Alistair Francis writes:
> Let's creaate a function that tests if floating point support is
Typo: create
> enabled. We can then protect all floating point operations based on if
> they are enabled.
>
> This patch so far doesn't change anything, it's just preparing for the
> Hypervisor support for floating point operations.
>
> Signed-off-by: Alistair Francis <alistair.fran...@wdc.com>
> ---
> target/riscv/cpu.h | 6 +++++-
> target/riscv/cpu_helper.c | 10 ++++++++++
> target/riscv/csr.c | 19 ++++++++++---------
> 3 files changed, 25 insertions(+), 10 deletions(-)
>
> diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
> index 0adb307f32..2dc9b17678 100644
> --- a/target/riscv/cpu.h
> +++ b/target/riscv/cpu.h
> @@ -255,6 +255,7 @@ void riscv_cpu_do_interrupt(CPUState *cpu);
> int riscv_cpu_gdb_read_register(CPUState *cpu, uint8_t *buf, int reg);
> int riscv_cpu_gdb_write_register(CPUState *cpu, uint8_t *buf, int reg);
> bool riscv_cpu_exec_interrupt(CPUState *cs, int interrupt_request);
> +bool riscv_cpu_fp_enabled(CPURISCVState *env);
> int riscv_cpu_mmu_index(CPURISCVState *env, bool ifetch);
> hwaddr riscv_cpu_get_phys_page_debug(CPUState *cpu, vaddr addr);
> void riscv_cpu_do_unaligned_access(CPUState *cs, vaddr addr,
> @@ -298,7 +299,10 @@ static inline void cpu_get_tb_cpu_state(CPURISCVState
> *env, target_ulong *pc,
> #ifdef CONFIG_USER_ONLY
> *flags = TB_FLAGS_MSTATUS_FS;
> #else
> - *flags = cpu_mmu_index(env, 0) | (env->mstatus & MSTATUS_FS);
> + *flags = cpu_mmu_index(env, 0);
> + if (riscv_cpu_fp_enabled(env)) {
> + *flags |= env->mstatus & MSTATUS_FS;
> + }
> #endif
> }
>
> diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
> index f027be7f16..225e407cff 100644
> --- a/target/riscv/cpu_helper.c
> +++ b/target/riscv/cpu_helper.c
> @@ -71,6 +71,16 @@ bool riscv_cpu_exec_interrupt(CPUState *cs, int
> interrupt_request)
>
> #if !defined(CONFIG_USER_ONLY)
>
> +/* Return true is floating point support is currently enabled */
> +bool riscv_cpu_fp_enabled(CPURISCVState *env)
> +{
> + if (env->mstatus & MSTATUS_FS) {
> + return true;
> + }
> +
> + return false;
Will there be more conditions that lead to the "true" case?
If not, please consider making it a one-liner for readability, e.g.
return env->mstatus & MSTATUS_FS;
(just a personal preference, feel free to ignore)
> +}
> +
> int riscv_cpu_claim_interrupts(RISCVCPU *cpu, uint32_t interrupts)
> {
> CPURISCVState *env = &cpu->env;
> diff --git a/target/riscv/csr.c b/target/riscv/csr.c
> index af3b762c8b..7b73b73cf7 100644
> --- a/target/riscv/csr.c
> +++ b/target/riscv/csr.c
> @@ -46,7 +46,7 @@ void riscv_set_csr_ops(int csrno, riscv_csr_operations *ops)
> static int fs(CPURISCVState *env, int csrno)
> {
> #if !defined(CONFIG_USER_ONLY)
> - if (!env->debugger && !(env->mstatus & MSTATUS_FS)) {
> + if (!env->debugger && !riscv_cpu_fp_enabled(env)) {
This was existing behavior, but I'm curious why all these
tests are disabled when env->debugger is set. This was introduced
in 753e3fe20, but I see no rationale in the commit message.
