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android_kernel_xiaomi_sm8350/arch/x86/include/asm/fixmap.h
Jan Beulich 499a5f1efa x86: Lift restriction on the location of FIX_BTMAP_* 
The early ioremap fixmap entries cover half (or for 32-bit
non-PAE, a quarter) of a page table, yet they got
uncondtitionally aligned so far to a 256-entry boundary. This is
not necessary if the range of page table entries anyway falls
into a single page table.

This buys back, for (theoretically) 50% of all configurations
(25% of all non-PAE ones), at least some of the lowmem
necessarily lost with commit e621bd1895.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <4B2BB66F0200007800026AD6@vpn.id2.novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-30 11:57:30 +01:00

219 lines
6.4 KiB
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/*
* fixmap.h: compile-time virtual memory allocation
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 1998 Ingo Molnar
*
* Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
* x86_32 and x86_64 integration by Gustavo F. Padovan, February 2009
*/
#ifndef _ASM_X86_FIXMAP_H
#define _ASM_X86_FIXMAP_H
#ifndef __ASSEMBLY__
#include <linux/kernel.h>
#include <asm/acpi.h>
#include <asm/apicdef.h>
#include <asm/page.h>
#ifdef CONFIG_X86_32
#include <linux/threads.h>
#include <asm/kmap_types.h>
#else
#include <asm/vsyscall.h>
#endif
/*
* We can't declare FIXADDR_TOP as variable for x86_64 because vsyscall
* uses fixmaps that relies on FIXADDR_TOP for proper address calculation.
* Because of this, FIXADDR_TOP x86 integration was left as later work.
*/
#ifdef CONFIG_X86_32
/* used by vmalloc.c, vsyscall.lds.S.
*
* Leave one empty page between vmalloc'ed areas and
* the start of the fixmap.
*/
extern unsigned long __FIXADDR_TOP;
#define FIXADDR_TOP ((unsigned long)__FIXADDR_TOP)
#define FIXADDR_USER_START __fix_to_virt(FIX_VDSO)
#define FIXADDR_USER_END __fix_to_virt(FIX_VDSO - 1)
#else
#define FIXADDR_TOP (VSYSCALL_END-PAGE_SIZE)
/* Only covers 32bit vsyscalls currently. Need another set for 64bit. */
#define FIXADDR_USER_START ((unsigned long)VSYSCALL32_VSYSCALL)
#define FIXADDR_USER_END (FIXADDR_USER_START + PAGE_SIZE)
#endif
/*
* Here we define all the compile-time 'special' virtual
* addresses. The point is to have a constant address at
* compile time, but to set the physical address only
* in the boot process.
* for x86_32: We allocate these special addresses
* from the end of virtual memory (0xfffff000) backwards.
* Also this lets us do fail-safe vmalloc(), we
* can guarantee that these special addresses and
* vmalloc()-ed addresses never overlap.
*
* These 'compile-time allocated' memory buffers are
* fixed-size 4k pages (or larger if used with an increment
* higher than 1). Use set_fixmap(idx,phys) to associate
* physical memory with fixmap indices.
*
* TLB entries of such buffers will not be flushed across
* task switches.
*/
enum fixed_addresses {
#ifdef CONFIG_X86_32
FIX_HOLE,
FIX_VDSO,
#else
VSYSCALL_LAST_PAGE,
VSYSCALL_FIRST_PAGE = VSYSCALL_LAST_PAGE
+ ((VSYSCALL_END-VSYSCALL_START) >> PAGE_SHIFT) - 1,
VSYSCALL_HPET,
#endif
FIX_DBGP_BASE,
FIX_EARLYCON_MEM_BASE,
#ifdef CONFIG_X86_LOCAL_APIC
FIX_APIC_BASE, /* local (CPU) APIC) -- required for SMP or not */
#endif
#ifdef CONFIG_X86_IO_APIC
FIX_IO_APIC_BASE_0,
FIX_IO_APIC_BASE_END = FIX_IO_APIC_BASE_0 + MAX_IO_APICS - 1,
#endif
#ifdef CONFIG_X86_VISWS_APIC
FIX_CO_CPU, /* Cobalt timer */
FIX_CO_APIC, /* Cobalt APIC Redirection Table */
FIX_LI_PCIA, /* Lithium PCI Bridge A */
FIX_LI_PCIB, /* Lithium PCI Bridge B */
#endif
#ifdef CONFIG_X86_F00F_BUG
FIX_F00F_IDT, /* Virtual mapping for IDT */
#endif
#ifdef CONFIG_X86_CYCLONE_TIMER
FIX_CYCLONE_TIMER, /*cyclone timer register*/
#endif
#ifdef CONFIG_X86_32
FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */
FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1,
#ifdef CONFIG_PCI_MMCONFIG
FIX_PCIE_MCFG,
#endif
#endif
#ifdef CONFIG_PARAVIRT
FIX_PARAVIRT_BOOTMAP,
#endif
FIX_TEXT_POKE1, /* reserve 2 pages for text_poke() */
FIX_TEXT_POKE0, /* first page is last, because allocation is backward */
__end_of_permanent_fixed_addresses,
/*
* 256 temporary boot-time mappings, used by early_ioremap(),
* before ioremap() is functional.
