2 * Blackfin CPLB exception handling.
3 * Copyright 2004-2007 Analog Devices Inc.
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, see the file COPYING, or write
17 * to the Free Software Foundation, Inc.,
18 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
20 #include <linux/module.h>
23 #include <asm/blackfin.h>
24 #include <asm/cacheflush.h>
26 #include <asm/cplbinit.h>
27 #include <asm/mmu_context.h>
32 * This file is compiled with certain -ffixed-reg options. We have to
33 * make sure not to call any functions here that could clobber these
39 unsigned long *current_rwx_mask[NR_CPUS];
41 int nr_dcplb_miss[NR_CPUS], nr_icplb_miss[NR_CPUS];
42 int nr_icplb_supv_miss[NR_CPUS], nr_dcplb_prot[NR_CPUS];
43 int nr_cplb_flush[NR_CPUS];
46 * Given the contents of the status register, return the index of the
47 * CPLB that caused the fault.
49 static inline int faulting_cplb_index(int status)
51 int signbits = __builtin_bfin_norm_fr1x32(status & 0xFFFF);
56 * Given the contents of the status register and the DCPLB_DATA contents,
57 * return true if a write access should be permitted.
59 static inline int write_permitted(int status, unsigned long data)
61 if (status & FAULT_USERSUPV)
62 return !!(data & CPLB_SUPV_WR);
64 return !!(data & CPLB_USER_WR);
67 /* Counters to implement round-robin replacement. */
68 static int icplb_rr_index[NR_CPUS], dcplb_rr_index[NR_CPUS];
71 * Find an ICPLB entry to be evicted and return its index.
73 static int evict_one_icplb(unsigned int cpu)
76 for (i = first_switched_icplb; i < MAX_CPLBS; i++)
77 if ((icplb_tbl[cpu][i].data & CPLB_VALID) == 0)
79 i = first_switched_icplb + icplb_rr_index[cpu];
81 i -= MAX_CPLBS - first_switched_icplb;
82 icplb_rr_index[cpu] -= MAX_CPLBS - first_switched_icplb;
84 icplb_rr_index[cpu]++;
88 static int evict_one_dcplb(unsigned int cpu)
91 for (i = first_switched_dcplb; i < MAX_CPLBS; i++)
92 if ((dcplb_tbl[cpu][i].data & CPLB_VALID) == 0)
94 i = first_switched_dcplb + dcplb_rr_index[cpu];
96 i -= MAX_CPLBS - first_switched_dcplb;
97 dcplb_rr_index[cpu] -= MAX_CPLBS - first_switched_dcplb;
99 dcplb_rr_index[cpu]++;
103 static noinline int dcplb_miss(unsigned int cpu)
105 unsigned long addr = bfin_read_DCPLB_FAULT_ADDR();
106 int status = bfin_read_DCPLB_STATUS();
109 unsigned long d_data;
111 nr_dcplb_miss[cpu]++;
113 d_data = CPLB_SUPV_WR | CPLB_VALID | CPLB_DIRTY | PAGE_SIZE_4KB;
114 #ifdef CONFIG_BFIN_EXTMEM_DCACHEABLE
115 if (bfin_addr_dcacheable(addr)) {
116 d_data |= CPLB_L1_CHBL | ANOMALY_05000158_WORKAROUND;
117 # ifdef CONFIG_BFIN_EXTMEM_WRITETHROUGH
118 d_data |= CPLB_L1_AOW | CPLB_WT;
123 if (L2_LENGTH && addr >= L2_START && addr < L2_START + L2_LENGTH) {
126 } else if (addr >= physical_mem_end) {
127 if (addr >= ASYNC_BANK0_BASE && addr < ASYNC_BANK3_BASE + ASYNC_BANK3_SIZE
128 && (status & FAULT_USERSUPV)) {
130 d_data &= ~PAGE_SIZE_4KB;
131 d_data |= PAGE_SIZE_4MB;
132 } else if (addr >= BOOT_ROM_START && addr < BOOT_ROM_START + BOOT_ROM_LENGTH
133 && (status & (FAULT_RW | FAULT_USERSUPV)) == FAULT_USERSUPV) {
134 addr &= ~(1 * 1024 * 1024 - 1);
135 d_data &= ~PAGE_SIZE_4KB;
136 d_data |= PAGE_SIZE_1MB;
138 return CPLB_PROT_VIOL;
139 } else if (addr >= _ramend) {
140 d_data |= CPLB_USER_RD | CPLB_USER_WR;
142 mask = current_rwx_mask[cpu];
144 int page = addr >> PAGE_SHIFT;
146 int bit = 1 << (page & 31);
149 d_data |= CPLB_USER_RD;
151 mask += page_mask_nelts;
153 d_data |= CPLB_USER_WR;
156 idx = evict_one_dcplb(cpu);
159 dcplb_tbl[cpu][idx].addr = addr;
160 dcplb_tbl[cpu][idx].data = d_data;
163 bfin_write32(DCPLB_DATA0 + idx * 4, d_data);
164 bfin_write32(DCPLB_ADDR0 + idx * 4, addr);
170 static noinline int icplb_miss(unsigned int cpu)
172 unsigned long addr = bfin_read_ICPLB_FAULT_ADDR();
173 int status = bfin_read_ICPLB_STATUS();
175 unsigned long i_data;
177 nr_icplb_miss[cpu]++;
179 /* If inside the uncached DMA region, fault. */
180 if (addr >= _ramend - DMA_UNCACHED_REGION && addr < _ramend)
181 return CPLB_PROT_VIOL;
183 if (status & FAULT_USERSUPV)
184 nr_icplb_supv_miss[cpu]++;
187 * First, try to find a CPLB that matches this address. If we
188 * find one, then the fact that we're in the miss handler means
189 * that the instruction crosses a page boundary.
