1 /*
2 * Low-level SPU handling
3 *
4 * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
5 *
6 * Author: Arnd Bergmann <arndb@de.ibm.com>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2, or (at your option)
11 * any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21 */
22 #include <linux/sched/signal.h>
23 #include <linux/mm.h>
24
25 #include <asm/spu.h>
26 #include <asm/spu_csa.h>
27
28 #include "spufs.h"
29
30 /**
31 * Handle an SPE event, depending on context SPU_CREATE_EVENTS_ENABLED flag.
32 *
33 * If the context was created with events, we just set the return event.
34 * Otherwise, send an appropriate signal to the process.
35 */
spufs_handle_event(struct spu_context * ctx,unsigned long ea,int type)36 static void spufs_handle_event(struct spu_context *ctx,
37 unsigned long ea, int type)
38 {
39 siginfo_t info;
40
41 if (ctx->flags & SPU_CREATE_EVENTS_ENABLED) {
42 ctx->event_return |= type;
43 wake_up_all(&ctx->stop_wq);
44 return;
45 }
46
47 clear_siginfo(&info);
48
49 switch (type) {
50 case SPE_EVENT_INVALID_DMA:
51 info.si_signo = SIGBUS;
52 info.si_code = BUS_OBJERR;
53 break;
54 case SPE_EVENT_SPE_DATA_STORAGE:
55 info.si_signo = SIGSEGV;
56 info.si_addr = (void __user *)ea;
57 info.si_code = SEGV_ACCERR;
58 ctx->ops->restart_dma(ctx);
59 break;
60 case SPE_EVENT_DMA_ALIGNMENT:
61 info.si_signo = SIGBUS;
62 /* DAR isn't set for an alignment fault :( */
63 info.si_code = BUS_ADRALN;
64 break;
65 case SPE_EVENT_SPE_ERROR:
66 info.si_signo = SIGILL;
67 info.si_addr = (void __user *)(unsigned long)
68 ctx->ops->npc_read(ctx) - 4;
69 info.si_code = ILL_ILLOPC;
70 break;
71 }
72
73 if (info.si_signo)
74 force_sig_info(info.si_signo, &info, current);
75 }
76
spufs_handle_class0(struct spu_context * ctx)77 int spufs_handle_class0(struct spu_context *ctx)
78 {
79 unsigned long stat = ctx->csa.class_0_pending & CLASS0_INTR_MASK;
80
81 if (likely(!stat))
82 return 0;
83
84 if (stat & CLASS0_DMA_ALIGNMENT_INTR)
85 spufs_handle_event(ctx, ctx->csa.class_0_dar,
86 SPE_EVENT_DMA_ALIGNMENT);
87
88 if (stat & CLASS0_INVALID_DMA_COMMAND_INTR)
89 spufs_handle_event(ctx, ctx->csa.class_0_dar,
90 SPE_EVENT_INVALID_DMA);
91
92 if (stat & CLASS0_SPU_ERROR_INTR)
93 spufs_handle_event(ctx, ctx->csa.class_0_dar,
94 SPE_EVENT_SPE_ERROR);
95
96 ctx->csa.class_0_pending = 0;
97
98 return -EIO;
99 }
100
101 /*
102 * bottom half handler for page faults, we can't do this from
103 * interrupt context, since we might need to sleep.
104 * we also need to give up the mutex so we can get scheduled
105 * out while waiting for the backing store.
106 *
107 * TODO: try calling hash_page from the interrupt handler first
108 * in order to speed up the easy case.
109 */
spufs_handle_class1(struct spu_context * ctx)110 int spufs_handle_class1(struct spu_context *ctx)
111 {
112 u64 ea, dsisr, access;
113 unsigned long flags;
114 vm_fault_t flt = 0;
115 int ret;
116
117 /*
118 * dar and dsisr get passed from the registers
119 * to the spu_context, to this function, but not
120 * back to the spu if it gets scheduled again.
121 *
122 * if we don't handle the fault for a saved context
123 * in time, we can still expect to get the same fault
124 * the immediately after the context restore.
125 */
126 ea = ctx->csa.class_1_dar;
127 dsisr = ctx->csa.class_1_dsisr;
128
129 if (!(dsisr & (MFC_DSISR_PTE_NOT_FOUND | MFC_DSISR_ACCESS_DENIED)))
130 return 0;
131
132 spuctx_switch_state(ctx, SPU_UTIL_IOWAIT);
133
134 pr_debug("ctx %p: ea %016llx, dsisr %016llx state %d\n", ctx, ea,
135 dsisr, ctx->state);
136
137 ctx->stats.hash_flt++;
138 if (ctx->state == SPU_STATE_RUNNABLE)
139 ctx->spu->stats.hash_flt++;
140
141 /* we must not hold the lock when entering copro_handle_mm_fault */
142 spu_release(ctx);
143
144 access = (_PAGE_PRESENT | _PAGE_READ);
145 access |= (dsisr & MFC_DSISR_ACCESS_PUT) ? _PAGE_WRITE : 0UL;
146 local_irq_save(flags);
147 ret = hash_page(ea, access, 0x300, dsisr);
148 local_irq_restore(flags);
149
150 /* hashing failed, so try the actual fault handler */
151 if (ret)
152 ret = copro_handle_mm_fault(current->mm, ea, dsisr, &flt);
153
154 /*
155 * This is nasty: we need the state_mutex for all the bookkeeping even
156 * if the syscall was interrupted by a signal. ewww.
157 */
158 mutex_lock(&ctx->state_mutex);
159
160 /*
161 * Clear dsisr under ctxt lock after handling the fault, so that
162 * time slicing will not preempt the context while the page fault
163 * handler is running. Context switch code removes mappings.
164 */
165 ctx->csa.class_1_dar = ctx->csa.class_1_dsisr = 0;
166
167 /*
168 * If we handled the fault successfully and are in runnable
169 * state, restart the DMA.
170 * In case of unhandled error report the problem to user space.
171 */
172 if (!ret) {
173 if (flt & VM_FAULT_MAJOR)
174 ctx->stats.maj_flt++;
175 else
176 ctx->stats.min_flt++;
177 if (ctx->state == SPU_STATE_RUNNABLE) {
178 if (flt & VM_FAULT_MAJOR)
179 ctx->spu->stats.maj_flt++;
180 else
181 ctx->spu->stats.min_flt++;
182 }
183
184 if (ctx->spu)
185 ctx->ops->restart_dma(ctx);
186 } else
187 spufs_handle_event(ctx, ea, SPE_EVENT_SPE_DATA_STORAGE);
188
189 spuctx_switch_state(ctx, SPU_UTIL_SYSTEM);
190 return ret;
191 }
192
