linux-kernel - [PATCH 4/8] riscv: cpufeature: extend riscv_cpufeature_patch

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Date:   Thu,  6 Oct 2022 15:08:14 +0800
From:   Jisheng Zhang <jszhang@...nel.org>
To:     Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>
Cc:     linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH 4/8] riscv: cpufeature: extend riscv_cpufeature_patch_func to all ISA extensions

make the riscv_cpufeature_patch_func() scan all ISA extensions rather
than limited feature macros.

Signed-off-by: Jisheng Zhang <jszhang@...nel.org>
---
 arch/riscv/include/asm/errata_list.h |  9 ++--
 arch/riscv/kernel/cpufeature.c       | 61 +++-------------------------
 2 files changed, 9 insertions(+), 61 deletions(-)

diff --git a/arch/riscv/include/asm/errata_list.h b/arch/riscv/include/asm/errata_list.h
index 19a771085781..722525f4fc96 100644
--- a/arch/riscv/include/asm/errata_list.h
+++ b/arch/riscv/include/asm/errata_list.h
@@ -6,6 +6,7 @@
 #define ASM_ERRATA_LIST_H
 
 #include <asm/alternative.h>
+#include <asm/hwcap.h>
 #include <asm/vendorid_list.h>
 
 #ifdef CONFIG_ERRATA_SIFIVE
@@ -20,10 +21,6 @@
 #define	ERRATA_THEAD_NUMBER 2
 #endif
 
-#define	CPUFEATURE_SVPBMT 0
-#define	CPUFEATURE_ZICBOM 1
-#define	CPUFEATURE_NUMBER 2
-
 #ifdef __ASSEMBLY__
 
 #define ALT_INSN_FAULT(x)						\
@@ -53,7 +50,7 @@ asm(ALTERNATIVE("sfence.vma %0", "sfence.vma", SIFIVE_VENDOR_ID,	\
 #define ALT_SVPBMT(_val, prot)						\
 asm(ALTERNATIVE_2("li %0, 0\t\nnop",					\
 		  "li %0, %1\t\nslli %0,%0,%3", 0,			\
-			CPUFEATURE_SVPBMT, CONFIG_RISCV_ISA_SVPBMT,	\
+			RISCV_ISA_EXT_SVPBMT, CONFIG_RISCV_ISA_SVPBMT,	\
 		  "li %0, %2\t\nslli %0,%0,%4", THEAD_VENDOR_ID,	\
 			ERRATA_THEAD_PBMT, CONFIG_ERRATA_THEAD_PBMT)	\
 		: "=r"(_val)						\
@@ -127,7 +124,7 @@ asm volatile(ALTERNATIVE_2(						\
 	"add a0, a0, %0\n\t"						\
 	"2:\n\t"							\
 	"bltu a0, %2, 3b\n\t"						\
-	"nop", 0, CPUFEATURE_ZICBOM, CONFIG_RISCV_ISA_ZICBOM,		\
+	"nop", 0, RISCV_ISA_EXT_ZICBOM, CONFIG_RISCV_ISA_ZICBOM,	\
 	"mv a0, %1\n\t"							\
 	"j 2f\n\t"							\
 	"3:\n\t"							\
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index afa54635c180..2b1f18f97253 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -251,61 +251,11 @@ void __init riscv_fill_hwcap(void)
 }
 
 #ifdef CONFIG_RISCV_ALTERNATIVE
-static bool __init_or_module cpufeature_probe_svpbmt(unsigned int stage)
-{
-#ifdef CONFIG_RISCV_ISA_SVPBMT
-	switch (stage) {
-	case RISCV_ALTERNATIVES_EARLY_BOOT:
-		return false;
-	default:
-		return riscv_isa_extension_available(NULL, SVPBMT);
-	}
-#endif
-
-	return false;
-}
-
-static bool __init_or_module cpufeature_probe_zicbom(unsigned int stage)
-{
-#ifdef CONFIG_RISCV_ISA_ZICBOM
-	switch (stage) {
-	case RISCV_ALTERNATIVES_EARLY_BOOT:
-		return false;
-	default:
-		return riscv_isa_extension_available(NULL, ZICBOM);
-	}
-#endif
-
-	return false;
-}
-
-/*
- * Probe presence of individual extensions.
- *
- * This code may also be executed before kernel relocation, so we cannot use
- * addresses generated by the address-of operator as they won't be valid in
- * this context.
- */
-static u32 __init_or_module cpufeature_probe(unsigned int stage)
-{
-	u32 cpu_req_feature = 0;
-
-	if (cpufeature_probe_svpbmt(stage))
-		cpu_req_feature |= (1U << CPUFEATURE_SVPBMT);
-
-	if (cpufeature_probe_zicbom(stage))
-		cpu_req_feature |= (1U << CPUFEATURE_ZICBOM);
-
-	return cpu_req_feature;
-}
-
 void __init_or_module riscv_cpufeature_patch_func(struct alt_entry *begin,
 						  struct alt_entry *end,
 						  unsigned int stage)
 {
-	u32 cpu_req_feature = cpufeature_probe(stage);
 	struct alt_entry *alt;
-	u32 tmp;
 
 	if (stage == RISCV_ALTERNATIVES_EARLY_BOOT)
 		return;
@@ -313,15 +263,16 @@ void __init_or_module riscv_cpufeature_patch_func(struct alt_entry *begin,
 	for (alt = begin; alt < end; alt++) {
 		if (alt->vendor_id != 0)
 			continue;
-		if (alt->errata_id >= CPUFEATURE_NUMBER) {
-			WARN(1, "This feature id:%d is not in kernel cpufeature list",
+		if (alt->errata_id >= RISCV_ISA_EXT_ID_MAX) {
+			WARN(1, "This extension id:%d is not in ISA extension list",
 				alt->errata_id);
 			continue;
 		}
 
-		tmp = (1U << alt->errata_id);
-		if (cpu_req_feature & tmp)
-			patch_text_nosync(alt->old_ptr, alt->alt_ptr, alt->alt_len);
+		if (!test_bit(alt->errata_id, riscv_isa))
+			continue;
+
+		patch_text_nosync(alt->old_ptr, alt->alt_ptr, alt->alt_len);
 	}
 }
 #endif
-- 
2.37.2