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Re: [RFC v3] linux-user/riscv: Add syscall riscv_hwprobe
From: |
Robbin Ehn |
Subject: |
Re: [RFC v3] linux-user/riscv: Add syscall riscv_hwprobe |
Date: |
Mon, 19 Jun 2023 08:55:03 +0200 |
User-agent: |
Evolution 3.48.1-0ubuntu1 |
On Thu, 2023-06-15 at 10:12 -0700, Palmer Dabbelt wrote:
> On Thu, 08 Jun 2023 00:55:22 PDT (-0700), rehn@rivosinc.com wrote:
> > This patch adds the new syscall for the
> > "RISC-V Hardware Probing Interface"
> > (https://docs.kernel.org/riscv/hwprobe.html).
> >
> > Signed-off-by: Robbin Ehn <rehn@rivosinc.com>
> > ---
> > v1->v2: Moved to syscall.c
> > v2->v3: Separate function, get/put user
> > ---
> > linux-user/riscv/syscall32_nr.h | 1 +
> > linux-user/riscv/syscall64_nr.h | 1 +
> > linux-user/syscall.c | 146 ++++++++++++++++++++++++++++++++
> > 3 files changed, 148 insertions(+)
> >
> > diff --git a/linux-user/riscv/syscall32_nr.h
> > b/linux-user/riscv/syscall32_nr.h
> > index 1327d7dffa..412e58e5b2 100644
> > --- a/linux-user/riscv/syscall32_nr.h
> > +++ b/linux-user/riscv/syscall32_nr.h
> > @@ -228,6 +228,7 @@
> > #define TARGET_NR_accept4 242
> > #define TARGET_NR_arch_specific_syscall 244
> > #define TARGET_NR_riscv_flush_icache (TARGET_NR_arch_specific_syscall + 15)
> > +#define TARGET_NR_riscv_hwprobe (TARGET_NR_arch_specific_syscall + 14)
> > #define TARGET_NR_prlimit64 261
> > #define TARGET_NR_fanotify_init 262
> > #define TARGET_NR_fanotify_mark 263
> > diff --git a/linux-user/riscv/syscall64_nr.h
> > b/linux-user/riscv/syscall64_nr.h
> > index 6659751933..29e1eb2075 100644
> > --- a/linux-user/riscv/syscall64_nr.h
> > +++ b/linux-user/riscv/syscall64_nr.h
> > @@ -251,6 +251,7 @@
> > #define TARGET_NR_recvmmsg 243
> > #define TARGET_NR_arch_specific_syscall 244
> > #define TARGET_NR_riscv_flush_icache (TARGET_NR_arch_specific_syscall + 15)
> > +#define TARGET_NR_riscv_hwprobe (TARGET_NR_arch_specific_syscall + 14)
> > #define TARGET_NR_wait4 260
> > #define TARGET_NR_prlimit64 261
> > #define TARGET_NR_fanotify_init 262
> > diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> > index 83685f0aa5..e8859cd3be 100644
> > --- a/linux-user/syscall.c
> > +++ b/linux-user/syscall.c
> > @@ -8874,6 +8874,147 @@ static int do_getdents64(abi_long dirfd, abi_long
> > arg2, abi_long count)
> > }
> > #endif /* TARGET_NR_getdents64 */
> >
> > +#if defined(TARGET_NR_riscv_hwprobe)
> > +
> > +#define RISCV_HWPROBE_KEY_MVENDORID 0
> > +#define RISCV_HWPROBE_KEY_MARCHID 1
> > +#define RISCV_HWPROBE_KEY_MIMPID 2
> > +
> > +#define RISCV_HWPROBE_KEY_BASE_BEHAVIOR 3
> > +#define RISCV_HWPROBE_BASE_BEHAVIOR_IMA (1 << 0)
> > +
> > +#define RISCV_HWPROBE_KEY_IMA_EXT_0 4
> > +#define RISCV_HWPROBE_IMA_FD (1 << 0)
> > +#define RISCV_HWPROBE_IMA_C (1 << 1)
> > +
> > +#define RISCV_HWPROBE_KEY_CPUPERF_0 5
> > +#define RISCV_HWPROBE_MISALIGNED_UNKNOWN (0 << 0)
> > +#define RISCV_HWPROBE_MISALIGNED_EMULATED (1 << 0)
> > +#define RISCV_HWPROBE_MISALIGNED_SLOW (2 << 0)
> > +#define RISCV_HWPROBE_MISALIGNED_FAST (3 << 0)
> > +#define RISCV_HWPROBE_MISALIGNED_UNSUPPORTED (4 << 0)
> > +#define RISCV_HWPROBE_MISALIGNED_MASK (7 << 0)
> > +
> > +struct riscv_hwprobe {
> > + abi_llong key;
> > + abi_ullong value;
> > +};
> > +
> > +static void risc_hwprobe_fill_pairs(CPURISCVState *env,
> > + struct riscv_hwprobe *pair,
> > + size_t pair_count)
> > +{
> > + const RISCVCPUConfig *cfg = riscv_cpu_cfg(env);
> > +
> > + for (; pair_count > 0; pair_count--, pair++) {
> > + abi_llong key;
> > + abi_ullong value;
> > + __put_user(0, &pair->value);
> > + __get_user(key, &pair->key);
> > + switch (key) {
> > + case RISCV_HWPROBE_KEY_MVENDORID:
> > + __put_user(cfg->mvendorid, &pair->value);
> > + break;
> > + case RISCV_HWPROBE_KEY_MARCHID:
> > + __put_user(cfg->marchid, &pair->value);
> > + break;
> > + case RISCV_HWPROBE_KEY_MIMPID:
> > + __put_user(cfg->mimpid, &pair->value);
> > + break;
> > + case RISCV_HWPROBE_KEY_BASE_BEHAVIOR:
> > + value = riscv_has_ext(env, RVI) &&
> > + riscv_has_ext(env, RVM) &&
> > + riscv_has_ext(env, RVA) ?