191 for (idx = first_switched_icplb; idx < MAX_CPLBS; idx++) {
192 if (icplb_tbl[cpu][idx].data & CPLB_VALID) {
193 unsigned long this_addr = icplb_tbl[cpu][idx].addr;
194 if (this_addr <= addr && this_addr + PAGE_SIZE > addr) {
201 i_data = CPLB_VALID | CPLB_PORTPRIO | PAGE_SIZE_4KB;
203 #ifdef CONFIG_BFIN_EXTMEM_ICACHEABLE
205 * Normal RAM, and possibly the reserved memory area, are
208 if (addr < _ramend ||
209 (addr < physical_mem_end && reserved_mem_icache_on))
210 i_data |= CPLB_L1_CHBL | ANOMALY_05000158_WORKAROUND;
213 if (L2_LENGTH && addr >= L2_START && addr < L2_START + L2_LENGTH) {
216 } else if (addr >= physical_mem_end) {
217 if (addr >= BOOT_ROM_START && addr < BOOT_ROM_START + BOOT_ROM_LENGTH
218 && (status & FAULT_USERSUPV)) {
219 addr &= ~(1 * 1024 * 1024 - 1);
220 i_data &= ~PAGE_SIZE_4KB;
221 i_data |= PAGE_SIZE_1MB;
223 return CPLB_PROT_VIOL;
224 } else if (addr >= _ramend) {
225 i_data |= CPLB_USER_RD;
228 * Two cases to distinguish - a supervisor access must
229 * necessarily be for a module page; we grant it
230 * unconditionally (could do better here in the future).
231 * Otherwise, check the x bitmap of the current process.
233 if (!(status & FAULT_USERSUPV)) {
234 unsigned long *mask = current_rwx_mask[cpu];
237 int page = addr >> PAGE_SHIFT;
239 int bit = 1 << (page & 31);
241 mask += 2 * page_mask_nelts;
243 i_data |= CPLB_USER_RD;
247 idx = evict_one_icplb(cpu);
249 icplb_tbl[cpu][idx].addr = addr;
250 icplb_tbl[cpu][idx].data = i_data;
253 bfin_write32(ICPLB_DATA0 + idx * 4, i_data);
254 bfin_write32(ICPLB_ADDR0 + idx * 4, addr);
260 static noinline int dcplb_protection_fault(unsigned int cpu)
262 int status = bfin_read_DCPLB_STATUS();
264 nr_dcplb_prot[cpu]++;
266 if (status & FAULT_RW) {
267 int idx = faulting_cplb_index(status);
268 unsigned long data = dcplb_tbl[cpu][idx].data;
269 if (!(data & CPLB_WT) && !(data & CPLB_DIRTY) &&
270 write_permitted(status, data)) {
272 dcplb_tbl[cpu][idx].data = data;
273 bfin_write32(DCPLB_DATA0 + idx * 4, data);
277 return CPLB_PROT_VIOL;
280 int cplb_hdr(int seqstat, struct pt_regs *regs)
282 int cause = seqstat & 0x3f;
283 unsigned int cpu = raw_smp_processor_id();
286 return dcplb_protection_fault(cpu);
288 return icplb_miss(cpu);
290 return dcplb_miss(cpu);
296 void flush_switched_cplbs(unsigned int cpu)
301 nr_cplb_flush[cpu]++;
303 local_irq_save_hw(flags);
305 for (i = first_switched_icplb; i < MAX_CPLBS; i++) {
306 icplb_tbl[cpu][i].data = 0;
307 bfin_write32(ICPLB_DATA0 + i * 4, 0);
312 for (i = first_switched_dcplb; i < MAX_CPLBS; i++) {
313 dcplb_tbl[cpu][i].data = 0;
314 bfin_write32(DCPLB_DATA0 + i * 4, 0);
317 local_irq_restore_hw(flags);
321 void set_mask_dcplbs(unsigned long *masks, unsigned int cpu)
324 unsigned long addr = (unsigned long)masks;
325 unsigned long d_data;
329 current_rwx_mask[cpu] = masks;
333 local_irq_save_hw(flags);
334 current_rwx_mask[cpu] = masks;
336 if (L2_LENGTH && addr >= L2_START && addr < L2_START + L2_LENGTH) {
340 d_data = CPLB_SUPV_WR | CPLB_VALID | CPLB_DIRTY | PAGE_SIZE_4KB;
341 #ifdef CONFIG_BFIN_EXTMEM_DCACHEABLE
342 d_data |= CPLB_L1_CHBL;
343 # ifdef CONFIG_BFIN_EXTMEM_WRITETHROUGH
344 d_data |= CPLB_L1_AOW | CPLB_WT;
350 for (i = first_mask_dcplb; i < first_switched_dcplb; i++) {
351 dcplb_tbl[cpu][i].addr = addr;
352 dcplb_tbl[cpu][i].data = d_data;
353 bfin_write32(DCPLB_DATA0 + i * 4, d_data);
354 bfin_write32(DCPLB_ADDR0 + i * 4, addr);
358 local_irq_restore_hw(flags);