diff options
Diffstat (limited to 'arch/mips/kernel/cpu-probe.c')
| -rw-r--r-- | arch/mips/kernel/cpu-probe.c | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c index 46a24729fbba..6a1a7da4b2d2 100644 --- a/arch/mips/kernel/cpu-probe.c +++ b/arch/mips/kernel/cpu-probe.c @@ -860,6 +860,41 @@ static void decode_configs(struct cpuinfo_mips *c) if (ok) ok = decode_config5(c); + /* Probe the EBase.WG bit */ + if (cpu_has_mips_r2_r6) { + u64 ebase; + unsigned int status; + + /* {read,write}_c0_ebase_64() may be UNDEFINED prior to r6 */ + ebase = cpu_has_mips64r6 ? read_c0_ebase_64() + : (s32)read_c0_ebase(); + if (ebase & MIPS_EBASE_WG) { + /* WG bit already set, we can avoid the clumsy probe */ + c->options |= MIPS_CPU_EBASE_WG; + } else { + /* Its UNDEFINED to change EBase while BEV=0 */ + status = read_c0_status(); + write_c0_status(status | ST0_BEV); + irq_enable_hazard(); + /* + * On pre-r6 cores, this may well clobber the upper bits + * of EBase. This is hard to avoid without potentially + * hitting UNDEFINED dm*c0 behaviour if EBase is 32-bit. + */ + if (cpu_has_mips64r6) + write_c0_ebase_64(ebase | MIPS_EBASE_WG); + else + write_c0_ebase(ebase | MIPS_EBASE_WG); + back_to_back_c0_hazard(); + /* Restore BEV */ + write_c0_status(status); + if (read_c0_ebase() & MIPS_EBASE_WG) { + c->options |= MIPS_CPU_EBASE_WG; + write_c0_ebase(ebase); + } + } + } + mips_probe_watch_registers(c); #ifndef CONFIG_MIPS_CPS |