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368ff8f14d
We find the runtime address of _stext and relocate ourselves based
on the following calculation.
virtual_base = ALIGN(KERNELBASE,KERNEL_TLB_PIN_SIZE) +
MODULO(_stext.run,KERNEL_TLB_PIN_SIZE)
relocate() is called with the Effective Virtual Base Address (as
shown below)
| Phys. Addr| Virt. Addr |
Page |------------------------|
Boundary | | |
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| | |
Kernel Load |___________|_ __ _ _ _ _|<- Effective
Addr(_stext)| | ^ |Virt. Base Addr
| | | |
| | | |
| |reloc_offset|
| | | |
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| |______v_____|<-(KERNELBASE)%TLB_SIZE
| | |
| | |
| | |
Page |-----------|------------|
Boundary | | |
On BookE, we need __va() & __pa() early in the boot process to access
the device tree.
Currently this has been defined as :
#define __va(x) ((void *)(unsigned long)((phys_addr_t)(x) -
PHYSICAL_START + KERNELBASE)
where:
PHYSICAL_START is kernstart_addr - a variable updated at runtime.
KERNELBASE is the compile time Virtual base address of kernel.
This won't work for us, as kernstart_addr is dynamic and will yield different
results for __va()/__pa() for same mapping.
e.g.,
Let the kernel be loaded at 64MB and KERNELBASE be 0xc0000000 (same as
PAGE_OFFSET).
In this case, we would be mapping 0 to 0xc0000000, and kernstart_addr = 64M
Now __va(1MB) = (0x100000) - (0x4000000) + 0xc0000000
= 0xbc100000 , which is wrong.
it should be : 0xc0000000 + 0x100000 = 0xc0100000
On platforms which support AMP, like PPC_47x (based on 44x), the kernel
could be loaded at highmem. Hence we cannot always depend on the compile
time constants for mapping.
Here are the possible solutions:
1) Update kernstart_addr(PHSYICAL_START) to match the Physical address of
compile time KERNELBASE value, instead of the actual Physical_Address(_stext).
The disadvantage is that we may break other users of PHYSICAL_START. They
could be replaced with __pa(_stext).
2) Redefine __va() & __pa() with relocation offset
#ifdef CONFIG_RELOCATABLE_PPC32
#define __va(x) ((void *)(unsigned long)((phys_addr_t)(x) - PHYSICAL_START + (KERNELBASE + RELOC_OFFSET)))
#define __pa(x) ((unsigned long)(x) + PHYSICAL_START - (KERNELBASE + RELOC_OFFSET))
#endif
where, RELOC_OFFSET could be
a) A variable, say relocation_offset (like kernstart_addr), updated
at boot time. This impacts performance, as we have to load an additional
variable from memory.
OR
b) #define RELOC_OFFSET ((PHYSICAL_START & PPC_PIN_SIZE_OFFSET_MASK) - \
(KERNELBASE & PPC_PIN_SIZE_OFFSET_MASK))
This introduces more calculations for doing the translation.
3) Redefine __va() & __pa() with a new variable
i.e,
#define __va(x) ((void *)(unsigned long)((phys_addr_t)(x) + VIRT_PHYS_OFFSET))
where VIRT_PHYS_OFFSET :
#ifdef CONFIG_RELOCATABLE_PPC32
#define VIRT_PHYS_OFFSET virt_phys_offset
#else
#define VIRT_PHYS_OFFSET (KERNELBASE - PHYSICAL_START)
#endif /* CONFIG_RELOCATABLE_PPC32 */
where virt_phy_offset is updated at runtime to :
Effective KERNELBASE - kernstart_addr.
Taking our example, above:
virt_phys_offset = effective_kernelstart_vaddr - kernstart_addr
= 0xc0400000 - 0x400000
= 0xc0000000
and
__va(0x100000) = 0xc0000000 + 0x100000 = 0xc0100000
which is what we want.
I have implemented (3) in the following patch which has same cost of
operation as the existing one.
