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lib: sbi: Detect and print privileged spec version

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It is possible to guess privileged spec versions based on the CSRs
that where introduced in different privileged spec versions. In
future, if we are not able guess privileged spec version then we
can have platform provide it.

We add privileged spec version as per-hart feature and try to guess
it based on presence of mcounteren, mcountinhibit, and menvcfg CSRs.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
This commit is contained in:
Anup Patel
2022-04-28 17:30:02 +05:30
committed by Anup Patel
parent b0c9df514b
commit 1a754bb365
3 changed files with 63 additions and 6 deletions
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52
lib/sbi/sbi_hart.c
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@@ -28,6 +28,7 @@ extern void __sbi_expected_trap_hext(void);
void (*sbi_hart_expected_trap)(void) = &__sbi_expected_trap;
struct hart_features {
int priv_version;
unsigned long features;
unsigned int pmp_count;
unsigned int pmp_addr_bits;
@@ -334,6 +335,39 @@ int sbi_hart_pmp_configure(struct sbi_scratch *scratch)
return 0;
}
int sbi_hart_priv_version(struct sbi_scratch *scratch)
{
struct hart_features *hfeatures =
sbi_scratch_offset_ptr(scratch, hart_features_offset);
return hfeatures->priv_version;
}
void sbi_hart_get_priv_version_str(struct sbi_scratch *scratch,
char *version_str, int nvstr)
{
char *temp;
struct hart_features *hfeatures =
sbi_scratch_offset_ptr(scratch, hart_features_offset);
switch (hfeatures->priv_version) {
case SBI_HART_PRIV_VER_1_10:
temp = "v1.10";
break;
case SBI_HART_PRIV_VER_1_11:
temp = "v1.11";
break;
case SBI_HART_PRIV_VER_1_12:
temp = "v1.12";
break;
default:
temp = "unknown";
break;
}
sbi_snprintf(version_str, nvstr, "%s", temp);
}
/**
* Check whether a particular hart feature is available
*
@@ -583,6 +617,7 @@ __mhpm_skip:
/* Detect if hart supports SCOUNTEREN feature */
val = csr_read_allowed(CSR_SCOUNTEREN, (unsigned long)&trap);
if (!trap.cause) {
hfeatures->priv_version = SBI_HART_PRIV_VER_1_10;
csr_write_allowed(CSR_SCOUNTEREN, (unsigned long)&trap, val);
if (!trap.cause)
hfeatures->features |= SBI_HART_HAS_SCOUNTEREN;
@@ -591,6 +626,7 @@ __mhpm_skip:
/* Detect if hart supports MCOUNTEREN feature */
val = csr_read_allowed(CSR_MCOUNTEREN, (unsigned long)&trap);
if (!trap.cause) {
hfeatures->priv_version = SBI_HART_PRIV_VER_1_10;
csr_write_allowed(CSR_MCOUNTEREN, (unsigned long)&trap, val);
if (!trap.cause)
hfeatures->features |= SBI_HART_HAS_MCOUNTEREN;
@@ -600,8 +636,17 @@ __mhpm_skip:
val = csr_read_allowed(CSR_MCOUNTINHIBIT, (unsigned long)&trap);
if (!trap.cause) {
csr_write_allowed(CSR_MCOUNTINHIBIT, (unsigned long)&trap, val);
if (!trap.cause)
if (!trap.cause) {
hfeatures->priv_version = SBI_HART_PRIV_VER_1_11;
hfeatures->features |= SBI_HART_HAS_MCOUNTINHIBIT;
}
}
/* Detect if hart has menvcfg CSR */
csr_read_allowed(CSR_MENVCFG, (unsigned long)&trap);
if (!trap.cause) {
hfeatures->priv_version = SBI_HART_PRIV_VER_1_12;
hfeatures->features |= SBI_HART_HAS_MENVCFG;
}
/* Counter overflow/filtering is not useful without mcounter/inhibit */
@@ -625,11 +670,6 @@ __mhpm_skip:
hfeatures->features |= SBI_HART_HAS_AIA;
__aia_skip:
/* Detect if hart has menvcfg CSR */
csr_read_allowed(CSR_MENVCFG, (unsigned long)&trap);
if (!trap.cause)
hfeatures->features |= SBI_HART_HAS_MENVCFG;
/**
* Detect if hart supports stimecmp CSR(Sstc extension) and menvcfg is
* implemented.