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>
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 416ea41..0561fde 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -394,8 +394,7 @@
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)
{