arch/tile: support building big-endian kernel

The toolchain supports big-endian mode now, so add support for building
the kernel to run big-endian as well.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>

2 files changed, 23 insertions, 5 deletions

diff --git a/arch/tile/kernel/module.c b/arch/tile/kernel/module.c
index 98d476920106..001cbfa10ac6 100644
--- a/arch/tile/kernel/module.c
+++ b/arch/tile/kernel/module.c
@@ -159,7 +159,17 @@ int apply_relocate_add(Elf_Shdr *sechdrs,
 
                 switch (ELF_R_TYPE(rel[i].r_info)) {
 
-#define MUNGE(func) (*location = ((*location & ~func(-1)) | func(value)))
+#ifdef __LITTLE_ENDIAN
+# define MUNGE(func) \
+        (*location = ((*location & ~func(-1)) | func(value)))
+#else
+/*
+ * Instructions are always little-endian, so when we read them as data,
+ * we have to swap them around before and after modifying them.
+ */
+# define MUNGE(func) \
+        (*location = swab64((swab64(*location) & ~func(-1)) | func(value)))
+#endif
 
 #ifndef __tilegx__
                 case R_TILE_32:
diff --git a/arch/tile/kernel/single_step.c b/arch/tile/kernel/single_step.c
index 89529c9f0605..27742e87e255 100644
--- a/arch/tile/kernel/single_step.c
+++ b/arch/tile/kernel/single_step.c
@@ -172,9 +172,6 @@ static tile_bundle_bits rewrite_load_store_unaligned(
                 return (tilepro_bundle_bits) 0;
         }
 
-#ifndef __LITTLE_ENDIAN
-# error We assume little-endian representation with copy_xx_user size 2 here
-#endif
         /* Handle unaligned load/store */
         if (mem_op == MEMOP_LOAD || mem_op == MEMOP_LOAD_POSTINCR) {
                 unsigned short val_16;
@@ -195,8 +192,19 @@ static tile_bundle_bits rewrite_load_store_unaligned(
                         state->update = 1;
                 }
         } else {
+                unsigned short val_16;
                 val = (val_reg == TREG_ZERO) ? 0 : regs->regs[val_reg];
-                err = copy_to_user(addr, &val, size);
+                switch (size) {
+                case 2:
+                        val_16 = val;
+                        err = copy_to_user(addr, &val_16, sizeof(val_16));
+                        break;
+                case 4:
+                        err = copy_to_user(addr, &val, sizeof(val));
+                        break;
+                default:
+                        BUG();
+                }
         }
 
         if (err) {