I find it odd, maybe even suspicious, that activating the debugger
would change the behavior :-)
> return -1;
> }
> #endif
> @@ -108,7 +108,7 @@ static int pmp(CPURISCVState *env, int csrno)
> static int read_fflags(CPURISCVState *env, int csrno, target_ulong *val)
> {
> #if !defined(CONFIG_USER_ONLY)
> - if (!env->debugger && !(env->mstatus & MSTATUS_FS)) {
> + if (!env->debugger && !riscv_cpu_fp_enabled(env)) {
> return -1;
> }
> #endif
> @@ -119,7 +119,7 @@ static int read_fflags(CPURISCVState *env, int csrno,
> target_ulong *val)
> static int write_fflags(CPURISCVState *env, int csrno, target_ulong val)
> {
> #if !defined(CONFIG_USER_ONLY)
> - if (!env->debugger && !(env->mstatus & MSTATUS_FS)) {
> + if (!env->debugger && !riscv_cpu_fp_enabled(env)) {
> return -1;
> }
> env->mstatus |= MSTATUS_FS;
> @@ -131,7 +131,7 @@ static int write_fflags(CPURISCVState *env, int csrno,
> target_ulong val)
> static int read_frm(CPURISCVState *env, int csrno, target_ulong *val)
> {
> #if !defined(CONFIG_USER_ONLY)
> - if (!env->debugger && !(env->mstatus & MSTATUS_FS)) {
> + if (!env->debugger && !riscv_cpu_fp_enabled(env)) {
> return -1;
> }
> #endif
> @@ -142,7 +142,7 @@ static int read_frm(CPURISCVState *env, int csrno,
> target_ulong *val)
> static int write_frm(CPURISCVState *env, int csrno, target_ulong val)
> {
> #if !defined(CONFIG_USER_ONLY)
> - if (!env->debugger && !(env->mstatus & MSTATUS_FS)) {
> + if (!env->debugger && !riscv_cpu_fp_enabled(env)) {
> return -1;
> }
> env->mstatus |= MSTATUS_FS;
> @@ -154,7 +154,7 @@ static int write_frm(CPURISCVState *env, int csrno,
> target_ulong val)
> static int read_fcsr(CPURISCVState *env, int csrno, target_ulong *val)
> {
> #if !defined(CONFIG_USER_ONLY)
> - if (!env->debugger && !(env->mstatus & MSTATUS_FS)) {
> + if (!env->debugger && !riscv_cpu_fp_enabled(env)) {
> return -1;
> }
> #endif
> @@ -166,7 +166,7 @@ static int read_fcsr(CPURISCVState *env, int csrno,
> target_ulong *val)
> static int write_fcsr(CPURISCVState *env, int csrno, target_ulong val)
> {
> #if !defined(CONFIG_USER_ONLY)
> - if (!env->debugger && !(env->mstatus & MSTATUS_FS)) {
> + if (!env->debugger && !riscv_cpu_fp_enabled(env)) {
> return -1;
> }
> env->mstatus |= MSTATUS_FS;
> @@ -307,6 +307,7 @@ static int write_mstatus(CPURISCVState *env, int csrno,
> target_ulong val)
> {
> target_ulong mstatus = env->mstatus;
> target_ulong mask = 0;
> + int dirty;
>
> /* flush tlb on mstatus fields that affect VM */
> if (env->priv_ver <= PRIV_VERSION_1_09_1) {
> @@ -340,8 +341,8 @@ static int write_mstatus(CPURISCVState *env, int csrno,
> target_ulong val)
>
> mstatus = (mstatus & ~mask) | (val & mask);
>
> - int dirty = ((mstatus & MSTATUS_FS) == MSTATUS_FS) |
> - ((mstatus & MSTATUS_XS) == MSTATUS_XS);
> + dirty = riscv_cpu_fp_enabled(env) |
> + ((mstatus & MSTATUS_XS) == MSTATUS_XS);
> mstatus = set_field(mstatus, MSTATUS_SD, dirty);
> env->mstatus = mstatus;
Reviewed-by: Christophe de Dinechin <dinec...@redhat.com>
--
Cheers,
Christophe de Dinechin (IRC c3d)
