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From: Jisheng Zhang <jszhang@kernel.org>
To: Paul Walmsley <pjw@kernel.org>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Alexandre Ghiti <alex@ghiti.fr>
Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH] riscv: make thread_info smaller for RV64
Date: Sat, 10 Oct 2026 08:00:25 +0800	[thread overview]
Message-ID: <20261010000025.29569-1-jszhang@kernel.org> (raw)

On RV64 platforms, the thread_info structure is non-necessary bigger
due to padding. Move the "cpu" member to "preempt_count" to remove
the padding.

when !SHADOW_CALL_STACK and !RISCV_USER_CFI
Before the patch, sizeof(struct thread_info) == 72
After the patch, sizeof(struct thread_info) == 64

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
---
 arch/riscv/include/asm/thread_info.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/riscv/include/asm/thread_info.h b/arch/riscv/include/asm/thread_info.h
index 55019fdfa9ec..9f358c3ddeb0 100644
--- a/arch/riscv/include/asm/thread_info.h
+++ b/arch/riscv/include/asm/thread_info.h
@@ -53,6 +53,7 @@
 struct thread_info {
 	unsigned long		flags;		/* low level flags */
 	int                     preempt_count;  /* 0=>preemptible, <0=>BUG */
+	int			cpu;
 	/*
 	 * These stack pointers are overwritten on every system call or
 	 * exception.  SP is also saved to the stack it can be recovered when
@@ -60,7 +61,6 @@ struct thread_info {
 	 */
 	long			kernel_sp;	/* Kernel stack pointer */
 	long			user_sp;	/* User stack pointer */
-	int			cpu;
 	unsigned long		syscall_work;	/* SYSCALL_WORK_ flags */
 #ifdef CONFIG_SHADOW_CALL_STACK
 	void			*scs_base;
-- 
2.51.0


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                 reply	other threads:[~2026-10-10  0:20 UTC|newest]

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