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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copied from arch/arm64/kernel/cpufeature.c
*
* Copyright (C) 2015 ARM Ltd.
* Copyright (C) 2017 SiFive
*/
#include <linux/bitmap.h>
#include <linux/ctype.h>
#include <linux/libfdt.h>
#include <linux/module.h>
#include <linux/of.h>
#include <asm/alternative.h>
#include <asm/cacheflush.h>
#include <asm/errata_list.h>
#include <asm/hwcap.h>
#include <asm/patch.h>
#include <asm/pgtable.h>
#include <asm/processor.h>
#include <asm/smp.h>
#include <asm/switch_to.h>
#define NUM_ALPHA_EXTS ('z' - 'a' + 1)
unsigned long elf_hwcap __read_mostly;
/* Host ISA bitmap */
static DECLARE_BITMAP(riscv_isa, RISCV_ISA_EXT_MAX) __read_mostly;
__ro_after_init DEFINE_STATIC_KEY_ARRAY_FALSE(riscv_isa_ext_keys, RISCV_ISA_EXT_KEY_MAX);
EXPORT_SYMBOL(riscv_isa_ext_keys);
/**
* riscv_isa_extension_base() - Get base extension word
*
* @isa_bitmap: ISA bitmap to use
* Return: base extension word as unsigned long value
*
* NOTE: If isa_bitmap is NULL then Host ISA bitmap will be used.
*/
unsigned long riscv_isa_extension_base(const unsigned long *isa_bitmap)
{
if (!isa_bitmap)
return riscv_isa[0];
return isa_bitmap[0];
}
EXPORT_SYMBOL_GPL(riscv_isa_extension_base);
/**
* __riscv_isa_extension_available() - Check whether given extension
* is available or not
*
* @isa_bitmap: ISA bitmap to use
* @bit: bit position of the desired extension
* Return: true or false
*
* NOTE: If isa_bitmap is NULL then Host ISA bitmap will be used.
*/
bool __riscv_isa_extension_available(const unsigned long *isa_bitmap, int bit)
{
const unsigned long *bmap = (isa_bitmap) ? isa_bitmap : riscv_isa;
if (bit >= RISCV_ISA_EXT_MAX)
return false;
return test_bit(bit, bmap) ? true : false;
}
EXPORT_SYMBOL_GPL(__riscv_isa_extension_available);
void __init riscv_fill_hwcap(void)
{
struct device_node *node;
const char *isa;
char print_str[NUM_ALPHA_EXTS + 1];
int i, j, rc;
static unsigned long isa2hwcap[256] = {0};
unsigned long hartid;
isa2hwcap['i'] = isa2hwcap['I'] = COMPAT_HWCAP_ISA_I;
isa2hwcap['m'] = isa2hwcap['M'] = COMPAT_HWCAP_ISA_M;
isa2hwcap['a'] = isa2hwcap['A'] = COMPAT_HWCAP_ISA_A;
isa2hwcap['f'] = isa2hwcap['F'] = COMPAT_HWCAP_ISA_F;
isa2hwcap['d'] = isa2hwcap['D'] = COMPAT_HWCAP_ISA_D;
isa2hwcap['c'] = isa2hwcap['C'] = COMPAT_HWCAP_ISA_C;
elf_hwcap = 0;
bitmap_zero(riscv_isa, RISCV_ISA_EXT_MAX);
for_each_of_cpu_node(node) {
unsigned long this_hwcap = 0;
DECLARE_BITMAP(this_isa, RISCV_ISA_EXT_MAX);
const char *temp;
rc = riscv_of_processor_hartid(node, &hartid);
if (rc < 0)
continue;
if (of_property_read_string(node, "riscv,isa", &isa)) {
pr_warn("Unable to find \"riscv,isa\" devicetree entry\n");
continue;
}
temp = isa;
#if IS_ENABLED(CONFIG_32BIT)
if (!strncmp(isa, "rv32", 4))
isa += 4;
#elif IS_ENABLED(CONFIG_64BIT)
if (!strncmp(isa, "rv64", 4))
isa += 4;
#endif
/* The riscv,isa DT property must start with rv64 or rv32 */
if (temp == isa)
continue;
bitmap_zero(this_isa, RISCV_ISA_EXT_MAX);
for (; *isa; ++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 'x':
case 'z':
ext_long = true;
/* Multi-letter extension must be delimited */
for (; *isa && *isa != '_'; ++isa)
if (unlikely(!islower(*isa)
&& !isdigit(*isa)))
ext_err = true;
/* Parse backwards */
ext_end = isa;
if (unlikely(ext_err))
break;
if (!isdigit(ext_end[-1]))
break;
/* Skip the minor version */
while (isdigit(*--ext_end))
;
if (ext_end[0] != 'p'
|| !isdigit(ext_end[-1])) {
/* Advance it to offset the pre-decrement */
++ext_end;
break;
}
/* Skip the major version */
while (isdigit(*--ext_end))
;
++ext_end;
break;
default:
if (unlikely(!islower(*ext))) {
ext_err = true;
break;
}
/* Find next extension */
if (!isdigit(*isa))
break;
/* Skip the minor version */
while (isdigit(*++isa))
;
if (*isa != 'p')
break;
if (!isdigit(*++isa)) {
--isa;
break;
}
/* Skip the major version */
while (isdigit(*++isa))
;
break;
}
if (*isa != '_')
--isa;
#define SET_ISA_EXT_MAP(name, bit) \
do { \
if ((ext_end - ext == sizeof(name) - 1) && \
!memcmp(ext, name, sizeof(name) - 1)) \
set_bit(bit, this_isa); \
} while (false) \
if (unlikely(ext_err))
continue;
if (!ext_long) {
this_hwcap |= isa2hwcap[(unsigned char)(*ext)];
set_bit(*ext - 'a', this_isa);
} else {
SET_ISA_EXT_MAP("sscofpmf", RISCV_ISA_EXT_SSCOFPMF);
SET_ISA_EXT_MAP("svpbmt", RISCV_ISA_EXT_SVPBMT);
SET_ISA_EXT_MAP("zicbom", RISCV_ISA_EXT_ZICBOM);
SET_ISA_EXT_MAP("zihintpause", RISCV_ISA_EXT_ZIHINTPAUSE);
}
#undef SET_ISA_EXT_MAP
}
/*
* All "okay" hart should have same isa. Set HWCAP based on
* common capabilities of every "okay" hart, in case they don't
* have.
