[PATCH v5 6/6] arm64/mm: Move {idmap_pg_dir .. swapper_pg_dir} to rodata section.

From: Jun Yao
Date: Mon Sep 17 2018 - 00:44:18 EST


Move the idmap_pg_dir/tramp_pg_dir/reserved_ttbr0/swapper_pg_dir to
the rodata section. When the kernel is initialized, the
idmap_pg_dir, tramp_pg_dir and reserved_ttbr0 will not change. And
it's safe to move them to rodata section.

Signed-off-by: Jun Yao <yaojun8558363@xxxxxxxxx>
---
arch/arm64/kernel/vmlinux.lds.S | 39 ++++++++++++++++++++-------------
1 file changed, 24 insertions(+), 15 deletions(-)

diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
index a634def77442..328925b308fc 100644
--- a/arch/arm64/kernel/vmlinux.lds.S
+++ b/arch/arm64/kernel/vmlinux.lds.S
@@ -64,8 +64,13 @@ jiffies = jiffies_64;
*(.entry.tramp.text) \
. = ALIGN(PAGE_SIZE); \
__entry_tramp_text_end = .;
+
+#define TRAMP_PG_TABLE \
+ tramp_pg_dir = .; \
+ . += PAGE_SIZE;
#else
#define TRAMP_TEXT
+#define TRAMP_PG_TABLE
#endif

#define INIT_PG_TABLES \
@@ -74,6 +79,24 @@ jiffies = jiffies_64;
. += SWAPPER_DIR_SIZE; \
init_pg_end = .;

+#ifdef CONFIG_ARM64_SW_TTBR0_PAN
+#define RESERVED_PG_TABLE \
+ reserved_ttbr0 = .; \
+ . += RESERVED_TTBR0_SIZE;
+#else
+#define RESERVED_PG_TABLE
+#endif
+
+#define KERNEL_PG_TABLES \
+ . = ALIGN(PAGE_SIZE); \
+ idmap_pg_dir = .; \
+ . += IDMAP_DIR_SIZE; \
+ TRAMP_PG_TABLE \
+ RESERVED_PG_TABLE \
+ swapper_pg_dir = .; \
+ . += PAGE_SIZE; \
+ swapper_pg_end = .;
+
/*
* The size of the PE/COFF section that covers the kernel image, which
* runs from stext to _edata, must be a round multiple of the PE/COFF
@@ -143,6 +166,7 @@ SECTIONS
RO_DATA(PAGE_SIZE) /* everything from this point to */
EXCEPTION_TABLE(8) /* __init_begin will be marked RO NX */
NOTES
+ KERNEL_PG_TABLES

. = ALIGN(SEGMENT_ALIGN);
__init_begin = .;
@@ -224,21 +248,6 @@ SECTIONS
BSS_SECTION(0, 0, 0)

. = ALIGN(PAGE_SIZE);
- idmap_pg_dir = .;
- . += IDMAP_DIR_SIZE;
-
-#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
- tramp_pg_dir = .;
- . += PAGE_SIZE;
-#endif
-
-#ifdef CONFIG_ARM64_SW_TTBR0_PAN
- reserved_ttbr0 = .;
- . += RESERVED_TTBR0_SIZE;
-#endif
- swapper_pg_dir = .;
- . += PAGE_SIZE;
- swapper_pg_end = .;

__pecoff_data_size = ABSOLUTE(. - __initdata_begin);
_end = .;
--
2.17.1