linux-kernel - [PATCH 2/5] x86/Kconfig: only enable ROX cache in execmem when STRICT_MODULE

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Message-ID: <20250603111446.2609381-3-rppt@kernel.org>
Date: Tue,  3 Jun 2025 14:14:42 +0300
From: Mike Rapoport <rppt@...nel.org>
To: Peter Zijlstra <peterz@...radead.org>
Cc: Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	Ingo Molnar <mingo@...hat.com>,
	Jürgen Groß <jgross@...e.com>,
	Mike Rapoport <rppt@...nel.org>,
	"H. Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Xin Li <xin@...or.com>,
	linux-kernel@...r.kernel.org,
	stable@...r.kernel.org,
	x86@...nel.org
Subject: [PATCH 2/5] x86/Kconfig: only enable ROX cache in execmem when STRICT_MODULE_RWX is set

From: "Mike Rapoport (Microsoft)" <rppt@...nel.org>

Currently ROX cache in execmem is enabled regardless of
STRICT_MODULE_RWX setting. This breaks an assumption that module memory
is writable when STRICT_MODULE_RWX is disabled, for instance for kernel
debuggin.

Only enable ROX cache in execmem when STRICT_MODULE_RWX is set to
restore the original behaviour of module text permissions.

Fixes: 64f6a4e10c05 ("x86: re-enable EXECMEM_ROX support")
Signed-off-by: Mike Rapoport (Microsoft) <rppt@...nel.org>
---
 arch/x86/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index e21cca404943..47932d5f4499 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -88,7 +88,7 @@ config X86
 	select ARCH_HAS_DMA_OPS			if GART_IOMMU || XEN
 	select ARCH_HAS_EARLY_DEBUG		if KGDB
 	select ARCH_HAS_ELF_RANDOMIZE
-	select ARCH_HAS_EXECMEM_ROX		if X86_64
+	select ARCH_HAS_EXECMEM_ROX		if X86_64 && STRICT_MODULE_RWX
 	select ARCH_HAS_FAST_MULTIPLIER
 	select ARCH_HAS_FORTIFY_SOURCE
 	select ARCH_HAS_GCOV_PROFILE_ALL
-- 
2.47.2