diff options
| -rw-r--r-- | target/riscv/cpu.c | 23 |
1 files changed, 20 insertions, 3 deletions
diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c index 8071f05f15..34ac26e3ae 100644 --- a/target/riscv/cpu.c +++ b/target/riscv/cpu.c @@ -309,6 +309,17 @@ static uint8_t satp_mode_from_str(const char *satp_mode_str) uint8_t satp_mode_max_from_map(uint32_t map) { + /* + * 'map = 0' will make us return (31 - 32), which C will + * happily overflow to UINT_MAX. There's no good result to + * return if 'map = 0' (e.g. returning 0 will be ambiguous + * with the result for 'map = 1'). + * + * Assert out if map = 0. Callers will have to deal with + * it outside of this function. + */ + g_assert(map > 0); + /* map here has at least one bit set, so no problem with clz */ return 31 - __builtin_clz(map); } @@ -1333,9 +1344,15 @@ void riscv_cpu_validate_set_extensions(RISCVCPU *cpu, Error **errp) static void riscv_cpu_satp_mode_finalize(RISCVCPU *cpu, Error **errp) { bool rv32 = riscv_cpu_mxl(&cpu->env) == MXL_RV32; - uint8_t satp_mode_map_max; - uint8_t satp_mode_supported_max = - satp_mode_max_from_map(cpu->cfg.satp_mode.supported); + uint8_t satp_mode_map_max, satp_mode_supported_max; + + /* The CPU wants the OS to decide which satp mode to use */ + if (cpu->cfg.satp_mode.supported == 0) { + return; + } + + satp_mode_supported_max = + satp_mode_max_from_map(cpu->cfg.satp_mode.supported); if (cpu->cfg.satp_mode.map == 0) { if (cpu->cfg.satp_mode.init == 0) { |