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lib: sbi: Add functions to map/unmap shared memory

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When Smepmp is enabled, M-mode will need to map/unmap the
shared memory before it can read/write to it. This patch
adds functions to create dynamic short-lived mappings.

Signed-off-by: Himanshu Chauhan <hchauhan@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
This commit is contained in:
Himanshu Chauhan 2023-07-12 10:04:35 +05:30 • committed by Anup Patel
parent 5dd8db5b10
commit 6e44ef686a
2 changed files with 44 additions and 0 deletions
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2
include/sbi/sbi_hart.h
View file

@ -90,6 +90,8 @@ unsigned long sbi_hart_pmp_granularity(struct sbi_scratch *scratch);
unsigned int sbi_hart_pmp_addrbits(struct sbi_scratch *scratch);
unsigned int sbi_hart_mhpm_bits(struct sbi_scratch *scratch);
int sbi_hart_pmp_configure(struct sbi_scratch *scratch);
int sbi_hart_map_saddr(unsigned long base, unsigned long size);
int sbi_hart_unmap_saddr(void);
int sbi_hart_priv_version(struct sbi_scratch *scratch);
void sbi_hart_get_priv_version_str(struct sbi_scratch *scratch,
char *version_str, int nvstr);

42
lib/sbi/sbi_hart.c
View file

@ -347,6 +347,48 @@ unsigned int sbi_hart_get_smepmp_flags(struct sbi_scratch *scratch,
return pmp_flags;
}
int sbi_hart_map_saddr(unsigned long addr, unsigned long size)
{
/* shared R/W access for M and S/U mode */
unsigned int pmp_flags = (PMP_W | PMP_X);
unsigned long order, base = 0;
struct sbi_scratch *scratch = sbi_scratch_thishart_ptr();
/* If Smepmp is not supported no special mapping is required */
if (!sbi_hart_has_extension(scratch, SBI_HART_EXT_SMEPMP))
return SBI_OK;
if (is_pmp_entry_mapped(SBI_SMEPMP_RESV_ENTRY))
return SBI_ENOSPC;
for (order = log2roundup(size) ; order <= __riscv_xlen; order++) {
if (order < __riscv_xlen) {
base = addr & ~((1UL << order) - 1UL);
if ((base <= addr) &&
(addr < (base + (1UL << order))) &&
(base <= (addr + size - 1UL)) &&
((addr + size - 1UL) < (base + (1UL << order))))
break;
} else {
return SBI_EFAIL;
}
}
pmp_set(SBI_SMEPMP_RESV_ENTRY, pmp_flags, base, order);
return SBI_OK;
}
int sbi_hart_unmap_saddr(void)
{
struct sbi_scratch *scratch = sbi_scratch_thishart_ptr();
if (!sbi_hart_has_extension(scratch, SBI_HART_EXT_SMEPMP))
return SBI_OK;
return pmp_disable(SBI_SMEPMP_RESV_ENTRY);
}
int sbi_hart_pmp_configure(struct sbi_scratch *scratch)
{
struct sbi_domain_memregion *reg;