linux/arch/um/include/asm/page.h

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/*
* Copyright (C) 2000 - 2003 Jeff Dike (jdike@addtoit.com)
* Copyright 2003 PathScale, Inc.
* Licensed under the GPL
*/
#ifndef __UM_PAGE_H
#define __UM_PAGE_H
#include <linux/const.h>
/* PAGE_SHIFT determines the page size */
#define PAGE_SHIFT 12
#define PAGE_SIZE (_AC(1, UL) << PAGE_SHIFT)
#define PAGE_MASK (~(PAGE_SIZE-1))
#ifndef __ASSEMBLY__
struct page;
#include <linux/pfn.h>
#include <linux/types.h>
#include <asm/vm-flags.h>
/*
* These are used to make use of C type-checking..
*/
#define clear_page(page) memset((void *)(page), 0, PAGE_SIZE)
#define copy_page(to,from) memcpy((void *)(to), (void *)(from), PAGE_SIZE)
#define clear_user_page(page, vaddr, pg) clear_page(page)
#define copy_user_page(to, from, vaddr, pg) copy_page(to, from)
#if defined(CONFIG_3_LEVEL_PGTABLES) && !defined(CONFIG_64BIT)
um: asm/page.h: remove the pte_high member from struct pte_t Commit 16da306849d0 ("um: kill pfn_t") introduced a compile warning for defconfig (SUBARCH=i386): arch/um/kernel/skas/mmu.c:38:206: warning: right shift count >= width of type [-Wshift-count-overflow] Aforementioned patch changes the definition of the phys_to_pfn() macro from ((pfn_t) ((p) >> PAGE_SHIFT)) to ((p) >> PAGE_SHIFT) This effectively changes the phys_to_pfn() expansion's type from unsigned long long to unsigned long. Through the callchain init_stub_pte() => mk_pte(), the expansion of phys_to_pfn() is (indirectly) fed into the 'phys' argument of the pte_set_val(pte, phys, prot) macro, eventually leading to (pte).pte_high = (phys) >> 32; This results in the warning from above. Since UML only deals with 32 bit addresses, the upper 32 bits from 'phys' used to be always zero anyway. Also, all page protection flags defined by UML don't use any bits beyond bit 9. Since the contents of a PTE are defined within architecture scope only, the ->pte_high member can be safely removed. Remove the ->pte_high member from struct pte_t. Rename ->pte_low to ->pte. Adapt the pte helper macros in arch/um/include/asm/page.h. Noteworthy is the pte_copy() macro where a smp_wmb() gets dropped. This write barrier doesn't seem to be paired with any read barrier though and thus, was useless anyway. Fixes: 16da306849d0 ("um: kill pfn_t") Signed-off-by: Nicolai Stange <nicstange@gmail.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Richard Weinberger <richard@nod.at> Cc: Nicolai Stange <nicstange@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-05 23:36:44 +00:00
typedef struct { unsigned long pte; } pte_t;
typedef struct { unsigned long pmd; } pmd_t;
typedef struct { unsigned long pgd; } pgd_t;
um: asm/page.h: remove the pte_high member from struct pte_t Commit 16da306849d0 ("um: kill pfn_t") introduced a compile warning for defconfig (SUBARCH=i386): arch/um/kernel/skas/mmu.c:38:206: warning: right shift count >= width of type [-Wshift-count-overflow] Aforementioned patch changes the definition of the phys_to_pfn() macro from ((pfn_t) ((p) >> PAGE_SHIFT)) to ((p) >> PAGE_SHIFT) This effectively changes the phys_to_pfn() expansion's type from unsigned long long to unsigned long. Through the callchain init_stub_pte() => mk_pte(), the expansion of phys_to_pfn() is (indirectly) fed into the 'phys' argument of the pte_set_val(pte, phys, prot) macro, eventually leading to (pte).pte_high = (phys) >> 32; This results in the warning from above. Since UML only deals with 32 bit addresses, the upper 32 bits from 'phys' used to be always zero anyway. Also, all page protection flags defined by UML don't use any bits beyond bit 9. Since the contents of a PTE are defined within architecture scope only, the ->pte_high member can be safely removed. Remove the ->pte_high member from struct pte_t. Rename ->pte_low to ->pte. Adapt the pte helper macros in arch/um/include/asm/page.h. Noteworthy is the pte_copy() macro where a smp_wmb() gets dropped. This write barrier doesn't seem to be paired with any read barrier though and thus, was useless anyway. Fixes: 16da306849d0 ("um: kill pfn_t") Signed-off-by: Nicolai Stange <nicstange@gmail.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Richard Weinberger <richard@nod.at> Cc: Nicolai Stange <nicstange@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-05 23:36:44 +00:00
#define pte_val(p) ((p).pte)
#define pte_get_bits(p, bits) ((p).pte & (bits))
#define pte_set_bits(p, bits) ((p).pte |= (bits))
#define pte_clear_bits(p, bits) ((p).pte &= ~(bits))
#define pte_copy(to, from) ({ (to).pte = (from).pte; })
#define pte_is_zero(p) (!((p).pte & ~_PAGE_NEWPAGE))
#define pte_set_val(p, phys, prot) \
({ (p).pte = (phys) | pgprot_val(prot); })
#define pmd_val(x) ((x).pmd)
#define __pmd(x) ((pmd_t) { (x) } )
typedef unsigned long long phys_t;
#else
typedef struct { unsigned long pte; } pte_t;
