| Message ID | 20190515124006.25840-12-christophe.lyon@st.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | FDPIC ABI for ARM | expand |
Hi Christophe, On 5/15/19 1:39 PM, Christophe Lyon wrote: > 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. > At this point I'm looking that the code is FDPIC-specific and thus won't break other targets. I'll have to trust your testing that this is correct for FDPIC. Ok. Thanks, Kyrill > 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 >
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; }