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powerpc/mm: Add support for early ioremap on non-hash 64-bit processors

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This adds some code to do early ioremap's using page tables instead of
bolting entries in the hash table. This will be used by the upcoming
64-bits BookE port.

The patch also changes the test for early vs. late ioremap to use
slab_is_available() instead of our old hackish mem_init_done.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Benjamin Herrenschmidt 2009-07-23 23:15:16 +00:00
commit a245067e20
1 changed files with 54 additions and 5 deletions
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59
arch/powerpc/mm/pgtable_64.c
View file

@ -33,6 +33,8 @@
#include <linux/stddef.h>
#include <linux/vmalloc.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/lmb.h>
#include <asm/pgalloc.h>
#include <asm/page.h>
@ -55,19 +57,36 @@
unsigned long ioremap_bot = IOREMAP_BASE;
#ifdef CONFIG_PPC_MMU_NOHASH
static void *early_alloc_pgtable(unsigned long size)
{
void *pt;
if (init_bootmem_done)
pt = __alloc_bootmem(size, size, __pa(MAX_DMA_ADDRESS));
else
pt = __va(lmb_alloc_base(size, size,
__pa(MAX_DMA_ADDRESS)));
memset(pt, 0, size);
return pt;
}
#endif /* CONFIG_PPC_MMU_NOHASH */
/*
* map_io_page currently only called by __ioremap
* map_io_page adds an entry to the ioremap page table
* map_kernel_page currently only called by __ioremap
* map_kernel_page adds an entry to the ioremap page table
* and adds an entry to the HPT, possibly bolting it
*/
static int map_io_page(unsigned long ea, unsigned long pa, int flags)
static int map_kernel_page(unsigned long ea, unsigned long pa, int flags)
{
pgd_t *pgdp;
pud_t *pudp;
pmd_t *pmdp;
pte_t *ptep;
if (mem_init_done) {
if (slab_is_available()) {
pgdp = pgd_offset_k(ea);
pudp = pud_alloc(&init_mm, pgdp, ea);
if (!pudp)
@ -81,6 +100,35 @@ static int map_io_page(unsigned long ea, unsigned long pa, int flags)
set_pte_at(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT,
__pgprot(flags)));
} else {
#ifdef CONFIG_PPC_MMU_NOHASH
/* Warning ! This will blow up if bootmem is not initialized
* which our ppc64 code is keen to do that, we'll need to
* fix it and/or be more careful
*/
pgdp = pgd_offset_k(ea);
#ifdef PUD_TABLE_SIZE
if (pgd_none(*pgdp)) {
pudp = early_alloc_pgtable(PUD_TABLE_SIZE);
BUG_ON(pudp == NULL);
pgd_populate(&init_mm, pgdp, pudp);
}
#endif /* PUD_TABLE_SIZE */
pudp = pud_offset(pgdp, ea);
if (pud_none(*pudp)) {
pmdp = early_alloc_pgtable(PMD_TABLE_SIZE);
BUG_ON(pmdp == NULL);
pud_populate(&init_mm, pudp, pmdp);
}
pmdp = pmd_offset(pudp, ea);
if (!pmd_present(*pmdp)) {
ptep = early_alloc_pgtable(PAGE_SIZE);
BUG_ON(ptep == NULL);
pmd_populate_kernel(&init_mm, pmdp, ptep);
}
ptep = pte_offset_kernel(pmdp, ea);
set_pte_at(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT,
__pgprot(flags)));
#else /* CONFIG_PPC_MMU_NOHASH */
/*
* If the mm subsystem is not fully up, we cannot create a
* linux page table entry for this mapping. Simply bolt an
@ -93,6 +141,7 @@ static int map_io_page(unsigned long ea, unsigned long pa, int flags)
"memory at %016lx !\n", pa);
return -ENOMEM;
}
#endif /* !CONFIG_PPC_MMU_NOHASH */
}
return 0;
}
@ -124,7 +173,7 @@ void __iomem * __ioremap_at(phys_addr_t pa, void *ea, unsigned long size,
WARN_ON(size & ~PAGE_MASK);
for (i = 0; i < size; i += PAGE_SIZE)
if (map_io_page((unsigned long)ea+i, pa+i, flags))
if (map_kernel_page((unsigned long)ea+i, pa+i, flags))
return NULL;
return (void __iomem *)ea;