gwj / at91sam9263 · Commits

Commit 44cd42ee4082813cc4b45117bbb6156920957e47

Authored by edgar_igl
1 parent 86831435

CRIS: Add support for the pseudo randomized set that the mmu provides with TLB r… 

…efill faults. This makes linux guests use the four way TLB set associativty.

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@4425 c046a42c-6fe2-441c-8c8c-71466251a162
Inline Side-by-side
Showing 2 changed files with 41 additions and 13 deletions
target-cris/cpu.h
  View file @44cd42e
... ... @@ -153,6 +153,11 @@ typedef struct CPUCRISState {
153 153 */
154 154 uint32_t sregs[4][16];
155 155  
  156 + /* Linear feedback shift reg in the mmu. Used to provide pseudo
  157 + randomness for the 'hint' the mmu gives to sw for chosing valid
  158 + sets on TLB refills. */
  159 + uint32_t mmu_rand_lfsr;
  160 +
156 161 /*
157 162 * We just store the stores to the tlbset here for later evaluation
158 163 * when the hw needs access to them.
... ...
target-cris/mmu.c
  View file @44cd42e
... ... @@ -32,6 +32,24 @@
32 32  
33 33 #define D(x)
34 34  
  35 +void cris_mmu_init(CPUState *env)
  36 +{
  37 + env->mmu_rand_lfsr = 0xcccc;
  38 +}
  39 +
  40 +#define SR_POLYNOM 0x8805
  41 +static inline unsigned int compute_polynom(unsigned int sr)
  42 +{
  43 + unsigned int i;
  44 + unsigned int f;
  45 +
  46 + f = 0;
  47 + for (i = 0; i < 16; i++)
  48 + f += ((SR_POLYNOM >> i) & 1) & ((sr >> i) & 1);
  49 +
  50 + return f;
  51 +}
  52 +
35 53 static inline int cris_mmu_enabled(uint32_t rw_gc_cfg)
36 54 {
37 55 return (rw_gc_cfg & 12) != 0;
... ... @@ -152,11 +170,14 @@ static int cris_mmu_translate_page(struct cris_mmu_result_t *res,
152 170 hi = env->tlbsets[mmu][set][idx].hi;
153 171  
154 172 tlb_vpn = EXTRACT_FIELD(hi, 13, 31);
  173 + tlb_pid = EXTRACT_FIELD(hi, 0, 7);
155 174 tlb_pfn = EXTRACT_FIELD(lo, 13, 31);
  175 + tlb_g = EXTRACT_FIELD(lo, 4, 4);
156 176  
157 177 D(printf("TLB[%d][%d] v=%x vpage=%x -> pfn=%x lo=%x hi=%x\n",
158 178 i, idx, tlb_vpn, vpage, tlb_pfn, lo, hi));
159   - if (tlb_vpn == vpage) {
  179 + if ((tlb_g || (tlb_pid == (env->pregs[PR_PID] & 0xff)))
  180 + && tlb_vpn == vpage) {
160 181 match = 1;
161 182 break;
162 183 }
... ... @@ -169,9 +190,7 @@ static int cris_mmu_translate_page(struct cris_mmu_result_t *res,
169 190 cfg_x = EXTRACT_FIELD(r_cfg, 17, 17);
170 191 cfg_v = EXTRACT_FIELD(r_cfg, 16, 16);
171 192  
172   - tlb_pid = EXTRACT_FIELD(hi, 0, 7);
173 193 tlb_pfn = EXTRACT_FIELD(lo, 13, 31);
174   - tlb_g = EXTRACT_FIELD(lo, 4, 4);
175 194 tlb_v = EXTRACT_FIELD(lo, 3, 3);
176 195 tlb_k = EXTRACT_FIELD(lo, 2, 2);
177 196 tlb_w = EXTRACT_FIELD(lo, 1, 1);
... ... @@ -187,13 +206,7 @@ static int cris_mmu_translate_page(struct cris_mmu_result_t *res,
187 206 set_exception_vector(0x0a, d_mmu_access);
188 207 set_exception_vector(0x0b, d_mmu_write);
189 208 */
190   - if (!tlb_g
191   - && tlb_pid != (env->pregs[PR_PID] & 0xff)) {
192   - D(printf ("tlb: wrong pid %x %x pc=%x\n",
193   - tlb_pid, env->pregs[PR_PID], env->pc));
194   - match = 0;
195   - res->bf_vec = vect_base;
196   - } else if (cfg_k && tlb_k && usermode) {
  209 + if (cfg_k && tlb_k && usermode) {
197 210 D(printf ("tlb: kernel protected %x lo=%x pc=%x\n",
198 211 vaddr, lo, env->pc));
199 212 match = 0;
... ... @@ -229,17 +242,27 @@ static int cris_mmu_translate_page(struct cris_mmu_result_t *res,
229 242  
230 243 env->sregs[SFR_RW_MM_TLB_HI] = hi;
231 244 env->sregs[SFR_RW_MM_TLB_LO] = lo;
  245 + } else {
  246 + /* If refill, provide a randomized set. */
  247 + set = env->mmu_rand_lfsr & 3;
232 248 }
233 249  
234 250 if (!match) {
235   - /* miss. */
  251 + unsigned int f;
  252 +
  253 + /* Update lfsr at every fault. */
  254 + f = compute_polynom(env->mmu_rand_lfsr);
  255 + env->mmu_rand_lfsr >>= 1;
  256 + env->mmu_rand_lfsr |= (f << 15);
  257 + env->mmu_rand_lfsr &= 0xffff;
  258 +
  259 + /* Compute index. */
236 260 idx = vpage & 15;
237   - set = 0;
238 261  
239 262 /* Update RW_MM_TLB_SEL. */
240 263 env->sregs[SFR_RW_MM_TLB_SEL] = 0;
241 264 set_field(&env->sregs[SFR_RW_MM_TLB_SEL], idx, 0, 4);
242   - set_field(&env->sregs[SFR_RW_MM_TLB_SEL], set, 4, 5);
  265 + set_field(&env->sregs[SFR_RW_MM_TLB_SEL], set, 4, 2);
243 266  
244 267 /* Update RW_MM_CAUSE. */
245 268 set_field(&r_cause, rwcause, 8, 2);
... ...