diff options
| author | Jeremy Fitzhardinge <jeremy@goop.org> | 2008-05-28 15:02:14 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-07-08 12:48:13 +0200 |
| commit | a7bf0bd5e6af7fe69342dabf2a3b721f0163469a (patch) | |
| tree | 3f7e08f0df4c5eccf81732dcf95b8cc4efafa203 | |
| parent | 1ecd27657b735128a728ebf0c31fce5e1456718a (diff) | |
build: add __page_aligned_data and __page_aligned_bss
Making a variable page-aligned by using
__attribute__((section(".data.page_aligned"))) is fragile because if
sizeof(variable) is not also a multiple of page size, it leaves
variables in the remainder of the section unaligned.
This patch introduces two new qualifiers, __page_aligned_data and
__page_aligned_bss to set the section *and* the alignment of
variables. This makes page-aligned variables more robust because the
linker will make sure they're aligned properly. Unfortunately it
requires *all* page-aligned data to use these macros...
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | arch/x86/kernel/setup64.c | 2 | ||||
| -rw-r--r-- | arch/x86/mm/ioremap.c | 3 | ||||
| -rw-r--r-- | include/linux/linkage.h | 4 |
3 files changed, 6 insertions, 3 deletions
diff --git a/arch/x86/kernel/setup64.c b/arch/x86/kernel/setup64.c index 631ea6cc01d..fc1a56da824 100644 --- a/arch/x86/kernel/setup64.c +++ b/arch/x86/kernel/setup64.c @@ -40,7 +40,7 @@ EXPORT_SYMBOL(_cpu_pda); struct desc_ptr idt_descr = { 256 * 16 - 1, (unsigned long) idt_table }; -char boot_cpu_stack[IRQSTACKSIZE] __attribute__((section(".bss.page_aligned"))); +char boot_cpu_stack[IRQSTACKSIZE] __page_aligned_bss; unsigned long __supported_pte_mask __read_mostly = ~0UL; EXPORT_SYMBOL_GPL(__supported_pte_mask); diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c index 416ea415f5c..0561fde56a5 100644 --- a/arch/x86/mm/ioremap.c +++ b/arch/x86/mm/ioremap.c @@ -394,8 +394,7 @@ static int __init early_ioremap_debug_setup(char *str) early_param("early_ioremap_debug", early_ioremap_debug_setup); static __initdata int after_paging_init; -static pte_t bm_pte[PAGE_SIZE/sizeof(pte_t)] - __section(.bss.page_aligned); +static pte_t bm_pte[PAGE_SIZE/sizeof(pte_t)] __page_aligned_bss; static inline pmd_t * __init early_ioremap_pmd(unsigned long addr) { diff --git a/include/linux/linkage.h b/include/linux/linkage.h index 2119610b24f..9fd1f859021 100644 --- a/include/linux/linkage.h +++ b/include/linux/linkage.h @@ -1,6 +1,7 @@ #ifndef _LINUX_LINKAGE_H #define _LINUX_LINKAGE_H +#include <linux/compiler.h> #include <asm/linkage.h> #ifdef __cplusplus @@ -17,6 +18,9 @@ # define asmregparm #endif +#define __page_aligned_data __section(.data.page_aligned) __aligned(PAGE_SIZE) +#define __page_aligned_bss __section(.bss.page_aligned) __aligned(PAGE_SIZE) + /* * This is used by architectures to keep arguments on the stack * untouched by the compiler by keeping them live until the end. |