I have tested the patches on 440x platforms only. However this should
work fine for PPC_47x also, as we only depend on the runtime address
and the current TLB XLAT entry for the startup code, which is available
in r25. I don't have access to a 47x board yet. So, it would be great if
somebody could test this on 47x.
Signed-off-by: Suzuki K. Poulose <suzuki@in.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Signed-off-by: Josh Boyer <jwboyer@gmail.com>
387 lines
11 KiB
C
387 lines
11 KiB
C
#ifndef _ASM_POWERPC_PAGE_H
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#define _ASM_POWERPC_PAGE_H
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/*
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* Copyright (C) 2001,2005 IBM Corporation.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#ifndef __ASSEMBLY__
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#include <linux/types.h>
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#else
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#include <asm/types.h>
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#endif
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#include <asm/asm-compat.h>
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#include <asm/kdump.h>
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/*
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* On regular PPC32 page size is 4K (but we support 4K/16K/64K/256K pages
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* on PPC44x). For PPC64 we support either 4K or 64K software
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* page size. When using 64K pages however, whether we are really supporting
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* 64K pages in HW or not is irrelevant to those definitions.
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*/
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#if defined(CONFIG_PPC_256K_PAGES)
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#define PAGE_SHIFT 18
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#elif defined(CONFIG_PPC_64K_PAGES)
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#define PAGE_SHIFT 16
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#elif defined(CONFIG_PPC_16K_PAGES)
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#define PAGE_SHIFT 14
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#else
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#define PAGE_SHIFT 12
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#endif
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#define PAGE_SIZE (ASM_CONST(1) << PAGE_SHIFT)
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#ifndef __ASSEMBLY__
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#ifdef CONFIG_HUGETLB_PAGE
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extern unsigned int HPAGE_SHIFT;
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#else
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#define HPAGE_SHIFT PAGE_SHIFT
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#endif
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#define HPAGE_SIZE ((1UL) << HPAGE_SHIFT)
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#define HPAGE_MASK (~(HPAGE_SIZE - 1))
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#define HUGETLB_PAGE_ORDER (HPAGE_SHIFT - PAGE_SHIFT)
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#define HUGE_MAX_HSTATE (MMU_PAGE_COUNT-1)
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#endif
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/* We do define AT_SYSINFO_EHDR but don't use the gate mechanism */
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#define __HAVE_ARCH_GATE_AREA 1
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/*
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* Subtle: (1 << PAGE_SHIFT) is an int, not an unsigned long. So if we
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* assign PAGE_MASK to a larger type it gets extended the way we want
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* (i.e. with 1s in the high bits)
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*/
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#define PAGE_MASK (~((1 << PAGE_SHIFT) - 1))
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/*
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* KERNELBASE is the virtual address of the start of the kernel, it's often
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* the same as PAGE_OFFSET, but _might not be_.
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*
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* The kdump dump kernel is one example where KERNELBASE != PAGE_OFFSET.
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*
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* PAGE_OFFSET is the virtual address of the start of lowmem.
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*
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* PHYSICAL_START is the physical address of the start of the kernel.
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*
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* MEMORY_START is the physical address of the start of lowmem.
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*
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* KERNELBASE, PAGE_OFFSET, and PHYSICAL_START are all configurable on
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* ppc32 and based on how they are set we determine MEMORY_START.
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*
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* For the linear mapping the following equation should be true:
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* KERNELBASE - PAGE_OFFSET = PHYSICAL_START - MEMORY_START
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*
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* Also, KERNELBASE >= PAGE_OFFSET and PHYSICAL_START >= MEMORY_START
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*
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* There are two was to determine a physical address from a virtual one:
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* va = pa + PAGE_OFFSET - MEMORY_START
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* va = pa + KERNELBASE - PHYSICAL_START
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*
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* If you want to know something's offset from the start of the kernel you
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* should subtract KERNELBASE.
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*
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* If you want to test if something's a kernel address, use is_kernel_addr().