> > + RISCV_HWPROBE_BASE_BEHAVIOR_IMA : 0;
> > + __put_user(value, &pair->value);
> > + break;
> > + case RISCV_HWPROBE_KEY_IMA_EXT_0:
> > + value = riscv_has_ext(env, RVF) &&
> > + riscv_has_ext(env, RVD) ?
> > + RISCV_HWPROBE_IMA_FD : 0;
> > + value |= riscv_has_ext(env, RVC) ?
> > + RISCV_HWPROBE_IMA_C : pair->value;
> > + __put_user(value, &pair->value);
> > + break;
> > + case RISCV_HWPROBE_KEY_CPUPERF_0:
> > + __put_user(RISCV_HWPROBE_MISALIGNED_FAST, &pair->value);
> > + break;
> > + default:
> > + __put_user(-1, &pair->key);
> > + break;
> > + }
> > + }
> > +}
> > +
> > +static int cpu_set_valid(abi_long arg3, abi_long arg4)
> > +{
> > + int ret, i, tmp;
> > + size_t host_mask_size, target_mask_size;
> > + unsigned long *host_mask;
> > +
> > + /*
> > + * cpu_set_t represent CPU masks as bit masks of type unsigned long *.
> > + * arg3 contains the cpu count.
> > + */
> > + tmp = (8 * sizeof(abi_ulong));
> > + target_mask_size = ((arg3 + tmp - 1) / tmp) * sizeof(abi_ulong);
> > + host_mask_size = (target_mask_size + (sizeof(*host_mask) - 1)) &
> > + ~(sizeof(*host_mask) - 1);
> > +
> > + host_mask = alloca(host_mask_size);
> > +
> > + ret = target_to_host_cpu_mask(host_mask, host_mask_size,
> > + arg4, target_mask_size);
> > + if (ret != 0) {
> > + return ret;
> > + }
> > +
> > + for (i = 0 ; i < host_mask_size / sizeof(*host_mask); i++) {
> > + if (host_mask[i] != 0) {
> > + return 0;
> > + }
> > + }
> > + return -TARGET_EINVAL;
> > +}
> > +
> > +static abi_long do_riscv_hwprobe(CPUArchState *cpu_env, abi_long arg1,
> > + abi_long arg2, abi_long arg3,
> > + abi_long arg4, abi_long arg5)
> > +{
> > + int ret;
> > + struct riscv_hwprobe *host_pairs;
> > +
> > + /* flags must be 0 */
> > + if (arg5 != 0) {
> > + return -TARGET_EINVAL;
> > + }
> > +
> > + /* check cpu_set */
> > + if (arg3 != 0) {
> > + ret = cpu_set_valid(arg3, arg4);
> > + if (ret != 0) {
> > + return ret;
> > + }
> > + } else if (arg4 != 0) {
> > + return -TARGET_EINVAL;
> > + }
> > +
> > + /* no pairs */
> > + if (arg2 == 0) {
> > + return 0;
> > + }
> > +
> > + host_pairs = lock_user(VERIFY_WRITE, arg1,
> > + sizeof(*host_pairs) * (size_t)arg2, 0);
> > + if (host_pairs == NULL) {
> > + return -TARGET_EFAULT;
> > + }
> > + risc_hwprobe_fill_pairs(cpu_env, host_pairs, arg2);
> > + unlock_user(host_pairs, arg1, sizeof(*host_pairs) * (size_t)arg2);
> > + return 0;
> > +}
> > +#endif /* TARGET_NR_riscv_hwprobe */
> > +
> > #if defined(TARGET_NR_pivot_root) && defined(__NR_pivot_root)
> > _syscall2(int, pivot_root, const char *, new_root, const char *, put_old)
> > #endif
> > @@ -13571,6 +13712,11 @@ static abi_long do_syscall1(CPUArchState *cpu_env,
> > int num, abi_long arg1,
> > return ret;
> > #endif
> >
> > +#if defined(TARGET_NR_riscv_hwprobe)
> > + case TARGET_NR_riscv_hwprobe:
> > + return do_riscv_hwprobe(cpu_env, arg1, arg2, arg3, arg4, arg5);
> > +#endif
> > +
> > default:
> > qemu_log_mask(LOG_UNIMP, "Unsupported syscall: %d\n", num);
> > return -TARGET_ENOSYS;
> > --
> > 2.39.2
>
> Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>
>
Thanks, I'll send it out as a patch.
/Robbin
> riscv_hwprobe() hasn't been released yet, but it's in Linus' tree so
> unless something unforseen happens it should show up in 6.4 in a few
> weeks.