/* Common unwinding code for ARM EABI and C6X.
- Copyright (C) 2004, 2005, 2009, 2011 Free Software Foundation, Inc.
+ Copyright (C) 2004-2020 Free Software Foundation, Inc.
Contributed by Paul Brook
This file is free software; you can redistribute it and/or modify it
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
<http://www.gnu.org/licenses/>. */
+#include "tconfig.h"
+#include "tsystem.h"
#include "unwind.h"
+/* Used for SystemTap unwinder probe. */
+#ifdef HAVE_SYS_SDT_H
+#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);
#define UCB_PR_ADDR(ucbp) ((ucbp)->unwinder_cache.reserved2)
#define UCB_SAVED_CALLSITE_ADDR(ucbp) ((ucbp)->unwinder_cache.reserved3)
#define UCB_FORCED_STOP_ARG(ucbp) ((ucbp)->unwinder_cache.reserved4)
+#define UCB_PR_GOT(ucbp) ((ucbp)->unwinder_cache.reserved5)
/* Unwind descriptors. */
_uw content;
} __EIT_entry;
+#ifdef __FDPIC__
+
+/* Only used in FDPIC case. */
+struct funcdesc_t
+{
+ unsigned int ptr;
+ unsigned int got;
+};
+#endif
+
/* Assembly helper functions. */
/* Restore core register state. Never returns. */
static _uw __gnu_unwind_get_pr_addr (int idx);
+static void _Unwind_DebugHook (void *, void *)
+ __attribute__ ((__noinline__, __used__, __noclone__));
+
+/* This function is called during unwinding. It is intended as a hook
+ for a debugger to intercept exceptions. CFA is the CFA of the
+ target frame. HANDLER is the PC to which control will be
+ transferred. */
+
+static void
+_Unwind_DebugHook (void *cfa __attribute__ ((__unused__)),
+ void *handler __attribute__ ((__unused__)))
+{
+ /* We only want to use stap probes starting with v3. Earlier
+ versions added too much startup cost. */
+#if defined (HAVE_SYS_SDT_H) && defined (STAP_PROBE2) && _SDT_NOTE_TYPE >= 3
+ STAP_PROBE2 (libgcc, unwind, cfa, handler);
+#else
+ asm ("");
+#endif
+}
+
+/* This is a wrapper to be called when we need to restore core registers.
+ It will call `_Unwind_DebugHook' before restoring the registers, thus
+ making it possible to intercept and debug exceptions.
+
+ When calling `_Unwind_DebugHook', the first argument (the CFA) is zero
+ because we are not interested in it. However, it must be there (even
+ being zero) because GDB expects to find it when using the probe. */
+
+#define uw_restore_core_regs(TARGET, CORE) \
+ do \
+ { \
+ void *handler = __builtin_frob_return_addr ((void *) VRS_PC (TARGET)); \
+ _Unwind_DebugHook (0, handler); \
+ restore_core_regs (CORE); \
+ } \
+ while (0)
+
/* Perform a binary search for RETURN_ADDRESS in TABLE. The table contains
NREC entries. */
}
}
+#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. */
&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;
}
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;
}
/* 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;
}
{
/* One of the predefined standard routines. */
_uw idx = (*(_uw *) ucbp->pr_cache.ehtp >> 24) & 0xf;
+#if __FDPIC__
+ {
+ struct funcdesc_t *funcdesc
+ = (struct funcdesc_t *) __gnu_unwind_get_pr_addr (idx);
+ if (funcdesc)
+ {
+ UCB_PR_ADDR (ucbp) = funcdesc->ptr;
+ UCB_PR_GOT (ucbp) = funcdesc->got;
+ }
+ else
+ UCB_PR_ADDR (ucbp) = 0;
+ }
+#else
UCB_PR_ADDR (ucbp) = __gnu_unwind_get_pr_addr (idx);
+#endif
if (UCB_PR_ADDR (ucbp) == 0)
{
/* Failed */
{
/* Execute region offset to PR */
UCB_PR_ADDR (ucbp) = selfrel_offset31 (ucbp->pr_cache.ehtp);
+#if __FDPIC__
+ UCB_PR_GOT (ucbp)
+ = (unsigned int) _Unwind_gnu_Find_got ((_Unwind_Ptr) UCB_PR_ADDR (ucbp));
+#endif
}
return _URC_OK;
}
UCB_SAVED_CALLSITE_ADDR (ucbp) = VRS_PC(vrs);
/* Call the pr to decide what to do. */
