From 63d832d826b75fec2ed062e5a5dc107c5a5db158 Mon Sep 17 00:00:00 2001 From: Santosh Shilimkar Date: Wed, 31 Jul 2013 12:44:42 -0400 Subject: [PATCH] ARM: mm: Introduce virt_to_idmap() with an arch hook On some PAE systems (e.g. TI Keystone), memory is above the 32-bit addressable limit, and the interconnect provides an aliased view of parts of physical memory in the 32-bit addressable space. This alias is strictly for boot time usage, and is not otherwise usable because of coherency limitations. On such systems, the idmap mechanism needs to take this aliased mapping into account. This patch introduces virt_to_idmap() and a arch function pointer which can be populated by platform which needs it. Also populate necessary idmap spots with now available virt_to_idmap(). Avoided #ifdef approach to be compatible with multi-platform builds. Most architecture won't touch it and in that case virt_to_idmap() fall-back to existing virt_to_phys() macro. Cc: Russell King Acked-by: Nicolas Pitre Signed-off-by: Santosh Shilimkar (cherry picked from commit 4dc9a81715973cb137a14399420bb35b0ed7d6ef) Signed-off-by: Christoffer Dall --- arch/arm/include/asm/memory.h | 16 ++++++++++++++++ arch/arm/kernel/smp.c | 4 ++-- arch/arm/mm/idmap.c | 5 +++-- 3 files changed, 21 insertions(+), 4 deletions(-) diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h index 57870ab313c5..21b458e6b0b8 100644 --- a/arch/arm/include/asm/memory.h +++ b/arch/arm/include/asm/memory.h @@ -157,6 +157,7 @@ */ #define __PV_BITS_31_24 0x81000000 +extern phys_addr_t (*arch_virt_to_idmap) (unsigned long x); extern unsigned long __pv_phys_offset; #define PHYS_OFFSET __pv_phys_offset @@ -232,6 +233,21 @@ static inline void *phys_to_virt(phys_addr_t x) #define __va(x) ((void *)__phys_to_virt((unsigned long)(x))) #define pfn_to_kaddr(pfn) __va((pfn) << PAGE_SHIFT) +/* + * These are for systems that have a hardware interconnect supported alias of + * physical memory for idmap purposes. Most cases should leave these + * untouched. + */ +static inline phys_addr_t __virt_to_idmap(unsigned long x) +{ + if (arch_virt_to_idmap) + return arch_virt_to_idmap(x); + else + return __virt_to_phys(x); +} + +#define virt_to_idmap(x) __virt_to_idmap((unsigned long)(x)) + /* * Virtual <-> DMA view memory address translations * Again, these are *only* valid on the kernel direct mapped RAM diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index 5919eb451bb9..5a8ad2c8eda0 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -87,8 +87,8 @@ int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *idle) * its stack and the page tables. */ secondary_data.stack = task_stack_page(idle) + THREAD_START_SP; - secondary_data.pgdir = virt_to_phys(idmap_pgd); - secondary_data.swapper_pg_dir = virt_to_phys(swapper_pg_dir); + secondary_data.pgdir = virt_to_idmap(idmap_pgd); + secondary_data.swapper_pg_dir = virt_to_idmap(swapper_pg_dir); __cpuc_flush_dcache_area(&secondary_data, sizeof(secondary_data)); outer_clean_range(__pa(&secondary_data), __pa(&secondary_data + 1)); diff --git a/arch/arm/mm/idmap.c b/arch/arm/mm/idmap.c index 83cb3ac27095..c0a1e48f6733 100644 --- a/arch/arm/mm/idmap.c +++ b/arch/arm/mm/idmap.c @@ -10,6 +10,7 @@ #include pgd_t *idmap_pgd; +phys_addr_t (*arch_virt_to_idmap) (unsigned long x); #ifdef CONFIG_ARM_LPAE static void idmap_add_pmd(pud_t *pud, unsigned long addr, unsigned long end, @@ -67,8 +68,8 @@ static void identity_mapping_add(pgd_t *pgd, const char *text_start, unsigned long addr, end; unsigned long next; - addr = virt_to_phys(text_start); - end = virt_to_phys(text_end); + addr = virt_to_idmap(text_start); + end = virt_to_idmap(text_end); prot |= PMD_TYPE_SECT | PMD_SECT_AP_WRITE | PMD_SECT_AF; -- 2.34.1