linux-kernel - [PATCH] arch/Kconfig: JUMP_LABEL should depend on !XIP

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Message-Id: <20201221204004.16138-1-vitaly.wool@konsulko.com>
Date:   Mon, 21 Dec 2020 22:40:05 +0200
From:   Vitaly Wool <vitaly.wool@...sulko.com>
To:     linux-kernel@...r.kernel.org, linux-mm <linux-mm@...ck.org>
Cc:     Nicolas Pitre <nico@...xnic.net>,
        Vitaly Wool <vitaly.wool@...sulko.com>
Subject: [PATCH] arch/Kconfig: JUMP_LABEL should depend on !XIP

There's no point in trying to optimize the code when the code is
executed from a read-only medium (e. g. NOR flash) as in the XIP
case. Moreover, trying to do so in a XIP kernel may result in
faults and kernel crashes so let's explicitly disallow JUMP_LABEL
if XIP_KERNEL configuration option is set.

Signed-off-by: Vitaly Wool <vitaly.wool@...sulko.com>
---
 arch/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/Kconfig b/arch/Kconfig
index 56b6ccc0e32d..88632c9588ae 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -81,6 +81,7 @@ config JUMP_LABEL
 	bool "Optimize very unlikely/likely branches"
 	depends on HAVE_ARCH_JUMP_LABEL
 	depends on CC_HAS_ASM_GOTO
+	depends on !XIP_KERNEL
 	help
 	 This option enables a transparent branch optimization that
 	 makes certain almost-always-true or almost-always-false branch
-- 
2.29.2