1 files changed, 25 insertions, 18 deletions

diff --git a/arch/powerpc/mm/fsl_booke_mmu.c b/arch/powerpc/mm/fsl_booke_mmu.c
index f7802c8bba0..66a6fd38e9c 100644
--- a/arch/powerpc/mm/fsl_booke_mmu.c
+++ b/arch/powerpc/mm/fsl_booke_mmu.c
@@ -101,17 +101,17 @@ unsigned long p_mapped_by_tlbcam(phys_addr_t pa)
 
 /*
  * Set up a variable-size TLB entry (tlbcam). The parameters are not checked;
- * in particular size must be a power of 4 between 4k and 256M (or 1G, for cpus
- * that support extended page sizes).  Note that while some cpus support a
- * page size of 4G, we don't allow its use here.
+ * in particular size must be a power of 4 between 4k and the max supported by
+ * an implementation; max may further be limited by what can be represented in
+ * an unsigned long (for example, 32-bit implementations cannot support a 4GB
+ * size).
  */
 static void settlbcam(int index, unsigned long virt, phys_addr_t phys,
                 unsigned long size, unsigned long flags, unsigned int pid)
 {
-        unsigned int tsize, lz;
+        unsigned int tsize;
 
-        asm (PPC_CNTLZL "%0,%1" : "=r" (lz) : "r" (size));
-        tsize = 21 - lz;
+        tsize = __ilog2(size) - 10;
 
 #ifdef CONFIG_SMP
         if ((flags & _PAGE_NO_CACHE) == 0)
@@ -146,29 +146,36 @@ static void settlbcam(int index, unsigned long virt, phys_addr_t phys,
         loadcam_entry(index);
 }
 
+unsigned long calc_cam_sz(unsigned long ram, unsigned long virt,
+                          phys_addr_t phys)
+{
+        unsigned int camsize = __ilog2(ram) & ~1U;
+        unsigned int align = __ffs(virt | phys) & ~1U;
+        unsigned long max_cam = (mfspr(SPRN_TLB1CFG) >> 16) & 0xf;
+
+        /* Convert (4^max) kB to (2^max) bytes */
+        max_cam = max_cam * 2 + 10;
+
+        if (camsize > align)
+                camsize = align;
+        if (camsize > max_cam)
+                camsize = max_cam;
+
+        return 1UL << camsize;
+}
+
 unsigned long map_mem_in_cams(unsigned long ram, int max_cam_idx)
 {
         int i;
         unsigned long virt = PAGE_OFFSET;
         phys_addr_t phys = memstart_addr;
         unsigned long amount_mapped = 0;
-        unsigned long max_cam = (mfspr(SPRN_TLB1CFG) >> 16) & 0xf;
-
-        /* Convert (4^max) kB to (2^max) bytes */
-        max_cam = max_cam * 2 + 10;
 
         /* Calculate CAM values */
         for (i = 0; ram && i < max_cam_idx; i++) {
-                unsigned int camsize = __ilog2(ram) & ~1U;
-                unsigned int align = __ffs(virt | phys) & ~1U;
                 unsigned long cam_sz;
 
-                if (camsize > align)
-                        camsize = align;
-                if (camsize > max_cam)
-                        camsize = max_cam;
-
-                cam_sz = 1UL << camsize;
+                cam_sz = calc_cam_sz(ram, virt, phys);
                 settlbcam(i, virt, phys, cam_sz, PAGE_KERNEL_X, 0);
 
                 ram -= cam_sz;