sparc: Handle negative offsets in arch_jump_label_transform

Additionally, if the offset will overflow the immediate for a ba,pt
instruction, fall back on a standard ba to get an extra 3 bits.

Signed-off-by: James Clarke <jrtc27@jrtc27.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/arch/sparc/kernel/jump_label.c b/arch/sparc/kernel/jump_label.c
index 59bbeff..07933b9 100644 (file)
--- a/arch/sparc/kernel/jump_label.c
+++ b/arch/sparc/kernel/jump_label.c
@@ -13,19 +13,30 @@
 void arch_jump_label_transform(struct jump_entry *entry,
                               enum jump_label_type type)
 {
-       u32 val;
        u32 *insn = (u32 *) (unsigned long) entry->code;
+       u32 val;
 
        if (type == JUMP_LABEL_JMP) {
                s32 off = (s32)entry->target - (s32)entry->code;
+               bool use_v9_branch = false;
+
+               BUG_ON(off & 3);
 
 #ifdef CONFIG_SPARC64
-               /* ba,pt %xcc, . + (off << 2) */
-               val = 0x10680000 | ((u32) off >> 2);
-#else
-               /* ba . + (off << 2) */
-               val = 0x10800000 | ((u32) off >> 2);
+               if (off <= 0xfffff && off >= -0x100000)
+                       use_v9_branch = true;
 #endif
+               if (use_v9_branch) {
+                       /* WDISP19 - target is . + immed << 2 */
+                       /* ba,pt %xcc, . + off */
+                       val = 0x10680000 | (((u32) off >> 2) & 0x7ffff);
+               } else {
+                       /* WDISP22 - target is . + immed << 2 */
+                       BUG_ON(off > 0x7fffff);
+                       BUG_ON(off < -0x800000);
+                       /* ba . + off */
+                       val = 0x10800000 | (((u32) off >> 2) & 0x3fffff);
+               }
        } else {
                val = 0x01000000;
        }