linux-kernel - Re: [PATCH] modules: page-align module section allocations only for arches supporting strict module rwx

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Message-ID: <20190821085104.GA8668@linux-8ccs>
Date:   Wed, 21 Aug 2019 10:51:04 +0200
From:   Jessica Yu <jeyu@...nel.org>
To:     zhe.he@...driver.com
Cc:     linux-kernel@...r.kernel.org
Subject: Re: [PATCH] modules: page-align module section allocations only for
 arches supporting strict module rwx

+++ zhe.he@...driver.com [20/08/19 22:53 +0800]:
>From: He Zhe <zhe.he@...driver.com>
>
>We should keep the case of "#define debug_align(X) (X)" for all arches
>without CONFIG_HAS_STRICT_MODULE_RWX ability, which would save people, who
>are sensitive to system size, a lot of memory when using modules,
>especially for embedded systems. This is also the intention of the
>original #ifdef... statement and still valid for now.
>
>Note that this still keeps the effect of the fix of the following commit,
>38f054d549a8 ("modules: always page-align module section allocations"),
>since when CONFIG_ARCH_HAS_STRICT_MODULE_RWX is enabled, module pages are
>aligned.
>
>Signed-off-by: He Zhe <zhe.he@...driver.com>
>---
>This patch is based on the top of modules-next tree, 38f054d549a8.

I've applied this. Thanks!

Jessica

> kernel/module.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
>diff --git a/kernel/module.c b/kernel/module.c
>index cd8df51..9ee9342 100644
>--- a/kernel/module.c
>+++ b/kernel/module.c
>@@ -64,9 +64,14 @@
>
> /*
>  * Modules' sections will be aligned on page boundaries
>- * to ensure complete separation of code and data
>+ * to ensure complete separation of code and data, but
>+ * only when CONFIG_ARCH_HAS_STRICT_MODULE_RWX=y
>  */
>+#ifdef CONFIG_ARCH_HAS_STRICT_MODULE_RWX
> # define debug_align(X) ALIGN(X, PAGE_SIZE)
>+#else
>+# define debug_align(X) (X)
>+#endif
>
> /* If this is set, the section belongs in the init part of the module */
> #define INIT_OFFSET_MASK (1UL << (BITS_PER_LONG-1))
>-- 
>2.7.4
>