Skip to content

Commit

Permalink
Browse files Browse the repository at this point in the history
target/riscv: Compute mstatus.sd on demand
The position of this read-only field is dependent on the current xlen.
Rather than having to compute that difference in many places, compute
it only on read.

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20211020031709.359469-16-richard.henderson@linaro.org
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
  • Loading branch information
rth7680 authored and alistair23 committed Oct 22, 2021
1 parent 665b90d commit b550f89
Show file tree
Hide file tree
Showing 3 changed files with 25 additions and 20 deletions.
3 changes: 1 addition & 2 deletions target/riscv/cpu_helper.c
Expand Up @@ -185,10 +185,9 @@ bool riscv_cpu_fp_enabled(CPURISCVState *env)

void riscv_cpu_swap_hypervisor_regs(CPURISCVState *env)
{
uint64_t sd = riscv_cpu_mxl(env) == MXL_RV32 ? MSTATUS32_SD : MSTATUS64_SD;
uint64_t mstatus_mask = MSTATUS_MXR | MSTATUS_SUM | MSTATUS_FS |
MSTATUS_SPP | MSTATUS_SPIE | MSTATUS_SIE |
MSTATUS64_UXL | sd;
MSTATUS64_UXL;
bool current_virt = riscv_cpu_virt_enabled(env);

g_assert(riscv_has_ext(env, RVH));
Expand Down
37 changes: 22 additions & 15 deletions target/riscv/csr.c
Expand Up @@ -477,10 +477,28 @@ static RISCVException read_mhartid(CPURISCVState *env, int csrno,
}

/* Machine Trap Setup */

/* We do not store SD explicitly, only compute it on demand. */
static uint64_t add_status_sd(RISCVMXL xl, uint64_t status)
{
if ((status & MSTATUS_FS) == MSTATUS_FS ||
(status & MSTATUS_XS) == MSTATUS_XS) {
switch (xl) {
case MXL_RV32:
return status | MSTATUS32_SD;
case MXL_RV64:
return status | MSTATUS64_SD;
default:
g_assert_not_reached();
}
}
return status;
}

static RISCVException read_mstatus(CPURISCVState *env, int csrno,
target_ulong *val)
{
*val = env->mstatus;
*val = add_status_sd(riscv_cpu_mxl(env), env->mstatus);
return RISCV_EXCP_NONE;
}

Expand All @@ -498,7 +516,6 @@ static RISCVException write_mstatus(CPURISCVState *env, int csrno,
{
uint64_t mstatus = env->mstatus;
uint64_t mask = 0;
int dirty;

/* flush tlb on mstatus fields that affect VM */
if ((val ^ mstatus) & (MSTATUS_MXR | MSTATUS_MPP | MSTATUS_MPV |
Expand All @@ -520,12 +537,7 @@ static RISCVException write_mstatus(CPURISCVState *env, int csrno,

mstatus = (mstatus & ~mask) | (val & mask);

dirty = ((mstatus & MSTATUS_FS) == MSTATUS_FS) |
((mstatus & MSTATUS_XS) == MSTATUS_XS);
if (riscv_cpu_mxl(env) == MXL_RV32) {
mstatus = set_field(mstatus, MSTATUS32_SD, dirty);
} else {
mstatus = set_field(mstatus, MSTATUS64_SD, dirty);
if (riscv_cpu_mxl(env) == MXL_RV64) {
/* SXL and UXL fields are for now read only */
mstatus = set_field(mstatus, MSTATUS64_SXL, MXL_RV64);
mstatus = set_field(mstatus, MSTATUS64_UXL, MXL_RV64);
Expand Down Expand Up @@ -798,13 +810,8 @@ static RISCVException read_sstatus(CPURISCVState *env, int csrno,
{
target_ulong mask = (sstatus_v1_10_mask);

if (riscv_cpu_mxl(env) == MXL_RV32) {
mask |= SSTATUS32_SD;
} else {
mask |= SSTATUS64_SD;
}

*val = env->mstatus & mask;
/* TODO: Use SXL not MXL. */
*val = add_status_sd(riscv_cpu_mxl(env), env->mstatus & mask);
return RISCV_EXCP_NONE;
}

Expand Down
5 changes: 2 additions & 3 deletions target/riscv/translate.c
Expand Up @@ -280,15 +280,14 @@ static void gen_jal(DisasContext *ctx, int rd, target_ulong imm)
static void mark_fs_dirty(DisasContext *ctx)
{
TCGv tmp;
target_ulong sd = get_xl(ctx) == MXL_RV32 ? MSTATUS32_SD : MSTATUS64_SD;

if (ctx->mstatus_fs != MSTATUS_FS) {
/* Remember the state change for the rest of the TB. */
ctx->mstatus_fs = MSTATUS_FS;

tmp = tcg_temp_new();
tcg_gen_ld_tl(tmp, cpu_env, offsetof(CPURISCVState, mstatus));
tcg_gen_ori_tl(tmp, tmp, MSTATUS_FS | sd);
tcg_gen_ori_tl(tmp, tmp, MSTATUS_FS);
tcg_gen_st_tl(tmp, cpu_env, offsetof(CPURISCVState, mstatus));
tcg_temp_free(tmp);
}
Expand All @@ -299,7 +298,7 @@ static void mark_fs_dirty(DisasContext *ctx)

tmp = tcg_temp_new();
tcg_gen_ld_tl(tmp, cpu_env, offsetof(CPURISCVState, mstatus_hs));
tcg_gen_ori_tl(tmp, tmp, MSTATUS_FS | sd);
tcg_gen_ori_tl(tmp, tmp, MSTATUS_FS);
tcg_gen_st_tl(tmp, cpu_env, offsetof(CPURISCVState, mstatus_hs));
tcg_temp_free(tmp);
}
Expand Down

0 comments on commit b550f89

Please sign in to comment.