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[ARM/FDPIC v6 11/24] [ARM] FDPIC: Add support to unwind FDPIC signal frame

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2019-09-10  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.


Co-Authored-By: Mickaël Guêné <mickael.guene@st.com>

From-SVN: r275573
This commit is contained in:
Christophe Lyon 2019-09-10 09:55:20 +02:00 • committed by Christophe Lyon
parent e844c94f2a
commit ae1152e5a0
2 changed files with 135 additions and 0 deletions
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13
libgcc/ChangeLog
View file

@ -1,3 +1,16 @@
2019-09-10 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.
2019-09-10 Christophe Lyon <christophe.lyon@st.com>
Mickaël Guêné <mickael.guene@st.com>

122
libgcc/unwind-arm-common.inc
View file

@ -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;
}