linux-kernel - [tip: x86/asm] x86/irq/32: Use current_stack_pointer to avoid asm() in check_stack

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Message-ID: <174108458195.14745.16912760676522793123.tip-bot2@tip-bot2>
Date: Tue, 04 Mar 2025 10:36:21 -0000
From: "tip-bot2 for Uros Bizjak" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Uros Bizjak <ubizjak@...il.com>, Ingo Molnar <mingo@...nel.org>,
 Andy Lutomirski <luto@...nel.org>, Brian Gerst <brgerst@...il.com>,
 "H. Peter Anvin" <hpa@...or.com>,
 Linus Torvalds <torvalds@...ux-foundation.org>,
 Peter Zijlstra <peterz@...radead.org>, x86@...nel.org,
 linux-kernel@...r.kernel.org
Subject: [tip: x86/asm] x86/irq/32: Use current_stack_pointer to avoid asm()
 in check_stack_overflow()

The following commit has been merged into the x86/asm branch of tip:

Commit-ID:     9266be1052e0586ea932011ad671beefbaff1a64
Gitweb:        https://git.kernel.org/tip/9266be1052e0586ea932011ad671beefbaff1a64
Author:        Uros Bizjak <ubizjak@...il.com>
AuthorDate:    Mon, 03 Mar 2025 16:54:24 +01:00
Committer:     Ingo Molnar <mingo@...nel.org>
CommitterDate: Tue, 04 Mar 2025 11:21:40 +01:00

x86/irq/32: Use current_stack_pointer to avoid asm() in check_stack_overflow()

Make code more readable by using the 'current_stack_pointer' global variable.

Signed-off-by: Uros Bizjak <ubizjak@...il.com>
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Brian Gerst <brgerst@...il.com>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Link: https://lore.kernel.org/r/20250303155446.112769-4-ubizjak@gmail.com
---
 arch/x86/kernel/irq_32.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index f351fa1..2428d66 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -31,10 +31,7 @@ int sysctl_panic_on_stackoverflow __read_mostly;
 /* Debugging check for stack overflow: is there less than 1KB free? */
 static int check_stack_overflow(void)
 {
-	long sp;
-
-	__asm__ __volatile__("andl %%esp,%0" :
-			     "=r" (sp) : "0" (THREAD_SIZE - 1));
+	unsigned long sp = current_stack_pointer & (THREAD_SIZE - 1);

 	return sp < (sizeof(struct thread_info) + STACK_WARN);
 }