[ARM/FDPIC 13/21] [ARM] FDPIC: Support unwinding across thumb2 signal trampoline

[Christophe Lyon]

2018-XX-XX  Christophe Lyon  <christophe.lyon@st.com>
	Mickaël Guêné <mickael.guene@st.com>

	libgcc/
	* unwind-arm-common.inc (FDPIC_T2_LDR_R12_WITH_FUNCDESC)
	(FDPIC_T2_LDR_R9_WITH_GOT, FDPIC_T2_LDR_PC_WITH_RESTORER): New.
	(__gnu_personality_sigframe_fdpic): Support Thumb address.
	(get_eit_entry): Support Thumb code.

Change-Id: I2bb8994e733e48a89c6f4e0682921186c086f8bc

diff --git a/libgcc/unwind-arm-common.inc b/libgcc/unwind-arm-common.inc
index 80d1e88..7de4033 100644
--- a/libgcc/unwind-arm-common.inc
+++ b/libgcc/unwind-arm-common.inc
@@ -38,6 +38,9 @@
 #define FDPIC_LDR_R12_WITH_FUNCDESC	0xe59fc004
 #define FDPIC_LDR_R9_WITH_GOT		0xe59c9004
 #define FDPIC_LDR_PC_WITH_RESTORER	0xe59cf000
+#define FDPIC_T2_LDR_R12_WITH_FUNCDESC  0xc008f8df
+#define FDPIC_T2_LDR_R9_WITH_GOT	0x9004f8dc
+#define FDPIC_T2_LDR_PC_WITH_RESTORER   0xf000f8dc
 #define FDPIC_FUNCDESC_OFFSET		12
 /* Signal frame offsets.  */
 #define ARM_NEW_RT_SIGFRAME_UCONTEXT	0x80
@@ -228,7 +231,7 @@ __gnu_personality_sigframe_fdpic (_Unwind_State state,
     _Unwind_VRS_Get (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32, &sp);
     _Unwind_VRS_Get (context, _UVRSC_CORE, R_PC, _UVRSD_UINT32, &pc);
 
-    funcdesc = *(unsigned int *)(pc + FDPIC_FUNCDESC_OFFSET);
+    funcdesc = *(unsigned int *)((pc & ~1) + FDPIC_FUNCDESC_OFFSET);
     handler = *(unsigned int *)(funcdesc);
     first_handler_instruction = *(unsigned int *)(handler & ~1);
 
@@ -277,10 +280,13 @@ get_eit_entry (_Unwind_Control_Block *ucbp, _uw return_address)
 	  /* If we are unwinding a signal handler then perhaps we have
 	     reached a trampoline.  Try to detect jump to restorer
 	     sequence.  */
-	  _uw *pc = (_uw *)((return_address+2) & ~3);
-	  if (pc[0] == FDPIC_LDR_R12_WITH_FUNCDESC
-	      && pc[1] == FDPIC_LDR_R9_WITH_GOT
-	      && pc[2] == FDPIC_LDR_PC_WITH_RESTORER)
+	  _uw *pc = (_uw *)((return_address+2) & ~1);
+	  if ((pc[0] == FDPIC_LDR_R12_WITH_FUNCDESC
+	       && pc[1] == FDPIC_LDR_R9_WITH_GOT
+	       && pc[2] == FDPIC_LDR_PC_WITH_RESTORER)
+	      || (pc[0] == FDPIC_T2_LDR_R12_WITH_FUNCDESC
+		  && pc[1] == FDPIC_T2_LDR_R9_WITH_GOT
+		  && pc[2] == FDPIC_T2_LDR_PC_WITH_RESTORER))
 	    {
 	      struct funcdesc_t *funcdesc = (struct funcdesc_t *)
 		&__gnu_personality_sigframe_fdpic;
@@ -309,13 +315,16 @@ get_eit_entry (_Unwind_Control_Block *ucbp, _uw return_address)
       /* If we are unwinding a signal handler then perhaps we have
 	 reached a trampoline.  Try to detect jump to restorer
 	 sequence.  */
-      _uw *pc = (_uw *)((return_address+2) & ~3);
-      if (pc[0] == FDPIC_LDR_R12_WITH_FUNCDESC
-	  && pc[1] == FDPIC_LDR_R9_WITH_GOT
-	  && pc[2] == FDPIC_LDR_PC_WITH_RESTORER)
+      _uw *pc = (_uw *)((return_address+2) & ~1);
+      if ((pc[0] == FDPIC_LDR_R12_WITH_FUNCDESC
+	   && pc[1] == FDPIC_LDR_R9_WITH_GOT
+	   && pc[2] == FDPIC_LDR_PC_WITH_RESTORER)
+	  || (pc[0] == FDPIC_T2_LDR_R12_WITH_FUNCDESC
+	      && pc[1] == FDPIC_T2_LDR_R9_WITH_GOT
+	      && pc[2] == FDPIC_T2_LDR_PC_WITH_RESTORER))
 	{
-	  struct funcdesc_t *funcdesc = (struct funcdesc_t *)
-	    &__gnu_personality_sigframe_fdpic;
+	  struct funcdesc_t *funcdesc
+	    = (struct funcdesc_t *) &__gnu_personality_sigframe_fdpic;
 
 	  UCB_PR_ADDR (ucbp) = funcdesc->ptr;
 	  UCB_PR_GOT (ucbp) = funcdesc->got;
@@ -335,13 +344,16 @@ get_eit_entry (_Unwind_Control_Block *ucbp, _uw return_address)
       /* If we are unwinding a signal handler then perhaps we have
 	 reached a trampoline.  Try to detect jump to restorer
 	 sequence.  */
-      _uw *pc = (_uw *)((return_address+2) & ~3);
-      if (pc[0] == FDPIC_LDR_R12_WITH_FUNCDESC
-	  && pc[1] == FDPIC_LDR_R9_WITH_GOT
-	  && pc[2] == FDPIC_LDR_PC_WITH_RESTORER)
+      _uw *pc = (_uw *)((return_address+2) & ~1);
+      if ((pc[0] == FDPIC_LDR_R12_WITH_FUNCDESC
+	   && pc[1] == FDPIC_LDR_R9_WITH_GOT
+	   && pc[2] == FDPIC_LDR_PC_WITH_RESTORER)
+	  || (pc[0] == FDPIC_T2_LDR_R12_WITH_FUNCDESC
+	      && pc[1] == FDPIC_T2_LDR_R9_WITH_GOT
+	      && pc[2] == FDPIC_T2_LDR_PC_WITH_RESTORER))
 	{
-	  struct funcdesc_t *funcdesc = (struct funcdesc_t *)
-	    &__gnu_personality_sigframe_fdpic;
+	  struct funcdesc_t *funcdesc
+	    = (struct funcdesc_t *) &__gnu_personality_sigframe_fdpic;
 
 	  UCB_PR_ADDR (ucbp) = funcdesc->ptr;
 	  UCB_PR_GOT (ucbp) = funcdesc->got;
-- 
2.6.3