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*/
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#define KERNELBASE ASM_CONST(CONFIG_KERNEL_START)
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#define PAGE_OFFSET ASM_CONST(CONFIG_PAGE_OFFSET)
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#define LOAD_OFFSET ASM_CONST((CONFIG_KERNEL_START-CONFIG_PHYSICAL_START))
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#if defined(CONFIG_NONSTATIC_KERNEL)
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#ifndef __ASSEMBLY__
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extern phys_addr_t memstart_addr;
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extern phys_addr_t kernstart_addr;
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#ifdef CONFIG_RELOCATABLE_PPC32
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extern long long virt_phys_offset;
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#endif
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#endif /* __ASSEMBLY__ */
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#define PHYSICAL_START kernstart_addr
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#else /* !CONFIG_NONSTATIC_KERNEL */
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#define PHYSICAL_START ASM_CONST(CONFIG_PHYSICAL_START)
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#endif
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/* See Description below for VIRT_PHYS_OFFSET */
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#ifdef CONFIG_RELOCATABLE_PPC32
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#define VIRT_PHYS_OFFSET virt_phys_offset
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#else
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#define VIRT_PHYS_OFFSET (KERNELBASE - PHYSICAL_START)
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#endif
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#ifdef CONFIG_PPC64
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#define MEMORY_START 0UL
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#elif defined(CONFIG_NONSTATIC_KERNEL)
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#define MEMORY_START memstart_addr
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#else
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#define MEMORY_START (PHYSICAL_START + PAGE_OFFSET - KERNELBASE)
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#endif
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#ifdef CONFIG_FLATMEM
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#define ARCH_PFN_OFFSET ((unsigned long)(MEMORY_START >> PAGE_SHIFT))
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#define pfn_valid(pfn) ((pfn) >= ARCH_PFN_OFFSET && (pfn) < max_mapnr)
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#endif
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#define virt_to_page(kaddr) pfn_to_page(__pa(kaddr) >> PAGE_SHIFT)
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#define pfn_to_kaddr(pfn) __va((pfn) << PAGE_SHIFT)
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#define virt_addr_valid(kaddr) pfn_valid(__pa(kaddr) >> PAGE_SHIFT)
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/*
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* On Book-E parts we need __va to parse the device tree and we can't
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* determine MEMORY_START until then. However we can determine PHYSICAL_START
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* from information at hand (program counter, TLB lookup).
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*
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* On BookE with RELOCATABLE (RELOCATABLE_PPC32)
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*
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* With RELOCATABLE_PPC32, we support loading the kernel at any physical
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* address without any restriction on the page alignment.
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*
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* We find the runtime address of _stext and relocate ourselves based on
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* the following calculation:
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*
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* virtual_base = ALIGN_DOWN(KERNELBASE,256M) +
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* MODULO(_stext.run,256M)
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* and create the following mapping:
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*
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* ALIGN_DOWN(_stext.run,256M) => ALIGN_DOWN(KERNELBASE,256M)
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*
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* When we process relocations, we cannot depend on the
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* existing equation for the __va()/__pa() translations:
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*
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* __va(x) = (x) - PHYSICAL_START + KERNELBASE
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*
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* Where:
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* PHYSICAL_START = kernstart_addr = Physical address of _stext
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* KERNELBASE = Compiled virtual address of _stext.
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*
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* This formula holds true iff, kernel load address is TLB page aligned.
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*
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* In our case, we need to also account for the shift in the kernel Virtual
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* address.
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*
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* E.g.,
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*
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* Let the kernel be loaded at 64MB and KERNELBASE be 0xc0000000 (same as PAGE_OFFSET).
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* In this case, we would be mapping 0 to 0xc0000000, and kernstart_addr = 64M
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*
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* Now __va(1MB) = (0x100000) - (0x4000000) + 0xc0000000
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* = 0xbc100000 , which is wrong.
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*
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* Rather, it should be : 0xc0000000 + 0x100000 = 0xc0100000
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* according to our mapping.
