From 58004f266918912771ee71f46bfb92bf64ab9108 Mon Sep 17 00:00:00 2001 From: Tsukasa OI Date: Mon, 14 Mar 2022 13:38:40 -0700 Subject: [PATCH 1/6] RISC-V: Correctly print supported extensions This commit replaces BITS_PER_LONG with number of alphabet letters. Current ISA pretty-printing code expects extension 'a' (bit 0) through 'z' (bit 25). Although bit 26 and higher is not currently used (thus never cause an issue in practice), it will be an annoying problem if we start to use those in the future. This commit disables printing high bits for now. Reviewed-by: Anup Patel Tested-by: Heiko Stuebner Signed-off-by: Tsukasa OI Signed-off-by: Atish Patra Signed-off-by: Palmer Dabbelt --- arch/riscv/kernel/cpufeature.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c index d959d207a40d..dd3d57eb4eea 100644 --- a/arch/riscv/kernel/cpufeature.c +++ b/arch/riscv/kernel/cpufeature.c @@ -13,6 +13,8 @@ #include #include +#define NUM_ALPHA_EXTS ('z' - 'a' + 1) + unsigned long elf_hwcap __read_mostly; /* Host ISA bitmap */ @@ -63,7 +65,7 @@ void __init riscv_fill_hwcap(void) { struct device_node *node; const char *isa; - char print_str[BITS_PER_LONG + 1]; + char print_str[NUM_ALPHA_EXTS + 1]; size_t i, j, isa_len; static unsigned long isa2hwcap[256] = {0}; @@ -133,13 +135,13 @@ 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); 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); From 2a31c54be097c74344b4fab20ea6104012d2cb8b Mon Sep 17 00:00:00 2001 From: Tsukasa OI Date: Mon, 14 Mar 2022 13:38:41 -0700 Subject: [PATCH 2/6] RISC-V: Minimal parser for "riscv, isa" strings Current hart ISA ("riscv,isa") parser don't correctly parse: 1. Multi-letter extensions 2. Version numbers All ISA extensions ratified recently has multi-letter extensions (except 'H'). The current "riscv,isa" parser that is easily confused by multi-letter extensions and "p" in version numbers can be a huge problem for adding new extensions through the device tree. Leaving it would create incompatible hacks and would make "riscv,isa" value unreliable. This commit implements minimal parser for "riscv,isa" strings. With this, we can safely ignore multi-letter extensions and version numbers. [Improved commit text and fixed a bug around 's' in base extension] Signed-off-by: Atish Patra [Fixed workaround for QEMU] Signed-off-by: Tsukasa OI Tested-by: Heiko Stuebner Reviewed-by: Anup Patel Signed-off-by: Palmer Dabbelt --- arch/riscv/kernel/cpufeature.c | 72 ++++++++++++++++++++++++++++------ 1 file changed, 61 insertions(+), 11 deletions(-) diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c index dd3d57eb4eea..72c5f6ef56b5 100644 --- a/arch/riscv/kernel/cpufeature.c +++ b/arch/riscv/kernel/cpufeature.c @@ -7,6 +7,7 @@ */ #include +#include #include #include #include @@ -66,7 +67,7 @@ void __init riscv_fill_hwcap(void) struct device_node *node; const char *isa; char print_str[NUM_ALPHA_EXTS + 1]; - size_t i, j, isa_len; + int i, j; static unsigned long isa2hwcap[256] = {0}; isa2hwcap['i'] = isa2hwcap['I'] = COMPAT_HWCAP_ISA_I; @@ -92,23 +93,72 @@ void __init riscv_fill_hwcap(void) continue; } - i = 0; - isa_len = strlen(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])]; + 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 (!islower(*isa) && !isdigit(*isa)) + ext_err = true; + 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; /* - * TODO: X, Y and Z extension parsing for Host ISA - * bitmap will be added in-future. + * TODO: Full version-aware handling including + * multi-letter extensions will be added in-future. */ - if ('a' <= isa[i] && isa[i] < 'x') - this_isa |= (1UL << (isa[i] - 'a')); + if (ext_err || ext_long) + continue; + this_hwcap |= isa2hwcap[(unsigned char)(*ext)]; + this_isa |= (1UL << (*ext - 'a')); } /* From 40a4d0dfbcf00c8534ab8724041705b3db6c5ce2 Mon Sep 17 00:00:00 2001 From: Tsukasa OI Date: Mon, 14 Mar 2022 13:38:42 -0700 Subject: [PATCH 3/6] RISC-V: Extract multi-letter extension names from "riscv, isa" Currently, there is no usage for version numbers in extensions as any ratified non base ISA extension will always at v1.0. Extract the extension names in place for future parsing. Tested-by: Heiko Stuebner Reviewed-by: Anup Patel Signed-off-by: Tsukasa OI [Improved commit text and comments] Signed-off-by: Atish Patra Signed-off-by: Palmer Dabbelt --- arch/riscv/kernel/cpufeature.c | 35 ++++++++++++++++++++++++++-------- 1 file changed, 27 insertions(+), 8 deletions(-) diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c index 72c5f6ef56b5..b0df7eff47f7 100644 --- a/arch/riscv/kernel/cpufeature.c +++ b/arch/riscv/kernel/cpufeature.c @@ -124,8 +124,28 @@ void __init riscv_fill_hwcap(void) ext_long = true; /* Multi-letter extension must be delimited */ for (; *isa && *isa != '_'; ++isa) - if (!islower(*isa) && !isdigit(*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))) { @@ -151,14 +171,13 @@ void __init riscv_fill_hwcap(void) } if (*isa != '_') --isa; - /* - * TODO: Full version-aware handling including - * multi-letter extensions