[PATCH] lib: sbi: fwft: add support for SBI_FWFT_POINTER_MASKING_PMLEN
Anup Patel
anup at brainfault.org
Mon Sep 23 05:24:08 PDT 2024
On Wed, Aug 14, 2024 at 3:15 PM Samuel Holland
<samuel.holland at sifive.com> wrote:
>
> Add support for controlling the pointer masking mode on harts which
> support the Smnpm extension. This extension can only exist on harts
> where XLEN >= 64 bits. This implementation selects the mode with the
> smallest PMLEN that satisfies the caller's requested lower bound.
>
> Signed-off-by: Samuel Holland <samuel.holland at sifive.com>
LGTM.
Reviewed-by: Anup Patel <anup at brainfault.org>
Applied this patch to the riscv/opensbi repo.
Thanks,
Anup
> ---
> This patch implements the API I originally suggested while the FWFT
> extension was a draft and also submitted here:
> https://github.com/riscv-non-isa/riscv-sbi-doc/pull/161
>
> include/sbi/riscv_encoding.h | 4 ++
> include/sbi/sbi_ecall_interface.h | 3 +-
> include/sbi/sbi_hart.h | 2 +
> lib/sbi/sbi_fwft.c | 67 +++++++++++++++++++++++++++++++
> lib/sbi/sbi_hart.c | 1 +
> 5 files changed, 76 insertions(+), 1 deletion(-)
>
> diff --git a/include/sbi/riscv_encoding.h b/include/sbi/riscv_encoding.h
> index 2ed05f24..beb874af 100644
> --- a/include/sbi/riscv_encoding.h
> +++ b/include/sbi/riscv_encoding.h
> @@ -213,6 +213,10 @@
> #define ENVCFG_PBMTE (_ULL(1) << 62)
> #define ENVCFG_ADUE (_ULL(1) << 61)
> #define ENVCFG_CDE (_ULL(1) << 60)
> +#define ENVCFG_PMM (_ULL(0x3) << 32)
> +#define ENVCFG_PMM_PMLEN_0 (_ULL(0x0) << 32)
> +#define ENVCFG_PMM_PMLEN_7 (_ULL(0x2) << 32)
> +#define ENVCFG_PMM_PMLEN_16 (_ULL(0x3) << 32)
> #define ENVCFG_CBZE (_UL(1) << 7)
> #define ENVCFG_CBCFE (_UL(1) << 6)
> #define ENVCFG_CBIE_SHIFT 4
> diff --git a/include/sbi/sbi_ecall_interface.h b/include/sbi/sbi_ecall_interface.h
> index e9a81677..2958b418 100644
> --- a/include/sbi/sbi_ecall_interface.h
> +++ b/include/sbi/sbi_ecall_interface.h
> @@ -128,7 +128,8 @@ enum sbi_fwft_feature_t {
> SBI_FWFT_SHADOW_STACK = 0x2,
> SBI_FWFT_DOUBLE_TRAP = 0x3,
> SBI_FWFT_PTE_AD_HW_UPDATING = 0x4,
> - SBI_FWFT_LOCAL_RESERVED_START = 0x5,
> + SBI_FWFT_POINTER_MASKING_PMLEN = 0x5,
> + SBI_FWFT_LOCAL_RESERVED_START = 0x6,
> SBI_FWFT_LOCAL_RESERVED_END = 0x3fffffff,
> SBI_FWFT_LOCAL_PLATFORM_START = 0x40000000,
> SBI_FWFT_LOCAL_PLATFORM_END = 0x7fffffff,
> diff --git a/include/sbi/sbi_hart.h b/include/sbi/sbi_hart.h
> index 81ec061d..32545f41 100644
> --- a/include/sbi/sbi_hart.h
> +++ b/include/sbi/sbi_hart.h
> @@ -67,6 +67,8 @@ enum sbi_hart_extensions {
> SBI_HART_EXT_SVADE,
> /** Hart has Svadu extension */
> SBI_HART_EXT_SVADU,
> + /** Hart has Smnpm extension */
> + SBI_HART_EXT_SMNPM,
>
> /** Maximum index of Hart extension */
> SBI_HART_EXT_MAX,
> diff --git a/lib/sbi/sbi_fwft.c b/lib/sbi/sbi_fwft.c
