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 * This value can never be a valid CLOSID, and is used when mapping a
12 * (closid, rmid) pair to an index and back. On x86 only the RMID is
13 * needed. The index is a software defined value.
14 */
15#define X86_RESCTRL_EMPTY_CLOSID         ((u32)~0)
16
17/**
18 * struct resctrl_pqr_state - State cache for the PQR MSR
19 * @cur_rmid:		The cached Resource Monitoring ID
20 * @cur_closid:	The cached Class Of Service ID
21 * @default_rmid:	The user assigned Resource Monitoring ID
22 * @default_closid:	The user assigned cached Class Of Service ID
23 *
24 * The upper 32 bits of MSR_IA32_PQR_ASSOC contain closid and the
25 * lower 10 bits rmid. The update to MSR_IA32_PQR_ASSOC always
26 * contains both parts, so we need to cache them. This also
27 * stores the user configured per cpu CLOSID and RMID.
28 *
29 * The cache also helps to avoid pointless updates if the value does
30 * not change.
31 */
32struct resctrl_pqr_state {
33	u32			cur_rmid;
34	u32			cur_closid;
35	u32			default_rmid;
36	u32			default_closid;
37};
38
39DECLARE_PER_CPU(struct resctrl_pqr_state, pqr_state);
40
41extern bool rdt_alloc_capable;
42extern bool rdt_mon_capable;
43
44DECLARE_STATIC_KEY_FALSE(rdt_enable_key);
45DECLARE_STATIC_KEY_FALSE(rdt_alloc_enable_key);
46DECLARE_STATIC_KEY_FALSE(rdt_mon_enable_key);
47
48static inline bool resctrl_arch_alloc_capable(void)
49{
50	return rdt_alloc_capable;
51}
52
53static inline void resctrl_arch_enable_alloc(void)
54{
55	static_branch_enable_cpuslocked(&rdt_alloc_enable_key);
56	static_branch_inc_cpuslocked(&rdt_enable_key);
57}
58
59static inline void resctrl_arch_disable_alloc(void)
60{
61	static_branch_disable_cpuslocked(&rdt_alloc_enable_key);
62	static_branch_dec_cpuslocked(&rdt_enable_key);
63}
64
65static inline bool resctrl_arch_mon_capable(void)
66{
67	return rdt_mon_capable;
68}
69
70static inline void resctrl_arch_enable_mon(void)
71{
72	static_branch_enable_cpuslocked(&rdt_mon_enable_key);
73	static_branch_inc_cpuslocked(&rdt_enable_key);
74}
75
76static inline void resctrl_arch_disable_mon(void)
77{
78	static_branch_disable_cpuslocked(&rdt_mon_enable_key);
79	static_branch_dec_cpuslocked(&rdt_enable_key);
80}
81
82/*
83 * __resctrl_sched_in() - Writes the task's CLOSid/RMID to IA32_PQR_MSR
84 *
85 * Following considerations are made so that this has minimal impact
86 * on scheduler hot path:
87 * - This will stay as no-op unless we are running on an Intel SKU
88 *   which supports resource control or monitoring and we enable by
89 *   mounting the resctrl file system.
90 * - Caches the per cpu CLOSid/RMID values and does the MSR write only
91 *   when a task with a different CLOSid/RMID is scheduled in.
92 * - We allocate RMIDs/CLOSids globally in order to keep this as
93 *   simple as possible.
94 * Must be called with preemption disabled.
95 */
96static inline void __resctrl_sched_in(struct task_struct *tsk)
97{
98	struct resctrl_pqr_state *state = this_cpu_ptr(&pqr_state);
99	u32 closid = state->default_closid;
100	u32 rmid = state->default_rmid;
101	u32 tmp;
102
103	/*
104	 * If this task has a closid/rmid assigned, use it.
105	 * Else use the closid/rmid assigned to this cpu.
106	 */
107	if (static_branch_likely(&rdt_alloc_enable_key)) {
108		tmp = READ_ONCE(tsk->closid);
109		if (tmp)
110			closid = tmp;
111	}
112
113	if (static_branch_likely(&rdt_mon_enable_key)) {
114		tmp = READ_ONCE(tsk->rmid);
115		if (tmp)
116			rmid = tmp;
117	}
118
119	if (closid != state->cur_closid || rmid != state->cur_rmid) {
120		state->cur_closid = closid;
121		state->cur_rmid = rmid;
122		wrmsr(MSR_IA32_PQR_ASSOC, rmid, closid);
123	}
124}
125
126static inline unsigned int resctrl_arch_round_mon_val(unsigned int val)
127{
128	unsigned int scale = boot_cpu_data.x86_cache_occ_scale;
129
130	/* h/w works in units of "boot_cpu_data.x86_cache_occ_scale" */
131	val /= scale;
132	return val * scale;
133}
134
135static inline void resctrl_arch_set_closid_rmid(struct task_struct *tsk,
136						u32 closid, u32 rmid)
137{
138	WRITE_ONCE(tsk->closid, closid);
139	WRITE_ONCE(tsk->rmid, rmid);
140}
141
142static inline bool resctrl_arch_match_closid(struct task_struct *tsk, u32 closid)
143{
144	return READ_ONCE(tsk->closid) == closid;
145}
146
147static inline bool resctrl_arch_match_rmid(struct task_struct *tsk, u32 ignored,
148					   u32 rmid)
149{
150	return READ_ONCE(tsk->rmid) == rmid;
151}
152
153static inline void resctrl_sched_in(struct task_struct *tsk)
154{
155	if (static_branch_likely(&rdt_enable_key))
156		__resctrl_sched_in(tsk);
157}
158
159static inline u32 resctrl_arch_system_num_rmid_idx(void)
160{
161	/* RMID are independent numbers for x86. num_rmid_idx == num_rmid */
162	return boot_cpu_data.x86_cache_max_rmid + 1;
163}
164
165static inline void resctrl_arch_rmid_idx_decode(u32 idx, u32 *closid, u32 *rmid)
166{
167	*rmid = idx;
168	*closid = X86_RESCTRL_EMPTY_CLOSID;
169}
170
171static inline u32 resctrl_arch_rmid_idx_encode(u32 ignored, u32 rmid)
172{
173	return rmid;
174}
175
176/* x86 can always read an rmid, nothing needs allocating */
177struct rdt_resource;
178static inline void *resctrl_arch_mon_ctx_alloc(struct rdt_resource *r, int evtid)
179{
180	might_sleep();
181	return NULL;
182};
183
184static inline void resctrl_arch_mon_ctx_free(struct rdt_resource *r, int evtid,
185					     void *ctx) { };
186
187void resctrl_cpu_detect(struct cpuinfo_x86 *c);
188
189#else
190
191static inline void resctrl_sched_in(struct task_struct *tsk) {}
192static inline void resctrl_cpu_detect(struct cpuinfo_x86 *c) {}
193
194#endif /* CONFIG_X86_CPU_RESCTRL */
195
196#endif /* _ASM_X86_RESCTRL_H */
197