linux-kernel - [PATCH 1/3] x86/KASLR: Update document about KERNEL_IMAGE

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Message-Id: <20180921020550.13095-2-bhe@redhat.com>
Date:   Fri, 21 Sep 2018 10:05:48 +0800
From:   Baoquan He <bhe@...hat.com>
To:     mingo@...nel.org, tglx@...utronix.de, hpa@...or.com
Cc:     linux-kernel@...r.kernel.org, kirill.shutemov@...ux.intel.com,
        x86@...nel.org, thgarnie@...gle.com, corbet@....net,
        linux-doc@...r.kernel.org, peterz@...radead.org,
        Baoquan He <bhe@...hat.com>
Subject: [PATCH 1/3] x86/KASLR: Update document about KERNEL_IMAGE_SIZE

Currently CONFIG_RANDOMIZE_BASE=y is default set, update the relevant
document about KERNEL_IMAGE_SIZE.

Signed-off-by: Baoquan He <bhe@...hat.com>
---
 arch/x86/include/asm/page_64_types.h | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/page_64_types.h b/arch/x86/include/asm/page_64_types.h
index 6afac386a434..2288ceabdb9c 100644
--- a/arch/x86/include/asm/page_64_types.h
+++ b/arch/x86/include/asm/page_64_types.h
@@ -61,9 +61,10 @@
 /*
  * Kernel image size is limited to 1GiB due to the fixmap living in the
  * next 1GiB (see level2_kernel_pgt in arch/x86/kernel/head_64.S). Use
- * 512MiB by default, leaving 1.5GiB for modules once the page tables
- * are fully set up. If kernel ASLR is configured, it can extend the
- * kernel page table mapping, reducing the size of the modules area.
+ * 1 GiB by default, leaving 1 GiB for modules once the page tables are
+ * fully set up. If kernel ASLR is not configured, it can shrink the
+ * kernel page table mapping to decrease the size of kernel area to 512
+ * MiB, increase the size of the modules area to 1.5 GiB.
  */
 #if defined(CONFIG_RANDOMIZE_BASE)
 #define KERNEL_IMAGE_SIZE	(1024 * 1024 * 1024)
-- 
2.13.6