1/* SPDX-License-Identifier: GPL-2.0 */
  2#ifndef _ASM_X86_RESCTRL_H
  3#define _ASM_X86_RESCTRL_H
  4
  5#ifdef CONFIG_X86_CPU_RESCTRL
  6
  7#include <linux/sched.h>
  8#include <linux/jump_label.h>
  9
 10/**
 11 * struct resctrl_pqr_state - State cache for the PQR MSR
 12 * @cur_rmid:		The cached Resource Monitoring ID
 13 * @cur_closid:	The cached Class Of Service ID
 14 * @default_rmid:	The user assigned Resource Monitoring ID
 15 * @default_closid:	The user assigned cached Class Of Service ID
 16 *
 17 * The upper 32 bits of MSR_IA32_PQR_ASSOC contain closid and the
 18 * lower 10 bits rmid. The update to MSR_IA32_PQR_ASSOC always
 19 * contains both parts, so we need to cache them. This also
 20 * stores the user configured per cpu CLOSID and RMID.
 21 *
 22 * The cache also helps to avoid pointless updates if the value does
 23 * not change.
 24 */
 25struct resctrl_pqr_state {
 26	u32			cur_rmid;
 27	u32			cur_closid;
 28	u32			default_rmid;
 29	u32			default_closid;
 30};
 31
 32DECLARE_PER_CPU(struct resctrl_pqr_state, pqr_state);
 33
 34DECLARE_STATIC_KEY_FALSE(rdt_enable_key);
 35DECLARE_STATIC_KEY_FALSE(rdt_alloc_enable_key);
 36DECLARE_STATIC_KEY_FALSE(rdt_mon_enable_key);
 37
 38/*
 39 * __resctrl_sched_in() - Writes the task's CLOSid/RMID to IA32_PQR_MSR
 40 *
 41 * Following considerations are made so that this has minimal impact
 42 * on scheduler hot path:
 43 * - This will stay as no-op unless we are running on an Intel SKU
 44 *   which supports resource control or monitoring and we enable by
 45 *   mounting the resctrl file system.
 46 * - Caches the per cpu CLOSid/RMID values and does the MSR write only
 47 *   when a task with a different CLOSid/RMID is scheduled in.
 48 * - We allocate RMIDs/CLOSids globally in order to keep this as
 49 *   simple as possible.
 50 * Must be called with preemption disabled.
 51 */
 52static void __resctrl_sched_in(void)
 53{
 54	struct resctrl_pqr_state *state = this_cpu_ptr(&pqr_state);
 55	u32 closid = state->default_closid;
 56	u32 rmid = state->default_rmid;
 57	u32 tmp;
 58
 59	/*
 60	 * If this task has a closid/rmid assigned, use it.
 61	 * Else use the closid/rmid assigned to this cpu.
 62	 */
 63	if (static_branch_likely(&rdt_alloc_enable_key)) {
 64		tmp = READ_ONCE(current->closid);
 65		if (tmp)
 66			closid = tmp;
 67	}
 68
 69	if (static_branch_likely(&rdt_mon_enable_key)) {
 70		tmp = READ_ONCE(current->rmid);
 71		if (tmp)
 72			rmid = tmp;
 73	}
 74
 75	if (closid != state->cur_closid || rmid != state->cur_rmid) {
 76		state->cur_closid = closid;
 77		state->cur_rmid = rmid;
 78		wrmsr(MSR_IA32_PQR_ASSOC, rmid, closid);
 79	}
 80}
 81
 82static inline unsigned int resctrl_arch_round_mon_val(unsigned int val)
 83{
 84	unsigned int scale = boot_cpu_data.x86_cache_occ_scale;
 85
 86	/* h/w works in units of "boot_cpu_data.x86_cache_occ_scale" */
 87	val /= scale;
 88	return val * scale;
 89}
 90
 91static inline void resctrl_sched_in(void)
 92{
 93	if (static_branch_likely(&rdt_enable_key))
 94		__resctrl_sched_in();
 95}
 96
 97void resctrl_cpu_detect(struct cpuinfo_x86 *c);
 98
 99#else
100
101static inline void resctrl_sched_in(void) {}
102static inline void resctrl_cpu_detect(struct cpuinfo_x86 *c) {}
103
104#endif /* CONFIG_X86_CPU_RESCTRL */
105
106#endif /* _ASM_X86_RESCTRL_H */