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x86, vmlinux.lds: unify data output sections
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For 64 bit the following functional changes are 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.

[ Impact: 32-bit: cleanup, 64-bit: use 32-bit linker script ]

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Tim Abbott <tabbott@MIT.EDU>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <1240991249-27117-7-git-send-email-sam@ravnborg.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Sam Ravnborg authored and Ingo Molnar committed Apr 29, 2009
1 parent 448bc3a commit 1f6397b
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Showing 3 changed files with 55 additions and 65 deletions.
55 changes: 55 additions & 0 deletions arch/x86/kernel/vmlinux.lds.S
Original file line number Diff line number Diff line change
Expand Up @@ -104,6 +104,61 @@ 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"
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37 changes: 0 additions & 37 deletions arch/x86/kernel/vmlinux_32.lds.S
Original file line number Diff line number Diff line change
@@ -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) {
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28 changes: 0 additions & 28 deletions arch/x86/kernel/vmlinux_64.lds.S
Original file line number Diff line number Diff line change
@@ -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))
Expand Down Expand Up @@ -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);
Expand Down

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