forked from Minki/linux
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
This commit is contained in:
Palmer Dabbelt
commit
6b57ac02b4
@ -34,7 +34,32 @@ extern unsigned long elf_hwcap;
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#define RISCV_ISA_EXT_s ('s' - 'a')
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#define RISCV_ISA_EXT_u ('u' - 'a')
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/*
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* Increse this to higher value as kernel support more ISA extensions.
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*/
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#define RISCV_ISA_EXT_MAX 64
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#define RISCV_ISA_EXT_NAME_LEN_MAX 32
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/* The base ID for multi-letter ISA extensions */
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#define RISCV_ISA_EXT_BASE 26
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/*
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* This enum represent the logical ID for each multi-letter RISC-V ISA extension.
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* The logical ID should start from RISCV_ISA_EXT_BASE and must not exceed
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* RISCV_ISA_EXT_MAX. 0-25 range is reserved for single letter
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* extensions while all the multi-letter extensions should define the next
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* available logical extension id.
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*/
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enum riscv_isa_ext_id {
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RISCV_ISA_EXT_ID_MAX = RISCV_ISA_EXT_MAX,
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};
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struct riscv_isa_ext_data {
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/* Name of the extension displayed to userspace via /proc/cpuinfo */
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char uprop[RISCV_ISA_EXT_NAME_LEN_MAX];
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/* The logical ISA extension ID */
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unsigned int isa_ext_id;
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};
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unsigned long riscv_isa_extension_base(const unsigned long *isa_bitmap);
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@ -6,6 +6,7 @@
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#include <linux/init.h>
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#include <linux/seq_file.h>
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#include <linux/of.h>
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#include <asm/hwcap.h>
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#include <asm/smp.h>
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#include <asm/pgtable.h>
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@ -63,12 +64,72 @@ int riscv_of_parent_hartid(struct device_node *node)
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}
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#ifdef CONFIG_PROC_FS
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#define __RISCV_ISA_EXT_DATA(UPROP, EXTID) \
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{ \
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.uprop = #UPROP, \
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.isa_ext_id = EXTID, \
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}
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/**
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* Here are the ordering rules of extension naming defined by RISC-V
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* specification :
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* 1. All extensions should be separated from other multi-letter extensions
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* from other multi-letter extensions by an underscore.
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* 2. The first letter following the 'Z' conventionally indicates the most
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* closely related alphabetical extension category, IMAFDQLCBKJTPVH.
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* If multiple 'Z' extensions are named, they should be ordered first
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* by category, then alphabetically within a category.
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* 3. Standard supervisor-level extensions (starts with 'S') should be
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* listed after standard unprivileged extensions. If multiple
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* supervisor-level extensions are listed, they should be ordered
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* alphabetically.
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* 4. Non-standard extensions (starts with 'X') must be listed after all
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* standard extensions. They must be separated from other multi-letter
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* extensions by an underscore.
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*/
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static struct riscv_isa_ext_data isa_ext_arr[] = {
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__RISCV_ISA_EXT_DATA("", RISCV_ISA_EXT_MAX),
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};
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static void print_isa_ext(struct seq_file *f)
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{
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struct riscv_isa_ext_data *edata;
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int i = 0, arr_sz;
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arr_sz = ARRAY_SIZE(isa_ext_arr) - 1;
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/* No extension support available */
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if (arr_sz <= 0)
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return;
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for (i = 0; i <= arr_sz; i++) {
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edata = &isa_ext_arr[i];
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if (!__riscv_isa_extension_available(NULL, edata->isa_ext_id))
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continue;
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seq_printf(f, "_%s", edata->uprop);
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}
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}
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/**
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* These are the only valid base (single letter) ISA extensions as per the spec.
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* It also specifies the canonical order in which it appears in the spec.
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* Some of the extension may just be a place holder for now (B, K, P, J).
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* This should be updated once corresponding extensions are ratified.
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*/
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static const char base_riscv_exts[13] = "imafdqcbkjpvh";
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static void print_isa(struct seq_file *f, const char *isa)
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{
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/* Print the entire ISA as it is */
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int i;
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seq_puts(f, "isa\t\t: ");
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seq_write(f, isa, strlen(isa));
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/* Print the rv[64/32] part */
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seq_write(f, isa, 4);
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for (i = 0; i < sizeof(base_riscv_exts); i++) {
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if (__riscv_isa_extension_available(NULL, base_riscv_exts[i] - 'a'))
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/* Print only enabled the base ISA extensions */
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seq_write(f, &base_riscv_exts[i], 1);
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}
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print_isa_ext(f);
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seq_puts(f, "\n");
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}
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@ -7,12 +7,15 @@
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*/
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#include <linux/bitmap.h>
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#include <linux/ctype.h>
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#include <linux/of.h>
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#include <asm/processor.h>
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#include <asm/hwcap.h>
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#include <asm/smp.h>
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#include <asm/switch_to.h>
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#define NUM_ALPHA_EXTS ('z' - 'a' + 1)
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unsigned long elf_hwcap __read_mostly;
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/* Host ISA bitmap */
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@ -63,8 +66,8 @@ void __init riscv_fill_hwcap(void)
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{
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struct device_node *node;
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const char *isa;
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char print_str[BITS_PER_LONG + 1];
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size_t i, j, isa_len;
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char print_str[NUM_ALPHA_EXTS + 1];
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int i, j;
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static unsigned long isa2hwcap[256] = {0};
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isa2hwcap['i'] = isa2hwcap['I'] = COMPAT_HWCAP_ISA_I;
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@ -80,7 +83,8 @@ void __init riscv_fill_hwcap(void)
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for_each_of_cpu_node(node) {
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unsigned long this_hwcap = 0;
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unsigned long this_isa = 0;
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DECLARE_BITMAP(this_isa, RISCV_ISA_EXT_MAX);
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const char *temp;
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if (riscv_of_processor_hartid(node) < 0)
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continue;
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@ -90,23 +94,104 @@ void __init riscv_fill_hwcap(void)
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continue;
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}
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i = 0;
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isa_len = strlen(isa);
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temp = isa;
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#if IS_ENABLED(CONFIG_32BIT)
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if (!strncmp(isa, "rv32", 4))
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i += 4;
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isa += 4;
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#elif IS_ENABLED(CONFIG_64BIT)
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if (!strncmp(isa, "rv64", 4))
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i += 4;
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isa += 4;
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#endif
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for (; i < isa_len; ++i) {
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this_hwcap |= isa2hwcap[(unsigned char)(isa[i])];
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/*
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* TODO: X, Y and Z extension parsing for Host ISA
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* bitmap will be added in-future.
