2019-XX-XX Christophe Lyon <christophe.lyon@st.com>
Mickaël Guêné <mickael.guene@st.com>
libgcc/
* unwind-arm-common.inc (ARM_SET_R7_RT_SIGRETURN)
(THUMB2_SET_R7_RT_SIGRETURN, FDPIC_LDR_R12_WITH_FUNCDESC)
(FDPIC_LDR_R9_WITH_GOT, FDPIC_LDR_PC_WITH_RESTORER)
(FDPIC_FUNCDESC_OFFSET, ARM_NEW_RT_SIGFRAME_UCONTEXT)
(ARM_UCONTEXT_SIGCONTEXT, ARM_SIGCONTEXT_R0,
FDPIC_T2_LDR_R12_WITH_FUNCDESC)
(FDPIC_T2_LDR_R9_WITH_GOT, FDPIC_T2_LDR_PC_WITH_RESTORER): New.
(__gnu_personality_sigframe_fdpic): New.
(get_eit_entry): Add FDPIC signal frame support.
Change-Id: I7f9527cc50665dd1a731b7badf71c319fb38bf57
diff --git a/libgcc/unwind-arm-common.inc b/libgcc/unwind-arm-common.inc
index 0bacc11..c9a82b7 100644
--- a/libgcc/unwind-arm-common.inc
+++ b/libgcc/unwind-arm-common.inc
@@ -30,6 +30,26 @@
#include <sys/sdt.h>
#endif
+#if __FDPIC__
+/* Load r7 with rt_sigreturn value. */
+#define ARM_SET_R7_RT_SIGRETURN 0xe3a070ad /* mov r7, #0xad */
+#define THUMB2_SET_R7_RT_SIGRETURN 0x07adf04f /* mov.w r7,
#0xad */
+
+/* FDPIC jump to restorer sequence. */
+#define FDPIC_LDR_R12_WITH_FUNCDESC 0xe59fc004 /* ldr r12,
[pc, #4] */
+#define FDPIC_LDR_R9_WITH_GOT 0xe59c9004 /* ldr r9,
[r12, #4] */
+#define FDPIC_LDR_PC_WITH_RESTORER 0xe59cf000 /* ldr pc,
[r12] */
+#define FDPIC_T2_LDR_R12_WITH_FUNCDESC 0xc008f8df /* ldr.w r12,
[pc, #8] */
+#define FDPIC_T2_LDR_R9_WITH_GOT 0x9004f8dc /* ldr.w r9,
[r12, #4] */
+#define FDPIC_T2_LDR_PC_WITH_RESTORER 0xf000f8dc /* ldr.w pc,
[r12] */
+#define FDPIC_FUNCDESC_OFFSET 12
+
+/* Signal frame offsets. */
+#define ARM_NEW_RT_SIGFRAME_UCONTEXT 0x80
+#define ARM_UCONTEXT_SIGCONTEXT 0x14
+#define ARM_SIGCONTEXT_R0 0xc
+#endif
+
/* We add a prototype for abort here to avoid creating a dependency on
target headers. */
extern void abort (void);
@@ -199,6 +219,45 @@ search_EIT_table (const __EIT_entry * table, int
nrec, _uw return_address)
}
}
+#if __FDPIC__
+/* VFP is not restored, but this is sufficient to allow unwinding. */
+static _Unwind_Reason_Code
+__gnu_personality_sigframe_fdpic (_Unwind_State state,
+ _Unwind_Control_Block *ucbp,
+ _Unwind_Context *context)
+{
+ unsigned int sp;
+ unsigned int pc;
+ unsigned int funcdesc;
+ unsigned int handler;
+ unsigned int first_handler_instruction;
+ int i;
+
+ _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 & ~1) + FDPIC_FUNCDESC_OFFSET);
+ handler = *(unsigned int *)(funcdesc);
+ first_handler_instruction = *(unsigned int *)(handler & ~1);
+
+ /* Adjust SP to point to the start of registers according to
+ signal type. */
+ if (first_handler_instruction == ARM_SET_R7_RT_SIGRETURN
+ || first_handler_instruction == THUMB2_SET_R7_RT_SIGRETURN)
+ sp += ARM_NEW_RT_SIGFRAME_UCONTEXT
+ + ARM_UCONTEXT_SIGCONTEXT
+ + ARM_SIGCONTEXT_R0;
+ else
+ sp += ARM_UCONTEXT_SIGCONTEXT
+ + ARM_SIGCONTEXT_R0;
+ /* Restore regs saved on stack by the kernel. */
+ for (i = 0; i < 16; i++)
+ _Unwind_VRS_Set (context, _UVRSC_CORE, i, _UVRSD_UINT32, sp +
4 * i);
+
+ return _URC_CONTINUE_UNWIND;
+}
+#endif
+
/* Find the exception index table eintry for the given address.
Fill in the relevant fields of the UCB.
Returns _URC_FAILURE if an error occurred, _URC_OK on success. */
@@ -222,6 +281,27 @@ get_eit_entry (_Unwind_Control_Block *ucbp, _uw
return_address)
&nrec);
if (!eitp)
{
+#if __FDPIC__
+ /* 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) & ~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;
+
+ UCB_PR_ADDR (ucbp) = funcdesc->ptr;
+ UCB_PR_GOT (ucbp) = funcdesc->got;
+
+ return _URC_OK;
+ }
+#endif
UCB_PR_ADDR (ucbp) = 0;
return _URC_FAILURE;
}
@@ -236,6 +316,27 @@ get_eit_entry (_Unwind_Control_Block *ucbp, _uw
return_address)
if (!eitp)
{
+#if __FDPIC__
+ /* 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) & ~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;
+
+ UCB_PR_ADDR (ucbp) = funcdesc->ptr;
+ UCB_PR_GOT (ucbp) = funcdesc->got;
+
+ return _URC_OK;
+ }
+#endif
UCB_PR_ADDR (ucbp) = 0;
return _URC_FAILURE;
}
@@ -244,6 +345,27 @@ get_eit_entry (_Unwind_Control_Block *ucbp, _uw
return_address)
/* Can this frame be unwound at all? */
if (eitp->content == EXIDX_CANTUNWIND)
{
+#if __FDPIC__
+ /* 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) & ~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;
+
+ UCB_PR_ADDR (ucbp) = funcdesc->ptr;
+ UCB_PR_GOT (ucbp) = funcdesc->got;
+
+ return _URC_OK;
+ }
+#endif
UCB_PR_ADDR (ucbp) = 0;
return _URC_END_OF_STACK;
}
--
2.6.3