1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
|
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_RISCV_QOS_H
#define _ASM_RISCV_QOS_H
#include <linux/percpu-defs.h>
#ifdef CONFIG_RISCV_ISA_SSQOSID
#include <linux/bitfield.h>
#include <linux/cpufeature.h>
#include <linux/sched.h>
#include <asm/csr.h>
#include <asm/hwcap.h>
/* cached value of srmcfg csr for each cpu */
DECLARE_PER_CPU(u32, cpu_srmcfg);
/* default srmcfg value for each cpu, set via resctrl cpu assignment */
DECLARE_PER_CPU(u32, cpu_srmcfg_default);
static inline void __switch_to_srmcfg(struct task_struct *next)
{
u32 thread_srmcfg, default_srmcfg;
thread_srmcfg = READ_ONCE(next->thread.srmcfg);
default_srmcfg = __this_cpu_read(cpu_srmcfg_default);
/*
* RCID and MCID inherit from cpu_srmcfg_default independently.
* RESCTRL_RESERVED_CLOSID and RESCTRL_RESERVED_RMID are both 0, so a
* zero field means "unassigned" and takes the CPU default.
*/
if (thread_srmcfg == 0) {
thread_srmcfg = default_srmcfg;
} else {
u32 rcid = FIELD_GET(SRMCFG_RCID_MASK, thread_srmcfg);
u32 mcid = FIELD_GET(SRMCFG_MCID_MASK, thread_srmcfg);
if (rcid == 0 || mcid == 0) {
if (rcid == 0)
rcid = FIELD_GET(SRMCFG_RCID_MASK, default_srmcfg);
if (mcid == 0)
mcid = FIELD_GET(SRMCFG_MCID_MASK, default_srmcfg);
thread_srmcfg = FIELD_PREP(SRMCFG_RCID_MASK, rcid) |
FIELD_PREP(SRMCFG_MCID_MASK, mcid);
}
}
if (thread_srmcfg != __this_cpu_read(cpu_srmcfg)) {
/*
* No fence around the csrw. Ssqosid is silent on srmcfg
* ordering versus memory accesses, so a few accesses at the
* switch boundary may carry the previous RCID/MCID. The
* tagging inaccuracy is bounded and acceptable for QoS.
*/
__this_cpu_write(cpu_srmcfg, thread_srmcfg);
csr_write(CSR_SRMCFG, thread_srmcfg);
}
}
static __always_inline bool has_srmcfg(void)
{
return riscv_has_extension_unlikely(RISCV_ISA_EXT_SSQOSID);
}
#else /* ! CONFIG_RISCV_ISA_SSQOSID */
struct task_struct;
static __always_inline bool has_srmcfg(void) { return false; }
static inline void __switch_to_srmcfg(struct task_struct *next) { }
#endif /* CONFIG_RISCV_ISA_SSQOSID */
#endif /* _ASM_RISCV_QOS_H */
|