*/
if (elf_hwcap)
elf_hwcap &= this_hwcap;
else
elf_hwcap = this_hwcap;
if (bitmap_empty(riscv_isa, RISCV_ISA_EXT_MAX))
bitmap_copy(riscv_isa, this_isa, RISCV_ISA_EXT_MAX);
else
bitmap_and(riscv_isa, riscv_isa, this_isa, RISCV_ISA_EXT_MAX);
}
/* We don't support systems with F but without D, so mask those out
* here. */
if ((elf_hwcap & COMPAT_HWCAP_ISA_F) && !(elf_hwcap & COMPAT_HWCAP_ISA_D)) {
pr_info("This kernel does not support systems with F but not D\n");
elf_hwcap &= ~COMPAT_HWCAP_ISA_F;
}
memset(print_str, 0, sizeof(print_str));
for (i = 0, j = 0; i < NUM_ALPHA_EXTS; i++)
if (riscv_isa[0] & BIT_MASK(i))
print_str[j++] = (char)('a' + i);
pr_info("riscv: base ISA extensions %s\n", print_str);
memset(print_str, 0, sizeof(print_str));
for (i = 0, j = 0; i < NUM_ALPHA_EXTS; i++)
if (elf_hwcap & BIT_MASK(i))
print_str[j++] = (char)('a' + i);
pr_info("riscv: ELF capabilities %s\n", print_str);
for_each_set_bit(i, riscv_isa, RISCV_ISA_EXT_MAX) {
j = riscv_isa_ext2key(i);
if (j >= 0)
static_branch_enable(&riscv_isa_ext_keys[j]);
}
}
#ifdef CONFIG_RISCV_ALTERNATIVE
static bool __init_or_module cpufeature_probe_svpbmt(unsigned int stage)
{
#ifdef CONFIG_RISCV_ISA_SVPBMT
switch (stage) {
case RISCV_ALTERNATIVES_EARLY_BOOT:
return false;
default:
return riscv_isa_extension_available(NULL, SVPBMT);
}
#endif
return false;
}
static bool __init_or_module cpufeature_probe_zicbom(unsigned int stage)
{
#ifdef CONFIG_RISCV_ISA_ZICBOM
switch (stage) {
case RISCV_ALTERNATIVES_EARLY_BOOT:
return false;
default:
if (riscv_isa_extension_available(NULL, ZICBOM)) {
riscv_noncoherent_supported();
return true;
} else {
return false;
}
}
#endif
return false;
}
/*
* Probe presence of individual extensions.
*
* This code may also be executed before kernel relocation, so we cannot use
* addresses generated by the address-of operator as they won't be valid in
* this context.
*/
static u32 __init_or_module cpufeature_probe(unsigned int stage)
{
u32 cpu_req_feature = 0;
if (cpufeature_probe_svpbmt(stage))
cpu_req_feature |= (1U << CPUFEATURE_SVPBMT);
if (cpufeature_probe_zicbom(stage))
cpu_req_feature |= (1U << CPUFEATURE_ZICBOM);
return cpu_req_feature;
}
void __init_or_module riscv_cpufeature_patch_func(struct alt_entry *begin,
struct alt_entry *end,
unsigned int stage)
{
u32 cpu_req_feature = cpufeature_probe(stage);
struct alt_entry *alt;
u32 tmp;
for (alt = begin; alt < end; alt++) {
if (alt->vendor_id != 0)
continue;
if (alt->errata_id >= CPUFEATURE_NUMBER) {
WARN(1, "This feature id:%d is not in kernel cpufeature list",
alt->errata_id);
continue;
}
tmp = (1U << alt->errata_id);
if (cpu_req_feature & tmp)
patch_text_nosync(alt->old_ptr, alt->alt_ptr, alt->alt_len);
}
}
#endif
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