linux-kernel - [RFC PATCH 6/8] powerpc/irq: cleanup check_stack

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Date:   Mon, 23 Dec 2019 15:26:16 +0000 (UTC)
From:   Christophe Leroy <christophe.leroy@....fr>
To:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [RFC PATCH 6/8] powerpc/irq: cleanup check_stack_overflow() a bit

Instead of #ifdef, use IS_ENABLED(CONFIG_DEBUG_STACKOVERFLOW).
This enable GCC to check for code validity even when the option
is not selected.

The function is not using current_stack_pointer() anymore so no
need to declare it inline, let GCC decide.

Signed-off-by: Christophe Leroy <christophe.leroy@....fr>
---
 arch/powerpc/kernel/irq.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 4df49f6e9987..a1122ef4a16c 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -596,20 +596,19 @@ u64 arch_irq_stat_cpu(unsigned int cpu)
 	return sum;
 }
 
-static inline void check_stack_overflow(struct pt_regs *regs)
+static void check_stack_overflow(struct pt_regs *regs)
 {
-#ifdef CONFIG_DEBUG_STACKOVERFLOW
 	bool is_user = user_mode(regs);
-	long sp;
+	long sp = regs->gpr[1] & (THREAD_SIZE - 1);
 
-	sp = regs->gpr[1] & (THREAD_SIZE - 1);
+	if (!IS_ENABLED(CONFIG_DEBUG_STACKOVERFLOW))
+		return;
 
 	/* check for stack overflow: is there less than 2KB free? */
 	if (unlikely(!is_user && sp < 2048)) {
 		pr_err("do_IRQ: stack overflow: %ld\n", sp);
 		dump_stack();
 	}
-#endif
 }
 
 #ifdef CONFIG_PPC32
-- 
2.13.3