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RISC-V: split riscv_fill_hwcap() in 3

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Before adding more complexity to it, split riscv_fill_hwcap() into 3
distinct sections:
- riscv_fill_hwcap() still is the top level function, into which the
  additional complexity will be added.
- riscv_fill_hwcap_from_isa_string() handles getting the information
  from the riscv,isa/ACPI equivalent across harts & the various quirks
  there
- riscv_parse_isa_string() does what it says on the tin.

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230713-daylight-puritan-37aeb41a4d9b@wendy
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This commit is contained in:
Conor Dooley
2023-07-13 13:11:06 +01:00
committed by Palmer Dabbelt
parent effc122ad1
commit 4265b0ec5e
1 changed files with 177 additions and 168 deletions
Download Patch File Download Diff File Expand all files Collapse all files

345
arch/riscv/kernel/cpufeature.c
View File

@@ -178,29 +178,172 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
const size_t riscv_isa_ext_count = ARRAY_SIZE(riscv_isa_ext);
void __init riscv_fill_hwcap(void)
static void __init riscv_parse_isa_string(unsigned long *this_hwcap, struct riscv_isainfo *isainfo,
unsigned long *isa2hwcap, const char *isa)
{
/*
* For all possible cpus, we have already validated in
* the boot process that they at least contain "rv" and
* whichever of "32"/"64" this kernel supports, and so this
* section can be skipped.
*/
isa += 4;
while (*isa) {
const char *ext = isa++;
const char *ext_end = isa;
bool ext_long = false, ext_err = false;
switch (*ext) {
case 's':
/*
* Workaround for invalid single-letter 's' & 'u'(QEMU).
* No need to set the bit in riscv_isa as 's' & 'u' are
* not valid ISA extensions. It works until multi-letter
* extension starting with "Su" appears.
*/
if (ext[-1] != '_' && ext[1] == 'u') {
++isa;
ext_err = true;
break;
}
fallthrough;
case 'S':
case 'x':
case 'X':
case 'z':
case 'Z':
/*
* Before attempting to parse the extension itself, we find its end.
* As multi-letter extensions must be split from other multi-letter
* extensions with an "_", the end of a multi-letter extension will
* either be the null character or the "_" at the start of the next
* multi-letter extension.
*
* Next, as the extensions version is currently ignored, we
* eliminate that portion. This is done by parsing backwards from
* the end of the extension, removing any numbers. This may be a
* major or minor number however, so the process is repeated if a
* minor number was found.
*
* ext_end is intended to represent the first character *after* the
* name portion of an extension, but will be decremented to the last
* character itself while eliminating the extensions version number.
* A simple re-increment solves this problem.
*/
ext_long = true;
for (; *isa && *isa != '_'; ++isa)
if (unlikely(!isalnum(*isa)))
ext_err = true;
ext_end = isa;
if (unlikely(ext_err))
break;
if (!isdigit(ext_end[-1]))
break;
while (isdigit(*--ext_end))
;
if (tolower(ext_end[0]) != 'p' || !isdigit(ext_end[-1])) {
++ext_end;
break;
}
while (isdigit(*--ext_end))
;
++ext_end;
break;
default:
/*
* Things are a little easier for single-letter extensions, as they
* are parsed forwards.
*
* After checking that our starting position is valid, we need to
* ensure that, when isa was incremented at the start of the loop,
* that it arrived at the start of the next extension.
*
* If we are already on a non-digit, there is nothing to do. Either
* we have a multi-letter extension's _, or the start of an
* extension.
*
* Otherwise we have found the current extension's major version
* number. Parse past it, and a subsequent p/minor version number
* if present. The `p` extension must not appear immediately after
* a number, so there is no fear of missing it.
