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 inline void __resctrl_sched_in(struct task_struct *tsk)
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(tsk->closid);
65		if (tmp)
66			closid = tmp;
67	}
68
69	if (static_branch_likely(&rdt_mon_enable_key)) {
70		tmp = READ_ONCE(tsk->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(struct task_struct *tsk)
92{
93	if (static_branch_likely(&rdt_enable_key))
94		__resctrl_sched_in(tsk);
95}
96
97void resctrl_cpu_detect(struct cpuinfo_x86 *c);
98
99#else
100
101static inline void resctrl_sched_in(struct task_struct *tsk) {}
102static inline void resctrl_cpu_detect(struct cpuinfo_x86 *c) {}
103
104#endif /* CONFIG_X86_CPU_RESCTRL */
105
106#endif /* _ASM_X86_RESCTRL_H */
107