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
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
|
// SPDX-License-Identifier: GPL-2.0-only
#define pr_fmt(fmt) "rtas-work-area: " fmt
#include <linux/genalloc.h>
#include <linux/log2.h>
#include <linux/kernel.h>
#include <linux/memblock.h>
#include <linux/mempool.h>
#include <linux/minmax.h>
#include <linux/mutex.h>
#include <linux/numa.h>
#include <linux/sizes.h>
#include <linux/wait.h>
#include <asm/machdep.h>
#include <asm/rtas-work-area.h>
#include <asm/rtas.h>
enum {
/*
* Ensure the pool is page-aligned.
*/
RTAS_WORK_AREA_ARENA_ALIGN = PAGE_SIZE,
/*
* Don't let a single allocation claim the whole arena.
*/
RTAS_WORK_AREA_ARENA_SZ = RTAS_WORK_AREA_MAX_ALLOC_SZ * 2,
/*
* The smallest known work area size is for ibm,get-vpd's
* location code argument, which is limited to 79 characters
* plus 1 nul terminator.
*
* PAPR+ 7.3.20 ibm,get-vpd RTAS Call
* PAPR+ 12.3.2.4 Converged Location Code Rules - Length Restrictions
*/
RTAS_WORK_AREA_MIN_ALLOC_SZ = roundup_pow_of_two(80),
};
static struct {
struct gen_pool *gen_pool;
char *arena;
struct mutex mutex; /* serializes allocations */
struct wait_queue_head wqh;
mempool_t descriptor_pool;
bool available;
} rwa_state = {
.mutex = __MUTEX_INITIALIZER(rwa_state.mutex),
.wqh = __WAIT_QUEUE_HEAD_INITIALIZER(rwa_state.wqh),
};
/*
* A single work area buffer and descriptor to serve requests early in
* boot before the allocator is fully initialized. We know 4KB is the
* most any boot time user needs (they all call ibm,get-system-parameter).
*/
static bool early_work_area_in_use __initdata;
static char early_work_area_buf[SZ_4K] __initdata __aligned(SZ_4K);
static struct rtas_work_area early_work_area __initdata = {
.buf = early_work_area_buf,
.size = sizeof(early_work_area_buf),
};
static struct rtas_work_area * __init rtas_work_area_alloc_early(size_t size)
{
WARN_ON(size > early_work_area.size);
WARN_ON(early_work_area_in_use);
early_work_area_in_use = true;
memset(early_work_area.buf, 0, early_work_area.size);
return &early_work_area;
}
static void __init rtas_work_area_free_early(struct rtas_work_area *work_area)
{
WARN_ON(work_area != &early_work_area);
WARN_ON(!early_work_area_in_use);
early_work_area_in_use = false;
}
struct rtas_work_area * __ref __rtas_work_area_alloc(size_t size)
{
struct rtas_work_area *area;
unsigned long addr;
might_sleep();
/*
* The rtas_work_area_alloc() wrapper enforces this at build
* time. Requests that exceed the arena size will block
* indefinitely.
*/
WARN_ON(size > RTAS_WORK_AREA_MAX_ALLOC_SZ);
if (!rwa_state.available)
return rtas_work_area_alloc_early(size);
/*
* To ensure FCFS behavior and prevent a high rate of smaller
* requests from starving larger ones, use the mutex to queue
* allocations.
*/
mutex_lock(&rwa_state.mutex);
wait_event(rwa_state.wqh,
(addr = gen_pool_alloc(rwa_state.gen_pool, size)) != 0);
mutex_unlock(&rwa_state.mutex);
area = mempool_alloc(&rwa_state.descriptor_pool, GFP_KERNEL);
area->buf = (char *)addr;
area->size = size;
return area;
}
void __ref rtas_work_area_free(struct rtas_work_area *area)
{
if (!rwa_state.available) {
rtas_work_area_free_early(area);
return;
}
gen_pool_free(rwa_state.gen_pool, (unsigned long)area->buf, area->size);
mempool_free(area, &rwa_state.descriptor_pool);
wake_up(&rwa_state.wqh);
}
/*
* Initialization of the work area allocator happens in two parts. To
* reliably reserve an arena that satisfies RTAS addressing
* requirements, we must perform a memblock allocation early,
* immmediately after RTAS instantiation. Then we have to wait until
* the slab allocator is up before setting up the descriptor mempool
* and adding the arena to a gen_pool.
*/
static __init int rtas_work_area_allocator_init(void)
{
const unsigned int order = ilog2(RTAS_WORK_AREA_MIN_ALLOC_SZ);
const phys_addr_t pa_start = __pa(rwa_state.arena);
const phys_addr_t pa_end = pa_start + RTAS_WORK_AREA_ARENA_SZ - 1;
struct gen_pool *pool;
const int nid = NUMA_NO_NODE;
int err;
err = -ENOMEM;
if (!rwa_state.arena)
goto err_out;
pool = gen_pool_create(order, nid);
if (!pool)
goto err_out;
/*
* All RTAS functions that consume work areas are OK with
* natural alignment, when they have alignment requirements at
* all.
*/
gen_pool_set_algo(pool, gen_pool_first_fit_order_align, NULL);
err = gen_pool_add(pool, (unsigned long)rwa_state.arena,
RTAS_WORK_AREA_ARENA_SZ, nid);
if (err)
goto err_destroy;
err = mempool_init_kmalloc_pool(&rwa_state.descriptor_pool, 1,
sizeof(struct rtas_work_area));
if (err)
goto err_destroy;
rwa_state.gen_pool = pool;
rwa_state.available = true;
pr_debug("arena [%pa-%pa] (%uK), min/max alloc sizes %u/%u\n",
&pa_start, &pa_end,
RTAS_WORK_AREA_ARENA_SZ / SZ_1K,
RTAS_WORK_AREA_MIN_ALLOC_SZ,
RTAS_WORK_AREA_MAX_ALLOC_SZ);
return 0;
err_destroy:
gen_pool_destroy(pool);
err_out:
return err;
}
machine_arch_initcall(pseries, rtas_work_area_allocator_init);
/**
* rtas_work_area_reserve_arena() - Reserve memory suitable for RTAS work areas.
* @limit: Upper limit for memblock allocation.
*/
void __init rtas_work_area_reserve_arena(const phys_addr_t limit)
{
const phys_addr_t align = RTAS_WORK_AREA_ARENA_ALIGN;
const phys_addr_t size = RTAS_WORK_AREA_ARENA_SZ;
const phys_addr_t min = MEMBLOCK_LOW_LIMIT;
const int nid = NUMA_NO_NODE;
/*
* Too early for a machine_is(pseries) check. But PAPR
* effectively mandates that ibm,get-system-parameter is
* present:
*
* R1–7.3.16–1. All platforms must support the System
* Parameters option.
*
* So set up the arena if we find that, with a fallback to
* ibm,configure-connector, just in case.
*/
if (rtas_function_implemented(RTAS_FN_IBM_GET_SYSTEM_PARAMETER) ||
rtas_function_implemented(RTAS_FN_IBM_CONFIGURE_CONNECTOR))
rwa_state.arena = memblock_alloc_try_nid(size, align, min, limit, nid);
}
|