*
* If necessary we round it up to the next 256 pages boundary so
* that we can have a single pgd entry and a single pte table:
*/
#define NR_FIX_BTMAPS 64
#define FIX_BTMAPS_SLOTS 4
#define TOTAL_FIX_BTMAPS (NR_FIX_BTMAPS * FIX_BTMAPS_SLOTS)
FIX_BTMAP_END =
(__end_of_permanent_fixed_addresses ^
(__end_of_permanent_fixed_addresses + TOTAL_FIX_BTMAPS - 1)) &
-PTRS_PER_PTE
? __end_of_permanent_fixed_addresses + TOTAL_FIX_BTMAPS -
(__end_of_permanent_fixed_addresses & (TOTAL_FIX_BTMAPS - 1))
: __end_of_permanent_fixed_addresses,
FIX_BTMAP_BEGIN = FIX_BTMAP_END + TOTAL_FIX_BTMAPS - 1,
#ifdef CONFIG_PROVIDE_OHCI1394_DMA_INIT
FIX_OHCI1394_BASE,
#endif
#ifdef CONFIG_X86_32
FIX_WP_TEST,
#endif
#ifdef CONFIG_INTEL_TXT
FIX_TBOOT_BASE,
#endif
__end_of_fixed_addresses
};
extern void reserve_top_address(unsigned long reserve);
#define FIXADDR_SIZE (__end_of_permanent_fixed_addresses << PAGE_SHIFT)
#define FIXADDR_BOOT_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
#define FIXADDR_BOOT_START (FIXADDR_TOP - FIXADDR_BOOT_SIZE)
extern int fixmaps_set;
extern pte_t *kmap_pte;
extern pgprot_t kmap_prot;
extern pte_t *pkmap_page_table;
void __native_set_fixmap(enum fixed_addresses idx, pte_t pte);
void native_set_fixmap(enum fixed_addresses idx,
phys_addr_t phys, pgprot_t flags);
#ifndef CONFIG_PARAVIRT
static inline void __set_fixmap(enum fixed_addresses idx,
phys_addr_t phys, pgprot_t flags)
{
native_set_fixmap(idx, phys, flags);
}
#endif
#define set_fixmap(idx, phys) \
__set_fixmap(idx, phys, PAGE_KERNEL)
/*
* Some hardware wants to get fixmapped without caching.
*/
#define set_fixmap_nocache(idx, phys) \
__set_fixmap(idx, phys, PAGE_KERNEL_NOCACHE)
#define clear_fixmap(idx) \
__set_fixmap(idx, 0, __pgprot(0))
#define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT))
#define __virt_to_fix(x) ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
extern void __this_fixmap_does_not_exist(void);
/*
* 'index to address' translation. If anyone tries to use the idx
* directly without translation, we catch the bug with a NULL-deference
* kernel oops. Illegal ranges of incoming indices are caught too.
*/
static __always_inline unsigned long fix_to_virt(const unsigned int idx)
{
/*
* this branch gets completely eliminated after inlining,
* except when someone tries to use fixaddr indices in an
* illegal way. (such as mixing up address types or using
* out-of-range indices).
*
* If it doesn't get removed, the linker will complain
* loudly with a reasonably clear error message..
*/
if (idx >= __end_of_fixed_addresses)
__this_fixmap_does_not_exist();
return __fix_to_virt(idx);
}
static inline unsigned long virt_to_fix(const unsigned long vaddr)
{
BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
return __virt_to_fix(vaddr);
}
#endif /* !__ASSEMBLY__ */
#endif /* _ASM_X86_FIXMAP_H */
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