1 files changed, 11 insertions, 8 deletions

diff --git a/arch/arm/vfp/vfphw.S b/arch/arm/vfp/vfphw.S
index 2d30c7f6edd3..3a0efaad6090 100644
--- a/arch/arm/vfp/vfphw.S
+++ b/arch/arm/vfp/vfphw.S
@@ -61,13 +61,13 @@
 
 @ VFP hardware support entry point.
 @
-@  r0  = faulted instruction
-@  r2  = faulted PC+4
-@  r9  = successful return
+@  r0  = instruction opcode (32-bit ARM or two 16-bit Thumb)
+@  r2  = PC value to resume execution after successful emulation
+@  r9  = normal "successful" return address
 @  r10 = vfp_state union
 @  r11 = CPU number
-@  lr  = failure return
-
+@  lr  = unrecognised instruction return address
+@  IRQs enabled.
 ENTRY(vfp_support_entry)
         DBGSTR3 "instr %08x pc %08x state %p", r0, r2, r10
 
@@ -161,9 +161,12 @@ vfp_hw_state_valid:
                                         @ exception before retrying branch
                                         @ out before setting an FPEXC that
                                         @ stops us reading stuff
-        VFPFMXR FPEXC, r1               @ restore FPEXC last
-        sub     r2, r2, #4
-        str     r2, [sp, #S_PC]         @ retry the instruction
+        VFPFMXR FPEXC, r1               @ Restore FPEXC last
+        sub     r2, r2, #4              @ Retry current instruction - if Thumb
+        str     r2, [sp, #S_PC]         @ mode it's two 16-bit instructions,
+                                        @ else it's one 32-bit instruction, so
+                                        @ always subtract 4 from the following
+                                        @ instruction address.
 #ifdef CONFIG_PREEMPT
         get_thread_info r10
         ldr     r4, [r10, #TI_PREEMPT]  @ get preempt count