| Message ID | 20240829233425.1005029-2-debug@rivosinc.com |
|---|---|
| State | New |
| Headers | show |
| Series | riscv support for control flow integrity extensions | expand |
On 8/30/24 09:34, Deepak Gupta wrote: > Execution environment config CSR controlling user env and current > privilege state shouldn't be limited to qemu-system only. *envcfg > CSRs control enabling of features in next lesser mode. In some cases > bits *envcfg CSR can be lit up by kernel as part of kernel policy or > software (user app) can choose to opt-in by issuing a system call > (e.g. prctl). In case of qemu-user, it should be no different because > qemu is providing underlying execution environment facility and thus > either should provide some default value in *envcfg CSRs or react to > system calls (prctls) initiated from application. priv is set to PRV_U > and menvcfg/senvcfg set to 0 for qemu-user on reest. > > `henvcfg` has been left for qemu-system only because it is not expected > that someone will use qemu-user where application is expected to have > hypervisor underneath which is controlling its execution environment. If > such a need arises then `henvcfg` could be exposed as well. > > Relevant discussion: > https://lore.kernel.org/all/ > CAKmqyKOTVWPFep2msTQVdUmJErkH+bqCcKEQ4hAnyDFPdWKe0Q@mail.gmail.com/ > > Signed-off-by: Deepak Gupta<debug@rivosinc.com> > Suggested-by: Richard Henderson<richard.henderson@linaro.org> > Reviewed-by: Alistair Francis<alistair.francis@wdc.com> > --- > target/riscv/cpu.c | 5 +++++ > target/riscv/cpu.h | 9 +++++---- > 2 files changed, 10 insertions(+), 4 deletions(-) Reviewed-by: Richard Henderson <richard.henderson@linaro.org> r~
diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c index 33ef4eb795..c4ea1d4038 100644 --- a/target/riscv/cpu.c +++ b/target/riscv/cpu.c @@ -1011,7 +1011,12 @@ static void riscv_cpu_reset_hold(Object *obj, ResetType type) } pmp_unlock_entries(env); +#else + env->priv = PRV_U; + env->senvcfg = 0; + env->menvcfg = 0; #endif + env->xl = riscv_cpu_mxl(env); riscv_cpu_update_mask(env); cs->exception_index = RISCV_EXCP_NONE; diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h index 87742047ce..270a2a031c 100644 --- a/target/riscv/cpu.h +++ b/target/riscv/cpu.h @@ -226,8 +226,12 @@ struct CPUArchState { uint32_t elf_flags; #endif -#ifndef CONFIG_USER_ONLY target_ulong priv; + /* CSRs for execution environment configuration */ + uint64_t menvcfg; + target_ulong senvcfg; + +#ifndef CONFIG_USER_ONLY /* This contains QEMU specific information about the virt state. */ bool virt_enabled; target_ulong geilen; @@ -429,12 +433,9 @@ struct CPUArchState { target_ulong upmmask; target_ulong upmbase; - /* CSRs for execution environment configuration */ - uint64_t menvcfg; uint64_t mstateen[SMSTATEEN_MAX_COUNT]; uint64_t hstateen[SMSTATEEN_MAX_COUNT]; uint64_t sstateen[SMSTATEEN_MAX_COUNT]; - target_ulong senvcfg; uint64_t henvcfg; #endif target_ulong cur_pmmask;