> index ef881ef5..c5803300 100644
> --- a/lib/sbi/sbi_fwft.c
> +++ b/lib/sbi/sbi_fwft.c
> @@ -59,6 +59,7 @@ static const unsigned long fwft_defined_features[] = {
> SBI_FWFT_SHADOW_STACK,
> SBI_FWFT_DOUBLE_TRAP,
> SBI_FWFT_PTE_AD_HW_UPDATING,
> + SBI_FWFT_POINTER_MASKING_PMLEN,
> };
>
> static bool fwft_is_defined_feature(enum sbi_fwft_feature_t feature)
> @@ -145,6 +146,64 @@ static int fwft_get_adue(struct fwft_config *conf, unsigned long *value)
> return SBI_OK;
> }
>
> +#if __riscv_xlen > 32
> +static int fwft_pmlen_supported(struct fwft_config *conf)
> +{
> + if (!sbi_hart_has_extension(sbi_scratch_thishart_ptr(),
> + SBI_HART_EXT_SMNPM))
> + return SBI_ENOTSUPP;
> +
> + return SBI_OK;
> +}
> +
> +static bool fwft_try_to_set_pmm(unsigned long pmm)
> +{
> + csr_set(CSR_MENVCFG, pmm);
> + return (csr_read(CSR_MENVCFG) & ENVCFG_PMM) == pmm;
> +}
> +
> +static int fwft_set_pmlen(struct fwft_config *conf, unsigned long value)
> +{
> + unsigned long prev;
> +
> + if (value > 16)
> + return SBI_EINVAL;
> +
> + prev = csr_read_clear(CSR_MENVCFG, ENVCFG_PMM);
> + if (value == 0)
> + return SBI_OK;
> + if (value <= 7) {
> + if (fwft_try_to_set_pmm(ENVCFG_PMM_PMLEN_7))
> + return SBI_OK;
> + csr_clear(CSR_MENVCFG, ENVCFG_PMM);
> + }
> + if (fwft_try_to_set_pmm(ENVCFG_PMM_PMLEN_16))
> + return SBI_OK;
> + csr_write(CSR_MENVCFG, prev);
> +
> + return SBI_EINVAL;
> +}
> +
> +static int fwft_get_pmlen(struct fwft_config *conf, unsigned long *value)
> +{
> + switch (csr_read(CSR_MENVCFG) & ENVCFG_PMM) {
> + case ENVCFG_PMM_PMLEN_0:
> + *value = 0;
> + break;
> + case ENVCFG_PMM_PMLEN_7:
> + *value = 7;
> + break;
> + case ENVCFG_PMM_PMLEN_16:
> + *value = 16;
> + break;
> + default:
> + return SBI_EFAIL;
> + }
> +
> + return SBI_OK;
> +}
> +#endif
> +
> static struct fwft_config* get_feature_config(enum sbi_fwft_feature_t feature)
> {
> int i;
> @@ -236,6 +295,14 @@ static const struct fwft_feature features[] =
> .set = fwft_set_adue,
> .get = fwft_get_adue,
> },
> +#if __riscv_xlen > 32
> + {
> + .id = SBI_FWFT_POINTER_MASKING_PMLEN,
> + .supported = fwft_pmlen_supported,
> + .set = fwft_set_pmlen,
> + .get = fwft_get_pmlen,
> + },
> +#endif
> };
>
> int sbi_fwft_init(struct sbi_scratch *scratch, bool cold_boot)
> diff --git a/lib/sbi/sbi_hart.c b/lib/sbi/sbi_hart.c
> index c3667019..8c5bcf85 100644
> --- a/lib/sbi/sbi_hart.c
> +++ b/lib/sbi/sbi_hart.c
> @@ -680,6 +680,7 @@ const struct sbi_hart_ext_data sbi_hart_ext[] = {
> __SBI_HART_EXT_DATA(ssccfg, SBI_HART_EXT_SSCCFG),
> __SBI_HART_EXT_DATA(svade, SBI_HART_EXT_SVADE),
> __SBI_HART_EXT_DATA(svadu, SBI_HART_EXT_SVADU),
> + __SBI_HART_EXT_DATA(smnpm, SBI_HART_EXT_SMNPM),
> };
>
> _Static_assert(SBI_HART_EXT_MAX == array_size(sbi_hart_ext),
> --
> 2.45.1
>
>
> --
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