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: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c
index bfa7db6..93ed1a3 100644
--- a/arch/powerpc/mm/pgtable_64.c
+++ b/arch/powerpc/mm/pgtable_64.c
@@ -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 @@
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 @@
"memory at %016lx !\n", pa);
return -ENOMEM;
}
+#endif /* !CONFIG_PPC_MMU_NOHASH */
}
return 0;
}
@@ -124,7 +173,7 @@
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;