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lib: sbi: fwft: add support for SBI_FWFT_POINTER_MASKING_PMLEN

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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@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
This commit is contained in:
Samuel Holland
2024-08-14 01:40:30 -07:00
committed by Anup Patel
parent ebfaf1974e
commit 1cb234b1c9
5 changed files with 76 additions and 1 deletions
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67
lib/sbi/sbi_fwft.c
View File

@@ -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)

1
lib/sbi/sbi_hart.c
View File

@@ -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),