[PATCH 2/4] arm64: fixmap: move translation tables to dedicated region
From: Ard Biesheuvel <hidden>
Date: 2015-03-23 15:36:54
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
This moves the fixmap translation tables to a dedicated region in the linker map. This is needed for a split kernel text from the linear mapping, to ensure that the contents of the tables rely on a single translation regime. Also make the population of the translation levels conditional, so that the kernel text can share some levels of translation if needed. Signed-off-by: Ard Biesheuvel <redacted> --- arch/arm64/include/asm/linkage.h | 2 ++ arch/arm64/kernel/vmlinux.lds.S | 15 ++++++++++----- arch/arm64/mm/mmu.c | 15 +++++++++------ 3 files changed, 21 insertions(+), 11 deletions(-)
diff --git a/arch/arm64/include/asm/linkage.h b/arch/arm64/include/asm/linkage.h
index 636c1bced7d4..dc9354de6f52 100644
--- a/arch/arm64/include/asm/linkage.h
+++ b/arch/arm64/include/asm/linkage.h@@ -4,4 +4,6 @@ #define __ALIGN .align 4 #define __ALIGN_STR ".align 4" +#define __pgdir __attribute__((__section__(".pgdir"))) + #endif
diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
index 434ef407ef0f..d3885043f0b7 100644
--- a/arch/arm64/kernel/vmlinux.lds.S
+++ b/arch/arm64/kernel/vmlinux.lds.S@@ -149,11 +149,16 @@ SECTIONS BSS_SECTION(0, 0, 0) - . = ALIGN(PAGE_SIZE); - idmap_pg_dir = .; - . += IDMAP_DIR_SIZE; - swapper_pg_dir = .; - . += SWAPPER_DIR_SIZE; + .pgdir : { + . = ALIGN(PAGE_SIZE); + __pgdir_start = .; + idmap_pg_dir = .; + . += IDMAP_DIR_SIZE; + *(.pgdir) + swapper_pg_dir = .; + . += SWAPPER_DIR_SIZE; + __pgdir_stop = .; + } _end = .;
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 43496748e3d9..bb3ce41130f3 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c@@ -549,12 +549,12 @@ void vmemmap_free(unsigned long start, unsigned long end) } #endif /* CONFIG_SPARSEMEM_VMEMMAP */ -static pte_t bm_pte[PTRS_PER_PTE] __page_aligned_bss; +static pte_t bm_pte[PTRS_PER_PTE] __pgdir; #if CONFIG_ARM64_PGTABLE_LEVELS > 2 -static pmd_t bm_pmd[PTRS_PER_PMD] __page_aligned_bss; +static pmd_t bm_pmd[PTRS_PER_PMD] __pgdir; #endif #if CONFIG_ARM64_PGTABLE_LEVELS > 3 -static pud_t bm_pud[PTRS_PER_PUD] __page_aligned_bss; +static pud_t bm_pud[PTRS_PER_PUD] __pgdir; #endif static inline pud_t * fixmap_pud(unsigned long addr)
@@ -592,11 +592,14 @@ void __init early_fixmap_init(void) unsigned long addr = FIXADDR_START; pgd = pgd_offset_k(addr); - pgd_populate(&init_mm, pgd, bm_pud); + if (pgd_none(*pgd)) + pgd_populate(&init_mm, pgd, bm_pud); pud = pud_offset(pgd, addr); - pud_populate(&init_mm, pud, bm_pmd); + if (pud_none(*pud)) + pud_populate(&init_mm, pud, bm_pmd); pmd = pmd_offset(pud, addr); - pmd_populate_kernel(&init_mm, pmd, bm_pte); + if (pmd_none(*pmd)) + pmd_populate_kernel(&init_mm, pmd, bm_pte); /* * The boot-ioremap range spans multiple pmds, for which
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1.8.3.2