[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, 9 insertions, 7 deletions

diff --git a/arch/powerpc/platforms/iseries/viopath.c b/arch/powerpc/platforms/iseries/viopath.c
index fe97bfbf7463..842672695598 100644
--- a/arch/powerpc/platforms/iseries/viopath.c
+++ b/arch/powerpc/platforms/iseries/viopath.c
@@ -68,7 +68,8 @@ static DEFINE_SPINLOCK(statuslock);
  * For each kind of event we allocate a buffer that is
  * guaranteed not to cross a page boundary
  */
-static unsigned char event_buffer[VIO_MAX_SUBTYPES * 256] __page_aligned;
+static unsigned char event_buffer[VIO_MAX_SUBTYPES * 256]
+        __attribute__((__aligned__(4096)));
 static atomic_t event_buffer_available[VIO_MAX_SUBTYPES];
 static int event_buffer_initialised;
 
@@ -116,12 +117,12 @@ static int proc_viopath_show(struct seq_file *m, void *v)
         HvLpEvent_Rc hvrc;
         DECLARE_MUTEX_LOCKED(Semaphore);
 
-        buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
+        buf = kmalloc(HW_PAGE_SIZE, GFP_KERNEL);
         if (!buf)
                 return 0;
-        memset(buf, 0, PAGE_SIZE);
+        memset(buf, 0, HW_PAGE_SIZE);
 
-        handle = dma_map_single(iSeries_vio_dev, buf, PAGE_SIZE,
+        handle = dma_map_single(iSeries_vio_dev, buf, HW_PAGE_SIZE,
                                 DMA_FROM_DEVICE);
 
         hvrc = HvCallEvent_signalLpEventFast(viopath_hostLp,
@@ -131,7 +132,7 @@ static int proc_viopath_show(struct seq_file *m, void *v)
                         viopath_sourceinst(viopath_hostLp),
                         viopath_targetinst(viopath_hostLp),
                         (u64)(unsigned long)&Semaphore, VIOVERSION << 16,
-                        ((u64)handle) << 32, PAGE_SIZE, 0, 0);
+                        ((u64)handle) << 32, HW_PAGE_SIZE, 0, 0);
 
         if (hvrc != HvLpEvent_Rc_Good)
                 printk(VIOPATH_KERN_WARN "hv error on op %d\n", (int)hvrc);
@@ -140,7 +141,7 @@ static int proc_viopath_show(struct seq_file *m, void *v)
 
         vlanMap = HvLpConfig_getVirtualLanIndexMap();
 
-        buf[PAGE_SIZE-1] = '\0';
+        buf[HW_PAGE_SIZE-1] = '\0';
         seq_printf(m, "%s", buf);
         seq_printf(m, "AVAILABLE_VETH=%x\n", vlanMap);
         seq_printf(m, "SRLNBR=%c%c%c%c%c%c%c\n",
@@ -152,7 +153,8 @@ static int proc_viopath_show(struct seq_file *m, void *v)
                    e2a(xItExtVpdPanel.systemSerial[4]),
                    e2a(xItExtVpdPanel.systemSerial[5]));
 
-        dma_unmap_single(iSeries_vio_dev, handle, PAGE_SIZE, DMA_FROM_DEVICE);
+        dma_unmap_single(iSeries_vio_dev, handle, HW_PAGE_SIZE,
+                         DMA_FROM_DEVICE);
         kfree(buf);
 
         return 0;