typedef struct { unsigned long pgd; } pgd_t;
#ifdef CONFIG_3_LEVEL_PGTABLES
typedef struct { unsigned long pmd; } pmd_t;
#define pmd_val(x) ((x).pmd)
#define __pmd(x) ((pmd_t) { (x) } )
#endif
#define pte_val(x) ((x).pte)
#define pte_get_bits(p, bits) ((p).pte & (bits))
#define pte_set_bits(p, bits) ((p).pte |= (bits))
#define pte_clear_bits(p, bits) ((p).pte &= ~(bits))
#define pte_copy(to, from) ((to).pte = (from).pte)
#define pte_is_zero(p) (!((p).pte & ~_PAGE_NEWPAGE))
#define pte_set_val(p, phys, prot) (p).pte = (phys | pgprot_val(prot))
typedef unsigned long phys_t;
#endif
typedef struct { unsigned long pgprot; } pgprot_t;
CONFIG_HIGHPTE vs. sub-page page tables. Background: I've implemented 1K/2K page tables for s390. These sub-page page tables are required to properly support the s390 virtualization instruction with KVM. The SIE instruction requires that the page tables have 256 page table entries (pte) followed by 256 page status table entries (pgste). The pgstes are only required if the process is using the SIE instruction. The pgstes are updated by the hardware and by the hypervisor for a number of reasons, one of them is dirty and reference bit tracking. To avoid wasting memory the standard pte table allocation should return 1K/2K (31/64 bit) and 2K/4K if the process is using SIE. Problem: Page size on s390 is 4K, page table size is 1K or 2K. That means the s390 version for pte_alloc_one cannot return a pointer to a struct page. Trouble is that with the CONFIG_HIGHPTE feature on x86 pte_alloc_one cannot return a pointer to a pte either, since that would require more than 32 bit for the return value of pte_alloc_one (and the pte * would not be accessible since its not kmapped). Solution: The only solution I found to this dilemma is a new typedef: a pgtable_t. For s390 pgtable_t will be a (pte *) - to be introduced with a later patch. For everybody else it will be a (struct page *). The additional problem with the initialization of the ptl lock and the NR_PAGETABLE accounting is solved with a constructor pgtable_page_ctor and a destructor pgtable_page_dtor. The page table allocation and free functions need to call these two whenever a page table page is allocated or freed. pmd_populate will get a pgtable_t instead of a struct page pointer. To get the pgtable_t back from a pmd entry that has been installed with pmd_populate a new function pmd_pgtable is added. It replaces the pmd_page call in free_pte_range and apply_to_pte_range. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 12:22:04 +00:00
typedef struct page *pgtable_t;
#define pgd_val(x) ((x).pgd)
#define pgprot_val(x) ((x).pgprot)
#define __pte(x) ((pte_t) { (x) } )
#define __pgd(x) ((pgd_t) { (x) } )
#define __pgprot(x) ((pgprot_t) { (x) } )
extern unsigned long uml_physmem;
#define PAGE_OFFSET (uml_physmem)
#define KERNELBASE PAGE_OFFSET
#define __va_space (8*1024*1024)
#include <mem.h>
/* Cast to unsigned long before casting to void * to avoid a warning from
* mmap_kmem about cutting a long long down to a void *. Not sure that
* casting is the right thing, but 32-bit UML can't have 64-bit virtual
* addresses
*/
#define __pa(virt) to_phys((void *) (unsigned long) (virt))
#define __va(phys) to_virt((unsigned long) (phys))
#define phys_to_pfn(p) ((p) >> PAGE_SHIFT)
#define pfn_to_phys(pfn) PFN_PHYS(pfn)
#define pfn_valid(pfn) ((pfn) < max_mapnr)
#define virt_addr_valid(v) pfn_valid(phys_to_pfn(__pa(v)))
#include <asm-generic/memory_model.h>
#include <asm-generic/getorder.h>
#endif /* __ASSEMBLY__ */
arm64,ia64,ppc,s390,sh,tile,um,x86,mm: remove default gate area The core mm code will provide a default gate area based on FIXADDR_USER_START and FIXADDR_USER_END if !defined(__HAVE_ARCH_GATE_AREA) && defined(AT_SYSINFO_EHDR). This default is only useful for ia64. arm64, ppc, s390, sh, tile, 64-bit UML, and x86_32 have their own code just to disable it. arm, 32-bit UML, and x86_64 have gate areas, but they have their own implementations. This gets rid of the default and moves the code into ia64. This should save some code on architectures without a gate area: it's now possible to inline the gate_area functions in the default case. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Acked-by: Nathan Lynch <nathan_lynch@mentor.com> Acked-by: H. Peter Anvin <hpa@linux.intel.com> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> [in principle] Acked-by: Richard Weinberger <richard@nod.at> [for um] Acked-by: Will Deacon <will.deacon@arm.com> [for arm64] Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Richard Weinberger <richard@nod.at> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Nathan Lynch <Nathan_Lynch@mentor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-08 21:23:40 +00:00
#ifdef CONFIG_X86_32
#define __HAVE_ARCH_GATE_AREA 1
#endif
#endif /* __UM_PAGE_H */