[PATCH 07/13] x86, vmlinux.lds: unify data output sections

From: Sam Ravnborg
Date: Wed Apr 29 2009 - 03:46:44 EST


For 32 bit this is a non-functional change.

For 64 bit the following functional changes is introduced:
- .data.page_aligned has moved
- .data.cacheline_aligned has moved
- .data.read_mostly has moved
- ALIGN() moved out of output section for .data.cacheline_aligned
- ALIGN() moved out of output section for .data.page_aligned

Notice that 32 bit and 64 bit has different location of _edata.
.data_nosave is 32 bit only as 64 bit is special due to PERCPU.

Signed-off-by: Sam Ravnborg <sam@xxxxxxxxxxxx>
Cc: Tim Abbott <tabbott@xxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/vmlinux.lds.S | 55 ++++++++++++++++++++++++++++++++++++++
arch/x86/kernel/vmlinux_32.lds.S | 37 -------------------------
arch/x86/kernel/vmlinux_64.lds.S | 28 -------------------
3 files changed, 55 insertions(+), 65 deletions(-)

diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index 94b67bf..3d741dd 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -99,6 +99,61 @@ SECTIONS

RODATA

+ /* Data */
+ . = ALIGN(PAGE_SIZE);
+ .data : AT(ADDR(.data) - LOAD_OFFSET) {
+ DATA_DATA
+ CONSTRUCTORS
+
+#ifdef CONFIG_X86_64
+ /* End of data section */
+ _edata = .;
+#endif
+ } :data
+
+#ifdef CONFIG_X86_32
+ /* 32 bit has nosave before _edata */
+ . = ALIGN(PAGE_SIZE);
+ .data_nosave : AT(ADDR(.data_nosave) - LOAD_OFFSET) {
+ __nosave_begin = .;
+ *(.data.nosave)
+ . = ALIGN(PAGE_SIZE);
+ __nosave_end = .;
+ }
+#endif
+
+ . = ALIGN(PAGE_SIZE);
+ .data.page_aligned : AT(ADDR(.data.page_aligned) - LOAD_OFFSET) {
+ *(.data.page_aligned)
+ *(.data.idt)
+ }
+
+#ifdef CONFIG_X86_32
+ . = ALIGN(32);
+#else
+ . = ALIGN(PAGE_SIZE);
+ . = ALIGN(CONFIG_X86_L1_CACHE_BYTES);
+#endif
+ .data.cacheline_aligned :
+ AT(ADDR(.data.cacheline_aligned) - LOAD_OFFSET) {
+ *(.data.cacheline_aligned)
+ }
+
+ /* rarely changed data like cpu maps */
+#ifdef CONFIG_X86_32
+ . = ALIGN(32);
+#else
+ . = ALIGN(CONFIG_X86_INTERNODE_CACHE_BYTES);
+#endif
+ .data.read_mostly : AT(ADDR(.data.read_mostly) - LOAD_OFFSET) {
+ *(.data.read_mostly)
+
+#ifdef CONFIG_X86_32
+ /* End of data section */
+ _edata = .;
+#endif
+ }
+

#ifdef CONFIG_X86_32
# include "vmlinux_32.lds.S"
diff --git a/arch/x86/kernel/vmlinux_32.lds.S b/arch/x86/kernel/vmlinux_32.lds.S
index 920cc69..8ade846 100644
--- a/arch/x86/kernel/vmlinux_32.lds.S
+++ b/arch/x86/kernel/vmlinux_32.lds.S
@@ -1,40 +1,3 @@
- /* writeable */
- . = ALIGN(PAGE_SIZE);
- /* Data */
- .data : AT(ADDR(.data) - LOAD_OFFSET) {
- DATA_DATA
- CONSTRUCTORS
- } :data
-
- . = ALIGN(PAGE_SIZE);
- .data_nosave : AT(ADDR(.data_nosave) - LOAD_OFFSET) {
- __nosave_begin = .;
- *(.data.nosave)
- . = ALIGN(PAGE_SIZE);
- __nosave_end = .;
- }
-
- . = ALIGN(PAGE_SIZE);
- .data.page_aligned : AT(ADDR(.data.page_aligned) - LOAD_OFFSET) {
- *(.data.page_aligned)
- *(.data.idt)
- }
-
- . = ALIGN(32);
- .data.cacheline_aligned :
- AT(ADDR(.data.cacheline_aligned) - LOAD_OFFSET) {
- *(.data.cacheline_aligned)
- }
-
- /* rarely changed data like cpu maps */
- . = ALIGN(32);
- .data.read_mostly : AT(ADDR(.data.read_mostly) - LOAD_OFFSET) {
- *(.data.read_mostly)
-
- /* End of data section */
- _edata = .;
- }
-
/* init_task */
. = ALIGN(THREAD_SIZE);
.data.init_task : AT(ADDR(.data.init_task) - LOAD_OFFSET) {
diff --git a/arch/x86/kernel/vmlinux_64.lds.S b/arch/x86/kernel/vmlinux_64.lds.S
index 641f3f9..8262701 100644
--- a/arch/x86/kernel/vmlinux_64.lds.S
+++ b/arch/x86/kernel/vmlinux_64.lds.S
@@ -1,26 +1,3 @@
- /* Align data segment to page size boundary */
- . = ALIGN(PAGE_SIZE);
- /* Data */
- .data : AT(ADDR(.data) - LOAD_OFFSET) {
- DATA_DATA
- CONSTRUCTORS
- /* End of data section */
- _edata = .;
- } :data
-
-
- .data.cacheline_aligned :
- AT(ADDR(.data.cacheline_aligned) - LOAD_OFFSET) {
- . = ALIGN(PAGE_SIZE);
- . = ALIGN(CONFIG_X86_L1_CACHE_BYTES);
- *(.data.cacheline_aligned)
- }
-
- . = ALIGN(CONFIG_X86_INTERNODE_CACHE_BYTES);
- .data.read_mostly : AT(ADDR(.data.read_mostly) - LOAD_OFFSET) {
- *(.data.read_mostly)
- }
-
#define VSYSCALL_ADDR (-10*1024*1024)
#define VSYSCALL_PHYS_ADDR ((LOADADDR(.data.read_mostly) + \
SIZEOF(.data.read_mostly) + 4095) & ~(4095))
@@ -95,11 +72,6 @@
*(.data.init_task)
} :data.init

- .data.page_aligned : AT(ADDR(.data.page_aligned) - LOAD_OFFSET) {
- . = ALIGN(PAGE_SIZE);
- *(.data.page_aligned)
- }
-
.smp_locks : AT(ADDR(.smp_locks) - LOAD_OFFSET) {
/* might get freed after init */
. = ALIGN(PAGE_SIZE);
--
1.6.0.6

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