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lib: sbi: Add functions to manipulate PMP entries

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- Add a function to disable a given PMP entry.
- Add a function to check if a given entry is disabled.

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 10:04:28 +05:30 • committed by Anup Patel
parent c3b98c610b
commit 1c099c4f36
2 changed files with 48 additions and 0 deletions
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6
include/sbi/riscv_asm.h
View file

@ -181,6 +181,12 @@ int misa_xlen(void);
/* Get RISC-V ISA string representation */
void misa_string(int xlen, char *out, unsigned int out_sz);
/* Disable pmp entry at a given index */
int pmp_disable(unsigned int n);
/* Check if the matching field is set */
int is_pmp_entry_mapped(unsigned long entry);
int pmp_set(unsigned int n, unsigned long prot, unsigned long addr,
unsigned long log2len);

42
lib/sbi/riscv_asm.c
View file

@ -246,6 +246,48 @@ static unsigned long ctz(unsigned long x)
return ret;
}
int pmp_disable(unsigned int n)
{
int pmpcfg_csr, pmpcfg_shift;
unsigned long cfgmask, pmpcfg;
if (n >= PMP_COUNT)
return SBI_EINVAL;
#if __riscv_xlen == 32
pmpcfg_csr = CSR_PMPCFG0 + (n >> 2);
pmpcfg_shift = (n & 3) << 3;
#elif __riscv_xlen == 64
pmpcfg_csr = (CSR_PMPCFG0 + (n >> 2)) & ~1;
pmpcfg_shift = (n & 7) << 3;
#else
# error "Unexpected __riscv_xlen"
#endif
/* Clear the address matching bits to disable the pmp entry */
cfgmask = ~(0xffUL << pmpcfg_shift);
pmpcfg = (csr_read_num(pmpcfg_csr) & cfgmask);
csr_write_num(pmpcfg_csr, pmpcfg);
return SBI_OK;
}
int is_pmp_entry_mapped(unsigned long entry)
{
unsigned long prot;
unsigned long addr;
unsigned long log2len;
pmp_get(entry, &prot, &addr, &log2len);
/* If address matching bits are non-zero, the entry is enable */
if (prot & PMP_A)
return true;
return false;
}
int pmp_set(unsigned int n, unsigned long prot, unsigned long addr,
unsigned long log2len)
{