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-rw-r--r--arch/x86/kernel/vmlinux.lds.S13
1 files changed, 12 insertions, 1 deletions
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index 14763790e415..fd2dabec1dff 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -42,7 +42,18 @@ jiffies_64 = jiffies;
42#endif 42#endif
43 43
44#if defined(CONFIG_X86_64) && defined(CONFIG_DEBUG_RODATA) 44#if defined(CONFIG_X86_64) && defined(CONFIG_DEBUG_RODATA)
45 45/*
46 * On 64-bit, align RODATA to 2MB so that even with CONFIG_DEBUG_RODATA
47 * we retain large page mappings for boundaries spanning kernel text, rodata
48 * and data sections.
49 *
50 * However, kernel identity mappings will have different RWX permissions
51 * to the pages mapping to text and to the pages padding (which are freed) the
52 * text section. Hence kernel identity mappings will be broken to smaller
53 * pages. For 64-bit, kernel text and kernel identity mappings are different,
54 * so we can enable protection checks that come with CONFIG_DEBUG_RODATA,
55 * as well as retain 2MB large page mappings for kernel text.
56 */
46#define X64_ALIGN_DEBUG_RODATA_BEGIN . = ALIGN(HPAGE_SIZE); 57#define X64_ALIGN_DEBUG_RODATA_BEGIN . = ALIGN(HPAGE_SIZE);
47 58
48#define X64_ALIGN_DEBUG_RODATA_END \ 59#define X64_ALIGN_DEBUG_RODATA_END \