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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