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Mon, 10 Jul 2023 02:36:48 -0700 From: Conor Dooley To: Subject: [PATCH v4 08/11] RISC-V: split riscv_fill_hwcap() in 3 Date: Mon, 10 Jul 2023 10:35:43 +0100 Message-ID: <20230710-goatskin-thieving-a49e93cb9a7e@wendy> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230710-equipment-stained-dd042d66ba5d@wendy> References: <20230710-equipment-stained-dd042d66ba5d@wendy> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=11968; i=conor.dooley@microchip.com; h=from:subject:message-id; bh=iGe+YwVNmPq1+zqO9UyiaCBbCGF6aB1MOiyT8TFuwhg=; b=owGbwMvMwCFWscWwfUFT0iXG02pJDCmrL9wo3pirwOm+UyWweEvGr0nHcjlZk1nW625lPJKtrWAt fm9FRykLgxgHg6yYIkvi7b4WqfV/XHY497yFmcPKBDKEgYtTACZio8jwTyU+aHHcbduzk1rYe5melG 6JUNA9udDGYaOH5tMW0/PhtYwM047zmvkem+w5VcvFYtr3877VX3a9thYV2Mhj939p5PLTDAA= X-Developer-Key: i=conor.dooley@microchip.com; a=openpgp; fpr=F9ECA03CF54F12CD01F1655722E2C55B37CF380C X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230710_023653_603607_D4F1388B X-CRM114-Status: GOOD ( 29.67 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: devicetree@vger.kernel.org, Albert Ou , Jonathan Corbet , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, conor@kernel.org, conor.dooley@microchip.com, Rob Herring , Evan Green , Krzysztof Kozlowski , Paul Walmsley , linux-riscv@lists.infradead.org, Heiko Stuebner , Andrew Jones Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org 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 Signed-off-by: Conor Dooley --- Changes in v2: - Drop unused variables --- arch/riscv/kernel/cpufeature.c | 345 +++++++++++++++++---------------- 1 file changed, 177 insertions(+), 168 deletions(-) diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c index bf7e8e8852f0..41aedeaecb61 100644 --- a/arch/riscv/kernel/cpufeature.c +++ b/arch/riscv/kernel/cpufeature.c @@ -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 == sizeof(name) - 1) && \ + !strncasecmp(ext, name, sizeof(name) - 1) && \ + 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 == sizeof(name) - 1) && \ - !strncasecmp(ext, name, sizeof(name) - 1) && \ - 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. */