*
*/
if (unlikely(!isalpha(*ext))) {
ext_err = true;
break;
}
if (!isdigit(*isa))
break;
while (isdigit(*++isa))
;
if (tolower(*isa) != 'p')
break;
if (!isdigit(*++isa)) {
--isa;
break;
}
while (isdigit(*++isa))
;
break;
}
/*
* The parser expects that at the start of an iteration isa points to the
* first character of the next extension. As we stop parsing an extension
* on meeting a non-alphanumeric character, an extra increment is needed
* where the succeeding extension is a multi-letter prefixed with an "_".
*/
if (*isa == '_')
++isa;
#define SET_ISA_EXT_MAP(name, bit) \
do { \
if ((ext_end - ext == strlen(name)) && \
!strncasecmp(ext, name, strlen(name)) && \
riscv_isa_extension_check(bit)) \
set_bit(bit, isainfo->isa); \
} while (false) \
if (unlikely(ext_err))
continue;
if (!ext_long) {
int nr = tolower(*ext) - 'a';
if (riscv_isa_extension_check(nr)) {
*this_hwcap |= isa2hwcap[nr];
set_bit(nr, isainfo->isa);
}
} else {
for (int i = 0; i < riscv_isa_ext_count; i++)
SET_ISA_EXT_MAP(riscv_isa_ext[i].name,
riscv_isa_ext[i].id);
}
#undef SET_ISA_EXT_MAP
}
}
static void __init riscv_fill_hwcap_from_isa_string(unsigned long *isa2hwcap)
{
struct device_node *node;
const char *isa;
char print_str[NUM_ALPHA_EXTS + 1];
int i, j, rc;
unsigned long isa2hwcap[26] = {0};
int rc;
struct acpi_table_header *rhct;
acpi_status status;
unsigned int cpu;
isa2hwcap['i' - 'a'] = COMPAT_HWCAP_ISA_I;
isa2hwcap['m' - 'a'] = COMPAT_HWCAP_ISA_M;
isa2hwcap['a' - 'a'] = COMPAT_HWCAP_ISA_A;
isa2hwcap['f' - 'a'] = COMPAT_HWCAP_ISA_F;
isa2hwcap['d' - 'a'] = COMPAT_HWCAP_ISA_D;
isa2hwcap['c' - 'a'] = COMPAT_HWCAP_ISA_C;
isa2hwcap['v' - 'a'] = COMPAT_HWCAP_ISA_V;
elf_hwcap = 0;
bitmap_zero(riscv_isa, RISCV_ISA_EXT_MAX);
if (!acpi_disabled) {
status = acpi_get_table(ACPI_SIG_RHCT, 0, &rhct);
if (ACPI_FAILURE(status))
@@ -232,158 +375,7 @@ void __init riscv_fill_hwcap(void)
}
}
/*
* For all possible cpus, we have already validated in
* the boot process that they at least contain "rv" and
* whichever of "32"/"64" this kernel supports, and so this
* section can be skipped.
*/
isa += 4;
while (*isa) {
const char *ext = isa++;
const char *ext_end = isa;
bool ext_long = false, ext_err = false;
switch (*ext) {
case 's':
/*
* Workaround for invalid single-letter 's' & 'u'(QEMU).
* No need to set the bit in riscv_isa as 's' & 'u' are
* not valid ISA extensions. It works until multi-letter
* extension starting with "Su" appears.
*/
if (ext[-1] != '_' && ext[1] == 'u') {
++isa;
ext_err = true;
break;
}
fallthrough;
case 'S':
case 'x':
case 'X':
case 'z':
case 'Z':
/*
* Before attempting to parse the extension itself, we find its end.
* As multi-letter extensions must be split from other multi-letter
* extensions with an "_", the end of a multi-letter extension will
* either be the null character or the "_" at the start of the next
* multi-letter extension.
*
* Next, as the extensions version is currently ignored, we
* eliminate that portion. This is done by parsing backwards from
* the end of the extension, removing any numbers. This may be a
* major or minor number however, so the process is repeated if a
* minor number was found.
