Commit a245067e authored by Benjamin Herrenschmidt's avatar Benjamin Herrenschmidt
Browse files

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



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: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 1fe1a210

arch/powerpc/mm/pgtable_64.c

+54 −5
Original line number Diff line number Diff line
@@ -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;

CRA Git | Maintained and supported by SUSTech CRA and CCSE