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From:   Conor Dooley <conor.dooley@microchip.com>
To:     <palmer@dabbelt.com>
CC:     <conor@kernel.org>, <conor.dooley@microchip.com>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Andrew Jones <ajones@ventanamicro.com>,
        Heiko Stuebner <heiko.stuebner@vrull.eu>,
        "Evan Green" <evan@rivosinc.com>,
        Sunil V L <sunilvl@ventanamicro.com>,
        <linux-riscv@lists.infradead.org>, <devicetree@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>
Subject: [PATCH v1 6/9] RISC-V: add single letter extensions to riscv_isa_ext
Date:   Mon, 26 Jun 2023 12:19:44 +0100
Message-ID: <20230626-sensuous-clothing-124f7ae0aedf@wendy>
In-Reply-To: <20230626-provable-angrily-81760e8c3cc6@wendy>
References: <20230626-provable-angrily-81760e8c3cc6@wendy>
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So that riscv_fill_hwcap() can use riscv_isa_ext to probe for single
letter extensions, add them to it. riscv_isa_ext_data grows a new
member, signifying whether an extension is multi-letter & thus requiring
special handling.
As a result, what gets spat out in /proc/cpuinfo will become borked, as
single letter extensions will be printed as part of the base extensions
and while printing from riscv_isa_arr. Take the opportunity to unify the
printing of the isa string, using the new member of riscv_isa_ext_data
in the process.

Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
---
 arch/riscv/include/asm/hwcap.h |  1 +
 arch/riscv/kernel/cpu.c        | 36 ++++++----------------
 arch/riscv/kernel/cpufeature.c | 56 +++++++++++++++++++++-------------
 3 files changed, 46 insertions(+), 47 deletions(-)

diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h
index a35bee219dd7..6ad896dc4342 100644
--- a/arch/riscv/include/asm/hwcap.h
+++ b/arch/riscv/include/asm/hwcap.h
@@ -77,6 +77,7 @@ unsigned long riscv_get_elf_hwcap(void);
 struct riscv_isa_ext_data {
 	const unsigned int id;
 	const char *name;
+	const bool multi_letter;
 };
 
 extern const struct riscv_isa_ext_data riscv_isa_ext[];
diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c
index beb8b16bbf87..046d9d3dac16 100644
--- a/arch/riscv/kernel/cpu.c
+++ b/arch/riscv/kernel/cpu.c
@@ -160,41 +160,25 @@ arch_initcall(riscv_cpuinfo_init);
 
 #ifdef CONFIG_PROC_FS
 
-static void print_isa_ext(struct seq_file *f)
-{
-	for (int i = 0; i < riscv_isa_ext_count; i++) {
-		const struct riscv_isa_ext_data *edata = &riscv_isa_ext[i];
-		if (!__riscv_isa_extension_available(NULL, edata->id))
-			continue;
-
-		seq_printf(f, "_%s", edata->name);
-	}
-}
-
-/*
- * 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)
 {
-	int i;
-
 	seq_puts(f, "isa\t\t: ");
+
 	if (IS_ENABLED(CONFIG_32BIT))
 		seq_write(f, "rv32", 4);
 	else
 		seq_write(f, "rv64", 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);
+	for (int i = 0; i < riscv_isa_ext_count; i++) {
+		if (!__riscv_isa_extension_available(NULL, riscv_isa_ext[i].id))
+			continue;
+
+		if (riscv_isa_ext[i].multi_letter)
+			seq_puts(f, "_");
+
+		seq_printf(f, "%s", riscv_isa_ext[i].name);
 	}
-	print_isa_ext(f);
+
 	seq_puts(f, "\n");
 }
 
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index b5e23506c4f0..5405d8a58537 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -99,9 +99,10 @@ static bool riscv_isa_extension_check(int id)
 	return true;
 }
 
-#define __RISCV_ISA_EXT_DATA(_name, _id) {	\
-	.name = #_name,				\
-	.id = _id,				\
+#define __RISCV_ISA_EXT_DATA(_name, _id, _multi) {	\
+	.name = #_name,					\
+	.id = _id,					\
+	.multi_letter = _multi,				\
 }
 
