Avoid creating sections simultaneously writable and readable
to prepare for W^X implementation. Align sections on page size (4KB) to
allow protecting them in the page tables.
Split init code form ".init" segment into separate R_X ".inittext"
segment and make ".init" segment non-executable.
Also add these segments to x86_32 architecture for consistency.
Currently paging is disabled in x86_32 in compressed kernel, so
protection is not applied anyways, but .init code was incorrectly
placed in non-executable ".data" segment. This should not change
anything meaningful in memory layout now, but might be required in case
memory protection will also be implemented in compressed kernel for
x86_32.
Tested-by: Mario Limonciello <mario.limonciello@xxxxxxx>
Signed-off-by: Evgeniy Baskov <baskov@xxxxxxxxx>
---
arch/x86/kernel/vmlinux.lds.S | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index 15f29053cec4..6587e0201b50 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -102,12 +102,11 @@ jiffies = jiffies_64;
PHDRS {
text PT_LOAD FLAGS(5); /* R_E */
data PT_LOAD FLAGS(6); /* RW_ */
-#ifdef CONFIG_X86_64
-#ifdef CONFIG_SMP
+#if defined(CONFIG_X86_64) && defined(CONFIG_SMP)
percpu PT_LOAD FLAGS(6); /* RW_ */
#endif
- init PT_LOAD FLAGS(7); /* RWE */
-#endif
+ inittext PT_LOAD FLAGS(5); /* R_E */
+ init PT_LOAD FLAGS(6); /* RW_ */
note PT_NOTE FLAGS(0); /* ___ */
}
@@ -226,9 +225,10 @@ SECTIONS
#endif
INIT_TEXT_SECTION(PAGE_SIZE)
-#ifdef CONFIG_X86_64
- :init
-#endif
+ :inittext
+
+ . = ALIGN(PAGE_SIZE);
+
/*
* Section for code used exclusively before alternatives are run. All
@@ -240,6 +240,7 @@ SECTIONS
.altinstr_aux : AT(ADDR(.altinstr_aux) - LOAD_OFFSET) {
*(.altinstr_aux)
}
+ :init
INIT_DATA_SECTION(16)
--
2.37.4
