linux-kernel - [PATCH v2 13/18] riscv: alternative: Add an ALTERNATIVE

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Message-ID: <20251009015839.3460231-14-samuel.holland@sifive.com>
Date: Wed,  8 Oct 2025 18:57:49 -0700
From: Samuel Holland <samuel.holland@...ive.com>
To: Palmer Dabbelt <palmer@...belt.com>,
	Paul Walmsley <pjw@...nel.org>,
	linux-riscv@...ts.infradead.org
Cc: devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-mm@...ck.org,
	Conor Dooley <conor@...nel.org>,
	Alexandre Ghiti <alex@...ti.fr>,
	Emil Renner Berthing <kernel@...il.dk>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Rob Herring <robh+dt@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Samuel Holland <samuel.holland@...ive.com>,
	Andrew Jones <ajones@...tanamicro.com>
Subject: [PATCH v2 13/18] riscv: alternative: Add an ALTERNATIVE_3 macro

ALT_FIXUP_MT() is already using ALTERNATIVE_2(), but it needs to be
extended to handle a fourth case. Add ALTERNATIVE_3(), which extends
ALTERNATIVE_2() with another block of new content.

Reviewed-by: Andrew Jones <ajones@...tanamicro.com>
Signed-off-by: Samuel Holland <samuel.holland@...ive.com>
---

Changes in v2:
 - Fix erroneously-escaped newline in assembly ALTERNATIVE_CFG_3 macro

 arch/riscv/include/asm/alternative-macros.h | 45 ++++++++++++++++++---
 1 file changed, 40 insertions(+), 5 deletions(-)

diff --git a/arch/riscv/include/asm/alternative-macros.h b/arch/riscv/include/asm/alternative-macros.h
index 231d777d936c2..2d79abecf9a87 100644
--- a/arch/riscv/include/asm/alternative-macros.h
+++ b/arch/riscv/include/asm/alternative-macros.h
@@ -50,8 +50,17 @@
 	ALT_NEW_CONTENT \vendor_id_2, \patch_id_2, \enable_2, "\new_c_2"
 .endm
 
+.macro ALTERNATIVE_CFG_3 old_c, new_c_1, vendor_id_1, patch_id_1, enable_1,	\
+				new_c_2, vendor_id_2, patch_id_2, enable_2,	\
+				new_c_3, vendor_id_3, patch_id_3, enable_3
+	ALTERNATIVE_CFG_2 "\old_c", "\new_c_1", \vendor_id_1, \patch_id_1, \enable_1 \
+				    "\new_c_2", \vendor_id_2, \patch_id_2, \enable_2
+	ALT_NEW_CONTENT \vendor_id_3, \patch_id_3, \enable_3, "\new_c_3"
+.endm
+
 #define __ALTERNATIVE_CFG(...)		ALTERNATIVE_CFG __VA_ARGS__
 #define __ALTERNATIVE_CFG_2(...)	ALTERNATIVE_CFG_2 __VA_ARGS__
+#define __ALTERNATIVE_CFG_3(...)	ALTERNATIVE_CFG_3 __VA_ARGS__
 
 #else /* !__ASSEMBLY__ */
 
@@ -98,6 +107,13 @@
 	__ALTERNATIVE_CFG(old_c, new_c_1, vendor_id_1, patch_id_1, enable_1)	\
 	ALT_NEW_CONTENT(vendor_id_2, patch_id_2, enable_2, new_c_2)
 
+#define __ALTERNATIVE_CFG_3(old_c, new_c_1, vendor_id_1, patch_id_1, enable_1,	\
+				   new_c_2, vendor_id_2, patch_id_2, enable_2,	\
+				   new_c_3, vendor_id_3, patch_id_3, enable_3)	\
+	__ALTERNATIVE_CFG_2(old_c, new_c_1, vendor_id_1, patch_id_1, enable_1,	\
+				   new_c_2, vendor_id_2, patch_id_2, enable_2)	\
+	ALT_NEW_CONTENT(vendor_id_3, patch_id_3, enable_3, new_c_3)
+
 #endif /* __ASSEMBLY__ */
 
