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From: K Prateek Nayak <kprateek.nayak@amd.com>
To: Thomas Gleixner <tglx@kernel.org>, Ingo Molnar <mingo@redhat.com>,
	"Peter Zijlstra" <peterz@infradead.org>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	Paul Walmsley <pjw@kernel.org>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>, Guo Ren <guoren@kernel.org>
Cc: "Darren Hart" <dvhart@infradead.org>,
	"Davidlohr Bueso" <dave@stgolabs.net>,
	"André Almeida" <andrealmeid@igalia.com>,
	linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-s390@vger.kernel.org, linux-riscv@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org,
	"K Prateek Nayak" <kprateek.nayak@amd.com>,
	"Alexandre Ghiti" <alex@ghiti.fr>,
	"Charlie Jenkins" <charlie@rivosinc.com>,
	"Jisheng Zhang" <jszhang@kernel.org>,
	"Charles Mirabile" <cmirabil@redhat.com>
Subject: [PATCH v4 4/8] riscv/runtime-const: Replace open-coded placeholder with RUNTIME_MAGIC
Date: Thu, 30 Apr 2026 09:47:26 +0000	[thread overview]
Message-ID: <20260430094730.31624-5-kprateek.nayak@amd.com> (raw)
In-Reply-To: <20260430094730.31624-1-kprateek.nayak@amd.com>

Define the placeholder used for lui + addi[w] patching sequence as
RUNTIME_MAGIC and use that instead of open coding the constants in the
inline assembly.

No functional changes intended.

Suggested-by: Guo Ren <guoren@kernel.org>
Signed-off-by: K Prateek Nayak <kprateek.nayak@amd.com>
---
changelog v3..v4:

o New patch based on suggestions from Guo. (Thank you!)
---
 arch/riscv/include/asm/runtime-const.h | 38 ++++++++++++++------------
 1 file changed, 20 insertions(+), 18 deletions(-)

diff --git a/arch/riscv/include/asm/runtime-const.h b/arch/riscv/include/asm/runtime-const.h
index 900db0a103d05..1ce02605d2e43 100644
--- a/arch/riscv/include/asm/runtime-const.h
+++ b/arch/riscv/include/asm/runtime-const.h
@@ -15,21 +15,23 @@
 
 #include <linux/uaccess.h>
 
+#define RUNTIME_MAGIC __ASM_STR(0x89ABCDEF)
+
 #ifdef CONFIG_32BIT
-#define runtime_const_ptr(sym)					\
-({								\
-	typeof(sym) __ret;					\
-	asm_inline(".option push\n\t"				\
-		".option norvc\n\t"				\
-		"1:\t"						\
-		"lui	%[__ret],0x89abd\n\t"			\
-		"addi	%[__ret],%[__ret],-0x211\n\t"		\
-		".option pop\n\t"				\
-		".pushsection runtime_ptr_" #sym ",\"a\"\n\t"	\
-		".long 1b - .\n\t"				\
-		".popsection"					\
-		: [__ret] "=r" (__ret));			\
-	__ret;							\
+#define runtime_const_ptr(sym)						\
+({									\
+	typeof(sym) __ret;						\
+	asm_inline(".option push\n\t"					\
+		".option norvc\n\t"					\
+		"1:\t"							\
+		"lui	%[__ret], %%hi(" RUNTIME_MAGIC ")\n\t"		\
+		"addi	%[__ret],%[__ret], %%lo(" RUNTIME_MAGIC ")\n\t"	\
+		".option pop\n\t"					\
+		".pushsection runtime_ptr_" #sym ",\"a\"\n\t"		\
+		".long 1b - .\n\t"					\
+		".popsection"						\
+		: [__ret] "=r" (__ret));				\
+	__ret;								\
 })
 #else
 /*
@@ -46,10 +48,10 @@
 	".option push\n\t"					\
 	".option norvc\n\t"					\
 	"1:\t"							\
-	"lui	%[__ret],0x89abd\n\t"				\
-	"lui	%[__tmp],0x1234\n\t"				\
-	"addiw	%[__ret],%[__ret],-0x211\n\t"			\
-	"addiw	%[__tmp],%[__tmp],0x567\n\t"			\
+	"lui	%[__ret], %%hi(" RUNTIME_MAGIC ")\n\t"		\
+	"lui	%[__tmp], %%hi(" RUNTIME_MAGIC ")\n\t"		\
+	"addiw	%[__ret],%[__ret], %%lo(" RUNTIME_MAGIC ")\n\t"	\
+	"addiw	%[__tmp],%[__tmp], %%lo(" RUNTIME_MAGIC ")\n\t"	\
 
 #define RISCV_RUNTIME_CONST_64_BASE				\
 	"slli	%[__tmp],%[__tmp],32\n\t"			\
-- 
2.34.1



  parent reply	other threads:[~2026-04-30  9:49 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-04-30  9:47 [PATCH v4 0/8] futex: Use runtime constants for futex_hash computation K Prateek Nayak
2026-04-30  9:47 ` [PATCH v4 1/8] x86/runtime-const: Introduce runtime_const_mask_32() K Prateek Nayak
2026-04-30  9:47 ` [PATCH v4 2/8] arm64/runtime-const: Use aarch64_insn_patch_text_nosync() for patching K Prateek Nayak
2026-04-30  9:47 ` [PATCH v4 3/8] arm64/runtime-const: Introduce runtime_const_mask_32() K Prateek Nayak
2026-04-30  9:47 ` K Prateek Nayak [this message]
2026-04-30  9:47 ` [PATCH v4 5/8] riscv/runtime-const: " K Prateek Nayak
2026-04-30  9:47 ` [PATCH v4 6/8] s390/runtime-const: " K Prateek Nayak
2026-04-30  9:47 ` [PATCH v4 7/8] asm-generic/runtime-const: Add dummy runtime_const_mask_32() K Prateek Nayak
2026-04-30  9:47 ` [PATCH v4 8/8] futex: Use runtime constants for __futex_hash() hot path K Prateek Nayak

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