[POWERPC] Spufs support for 64K LS mappings on 4K kernels

This adds an option to spufs when the kernel is configured for
4K page to give it the ability to use 64K pages for SPE local store
mappings.

Currently, we are optimistic and try order 4 allocations when creating
contexts. If that fails, the code will fallback to 4K automatically.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 67 insertions, 13 deletions

diff --git a/arch/powerpc/platforms/cell/spufs/file.c b/arch/powerpc/platforms/cell/spufs/file.c
index d010b2464a98..45614c73c784 100644
--- a/arch/powerpc/platforms/cell/spufs/file.c
+++ b/arch/powerpc/platforms/cell/spufs/file.c
@@ -118,14 +118,32 @@ spufs_mem_write(struct file *file, const char __user *buffer,
 static unsigned long spufs_mem_mmap_nopfn(struct vm_area_struct *vma,
 					  unsigned long address)
 {
-	struct spu_context *ctx = vma->vm_file->private_data;
-	unsigned long pfn, offset = address - vma->vm_start;
-
-	offset += vma->vm_pgoff << PAGE_SHIFT;
+	struct spu_context *ctx	= vma->vm_file->private_data;
+	unsigned long pfn, offset, addr0 = address;
+#ifdef CONFIG_SPU_FS_64K_LS
+	struct spu_state *csa = &ctx->csa;
+	int psize;
+
+	/* Check what page size we are using */
+	psize = get_slice_psize(vma->vm_mm, address);
+
+	/* Some sanity checking */
+	BUG_ON(csa->use_big_pages != (psize == MMU_PAGE_64K));
+
+	/* Wow, 64K, cool, we need to align the address though */
+	if (csa->use_big_pages) {
+		BUG_ON(vma->vm_start & 0xffff);
+		address &= ~0xfffful;
+	}
+#endif /* CONFIG_SPU_FS_64K_LS */
 
+	offset = (address - vma->vm_start) + (vma->vm_pgoff << PAGE_SHIFT);
 	if (offset >= LS_SIZE)
 		return NOPFN_SIGBUS;
 
+	pr_debug("spufs_mem_mmap_nopfn address=0x%lx -> 0x%lx, offset=0x%lx\n",
+		 addr0, address, offset);
+
 	spu_acquire(ctx);
 
 	if (ctx->state == SPU_STATE_SAVED) {
@@ -149,9 +167,24 @@ static struct vm_operations_struct spufs_mem_mmap_vmops = {
 	.nopfn = spufs_mem_mmap_nopfn,
 };
 
-static int
-spufs_mem_mmap(struct file *file, struct vm_area_struct *vma)
-{
+static int spufs_mem_mmap(struct file *file, struct vm_area_struct *vma)
+{
+#ifdef CONFIG_SPU_FS_64K_LS
+	struct spu_context	*ctx = file->private_data;
+	struct spu_state	*csa = &ctx->csa;
+
+	/* Sanity check VMA alignment */
+	if (csa->use_big_pages) {
+		pr_debug("spufs_mem_mmap 64K, start=0x%lx, end=0x%lx,"
+			 " pgoff=0x%lx\n", vma->vm_start, vma->vm_end,
+			 vma->vm_pgoff);
+		if (vma->vm_start & 0xffff)
+			return -EINVAL;
+		if (vma->vm_pgoff & 0xf)
+			return -EINVAL;
+	}
+#endif /* CONFIG_SPU_FS_64K_LS */
+
 	if (!(vma->vm_flags & VM_SHARED))
 		return -EINVAL;
 
@@ -163,13 +196,34 @@ spufs_mem_mmap(struct file *file, struct vm_area_struct *vma)
 	return 0;
 }
 
+#ifdef CONFIG_SPU_FS_64K_LS
+unsigned long spufs_get_unmapped_area(struct file *file, unsigned long addr,
+				      unsigned long len, unsigned long pgoff,
+				      unsigned long flags)
+{
+	struct spu_context	*ctx = file->private_data;
+	struct spu_state	*csa = &ctx->csa;
+
+	/* If not using big pages, fallback to normal MM g_u_a */
+	if (!csa->use_big_pages)
+		return current->mm->get_unmapped_area(file, addr, len,
+						      pgoff, flags);
+
+	/* Else, try to obtain a 64K pages slice */
+	return slice_get_unmapped_area(addr, len, flags,
+				       MMU_PAGE_64K, 1, 0);
+}
+#endif /* CONFIG_SPU_FS_64K_LS */
+
 static const struct file_operations spufs_mem_fops = {
-	.open	 = spufs_mem_open,
-	.release = spufs_mem_release,
-	.read    = spufs_mem_read,
-	.write   = spufs_mem_write,
-	.llseek  = generic_file_llseek,
-	.mmap    = spufs_mem_mmap,
+	.open	 		= spufs_mem_open,
+	.read   		= spufs_mem_read,
+	.write   		= spufs_mem_write,
+	.llseek  		= generic_file_llseek,
+	.mmap    		= spufs_mem_mmap,
+#ifdef CONFIG_SPU_FS_64K_LS
+	.get_unmapped_area	= spufs_get_unmapped_area,
+#endif
 };
 
 static unsigned long spufs_ps_nopfn(struct vm_area_struct *vma,