[RFC PATCH 09/24] x86/mm: Introduce VMEMMAP_SIZE/VMEMMAP_END macro
From: Muchun Song <hidden>
Date: 2020-09-16 00:44:12
Also in:
linux-fsdevel, linux-mm, lkml
Subsystem:
the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
In the later patch, we will walk the page table for vmemmap area. So we want to know the range of vmemmap area addresses in order to distinguish whether it comes from vememmap areas. If not, just we can do not walk the page table. Signed-off-by: Muchun Song <redacted> --- arch/x86/include/asm/pgtable_64_types.h | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm/pgtable_64_types.h
index 52e5f5f2240d..bedbd2e7d06c 100644
--- a/arch/x86/include/asm/pgtable_64_types.h
+++ b/arch/x86/include/asm/pgtable_64_types.h@@ -139,6 +139,14 @@ extern unsigned int ptrs_per_p4d; # define VMEMMAP_START __VMEMMAP_BASE_L4 #endif /* CONFIG_DYNAMIC_MEMORY_LAYOUT */ +/* + * VMEMMAP_SIZE - allows the whole linear region to be covered by + * a struct page array. + */ +#define VMEMMAP_SIZE (1UL << (__VIRTUAL_MASK_SHIFT - PAGE_SHIFT - \ + 1 + ilog2(sizeof(struct page)))) +#define VMEMMAP_END (VMEMMAP_START + VMEMMAP_SIZE) + #define VMALLOC_END (VMALLOC_START + (VMALLOC_SIZE_TB << 40) - 1) #define MODULES_VADDR (__START_KERNEL_map + KERNEL_IMAGE_SIZE)
--
2.20.1