x86: mm: refer to the intended config STRICT_DEVMEM in a comment

Commit a4866aa81251 ("mm: Tighten x86 /dev/mem with zeroing reads") adds a
comment to the function devmem_is_allowed() referring to a non-existing
config STRICT_IOMEM, whereas the comment very likely intended to refer to
the config STRICT_DEVMEM, as the commit adds some behavior for the config
STRICT_DEVMEM.

Most of the initial analysis was actually done by Dave Hansen in the
email thread below (see Link).

Refer to the intended and existing config STRICT_DEVMEM.

Link: https://lore.kernel.org/r/f9074e8d-9314-9d7d-7bf5-5b5538c8be8d@intel.com/
Suggested-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220707115442.21107-1-lukas.bulwahn@gmail.com

diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index d8cfce221275e078e06a4371a31acad6467671b9..5d747a1923cb059271292c243d5b61dd97c33c44 100644 (file)
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -846,7 +846,7 @@ int devmem_is_allowed(unsigned long pagenr)
 
        /*
         * This must follow RAM test, since System RAM is considered a
-        * restricted resource under CONFIG_STRICT_IOMEM.
+        * restricted resource under CONFIG_STRICT_DEVMEM.
         */
        if (iomem_is_exclusive(pagenr << PAGE_SHIFT)) {
                /* Low 1MB bypasses iomem restrictions. */