alistair23-linux/arch/um/include/asm/page.h
Nicolai Stange 012a4163be um: asm/page.h: remove the pte_high member from struct pte_t
Commit 16da306849 ("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: 16da306849 ("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 18:10:40 -08:00

124 lines
3.2 KiB
C

/*
* 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)
typedef struct { unsigned long pte; } pte_t;
typedef struct { unsigned long pmd; } pmd_t;
typedef struct { unsigned long pgd; } pgd_t;
#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;
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__ */
#ifdef CONFIG_X86_32
#define __HAVE_ARCH_GATE_AREA 1
#endif
#endif /* __UM_PAGE_H */