 /*
@@ -144,24 +145,37 @@ static bool riscv_isa_extension_check(int id)
  * New entries to this struct should follow the ordering rules described above.
  */
 const struct riscv_isa_ext_data riscv_isa_ext[] = {
-	__RISCV_ISA_EXT_DATA(zicbom, RISCV_ISA_EXT_ZICBOM),
-	__RISCV_ISA_EXT_DATA(zicboz, RISCV_ISA_EXT_ZICBOZ),
-	__RISCV_ISA_EXT_DATA(zicntr, RISCV_ISA_EXT_ZICNTR),
-	__RISCV_ISA_EXT_DATA(zicsr, RISCV_ISA_EXT_ZICSR),
-	__RISCV_ISA_EXT_DATA(zifencei, RISCV_ISA_EXT_ZIFENCEI),
-	__RISCV_ISA_EXT_DATA(zihintpause, RISCV_ISA_EXT_ZIHINTPAUSE),
-	__RISCV_ISA_EXT_DATA(zihpm, RISCV_ISA_EXT_ZIHPM),
-	__RISCV_ISA_EXT_DATA(zba, RISCV_ISA_EXT_ZBA),
-	__RISCV_ISA_EXT_DATA(zbb, RISCV_ISA_EXT_ZBB),
-	__RISCV_ISA_EXT_DATA(zbs, RISCV_ISA_EXT_ZBS),
-	__RISCV_ISA_EXT_DATA(smaia, RISCV_ISA_EXT_SMAIA),
-	__RISCV_ISA_EXT_DATA(ssaia, RISCV_ISA_EXT_SSAIA),
-	__RISCV_ISA_EXT_DATA(sscofpmf, RISCV_ISA_EXT_SSCOFPMF),
-	__RISCV_ISA_EXT_DATA(sstc, RISCV_ISA_EXT_SSTC),
-	__RISCV_ISA_EXT_DATA(svinval, RISCV_ISA_EXT_SVINVAL),
-	__RISCV_ISA_EXT_DATA(svnapot, RISCV_ISA_EXT_SVNAPOT),
-	__RISCV_ISA_EXT_DATA(svpbmt, RISCV_ISA_EXT_SVPBMT),
-	__RISCV_ISA_EXT_DATA("", RISCV_ISA_EXT_MAX),
+	__RISCV_ISA_EXT_DATA(i, RISCV_ISA_EXT_i, false),
+	__RISCV_ISA_EXT_DATA(m, RISCV_ISA_EXT_m, false),
+	__RISCV_ISA_EXT_DATA(a, RISCV_ISA_EXT_a, false),
+	__RISCV_ISA_EXT_DATA(f, RISCV_ISA_EXT_f, false),
+	__RISCV_ISA_EXT_DATA(d, RISCV_ISA_EXT_d, false),
+	__RISCV_ISA_EXT_DATA(q, RISCV_ISA_EXT_q, false),
+	__RISCV_ISA_EXT_DATA(c, RISCV_ISA_EXT_c, false),
+	__RISCV_ISA_EXT_DATA(b, RISCV_ISA_EXT_b, false),
+	__RISCV_ISA_EXT_DATA(k, RISCV_ISA_EXT_k, false),
+	__RISCV_ISA_EXT_DATA(j, RISCV_ISA_EXT_j, false),
+	__RISCV_ISA_EXT_DATA(p, RISCV_ISA_EXT_p, false),
+	__RISCV_ISA_EXT_DATA(v, RISCV_ISA_EXT_v, false),
+	__RISCV_ISA_EXT_DATA(h, RISCV_ISA_EXT_h, false),
+	__RISCV_ISA_EXT_DATA(zicbom, RISCV_ISA_EXT_ZICBOM, true),
+	__RISCV_ISA_EXT_DATA(zicboz, RISCV_ISA_EXT_ZICBOZ, true),
+	__RISCV_ISA_EXT_DATA(zicntr, RISCV_ISA_EXT_ZICNTR, true),
+	__RISCV_ISA_EXT_DATA(zicsr, RISCV_ISA_EXT_ZICSR, true),
+	__RISCV_ISA_EXT_DATA(zifencei, RISCV_ISA_EXT_ZIFENCEI, true),
+	__RISCV_ISA_EXT_DATA(zihintpause, RISCV_ISA_EXT_ZIHINTPAUSE, true),
+	__RISCV_ISA_EXT_DATA(zihpm, RISCV_ISA_EXT_ZIHPM, true),
+	__RISCV_ISA_EXT_DATA(zba, RISCV_ISA_EXT_ZBA, true),
+	__RISCV_ISA_EXT_DATA(zbb, RISCV_ISA_EXT_ZBB, true),
+	__RISCV_ISA_EXT_DATA(zbs, RISCV_ISA_EXT_ZBS, true),
+	__RISCV_ISA_EXT_DATA(smaia, RISCV_ISA_EXT_SMAIA, true),
+	__RISCV_ISA_EXT_DATA(ssaia, RISCV_ISA_EXT_SSAIA, true),
+	__RISCV_ISA_EXT_DATA(sscofpmf, RISCV_ISA_EXT_SSCOFPMF, true),
+	__RISCV_ISA_EXT_DATA(sstc, RISCV_ISA_EXT_SSTC, true),
+	__RISCV_ISA_EXT_DATA(svinval, RISCV_ISA_EXT_SVINVAL, true),
+	__RISCV_ISA_EXT_DATA(svnapot, RISCV_ISA_EXT_SVNAPOT, true),
+	__RISCV_ISA_EXT_DATA(svpbmt, RISCV_ISA_EXT_SVPBMT, true),
+	__RISCV_ISA_EXT_DATA("", RISCV_ISA_EXT_MAX, true),
 };
 
 const size_t riscv_isa_ext_count = ARRAY_SIZE(riscv_isa_ext);
-- 
2.40.1