diff options
author | Palmer Dabbelt <palmer@rivosinc.com> | 2022-03-17 14:09:16 -0700 |
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committer | Palmer Dabbelt <palmer@rivosinc.com> | 2022-03-17 14:09:16 -0700 |
commit | 6b57ac02b45f7f676c81b1357e7e5d63a974bf60 (patch) | |
tree | 1fdcd2eb0e2dd0b48102b47c27b59837fe950f70 /arch/riscv | |
parent | 9d1f0ec9f71780e69ceb9d91697600c747d6e02e (diff) | |
parent | a9b202606c69312cdaa4db187837820ebf7213b2 (diff) | |
download | linux-6b57ac02b45f7f676c81b1357e7e5d63a974bf60.tar.bz2 |
RISC-V: Provide a fraemework for RISC-V ISA extensions
This series implements a generic framework to parse multi-letter ISA
extensions.
* palmer/riscv-isa:
RISC-V: Improve /proc/cpuinfo output for ISA extensions
RISC-V: Do no continue isa string parsing without correct XLEN
RISC-V: Implement multi-letter ISA extension probing framework
RISC-V: Extract multi-letter extension names from "riscv, isa"
RISC-V: Minimal parser for "riscv, isa" strings
RISC-V: Correctly print supported extensions
Diffstat (limited to 'arch/riscv')
-rw-r--r-- | arch/riscv/include/asm/hwcap.h | 25 | ||||
-rw-r--r-- | arch/riscv/kernel/cpu.c | 65 | ||||
-rw-r--r-- | arch/riscv/kernel/cpufeature.c | 128 |
3 files changed, 195 insertions, 23 deletions
diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h index 5ce50468aff1..691fc9c8099b 100644 --- a/arch/riscv/include/asm/hwcap.h +++ b/arch/riscv/include/asm/hwcap.h @@ -34,7 +34,32 @@ extern unsigned long elf_hwcap; #define RISCV_ISA_EXT_s ('s' - 'a') #define RISCV_ISA_EXT_u ('u' - 'a') +/* + * Increse this to higher value as kernel support more ISA extensions. + */ #define RISCV_ISA_EXT_MAX 64 +#define RISCV_ISA_EXT_NAME_LEN_MAX 32 + +/* The base ID for multi-letter ISA extensions */ +#define RISCV_ISA_EXT_BASE 26 + +/* + * This enum represent the logical ID for each multi-letter RISC-V ISA extension. + * The logical ID should start from RISCV_ISA_EXT_BASE and must not exceed + * RISCV_ISA_EXT_MAX. 0-25 range is reserved for single letter + * extensions while all the multi-letter extensions should define the next + * available logical extension id. + */ +enum riscv_isa_ext_id { + RISCV_ISA_EXT_ID_MAX = RISCV_ISA_EXT_MAX, +}; + +struct riscv_isa_ext_data { + /* Name of the extension displayed to userspace via /proc/cpuinfo */ + char uprop[RISCV_ISA_EXT_NAME_LEN_MAX]; + /* The logical ISA extension ID */ + unsigned int isa_ext_id; +}; unsigned long riscv_isa_extension_base(const unsigned long *isa_bitmap); diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c index 3e7e35d50e69..ecc2a09a66a9 100644 --- a/arch/riscv/kernel/cpu.c +++ b/arch/riscv/kernel/cpu.c @@ -6,6 +6,7 @@ #include <linux/init.h> #include <linux/seq_file.h> #include <linux/of.h> +#include <asm/hwcap.h> #include <asm/smp.h> #include <asm/pgtable.h> @@ -63,12 +64,72 @@ int riscv_of_parent_hartid(struct device_node *node) } #ifdef CONFIG_PROC_FS +#define __RISCV_ISA_EXT_DATA(UPROP, EXTID) \ + { \ + .uprop = #UPROP, \ + .isa_ext_id = EXTID, \ + } +/** + * Here are the ordering rules of extension naming defined by RISC-V + * specification : + * 1. All extensions should be separated from other multi-letter extensions + * from other multi-letter extensions by an underscore. + * 2. The first letter following the 'Z' conventionally indicates the most + * closely related alphabetical extension category, IMAFDQLCBKJTPVH. + * If multiple 'Z' extensions are named, they should be ordered first + * by category, then alphabetically within a category. + * 3. Standard supervisor-level extensions (starts with 'S') should be + * listed after standard unprivileged extensions. If multiple + * supervisor-level extensions are listed, they should be ordered + * alphabetically. + * 4. Non-standard extensions (starts with 'X') must be listed after all + * standard extensions. They must be separated from other multi-letter + * extensions by an underscore. + */ +static struct riscv_isa_ext_data isa_ext_arr[] = { + __RISCV_ISA_EXT_DATA("", RISCV_ISA_EXT_MAX), +}; + +static void print_isa_ext(struct seq_file *f) +{ + struct riscv_isa_ext_data *edata; + int i = 0, arr_sz; + + arr_sz = ARRAY_SIZE(isa_ext_arr) - 1; + + /* No extension support available */ + if (arr_sz <= 0) + return; + + for (i = 0; i <= arr_sz; i++) { + edata = &isa_ext_arr[i]; + if (!