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*
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* Hence we use the following formula to get the translations right:
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*
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* __va(x) = (x) - [ PHYSICAL_START - Effective KERNELBASE ]
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*
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* Where :
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* PHYSICAL_START = dynamic load address.(kernstart_addr variable)
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* Effective KERNELBASE = virtual_base =
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* = ALIGN_DOWN(KERNELBASE,256M) +
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* MODULO(PHYSICAL_START,256M)
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*
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* To make the cost of __va() / __pa() more light weight, we introduce
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* a new variable virt_phys_offset, which will hold :
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*
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* virt_phys_offset = Effective KERNELBASE - PHYSICAL_START
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* = ALIGN_DOWN(KERNELBASE,256M) -
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* ALIGN_DOWN(PHYSICALSTART,256M)
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*
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* Hence :
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*
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* __va(x) = x - PHYSICAL_START + Effective KERNELBASE
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* = x + virt_phys_offset
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*
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* and
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* __pa(x) = x + PHYSICAL_START - Effective KERNELBASE
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* = x - virt_phys_offset
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*
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* On non-Book-E PPC64 PAGE_OFFSET and MEMORY_START are constants so use
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* the other definitions for __va & __pa.
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*/
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#ifdef CONFIG_BOOKE
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#define __va(x) ((void *)(unsigned long)((phys_addr_t)(x) + VIRT_PHYS_OFFSET))
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#define __pa(x) ((unsigned long)(x) - VIRT_PHYS_OFFSET)
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#else
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#define __va(x) ((void *)(unsigned long)((phys_addr_t)(x) + PAGE_OFFSET - MEMORY_START))
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#define __pa(x) ((unsigned long)(x) - PAGE_OFFSET + MEMORY_START)
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#endif
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/*
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* Unfortunately the PLT is in the BSS in the PPC32 ELF ABI,
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* and needs to be executable. This means the whole heap ends
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* up being executable.
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*/
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#define VM_DATA_DEFAULT_FLAGS32 (VM_READ | VM_WRITE | VM_EXEC | \
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VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
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#define VM_DATA_DEFAULT_FLAGS64 (VM_READ | VM_WRITE | \
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VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
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#ifdef __powerpc64__
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#include <asm/page_64.h>
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#else
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#include <asm/page_32.h>
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#endif
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/* align addr on a size boundary - adjust address up/down if needed */
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#define _ALIGN_UP(addr,size) (((addr)+((size)-1))&(~((size)-1)))
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#define _ALIGN_DOWN(addr,size) ((addr)&(~((size)-1)))
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/* align addr on a size boundary - adjust address up if needed */
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#define _ALIGN(addr,size) _ALIGN_UP(addr,size)
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/*
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* Don't compare things with KERNELBASE or PAGE_OFFSET to test for
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* "kernelness", use is_kernel_addr() - it should do what you want.
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*/
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#ifdef CONFIG_PPC_BOOK3E_64
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#define is_kernel_addr(x) ((x) >= 0x8000000000000000ul)
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#else
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#define is_kernel_addr(x) ((x) >= PAGE_OFFSET)
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#endif
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/*
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* Use the top bit of the higher-level page table entries to indicate whether
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* the entries we point to contain hugepages. This works because we know that
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* the page tables live in kernel space. If we ever decide to support having
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* page tables at arbitrary addresses, this breaks and will have to change.
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*/
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#ifdef CONFIG_PPC64
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#define PD_HUGE 0x8000000000000000
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#else
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#define PD_HUGE 0x80000000
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#endif
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/*
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* Some number of bits at the level of the page table that points to
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* a hugepte are used to encode the size. This masks those bits.
