diff options
| -rw-r--r-- | arch/mips/mm/c-r4k.c | 23 |
1 files changed, 15 insertions, 8 deletions
diff --git a/arch/mips/mm/c-r4k.c b/arch/mips/mm/c-r4k.c index 58e2eeddc391..0dbb65a51ce5 100644 --- a/arch/mips/mm/c-r4k.c +++ b/arch/mips/mm/c-r4k.c @@ -889,33 +889,39 @@ static inline void rm7k_erratum31(void) } } -static inline void alias_74k_erratum(struct cpuinfo_mips *c) +static inline int alias_74k_erratum(struct cpuinfo_mips *c) { unsigned int imp = c->processor_id & PRID_IMP_MASK; unsigned int rev = c->processor_id & PRID_REV_MASK; + int present = 0; /* * Early versions of the 74K do not update the cache tags on a * vtag miss/ptag hit which can occur in the case of KSEG0/KUSEG - * aliases. In this case it is better to treat the cache as always - * having aliases. + * aliases. In this case it is better to treat the cache as always + * having aliases. Also disable the synonym tag update feature + * where available. In this case no opportunistic tag update will + * happen where a load causes a virtual address miss but a physical + * address hit during a D-cache look-up. */ switch (imp) { case PRID_IMP_74K: if (rev <= PRID_REV_ENCODE_332(2, 4, 0)) - c->dcache.flags |= MIPS_CACHE_VTAG; + present = 1; if (rev == PRID_REV_ENCODE_332(2, 4, 0)) write_c0_config6(read_c0_config6() | MIPS_CONF6_SYND); break; case PRID_IMP_1074K: if (rev <= PRID_REV_ENCODE_332(1, 1, 0)) { - c->dcache.flags |= MIPS_CACHE_VTAG; + present = 1; write_c0_config6(read_c0_config6() | MIPS_CONF6_SYND); } break; default: BUG(); } + + return present; } static void b5k_instruction_hazard(void) @@ -939,6 +945,7 @@ static void probe_pcache(void) struct cpuinfo_mips *c = ¤t_cpu_data; unsigned int config = read_c0_config(); unsigned int prid = read_c0_prid(); + int has_74k_erratum = 0; unsigned long config1; unsigned int lsize; @@ -1247,7 +1254,7 @@ static void probe_pcache(void) case CPU_74K: case CPU_1074K: - alias_74k_erratum(c); + has_74k_erratum = alias_74k_erratum(c); /* Fall through. */ case CPU_M14KC: case CPU_M14KEC: @@ -1262,7 +1269,7 @@ static void probe_pcache(void) if (!(read_c0_config7() & MIPS_CONF7_IAR) && (c->icache.waysize > PAGE_SIZE)) c->icache.flags |= MIPS_CACHE_ALIASES; - if (read_c0_config7() & MIPS_CONF7_AR) { + if (!has_74k_erratum && (read_c0_config7() & MIPS_CONF7_AR)) { /* * Effectively physically indexed dcache, * thus no virtual aliases. @@ -1271,7 +1278,7 @@ static void probe_pcache(void) break; } default: - if (c->dcache.waysize > PAGE_SIZE) + if (has_74k_erratum || c->dcache.waysize > PAGE_SIZE) c->dcache.flags |= MIPS_CACHE_ALIASES; } |