+#if __FDPIC__
+ {
+ volatile struct funcdesc_t funcdesc;
+ funcdesc.ptr = UCB_PR_ADDR (ucbp);
+ funcdesc.got = UCB_PR_GOT (ucbp);
+ pr_result = ((personality_routine) &funcdesc)
+ (_US_UNWIND_FRAME_STARTING, ucbp, (_Unwind_Context *) vrs);
+ }
+#else
pr_result = ((personality_routine) UCB_PR_ADDR (ucbp))
(_US_UNWIND_FRAME_STARTING, ucbp, (_Unwind_Context *) vrs);
+#endif
}
while (pr_result == _URC_CONTINUE_UNWIND);
if (pr_result != _URC_INSTALL_CONTEXT)
abort();
-
- restore_core_regs (&vrs->core);
+
+#if __FDPIC__
+ /* r9 could have been lost due to PLT jump. Restore correct value. */
+ vrs->core.r[FDPIC_REGNUM] = _Unwind_gnu_Find_got (VRS_PC (vrs));
+#endif
+
+ uw_restore_core_regs (vrs, &vrs->core);
}
/* Perform phase2 forced unwinding. */
next_vrs = saved_vrs;
/* Call the pr to decide what to do. */
+#if __FDPIC__
+ {
+ volatile struct funcdesc_t funcdesc;
+ funcdesc.ptr = UCB_PR_ADDR (ucbp);
+ funcdesc.got = UCB_PR_GOT (ucbp);
+ pr_result = ((personality_routine) &funcdesc)
+ (action, ucbp, (void *) &next_vrs);
+ }
+#else
pr_result = ((personality_routine) UCB_PR_ADDR (ucbp))
(action, ucbp, (void *) &next_vrs);
+#endif
saved_vrs.prev_sp = VRS_SP (&next_vrs);
}
return _URC_FAILURE;
}
- restore_core_regs (&saved_vrs.core);
+#if __FDPIC__
+ /* r9 could have been lost due to PLT jump. Restore correct value. */
+ saved_vrs.core.r[FDPIC_REGNUM] = _Unwind_gnu_Find_got (VRS_PC (&saved_vrs));
+#endif
+
+ uw_restore_core_regs (&saved_vrs, &saved_vrs.core);
}
/* This is a very limited implementation of _Unwind_GetCFA. It returns
return _URC_FAILURE;
/* Call the pr to decide what to do. */
+#if __FDPIC__
+ {
+ volatile struct funcdesc_t funcdesc;
+ funcdesc.ptr = UCB_PR_ADDR (ucbp);
+ funcdesc.got = UCB_PR_GOT (ucbp);
+ pr_result = ((personality_routine) &funcdesc)
+ (_US_VIRTUAL_UNWIND_FRAME, ucbp, (void *) &saved_vrs);
+ }
+#else
pr_result = ((personality_routine) UCB_PR_ADDR (ucbp))
(_US_VIRTUAL_UNWIND_FRAME, ucbp, (void *) &saved_vrs);
+#endif
}
while (pr_result == _URC_CONTINUE_UNWIND);
}
/* Call the cached PR. */
+#if __FDPIC__
+ {
+ volatile struct funcdesc_t funcdesc;
+ funcdesc.ptr = UCB_PR_ADDR (ucbp);
+ funcdesc.got = UCB_PR_GOT (ucbp);
+ pr_result = ((personality_routine) &funcdesc)
+ (_US_UNWIND_FRAME_RESUME, ucbp, (_Unwind_Context *) entry_vrs);
+ }
+#else
pr_result = ((personality_routine) UCB_PR_ADDR (ucbp))
(_US_UNWIND_FRAME_RESUME, ucbp, (_Unwind_Context *) entry_vrs);
+#endif
switch (pr_result)
{
case _URC_INSTALL_CONTEXT:
/* Upload the registers to enter the landing pad. */
- restore_core_regs (&entry_vrs->core);
+#if __FDPIC__
+ /* r9 could have been lost due to PLT jump. Restore correct value. */
+ entry_vrs->core.r[FDPIC_REGNUM] = _Unwind_gnu_Find_got (VRS_PC (entry_vrs));
+#endif
+ uw_restore_core_regs (entry_vrs, &entry_vrs->core);
case _URC_CONTINUE_UNWIND:
/* Continue unwinding the next frame. */
}
/* Call the pr to decide what to do. */
+#if __FDPIC__
+ {
+ volatile struct funcdesc_t funcdesc;
+ funcdesc.ptr = UCB_PR_ADDR (ucbp);
+ funcdesc.got = UCB_PR_GOT (ucbp);
+ code = ((personality_routine) &funcdesc)
+ (_US_VIRTUAL_UNWIND_FRAME | _US_FORCE_UNWIND,
+ ucbp, (void *) &saved_vrs);
+ }
+#else
code = ((personality_routine) UCB_PR_ADDR (ucbp))
(_US_VIRTUAL_UNWIND_FRAME | _US_FORCE_UNWIND,
ucbp, (void *) &saved_vrs);
+#endif
}
while (code != _URC_END_OF_STACK
&& code != _URC_FAILURE);
uws.words_left = 0;
uws.bytes_left = 3;
}
- else
+ else if (id < 3)
{
uws.words_left = (uws.data >> 16) & 0xff;
uws.data <<= 16;
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