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122 lines · 2.6 KiB

1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright IBM Corp. 1999, 2023
4 */
5
6#include <linux/irqflags.h>
7#include <linux/spinlock.h>
8#include <linux/export.h>
9#include <linux/kernel.h>
10#include <linux/init.h>
11#include <linux/smp.h>
12#include <linux/cache.h>
13#include <asm/abs_lowcore.h>
14#include <asm/ctlreg.h>
15
16/*
17 * ctl_lock guards access to global control register contents which
18 * are kept in the control register save area within absolute lowcore
19 * at physical address zero.
20 */
21static DEFINE_SPINLOCK(system_ctl_lock);
22
23void system_ctlreg_lock(void)
24 __acquires(&system_ctl_lock)
25{
26 spin_lock(&system_ctl_lock);
27}
28
29void system_ctlreg_unlock(void)
30 __releases(&system_ctl_lock)
31{
32 spin_unlock(&system_ctl_lock);
33}
34
35static bool system_ctlreg_area_init __ro_after_init;
36
37void __init system_ctlreg_init_save_area(struct lowcore *lc)
38{
39 struct lowcore *abs_lc;
40
41 abs_lc = get_abs_lowcore();
42 __local_ctl_store(0, 15, lc->cregs_save_area);
43 __local_ctl_store(0, 15, abs_lc->cregs_save_area);
44 put_abs_lowcore(abs_lc);
45 system_ctlreg_area_init = true;
46}
47
48struct ctlreg_parms {
49 unsigned long andval;
50 unsigned long orval;
51 unsigned long val;
52 int request;
53 int cr;
54};
55
56static void ctlreg_callback(void *info)
57{
58 struct ctlreg_parms *pp = info;
59 struct ctlreg regs[16];
60
61 __local_ctl_store(0, 15, regs);
62 if (pp->request == CTLREG_LOAD) {
63 regs[pp->cr].val = pp->val;
64 } else {
65 regs[pp->cr].val &= pp->andval;
66 regs[pp->cr].val |= pp->orval;
67 }
68 __local_ctl_load(0, 15, regs);
69}
70
71static void system_ctlreg_update(void *info)
72{
73 unsigned long flags;
74
75 if (system_state == SYSTEM_BOOTING) {
76 /*
77 * For very early calls do not call on_each_cpu()
78 * since not everything might be setup.
79 */
80 local_irq_save(flags);
81 ctlreg_callback(info);
82 local_irq_restore(flags);
83 } else {
84 on_each_cpu(ctlreg_callback, info, 1);
85 }
86}
87
88void system_ctlreg_modify(unsigned int cr, unsigned long data, int request)
89{
90 struct ctlreg_parms pp = { .cr = cr, .request = request, };
91 struct lowcore *abs_lc;
92
93 switch (request) {
94 case CTLREG_SET_BIT:
95 pp.orval = 1UL << data;
96 pp.andval = -1UL;
97 break;
98 case CTLREG_CLEAR_BIT:
99 pp.orval = 0;
100 pp.andval = ~(1UL << data);
101 break;
102 case CTLREG_LOAD:
103 pp.val = data;
104 break;
105 }
106 if (system_ctlreg_area_init) {
107 system_ctlreg_lock();
108 abs_lc = get_abs_lowcore();
109 if (request == CTLREG_LOAD) {
110 abs_lc->cregs_save_area[cr].val = pp.val;
111 } else {
112 abs_lc->cregs_save_area[cr].val &= pp.andval;
113 abs_lc->cregs_save_area[cr].val |= pp.orval;
114 }
115 put_abs_lowcore(abs_lc);
116 system_ctlreg_update(&pp);
117 system_ctlreg_unlock();
118 } else {
119 system_ctlreg_update(&pp);
120 }
121}
122EXPORT_SYMBOL(system_ctlreg_modify);