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*/
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#define HUGEPD_SHIFT_MASK 0x3f
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#ifndef __ASSEMBLY__
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#undef STRICT_MM_TYPECHECKS
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#ifdef STRICT_MM_TYPECHECKS
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/* These are used to make use of C type-checking. */
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/* PTE level */
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typedef struct { pte_basic_t pte; } pte_t;
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#define pte_val(x) ((x).pte)
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#define __pte(x) ((pte_t) { (x) })
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/* 64k pages additionally define a bigger "real PTE" type that gathers
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* the "second half" part of the PTE for pseudo 64k pages
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*/
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#if defined(CONFIG_PPC_64K_PAGES) && defined(CONFIG_PPC_STD_MMU_64)
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typedef struct { pte_t pte; unsigned long hidx; } real_pte_t;
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#else
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typedef struct { pte_t pte; } real_pte_t;
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#endif
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/* PMD level */
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#ifdef CONFIG_PPC64
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typedef struct { unsigned long pmd; } pmd_t;
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#define pmd_val(x) ((x).pmd)
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#define __pmd(x) ((pmd_t) { (x) })
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/* PUD level exusts only on 4k pages */
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#ifndef CONFIG_PPC_64K_PAGES
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typedef struct { unsigned long pud; } pud_t;
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#define pud_val(x) ((x).pud)
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#define __pud(x) ((pud_t) { (x) })
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#endif /* !CONFIG_PPC_64K_PAGES */
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#endif /* CONFIG_PPC64 */
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/* PGD level */
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typedef struct { unsigned long pgd; } pgd_t;
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#define pgd_val(x) ((x).pgd)
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#define __pgd(x) ((pgd_t) { (x) })
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/* Page protection bits */
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typedef struct { unsigned long pgprot; } pgprot_t;
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#define pgprot_val(x) ((x).pgprot)
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#define __pgprot(x) ((pgprot_t) { (x) })
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#else
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/*
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* .. while these make it easier on the compiler
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*/
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typedef pte_basic_t pte_t;
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#define pte_val(x) (x)
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#define __pte(x) (x)
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#if defined(CONFIG_PPC_64K_PAGES) && defined(CONFIG_PPC_STD_MMU_64)
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typedef struct { pte_t pte; unsigned long hidx; } real_pte_t;
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#else
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typedef pte_t real_pte_t;
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#endif
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#ifdef CONFIG_PPC64
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typedef unsigned long pmd_t;
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#define pmd_val(x) (x)
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#define __pmd(x) (x)
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#ifndef CONFIG_PPC_64K_PAGES
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typedef unsigned long pud_t;
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#define pud_val(x) (x)
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#define __pud(x) (x)
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#endif /* !CONFIG_PPC_64K_PAGES */
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#endif /* CONFIG_PPC64 */
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typedef unsigned long pgd_t;
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#define pgd_val(x) (x)
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#define pgprot_val(x) (x)
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typedef unsigned long pgprot_t;
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#define __pgd(x) (x)
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#define __pgprot(x) (x)
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#endif
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typedef struct { signed long pd; } hugepd_t;
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#ifdef CONFIG_HUGETLB_PAGE
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static inline int hugepd_ok(hugepd_t hpd)
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{
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return (hpd.pd > 0);
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}
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#define is_hugepd(pdep) (hugepd_ok(*((hugepd_t *)(pdep))))
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#else /* CONFIG_HUGETLB_PAGE */
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#define is_hugepd(pdep) 0
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#endif /* CONFIG_HUGETLB_PAGE */
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struct page;
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extern void clear_user_page(void *page, unsigned long vaddr, struct page *pg);
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extern void copy_user_page(void *to, void *from, unsigned long vaddr,
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struct page *p);
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extern int page_is_ram(unsigned long pfn);
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extern int devmem_is_allowed(unsigned long pfn);
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#ifdef CONFIG_PPC_SMLPAR
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void arch_free_page(struct page *page, int order);
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#define HAVE_ARCH_FREE_PAGE
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#endif
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struct vm_area_struct;
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typedef struct page *pgtable_t;
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#include <asm-generic/memory_model.h>
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#endif /* __ASSEMBLY__ */
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#endif /* _ASM_POWERPC_PAGE_H */
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