 #define _ALTERNATIVE_CFG(old_c, new_c, vendor_id, patch_id, CONFIG_k)	\
@@ -108,6 +124,13 @@
 	__ALTERNATIVE_CFG_2(old_c, new_c_1, vendor_id_1, patch_id_1, IS_ENABLED(CONFIG_k_1),	\
 				   new_c_2, vendor_id_2, patch_id_2, IS_ENABLED(CONFIG_k_2))
 
+#define _ALTERNATIVE_CFG_3(old_c, new_c_1, vendor_id_1, patch_id_1, CONFIG_k_1,		\
+				  new_c_2, vendor_id_2, patch_id_2, CONFIG_k_2,		\
+				  new_c_3, vendor_id_3, patch_id_3, CONFIG_k_3)		\
+	__ALTERNATIVE_CFG_3(old_c, new_c_1, vendor_id_1, patch_id_1, IS_ENABLED(CONFIG_k_1),	\
+				   new_c_2, vendor_id_2, patch_id_2, IS_ENABLED(CONFIG_k_2),	\
+				   new_c_3, vendor_id_3, patch_id_3, IS_ENABLED(CONFIG_k_3))
+
 #else /* CONFIG_RISCV_ALTERNATIVE */
 #ifdef __ASSEMBLY__
 
@@ -118,11 +141,17 @@
 #define __ALTERNATIVE_CFG(old_c, ...)		ALTERNATIVE_CFG old_c
 #define __ALTERNATIVE_CFG_2(old_c, ...)		ALTERNATIVE_CFG old_c
 
+#define _ALTERNATIVE_CFG_3(old_c, ...)	\
+	ALTERNATIVE_CFG old_c
+
 #else /* !__ASSEMBLY__ */
 
 #define __ALTERNATIVE_CFG(old_c, ...)		old_c "\n"
 #define __ALTERNATIVE_CFG_2(old_c, ...)		old_c "\n"
 
+#define _ALTERNATIVE_CFG_3(old_c, ...)	\
+	__ALTERNATIVE_CFG(old_c)
+
 #endif /* __ASSEMBLY__ */
 
 #define _ALTERNATIVE_CFG(old_c, ...)		__ALTERNATIVE_CFG(old_c)
@@ -147,15 +176,21 @@
 	_ALTERNATIVE_CFG(old_content, new_content, vendor_id, patch_id, CONFIG_k)
 
 /*
- * A vendor wants to replace an old_content, but another vendor has used
- * ALTERNATIVE() to patch its customized content at the same location. In
- * this case, this vendor can create a new macro ALTERNATIVE_2() based
- * on the following sample code and then replace ALTERNATIVE() with
- * ALTERNATIVE_2() to append its customized content.
+ * Variant of ALTERNATIVE() that supports two sets of replacement content.
  */
 #define ALTERNATIVE_2(old_content, new_content_1, vendor_id_1, patch_id_1, CONFIG_k_1,		\
 				   new_content_2, vendor_id_2, patch_id_2, CONFIG_k_2)		\
 	_ALTERNATIVE_CFG_2(old_content, new_content_1, vendor_id_1, patch_id_1, CONFIG_k_1,	\
 					new_content_2, vendor_id_2, patch_id_2, CONFIG_k_2)
 
+/*
+ * Variant of ALTERNATIVE() that supports three sets of replacement content.
+ */
+#define ALTERNATIVE_3(old_content, new_content_1, vendor_id_1, patch_id_1, CONFIG_k_1,		\
+				   new_content_2, vendor_id_2, patch_id_2, CONFIG_k_2,		\
+				   new_content_3, vendor_id_3, patch_id_3, CONFIG_k_3)		\
+	_ALTERNATIVE_CFG_3(old_content, new_content_1, vendor_id_1, patch_id_1, CONFIG_k_1,	\
+					new_content_2, vendor_id_2, patch_id_2, CONFIG_k_2,	\
+					new_content_3, vendor_id_3, patch_id_3, CONFIG_k_3)
+
 #endif
-- 
2.47.2