[PATCH] ppc64: support 64k pages

Adds a new CONFIG_PPC_64K_PAGES which, when enabled, changes the kernel
base page size to 64K.  The resulting kernel still boots on any
hardware.  On current machines with 4K pages support only, the kernel
will maintain 16 "subpages" for each 64K page transparently.

Note that while real 64K capable HW has been tested, the current patch
will not enable it yet as such hardware is not released yet, and I'm
still verifying with the firmware architects the proper to get the
information from the newer hypervisors.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 7 insertions, 6 deletions

diff --git a/arch/powerpc/platforms/iseries/setup.c b/arch/powerpc/platforms/iseries/setup.c
index fda712b42168..c5207064977d 100644
--- a/arch/powerpc/platforms/iseries/setup.c
+++ b/arch/powerpc/platforms/iseries/setup.c
@@ -320,11 +320,11 @@ static void __init iSeries_init_early(void)
          */
         if (naca.xRamDisk) {
                 initrd_start = (unsigned long)__va(naca.xRamDisk);
-                initrd_end = initrd_start + naca.xRamDiskSize * PAGE_SIZE;
+                initrd_end = initrd_start + naca.xRamDiskSize * HW_PAGE_SIZE;
                 initrd_below_start_ok = 1;      // ramdisk in kernel space
                 ROOT_DEV = Root_RAM0;
-                if (((rd_size * 1024) / PAGE_SIZE) < naca.xRamDiskSize)
-                        rd_size = (naca.xRamDiskSize * PAGE_SIZE) / 1024;
+                if (((rd_size * 1024) / HW_PAGE_SIZE) < naca.xRamDiskSize)
+                        rd_size = (naca.xRamDiskSize * HW_PAGE_SIZE) / 1024;
         } else
 #endif /* CONFIG_BLK_DEV_INITRD */
         {
@@ -470,13 +470,14 @@ static void __init build_iSeries_Memory_Map(void)
          */
         hptFirstChunk = (u32)addr_to_chunk(HvCallHpt_getHptAddress());
         hptSizePages = (u32)HvCallHpt_getHptPages();
-        hptSizeChunks = hptSizePages >> (MSCHUNKS_CHUNK_SHIFT - PAGE_SHIFT);
+        hptSizeChunks = hptSizePages >>
+                (MSCHUNKS_CHUNK_SHIFT - HW_PAGE_SHIFT);
         hptLastChunk = hptFirstChunk + hptSizeChunks - 1;
 
         printk("HPT absolute addr = %016lx, size = %dK\n",
                         chunk_to_addr(hptFirstChunk), hptSizeChunks * 256);
 
-        ppc64_pft_size = __ilog2(hptSizePages * PAGE_SIZE);
+        ppc64_pft_size = __ilog2(hptSizePages * HW_PAGE_SIZE);
 
         /*
          * The actual hashed page table is in the hypervisor,
@@ -629,7 +630,7 @@ static void __init iSeries_fixup_klimit(void)
          */
         if (naca.xRamDisk)
                 klimit = KERNELBASE + (u64)naca.xRamDisk +
-                        (naca.xRamDiskSize * PAGE_SIZE);
+                        (naca.xRamDiskSize * HW_PAGE_SIZE);
         else {
                 /*
                  * No ram disk was included - check and see if there