diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c index 377661bae9..afdba29995 100644 --- a/target/riscv/cpu.c +++ b/target/riscv/cpu.c @@ -1014,6 +1014,8 @@ static void riscv_cpu_reset_hold(Object *obj, ResetType type) /* on reset elp is clear */ env->elp = false; + /* on reset ssp is set to 0 */ + env->ssp = 0; env->xl = riscv_cpu_mxl(env); riscv_cpu_update_mask(env); diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h index c3a03f878b..195eac81c0 100644 --- a/target/riscv/cpu.h +++ b/target/riscv/cpu.h @@ -232,6 +232,8 @@ struct CPUArchState { /* elp state for zicfilp extension */ bool elp; + /* shadow stack register for zicfiss extension */ + target_ulong ssp; /* sw check code for sw check exception */ target_ulong sw_check_code; #ifdef CONFIG_USER_ONLY @@ -550,6 +552,7 @@ bool riscv_cpu_vector_enabled(CPURISCVState *env); void riscv_cpu_set_virt_enabled(CPURISCVState *env, bool enable); int riscv_env_mmu_index(CPURISCVState *env, bool ifetch); bool cpu_get_fcfien(CPURISCVState *env); +bool cpu_get_bcfien(CPURISCVState *env); G_NORETURN void riscv_cpu_do_unaligned_access(CPUState *cs, vaddr addr, MMUAccessType access_type, int mmu_idx, uintptr_t retaddr); diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h index e7387c9b8f..8223beaceb 100644 --- a/target/riscv/cpu_bits.h +++ b/target/riscv/cpu_bits.h @@ -34,6 +34,9 @@ /* Control and Status Registers */ +/* zicfiss user ssp csr */ +#define CSR_SSP 0x011 + /* User Trap Setup */ #define CSR_USTATUS 0x000 #define CSR_UIE 0x004 @@ -761,6 +764,7 @@ typedef enum RISCVException { /* Execution environment configuration bits */ #define MENVCFG_FIOM BIT(0) #define MENVCFG_LPE BIT(2) /* zicfilp */ +#define MENVCFG_SSE BIT(3) /* zicfiss */ #define MENVCFG_CBIE (3UL << 4) #define MENVCFG_CBCFE BIT(6) #define MENVCFG_CBZE BIT(7) @@ -775,12 +779,14 @@ typedef enum RISCVException { #define SENVCFG_FIOM MENVCFG_FIOM #define SENVCFG_LPE MENVCFG_LPE +#define SENVCFG_SSE MENVCFG_SSE #define SENVCFG_CBIE MENVCFG_CBIE #define SENVCFG_CBCFE MENVCFG_CBCFE #define SENVCFG_CBZE MENVCFG_CBZE #define HENVCFG_FIOM MENVCFG_FIOM #define HENVCFG_LPE MENVCFG_LPE +#define HENVCFG_SSE MENVCFG_SSE #define HENVCFG_CBIE MENVCFG_CBIE #define HENVCFG_CBCFE MENVCFG_CBCFE #define HENVCFG_CBZE MENVCFG_CBZE diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c index 6a63c37083..b42abedf9e 100644 --- a/target/riscv/cpu_helper.c +++ b/target/riscv/cpu_helper.c @@ -91,6 +91,35 @@ bool cpu_get_fcfien(CPURISCVState *env) } } +bool cpu_get_bcfien(CPURISCVState *env) +{ + /* no cfi extension, return false */ + if (!env_archcpu(env)->cfg.ext_zicfiss) { + return false; + } + + switch (env->priv) { + case PRV_U: + /* + * If S is not implemented then shadow stack for U can't be turned on + * It is checked in `riscv_cpu_validate_set_extensions`, so no need to + * check here or assert here + */ + return env->senvcfg & SENVCFG_SSE; +#ifndef CONFIG_USER_ONLY + case PRV_S: + if (env->virt_enabled) { + return env->henvcfg & HENVCFG_SSE; + } + return env->menvcfg & MENVCFG_SSE; + case PRV_M: /* M-mode shadow stack is always off */ + return false; +#endif + default: + g_assert_not_reached(); + } +} + void cpu_get_tb_cpu_state(CPURISCVState *env, vaddr *pc, uint64_t *cs_base, uint32_t *pflags) { diff --git a/target/riscv/csr.c b/target/riscv/csr.c index ec1e2af72d..9846770820 100644 --- a/target/riscv/csr.c +++ b/target/riscv/csr.c @@ -184,6 +184,25 @@ static RISCVException zcmt(CPURISCVState *env, int csrno) return RISCV_EXCP_NONE; } +static RISCVException cfi_ss(CPURISCVState *env, int csrno) +{ + if (!env_archcpu(env)->cfg.ext_zicfiss) { + return RISCV_EXCP_ILLEGAL_INST; + } + + /* if bcfi not active for current env, access to csr is illegal */ + if (!cpu_get_bcfien(env)) { +#if !defined(CONFIG_USER_ONLY) + if (env->debugger) { + return RISCV_EXCP_NONE; + } +#endif + return RISCV_EXCP_ILLEGAL_INST; + } + + return RISCV_EXCP_NONE; +} + #if !defined(CONFIG_USER_ONLY) static RISCVException mctr(CPURISCVState *env, int csrno) { @@ -622,6 +641,19 @@ static RISCVException seed(CPURISCVState *env, int csrno) #endif } +/* zicfiss CSR_SSP read and write */ +static int read_ssp(CPURISCVState *env, int csrno, target_ulong *val) +{ + *val = env->ssp; + return RISCV_EXCP_NONE; +} + +static int write_ssp(CPURISCVState *env, int csrno, target_ulong val) +{ + env->ssp = val; + return RISCV_EXCP_NONE; +} + /* User Floating-Point CSRs */ static RISCVException read_fflags(CPURISCVState *env, int csrno, target_ulong *val) @@ -2354,6 +2386,10 @@ static RISCVException write_menvcfg(CPURISCVState *env, int csrno, if (env_archcpu(env)->cfg.ext_zicfilp) { mask |= MENVCFG_LPE; } + + if (env_archcpu(env)->cfg.ext_zicfiss) { + mask |= MENVCFG_SSE; + } } env->menvcfg = (env->menvcfg & ~mask) | (val & mask); @@ -2410,6 +2446,13 @@ static RISCVException write_senvcfg(CPURISCVState *env, int csrno, mask |= SENVCFG_LPE; } + /* Higher mode SSE must be ON for next-less mode SSE to be ON */ + if (env_archcpu(env)->cfg.ext_zicfiss && + get_field(env->menvcfg, MENVCFG_SSE) && + (env->virt_enabled ? get_field(env->henvcfg, HENVCFG_SSE) : true)) { + mask |= SENVCFG_SSE; + } + env->senvcfg = (env->senvcfg & ~mask) | (val & mask); return RISCV_EXCP_NONE; } @@ -2451,6 +2494,12 @@ static RISCVException write_henvcfg(CPURISCVState *env, int csrno, if (env_archcpu(env)->cfg.ext_zicfilp) { mask |= HENVCFG_LPE; } + + /* H can light up SSE for VS only if HS had it from menvcfg */ + if (env_archcpu(env)->cfg.ext_zicfiss && + get_field(env->menvcfg, MENVCFG_SSE)) { + mask |= HENVCFG_SSE; + } } env->henvcfg = (env->henvcfg & ~mask) | (val & mask); @@ -4966,6 +5015,9 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = { /* Zcmt Extension */ [CSR_JVT] = {"jvt", zcmt, read_jvt, write_jvt}, + /* zicfiss Extension, shadow stack register */ + [CSR_SSP] = { "ssp", cfi_ss, read_ssp, write_ssp }, + #if !defined(CONFIG_USER_ONLY) /* Machine Timers and Counters */ [CSR_MCYCLE] = { "mcycle", any, read_hpmcounter, diff --git a/target/riscv/machine.c b/target/riscv/machine.c index c3a06c288d..99f0af5077 100644 --- a/target/riscv/machine.c +++ b/target/riscv/machine.c @@ -368,6 +368,24 @@ static const VMStateDescription vmstate_elp = { } }; +static bool ssp_needed(void *opaque) +{ + RISCVCPU *cpu = opaque; + + return cpu->cfg.ext_zicfiss; +} + +static const VMStateDescription vmstate_ssp = { + .name = "cpu/ssp", + .version_id = 1, + .minimum_version_id = 1, + .needed = ssp_needed, + .fields = (const VMStateField[]) { + VMSTATE_UINTTL(env.ssp, RISCVCPU), + VMSTATE_END_OF_LIST() + } +}; + const VMStateDescription vmstate_riscv_cpu = { .name = "cpu", .version_id = 10, @@ -441,6 +459,7 @@ const VMStateDescription vmstate_riscv_cpu = { &vmstate_smstateen, &vmstate_jvt, &vmstate_elp, + &vmstate_ssp, NULL } };