diff options
| -rw-r--r-- | arch/mips/mm/tlbex.c | 38 |
1 files changed, 37 insertions, 1 deletions
diff --git a/arch/mips/mm/tlbex.c b/arch/mips/mm/tlbex.c index ed1c529..e649920 100644 --- a/arch/mips/mm/tlbex.c +++ b/arch/mips/mm/tlbex.c @@ -2015,6 +2015,26 @@ static void build_r3000_tlb_modify_handler(void) } #endif /* CONFIG_MIPS_PGD_C0_CONTEXT */ +static bool cpu_has_tlbex_tlbp_race(void) +{ + /* + * When a Hardware Table Walker is running it can replace TLB entries + * at any time, leading to a race between it & the CPU. + */ + if (cpu_has_htw) + return true; + + /* + * If the CPU shares FTLB RAM with its siblings then our entry may be + * replaced at any time by a sibling performing a write to the FTLB. + */ + if (cpu_has_shared_ftlb_ram) + return true; + + /* In all other cases there ought to be no race condition to handle */ + return false; +} + /* * R4000 style TLB load/store/modify handlers. */ @@ -2051,7 +2071,7 @@ build_r4000_tlbchange_handler_head(u32 **p, struct uasm_label **l, iPTE_LW(p, wr.r1, wr.r2); /* get even pte */ if (!m4kc_tlbp_war()) { build_tlb_probe_entry(p); - if (cpu_has_htw) { + if (cpu_has_tlbex_tlbp_race()) { /* race condition happens, leaving */ uasm_i_ehb(p); uasm_i_mfc0(p, wr.r3, C0_INDEX); @@ -2125,6 +2145,14 @@ static void build_r4000_tlb_load_handler(void) } uasm_i_nop(&p); + /* + * Warn if something may race with us & replace the TLB entry + * before we read it here. Everything with such races should + * also have dedicated RiXi exception handlers, so this + * shouldn't be hit. + */ + WARN(cpu_has_tlbex_tlbp_race(), "Unhandled race in RiXi path"); + uasm_i_tlbr(&p); switch (current_cpu_type()) { @@ -2192,6 +2220,14 @@ static void build_r4000_tlb_load_handler(void) } uasm_i_nop(&p); + /* + * Warn if something may race with us & replace the TLB entry + * before we read it here. Everything with such races should + * also have dedicated RiXi exception handlers, so this + * shouldn't be hit. + */ + WARN(cpu_has_tlbex_tlbp_race(), "Unhandled race in RiXi path"); + uasm_i_tlbr(&p); switch (current_cpu_type()) { |
