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git.proxmox.com Git - mirror_ubuntu-bionic-kernel.git/blob - arch/x86/mm/boot_ioremap_32.c
2 * arch/i386/mm/boot_ioremap.c
4 * Re-map functions for early boot-time before paging_init() when the
5 * boot-time pagetables are still in use
7 * Written by Dave Hansen <haveblue@us.ibm.com>
12 * We need to use the 2-level pagetable functions, but CONFIG_X86_PAE
13 * keeps that from happenning. If anyone has a better way, I'm listening.
15 * boot_pte_t is defined only if this all works correctly
19 #undef CONFIG_PARAVIRT
21 #include <asm/pgtable.h>
22 #include <asm/tlbflush.h>
23 #include <linux/init.h>
24 #include <linux/stddef.h>
27 * I'm cheating here. It is known that the two boot PTE pages are
28 * allocated next to each other. I'm pretending that they're just
32 #define BOOT_PTE_PTRS (PTRS_PER_PTE*2)
34 static unsigned long boot_pte_index(unsigned long vaddr
)
36 return __pa(vaddr
) >> PAGE_SHIFT
;
39 static inline boot_pte_t
* boot_vaddr_to_pte(void *address
)
41 boot_pte_t
* boot_pg
= (boot_pte_t
*)pg0
;
42 return &boot_pg
[boot_pte_index((unsigned long)address
)];
46 * This is only for a caller who is clever enough to page-align
47 * phys_addr and virtual_source, and who also has a preference
48 * about which virtual address from which to steal ptes
50 static void __boot_ioremap(unsigned long phys_addr
, unsigned long nrpages
,
55 char *vaddr
= virtual_source
;
57 pte
= boot_vaddr_to_pte(virtual_source
);
58 for (i
=0; i
< nrpages
; i
++, phys_addr
+= PAGE_SIZE
, pte
++) {
59 set_pte(pte
, pfn_pte(phys_addr
>>PAGE_SHIFT
, PAGE_KERNEL
));
60 __flush_tlb_one(&vaddr
[i
*PAGE_SIZE
]);
64 /* the virtual space we're going to remap comes from this array */
65 #define BOOT_IOREMAP_PAGES 4
66 #define BOOT_IOREMAP_SIZE (BOOT_IOREMAP_PAGES*PAGE_SIZE)
67 static __initdata
char boot_ioremap_space
[BOOT_IOREMAP_SIZE
]
68 __attribute__ ((aligned (PAGE_SIZE
)));
71 * This only applies to things which need to ioremap before paging_init()
72 * bt_ioremap() and plain ioremap() are both useless at this point.
74 * When used, we're still using the boot-time pagetables, which only
75 * have 2 PTE pages mapping the first 8MB
77 * There is no unmap. The boot-time PTE pages aren't used after boot.
78 * If you really want the space back, just remap it yourself.
79 * boot_ioremap(&ioremap_space-PAGE_OFFSET, BOOT_IOREMAP_SIZE)
81 __init
void* boot_ioremap(unsigned long phys_addr
, unsigned long size
)
83 unsigned long last_addr
, offset
;
86 last_addr
= phys_addr
+ size
- 1;
88 /* page align the requested address */
89 offset
= phys_addr
& ~PAGE_MASK
;
90 phys_addr
&= PAGE_MASK
;
91 size
= PAGE_ALIGN(last_addr
) - phys_addr
;
93 nrpages
= size
>> PAGE_SHIFT
;
94 if (nrpages
> BOOT_IOREMAP_PAGES
)
97 __boot_ioremap(phys_addr
, nrpages
, boot_ioremap_space
);
99 return &boot_ioremap_space
[offset
];