will be added in-future. - */ - if (ext_err || ext_long) + + if (unlikely(ext_err)) continue; - this_hwcap |= isa2hwcap[(unsigned char)(*ext)]; - this_isa |= (1UL << (*ext - 'a')); + if (!ext_long) { + this_hwcap |= isa2hwcap[(unsigned char)(*ext)]; + this_isa |= (1UL << (*ext - 'a')); + } } /* From 02d52fbd940af7d7fe0a523e99938113b2addd35 Mon Sep 17 00:00:00 2001 From: Atish Patra Date: Mon, 14 Mar 2022 13:38:43 -0700 Subject: [PATCH 4/6] RISC-V: Implement multi-letter ISA extension probing framework Multi-letter extensions can be probed using exising riscv_isa_extension_available API now. It doesn't support versioning right now as there is no use case for it. Individual extension specific implementation will be added during each extension support. Tested-by: Heiko Stuebner Signed-off-by: Atish Patra Reviewed-by: Anup Patel Signed-off-by: Palmer Dabbelt --- arch/riscv/include/asm/hwcap.h | 18 ++++++++++++++++++ arch/riscv/kernel/cpufeature.c | 22 ++++++++++++++++------ 2 files changed, 34 insertions(+), 6 deletions(-) diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h index 5ce50468aff1..170bd80da520 100644 --- a/arch/riscv/include/asm/hwcap.h +++ b/arch/riscv/include/asm/hwcap.h @@ -34,7 +34,25 @@ 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, +}; unsigned long riscv_isa_extension_base(const unsigned long *isa_bitmap); diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c index b0df7eff47f7..3455fdfd680e 100644 --- a/arch/riscv/kernel/cpufeature.c +++ b/arch/riscv/kernel/cpufeature.c @@ -83,7 +83,7 @@ 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); if (riscv_of_processor_hartid(node) < 0) continue; @@ -100,6 +100,7 @@ void __init riscv_fill_hwcap(void) if (!strncmp(isa, "rv64", 4)) isa += 4; #endif + bitmap_zero(this_isa, RISCV_ISA_EXT_MAX); for (; *isa; ++isa) { const char *ext = isa++; const char *ext_end = isa; @@ -172,12 +173,20 @@ void __init riscv_fill_hwcap(void) 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)]; - this_isa |= (1UL << (*ext - 'a')); + set_bit(*ext - 'a', this_isa); } +#undef SET_ISA_EXT_MAP } /* @@ -190,10 +199,11 @@ 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 @@ -207,7 +217,7 @@ void __init riscv_fill_hwcap(void) 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 < NUM_ALPHA_EXTS; i++) From 3f96db125d68127ffef6fdeeb777d94ccf95c09f Mon Sep 17 00:00:00 2001 From: Atish Patra Date: Mon, 14 Mar 2022 13:38:44 -0700 Subject: [PATCH 5/6] RISC-V: Do no continue isa string parsing without correct XLEN The isa string should begin with either rv64 or rv32. Otherwise, it is an incorrect isa string. Currently, the string parsing continues even if it doesnot begin with current XLEN. Fix this by checking if it found "rv64" or "rv32" in the beginning. Tested-by: Heiko Stuebner Signed-off-by: Atish Patra Reviewed-by: Anup Patel Signed-off-by: Palmer Dabbelt --- arch/riscv/kernel/cpufeature.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c index 3455fdfd680e..a43c08af5f4b 100644 --- a/arch/riscv/kernel/cpufeature.c +++ b/arch/riscv/kernel/cpufeature.c @@ -84,6 +84,7 @@ void __init riscv_fill_hwcap(void) for_each_of_cpu_node(node) { unsigned long this_hwcap = 0; DECLARE_BITMAP(this_isa, RISCV_ISA_EXT_MAX); + const char *temp; if (riscv_of_processor_hartid(node) < 0) continue; @@ -93,6 +94,7 @@ void __init riscv_fill_hwcap(void) continue; } + temp = isa; #if IS_ENABLED(CONFIG_32BIT) if (!strncmp(isa, "rv32", 4)) isa += 4; @@ -100,6 +102,9 @@ void __init riscv_fill_hwcap(void) 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++; From a9b202606c69312cdaa4db187837820ebf7213b2 Mon Sep 17 00:00:00 2001 From: Atish Patra Date: Mon, 14 Mar 2022 13:38:45 -0700 Subject: [PATCH 6/6] RISC-V: Improve /proc/cpuinfo output for ISA extensions Currently, the /proc/cpuinfo outputs the entire riscv,isa string which is not ideal when we have multiple ISA extensions present in the ISA string. Some of them may not be enabled in kernel as well. Same goes for the single letter extensions as well which prints the entire ISA string. Some of they may not be valid ISA extensions as well (e.g 'su') Parse only the valid & enabled ISA extension and print them. Tested-by: Heiko Stuebner Signed-off-by: Atish Patra Reviewed-by: Anup Patel Signed-off-by: Palmer Dabbelt --- arch/riscv/include/asm/hwcap.h | 7 ++++ arch/riscv/kernel/cpu.c | 65 ++++++++++++++++++++++++++++++++-- 2 files changed, 70 insertions(+), 2 deletions(-) diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h index 170bd80da520..691fc9c8099b 100644 --- a/arch/riscv/include/asm/hwcap.h +++ b/arch/riscv/include/asm/hwcap.h @@ -54,6 +54,13 @@ 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); #define riscv_isa_extension_mask(ext) BIT_MASK(RISCV_ISA_EXT_##ext) diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c index ad0a7e9f828b..fc115e307ef5 100644 --- a/arch/riscv/kernel/cpu.c +++ b/arch/riscv/kernel/cpu.c @@ -6,6 +6,7 @@ #include #include #include +#include #include #include @@ -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"); }