* [PATCH] arm64: make runtime const not usable by modules
@ 2026-02-21 2:38 Jisheng Zhang
2026-03-04 16:59 ` Will Deacon
0 siblings, 1 reply; 2+ messages in thread
From: Jisheng Zhang @ 2026-02-21 2:38 UTC (permalink / raw)
To: Catalin Marinas, Will Deacon; +Cc: linux-arm-kernel, linux-kernel
Similar as commit 284922f4c563 ("x86: uaccess: don't use runtime-const
rewriting in modules") does, make arm64's runtime const not usable by
modules too, to "make sure this doesn't get forgotten the next time
somebody wants to do runtime constant optimizations". The reason is
well explained in the above commit: "The runtime-const infrastructure
was never designed to handle the modular case, because the constant
fixup is only done at boot time for core kernel code."
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
---
arch/arm64/include/asm/runtime-const.h | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/arm64/include/asm/runtime-const.h b/arch/arm64/include/asm/runtime-const.h
index be5915669d23..c3dbd3ae68f6 100644
--- a/arch/arm64/include/asm/runtime-const.h
+++ b/arch/arm64/include/asm/runtime-const.h
@@ -2,6 +2,10 @@
#ifndef _ASM_RUNTIME_CONST_H
#define _ASM_RUNTIME_CONST_H
+#ifdef MODULE
+ #error "Cannot use runtime-const infrastructure from modules"
+#endif
+
#include <asm/cacheflush.h>
/* Sigh. You can still run arm64 in BE mode */
--
2.51.0
^ permalink raw reply related [flat|nested] 2+ messages in thread* Re: [PATCH] arm64: make runtime const not usable by modules
2026-02-21 2:38 [PATCH] arm64: make runtime const not usable by modules Jisheng Zhang
@ 2026-03-04 16:59 ` Will Deacon
0 siblings, 0 replies; 2+ messages in thread
From: Will Deacon @ 2026-03-04 16:59 UTC (permalink / raw)
To: Catalin Marinas, Jisheng Zhang
Cc: kernel-team, Will Deacon, linux-arm-kernel, linux-kernel
On Sat, 21 Feb 2026 10:38:47 +0800, Jisheng Zhang wrote:
> Similar as commit 284922f4c563 ("x86: uaccess: don't use runtime-const
> rewriting in modules") does, make arm64's runtime const not usable by
> modules too, to "make sure this doesn't get forgotten the next time
> somebody wants to do runtime constant optimizations". The reason is
> well explained in the above commit: "The runtime-const infrastructure
> was never designed to handle the modular case, because the constant
> fixup is only done at boot time for core kernel code."
>
> [...]
Applied to arm64 (for-next/fixes), thanks!
[1/1] arm64: make runtime const not usable by modules
https://git.kernel.org/arm64/c/0100e495cdf0
Cheers,
--
Will
https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev
^ permalink raw reply [flat|nested] 2+ messages in thread
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2026-03-04 16:59 ` Will Deacon
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