__riscv_isa_extension_available(NULL, edata->isa_ext_id)) + continue; + seq_printf(f, "_%s", edata->uprop); + } +} + +/** + * These are the only valid base (single letter) ISA extensions as per the spec. + * It also specifies the canonical order in which it appears in the spec. + * Some of the extension may just be a place holder for now (B, K, P, J). + * This should be updated once corresponding extensions are ratified. + */ +static const char base_riscv_exts[13] = "imafdqcbkjpvh"; static void print_isa(struct seq_file *f, const char *isa) { - /* Print the entire ISA as it is */ + int i; + seq_puts(f, "isa\t\t: "); - seq_write(f, isa, strlen(isa)); + /* Print the rv[64/32] part */ + seq_write(f, isa, 4); + for (i = 0; i < sizeof(base_riscv_exts); i++) { + if (__riscv_isa_extension_available(NULL, base_riscv_exts[i] - 'a')) + /* Print only enabled the base ISA extensions */ + seq_write(f, &base_riscv_exts[i], 1); + } + print_isa_ext(f); seq_puts(f, "\n"); } diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c index d959d207a40d..a43c08af5f4b 100644 --- a/arch/riscv/kernel/cpufeature.c +++ b/arch/riscv/kernel/cpufeature.c @@ -7,12 +7,15 @@ */ #include <linux/bitmap.h> +#include <linux/ctype.h> #include <linux/of.h> #include <asm/processor.h> #include <asm/hwcap.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 */ @@ -63,8 +66,8 @@ void __init riscv_fill_hwcap(void) { struct device_node *node; const char *isa; - char print_str[BITS_PER_LONG + 1]; - size_t i, j, isa_len; + char print_str[NUM_ALPHA_EXTS + 1]; + int i, j; static unsigned long isa2hwcap[256] = {0}; isa2hwcap['i'] = isa2hwcap['I'] = COMPAT_HWCAP_ISA_I; @@ -80,7 +83,8 @@ void __init riscv_fill_hwcap(void) for_each_of_cpu_node(node) { unsigned long this_hwcap = 0; - unsigned long this_isa = 0; + DECLARE_BITMAP(this_isa, RISCV_ISA_EXT_MAX); + const char *temp; if (riscv_of_processor_hartid(node) < 0) continue; @@ -90,23 +94,104 @@ void __init riscv_fill_hwcap(void) continue; } - i = 0; - isa_len = strlen(isa); + temp = isa; #if IS_ENABLED(CONFIG_32BIT) if (!strncmp(isa, "rv32", 4)) - i += 4; + isa += 4; #elif IS_ENABLED(CONFIG_64BIT) if (!strncmp(isa, "rv64", 4)) - i += 4; + isa += 4; #endif - for (; i < isa_len; ++i) { - this_hwcap |= isa2hwcap[(unsigned char)(isa[i])]; - /* - * TODO: X, Y and Z extension parsing for Host ISA - * bitmap will be added in-future. - */ - if ('a' <= isa[i] && isa[i] < 'x') - this_isa |= (1UL << (isa[i] - 'a')); + /* 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); + } +#undef SET_ISA_EXT_MAP } /* @@ -119,10 +204,11 @@ void __init riscv_fill_hwcap(void) else elf_hwcap = this_hwcap; - if (riscv_isa[0]) - riscv_isa[0] &= this_isa; + if (bitmap_weight(riscv_isa, RISCV_ISA_EXT_MAX)) + bitmap_and(riscv_isa, riscv_isa, this_isa, RISCV_ISA_EXT_MAX); else - riscv_isa[0] = this_isa; + bitmap_copy(riscv_isa, this_isa, RISCV_ISA_EXT_MAX); + } /* We don't support systems with F but without D, so mask those out @@ -133,13 +219,13 @@ void __init riscv_fill_hwcap(void) } memset(print_str, 0, sizeof(print_str)); - for (i = 0, j = 0; i < BITS_PER_LONG; i++) + 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: ISA extensions %s\n", print_str); + pr_info("riscv: base ISA extensions %s\n", print_str); memset(print_str, 0, sizeof(print_str)); - for (i = 0, j = 0; i < BITS_PER_LONG; i++) + 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); |