ioremap() fail on physical address 0x0 in 3.4 kernel
From: Russell King - ARM Linux <hidden>
Date: 2012-08-22 09:53:15
Also in:
linux-arm-msm
Subsystem:
arm port, the rest · Maintainers:
Russell King, Linus Torvalds
On Wed, Aug 22, 2012 at 12:16:08PM +0530, Trilok Soni wrote:
Thanks for the patch, but how about just checking pmd_none on such addresses and since there won't be any mapping created for such gaps? We need to check if this is fine for all, since I remember that Nico added these functions for the OMAP boot issue I guess.
A better solution would be as below - this requires no changes to the existing ioremap code, we just mark these differently.
diff --git a/arch/arm/mm/mm.h b/arch/arm/mm/mm.h
index 2e8a1ef..87fa3f2 100644
--- a/arch/arm/mm/mm.h
+++ b/arch/arm/mm/mm.h@@ -55,6 +55,9 @@ extern void __flush_dcache_page(struct address_space *mapping, struct page *page /* permanent static mappings from iotable_init() */ #define VM_ARM_STATIC_MAPPING 0x40000000 +/* empty mapping */ +#define VM_ARM_EMPTY_MAPPING 0x20000000 + /* mapping type (attributes) for permanent static mappings */ #define VM_ARM_MTYPE(mt) ((mt) << 20) #define VM_ARM_MTYPE_MASK (0x1f << 20)
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index cf4528d..da90ef1 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c@@ -813,7 +813,7 @@ static void __init pmd_empty_section_gap(unsigned long addr) vm = early_alloc_aligned(sizeof(*vm), __alignof__(*vm)); vm->addr = (void *)addr; vm->size = SECTION_SIZE; - vm->flags = VM_IOREMAP | VM_ARM_STATIC_MAPPING; + vm->flags = VM_IOREMAP | VM_ARM_EMPTY_MAPPING; vm->caller = pmd_empty_section_gap; vm_area_add_early(vm); }
@@ -826,7 +826,7 @@ static void __init fill_pmd_gaps(void) /* we're still single threaded hence no lock needed here */ for (vm = vmlist; vm; vm = vm->next) { - if (!(vm->flags & VM_ARM_STATIC_MAPPING)) + if (!(vm->flags & (VM_ARM_STATIC_MAPPING | VM_ARM_EMPTY_MAPPING)) continue; addr = (unsigned long)vm->addr; if (addr < next)