctl_attr attr_l##_level##_dist = { \ > + .attr = __ATTR(stream_detect_prefetcher_dist, 0600, \ > + pfctl_dist_show, pfctl_dist_store), \ > + .mask = _mask, \ > + .data = (void *)(u64)_min_dist, } > + > +static PFCTL_DIST_ATTR(1, A64FX_SDPF_L1_DIST, PFCTL_MIN_L1_DIST); > +static PFCTL_DIST_ATTR(2, A64FX_SDPF_L2_DIST, PFCTL_MIN_L2_DIST); > + > +static ssize_t > +pfctl_strength_show(struct device *pfctl_dev, struct device_attribute *attr, > + char *buf) > +{ > + unsigned int cpu = pfctl_dev_get_cpu(pfctl_dev); > + struct a64fx_pfctl_attr *aa; > + u64 val; > + > + aa = container_of(attr, struct a64fx_pfctl_attr, attr); > + > + val = pfctl_read_mask(cpu, aa->mask); > + > + switch (val) { > + case PFCTL_STRONG_VAL: > + return sysfs_emit(buf, "%s\n", strength_strong_string); > + case PFCTL_WEAK_VAL: > + return sysfs_emit(buf, "%s\n", strength_weak_string); > + default: > + return -EINVAL; > + } > +} > + > +static ssize_t > +pfctl_strength_store(struct device *pfctl_dev, struct device_attribute *attr, > + const char *buf, size_t size) > +{ > + unsigned int cpu = pfctl_dev_get_cpu(pfctl_dev); > + struct a64fx_pfctl_attr *aa; > + u64 val; > + int ret; > + > + aa = container_of(attr, struct a64fx_pfctl_attr, attr); > + > + if (sysfs_streq(buf, strength_strong_string)) > + val = PFCTL_STRONG_VAL; > + else if (sysfs_streq(buf, strength_weak_string)) > + val = PFCTL_WEAK_VAL; > + else > + return -EINVAL; > + > + ret = pfctl_write_mask(cpu, aa->mask, val); > + if (ret < 0) > + return ret; > + > + return size; > +} > + > +#define PFCTL_STRENGTH_ATTR(_level, _mask) \ > + struct a64fx_pfctl_attr attr_l##_level##_strength = { \ > + .attr = __ATTR(stream_detect_prefetcher_strength, 0600, \ > + pfctl_strength_show, \ > + pfctl_strength_store), \ > + .mask = _mask, } > + > +static PFCTL_STRENGTH_ATTR(1, A64FX_SDPF_L1W); > +static PFCTL_STRENGTH_ATTR(2, A64FX_SDPF_L2W); > + > +static ssize_t > +pfctl_strength_available_show(struct device *dev, struct device_attribute *attr, > + char *buf) > +{ > + return sysfs_emit(buf, "%s %s\n", strength_strong_string, > + strength_weak_string); > +} > + > +/* > + * A64FX has same kind of available strength for any caches, so define only one > + * attribute. > + */ > +struct a64fx_pfctl_attr attr_strength_available = { > + .attr = __ATTR(stream_detect_prefetcher_strength_available, 0400, > + pfctl_strength_available_show, NULL), }; > + > +static struct device_attribute *l1_attrs[] __ro_after_init = { > + &attr_l1_enable.attr, > + &attr_l1_dist.attr, > + &attr_l1_strength.attr, > + &attr_strength_available.attr, > + NULL, > +}; > + > +static struct device_attribute *l2_attrs[] __ro_after_init = { > + &attr_l2_enable.attr, > + &attr_l2_dist.attr, > + &attr_l2_strength.attr, > + &attr_strength_available.attr, > + NULL, > +}; > + > +static const struct pfctl_group a64fx_pfctl_groups[] = { > + { > + .level = 1, > + .type = CACHE_TYPE_DATA, > + .attrs = l1_attrs, > + }, > + { > + .level = 2, > + .type = CACHE_TYPE_UNIFIED, > + .attrs = l2_attrs, > + }, > + { > + .attrs = NULL, > + }, > +}; > + > +/* > + * This driver returns a negative value if it does not support the Hardware > + * Prefetch Control or if it is running on a VM guest. > + */ > +static int __init a64fx_pfctl_init(void) > +{ > + unsigned long implementor = read_cpuid_implementor(); > + unsigned long part_number = read_cpuid_part_number(); > + > + if (!is_kernel_in_hyp_mode()) > + return -EINVAL; > + > + if ((implementor != ARM_CPU_IMP_FUJITSU) || > + (part_number != FUJITSU_CPU_PART_A64FX)) > + return -ENODEV; > + > + return pfctl_register_attrs(a64fx_pfctl_groups); > +} > + > +static void __exit a64fx_pfctl_exit(void) > +{ > + return pfctl_unregister_attrs(a64fx_pfctl_groups); > +} > + > +late_initcall(a64fx_pfctl_init); > +module_exit(a64fx_pfctl_exit); > + > +MODULE_LICENSE("GPL"); > +MODULE_AUTHOR("FUJITSU LIMITED"); > +MODULE_DESCRIPTION("A64FX Hardware Prefetch Control Driver"); > -- > 2.27.0 >
How will this driver be properly loaded by the system if the hardware is present?
thanks,
greg k-h
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