*
* ext_end is intended to represent the first character *after* the
* name portion of an extension, but will be decremented to the last
* character itself while eliminating the extensions version number.
* A simple re-increment solves this problem.
*/
ext_long = true;
for (; *isa && *isa != '_'; ++isa)
if (unlikely(!isalnum(*isa)))
ext_err = true;
ext_end = isa;
if (unlikely(ext_err))
break;
if (!isdigit(ext_end[-1]))
break;
while (isdigit(*--ext_end))
;
if (tolower(ext_end[0]) != 'p' || !isdigit(ext_end[-1])) {
++ext_end;
break;
}
while (isdigit(*--ext_end))
;
++ext_end;
break;
default:
/*
* Things are a little easier for single-letter extensions, as they
* are parsed forwards.
*
* After checking that our starting position is valid, we need to
* ensure that, when isa was incremented at the start of the loop,
* that it arrived at the start of the next extension.
*
* If we are already on a non-digit, there is nothing to do. Either
* we have a multi-letter extension's _, or the start of an
* extension.
*
* Otherwise we have found the current extension's major version
* number. Parse past it, and a subsequent p/minor version number
* if present. The `p` extension must not appear immediately after
* a number, so there is no fear of missing it.
*
*/
if (unlikely(!isalpha(*ext))) {
ext_err = true;
break;
}
if (!isdigit(*isa))
break;
while (isdigit(*++isa))
;
if (tolower(*isa) != 'p')
break;
if (!isdigit(*++isa)) {
--isa;
break;
}
while (isdigit(*++isa))
;
break;
}
/*
* The parser expects that at the start of an iteration isa points to the
* first character of the next extension. As we stop parsing an extension
* on meeting a non-alphanumeric character, an extra increment is needed
* where the succeeding extension is a multi-letter prefixed with an "_".
*/
if (*isa == '_')
++isa;
#define SET_ISA_EXT_MAP(name, bit) \
do { \
if ((ext_end - ext == strlen(name)) && \
!strncasecmp(ext, name, strlen(name)) && \
riscv_isa_extension_check(bit)) \
set_bit(bit, isainfo->isa); \
} while (false) \
if (unlikely(ext_err))
continue;
if (!ext_long) {
int nr = tolower(*ext) - 'a';
if (riscv_isa_extension_check(nr)) {
this_hwcap |= isa2hwcap[nr];
set_bit(nr, isainfo->isa);
}
} else {
for (int i = 0; i < riscv_isa_ext_count; i++)
SET_ISA_EXT_MAP(riscv_isa_ext[i].name,
riscv_isa_ext[i].id);
}
#undef SET_ISA_EXT_MAP
}
riscv_parse_isa_string(&this_hwcap, isainfo, isa2hwcap, isa);
/*
* Linux requires the following extensions, so we may as well
@@ -420,6 +412,23 @@ void __init riscv_fill_hwcap(void)
if (!acpi_disabled && rhct)
acpi_put_table((struct acpi_table_header *)rhct);
}
void __init riscv_fill_hwcap(void)
{
char print_str[NUM_ALPHA_EXTS + 1];
int i, j;
unsigned long isa2hwcap[26] = {0};
isa2hwcap['i' - 'a'] = COMPAT_HWCAP_ISA_I;
isa2hwcap['m' - 'a'] = COMPAT_HWCAP_ISA_M;
isa2hwcap['a' - 'a'] = COMPAT_HWCAP_ISA_A;
isa2hwcap['f' - 'a'] = COMPAT_HWCAP_ISA_F;
isa2hwcap['d' - 'a'] = COMPAT_HWCAP_ISA_D;
isa2hwcap['c' - 'a'] = COMPAT_HWCAP_ISA_C;
isa2hwcap['v' - 'a'] = COMPAT_HWCAP_ISA_V;
riscv_fill_hwcap_from_isa_string(isa2hwcap);
/* We don't support systems with F but without D, so mask those out
* here. */