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*/
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if ('a' <= isa[i] && isa[i] < 'x')
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this_isa |= (1UL << (isa[i] - 'a'));
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/* The riscv,isa DT property must start with rv64 or rv32 */
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if (temp == isa)
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continue;
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bitmap_zero(this_isa, RISCV_ISA_EXT_MAX);
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for (; *isa; ++isa) {
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const char *ext = isa++;
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const char *ext_end = isa;
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bool ext_long = false, ext_err = false;
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switch (*ext) {
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case 's':
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/**
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* Workaround for invalid single-letter 's' & 'u'(QEMU).
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* No need to set the bit in riscv_isa as 's' & 'u' are
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* not valid ISA extensions. It works until multi-letter
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* extension starting with "Su" appears.
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*/
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if (ext[-1] != '_' && ext[1] == 'u') {
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++isa;
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ext_err = true;
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break;
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}
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fallthrough;
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case 'x':
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case 'z':
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ext_long = true;
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/* Multi-letter extension must be delimited */
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for (; *isa && *isa != '_'; ++isa)
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if (unlikely(!islower(*isa)
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&& !isdigit(*isa)))
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ext_err = true;
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/* Parse backwards */
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ext_end = isa;
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if (unlikely(ext_err))
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break;
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if (!isdigit(ext_end[-1]))
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break;
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/* Skip the minor version */
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while (isdigit(*--ext_end))
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;
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if (ext_end[0] != 'p'
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|| !isdigit(ext_end[-1])) {
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/* Advance it to offset the pre-decrement */
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++ext_end;
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break;
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}
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/* Skip the major version */
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while (isdigit(*--ext_end))
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;
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++ext_end;
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break;
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default:
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if (unlikely(!islower(*ext))) {
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ext_err = true;
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break;
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}
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/* Find next extension */
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if (!isdigit(*isa))
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break;
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/* Skip the minor version */
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while (isdigit(*++isa))
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;
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if (*isa != 'p')
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break;
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if (!isdigit(*++isa)) {
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--isa;
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break;
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}
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/* Skip the major version */
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while (isdigit(*++isa))
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;
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break;
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}
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if (*isa != '_')
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--isa;
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#define SET_ISA_EXT_MAP(name, bit) \
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do { \
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if ((ext_end - ext == sizeof(name) - 1) && \
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!memcmp(ext, name, sizeof(name) - 1)) \
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set_bit(bit, this_isa); \
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} while (false) \
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if (unlikely(ext_err))
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continue;
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if (!ext_long) {
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this_hwcap |= isa2hwcap[(unsigned char)(*ext)];
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set_bit(*ext - 'a', this_isa);
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}
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#undef SET_ISA_EXT_MAP
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}
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/*
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@ -119,10 +204,11 @@ void __init riscv_fill_hwcap(void)
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else
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elf_hwcap = this_hwcap;
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if (riscv_isa[0])
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riscv_isa[0] &= this_isa;
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if (bitmap_weight(riscv_isa, RISCV_ISA_EXT_MAX))
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bitmap_and(riscv_isa, riscv_isa, this_isa, RISCV_ISA_EXT_MAX);
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else
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riscv_isa[0] = this_isa;
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bitmap_copy(riscv_isa, this_isa, RISCV_ISA_EXT_MAX);
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}
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/* We don't support systems with F but without D, so mask those out
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@ -133,13 +219,13 @@ void __init riscv_fill_hwcap(void)
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}
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memset(print_str, 0, sizeof(print_str));
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for (i = 0, j = 0; i < BITS_PER_LONG; i++)
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for (i = 0, j = 0; i < NUM_ALPHA_EXTS; i++)
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if (riscv_isa[0] & BIT_MASK(i))
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print_str[j++] = (char)('a' + i);
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pr_info("riscv: ISA extensions %s\n", print_str);
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pr_info("riscv: base ISA extensions %s\n", print_str);
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memset(print_str, 0, sizeof(print_str));
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for (i = 0, j = 0; i < BITS_PER_LONG; i++)
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for (i = 0, j = 0; i < NUM_ALPHA_EXTS; i++)
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if (elf_hwcap & BIT_MASK(i))
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print_str[j++] = (char)('a' + i);
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pr_info("riscv: ELF capabilities %s\n", print_str);
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