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Diffstat (limited to 'gcc-4.9/gcc/ada/sigtramp-armvxw.c')
| -rw-r--r-- | gcc-4.9/gcc/ada/sigtramp-armvxw.c | 250 |
1 files changed, 250 insertions, 0 deletions
diff --git a/gcc-4.9/gcc/ada/sigtramp-armvxw.c b/gcc-4.9/gcc/ada/sigtramp-armvxw.c new file mode 100644 index 000000000..176be21b8 --- /dev/null +++ b/gcc-4.9/gcc/ada/sigtramp-armvxw.c @@ -0,0 +1,250 @@ +/**************************************************************************** + * * + * GNAT COMPILER COMPONENTS * + * * + * S I G T R A M P * + * * + * Asm Implementation File * + * * + * Copyright (C) 2013, Free Software Foundation, Inc. * + * * + * GNAT is free software; you can redistribute it and/or modify it under * + * terms of the GNU General Public License as published by the Free Soft- * + * ware Foundation; either version 3, or (at your option) any later ver- * + * sion. GNAT is distributed in the hope that it will be useful, but WITH- * + * OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY * + * or FITNESS FOR A PARTICULAR PURPOSE. * + * * + * As a special exception under Section 7 of GPL version 3, you are granted * + * additional permissions described in the GCC Runtime Library Exception, * + * version 3.1, as published by the Free Software Foundation. * + * * + * In particular, you can freely distribute your programs built with the * + * GNAT Pro compiler, including any required library run-time units, using * + * any licensing terms of your choosing. See the AdaCore Software License * + * for full details. * + * * + * GNAT was originally developed by the GNAT team at New York University. * + * Extensive contributions were provided by Ada Core Technologies Inc. * + * * + ****************************************************************************/ + +/****************************************************** + * ARM-VxWorks version of the __gnat_sigtramp service * + ******************************************************/ + +#include "sigtramp.h" +/* See sigtramp.h for a general explanation of functionality. */ + +#include <vxWorks.h> +#include <arch/../regs.h> +#include <sigLib.h> + +/* ---------------------- + -- General comments -- + ---------------------- + + Stubs are generated from toplevel asms and .cfi directives, much simpler + to use and check for correctness than manual encodings of CFI byte + sequences. The general idea is to establish CFA as sigcontext->sc_pregs + and state where to find the registers as offsets from there. + + As of today, we support a single stub, providing CFI info for common + registers (GPRs, LR, ...). We might need variants with support for floating + point or altivec registers as well at some point. + + Checking which variant should apply and getting at sc_pregs is simpler + to express in C (we can't use offsetof in toplevel asms and hardcoding + constants is not workable with the flurry of VxWorks variants), so this + is the choice for our toplevel interface. + + Note that the registers we "restore" here are those to which we have + direct access through the system sigcontext structure, which includes + only a partial set of the non-volatiles ABI-wise. */ + +/* ----------------------------------------- + -- Protypes for our internal asm stubs -- + ----------------------------------------- + + SC_PREGS is always expected to be SIGCONTEXT->sc_pregs. Eventhough our + symbols will remain local, the prototype claims "extern" and not + "static" to prevent compiler complaints about a symbol used but never + defined. */ + +/* sigtramp stub providing CFI info for common registers. */ + +extern void __gnat_sigtramp_common +(int signo, void *siginfo, void *sigcontext, + sighandler_t * handler, void * sc_pregs); + + +/* ------------------------------------- + -- Common interface implementation -- + ------------------------------------- + + We enforce optimization to minimize the overhead of the extra layer. */ + +void __gnat_sigtramp (int signo, void *si, void *sc, + sighandler_t * handler) + __attribute__((optimize(2))); + +void __gnat_sigtramp (int signo, void *si, void *sc, + sighandler_t * handler) +{ + struct sigcontext * sctx = (struct sigcontext *) sc; + + __gnat_sigtramp_common (signo, si, sctx, handler, sctx->sc_pregs); +} + + +/* --------------------------- + -- And now the asm stubs -- + --------------------------- + + They all have a common structure with blocks of asm sequences queued one + after the others. Typically: + + SYMBOL_START + + CFI_DIRECTIVES + CFI_DEF_CFA, + CFI_COMMON_REGISTERS, + ... + + STUB_BODY + asm code to establish frame, setup the cfa reg value, + call the real signal handler, ... + + SYMBOL_END +*/ + +/*-------------------------------- + -- Misc constants and helpers -- + -------------------------------- */ + +/* REGNO constants, dwarf column numbers for registers of interest. */ + +#define REGNO_G_REG_OFFSET(N) (N) + +#define REGNO_PC_OFFSET 15 /* PC_REGNUM */ + +/* asm string construction helpers. */ + +#define STR(TEXT) #TEXT +/* stringify expanded TEXT, surrounding it with double quotes. */ + +#define S(E) STR(E) +/* stringify E, which will resolve as text but may contain macros + still to be expanded. */ + +/* asm (TEXT) outputs <tab>TEXT. These facilitate the output of + multine contents: */ +#define TAB(S) "\t" S +#define CR(S) S "\n" + +#undef TCR +#define TCR(S) TAB(CR(S)) + +/*------------------------------ + -- Stub construction blocks -- + ------------------------------ */ + +/* CFA setup block + --------------- + Only non-volatile registers are suitable for a CFA base. These are the + only ones we can expect to be able retrieve from the unwinding context + while walking up the chain, saved by at least the bottom-most exception + propagation services. We use r8 here and set it to the value we need + in stub body that follows. Any of r4-r8 should work. */ + +#define CFA_REG 8 + +#define CFI_DEF_CFA \ +CR(".cfi_def_cfa " S(CFA_REG) ", 0") + +/* Register location blocks + ------------------------ + Rules to find registers of interest from the CFA. This should comprise + all the non-volatile registers relevant to the interrupted context. */ + +#define COMMON_CFI(REG) \ + ".cfi_offset " S(REGNO_##REG) "," S(REG_SET_##REG) + +#define CFI_COMMON_REGS \ +CR("# CFI for common registers\n") \ +TCR(COMMON_CFI(G_REG_OFFSET(0))) \ +TCR(COMMON_CFI(G_REG_OFFSET(1))) \ +TCR(COMMON_CFI(G_REG_OFFSET(2))) \ +TCR(COMMON_CFI(G_REG_OFFSET(3))) \ +TCR(COMMON_CFI(G_REG_OFFSET(4))) \ +TCR(COMMON_CFI(G_REG_OFFSET(5))) \ +TCR(COMMON_CFI(G_REG_OFFSET(6))) \ +TCR(COMMON_CFI(G_REG_OFFSET(7))) \ +TCR(COMMON_CFI(G_REG_OFFSET(8))) \ +TCR(COMMON_CFI(G_REG_OFFSET(9))) \ +TCR(COMMON_CFI(G_REG_OFFSET(10))) \ +TCR(COMMON_CFI(G_REG_OFFSET(11))) \ +TCR(COMMON_CFI(G_REG_OFFSET(12))) \ +TCR(COMMON_CFI(G_REG_OFFSET(13))) \ +TCR(COMMON_CFI(G_REG_OFFSET(14))) \ +TCR(COMMON_CFI(PC_OFFSET)) \ +TCR(".cfi_return_column " S(REGNO_PC_OFFSET)) + +/* Trampoline body block + --------------------- */ + +#define SIGTRAMP_BODY \ +CR("") \ +TCR("# Allocate frame and save the non-volatile") \ +TCR("# registers we're going to modify") \ +TCR("mov ip, sp") \ +TCR("stmfd sp!, {r"S(CFA_REG)", fp, ip, lr, pc}") \ +TCR("# Setup CFA_REG = sc_pregs, that we'll retrieve as our CFA value") \ +TCR("ldr r"S(CFA_REG)", [ip]") \ +TCR("") \ +TCR("# Call the real handler. The signo, siginfo and sigcontext") \ +TCR("# arguments are the same as those we received in r0, r1 and r2") \ +TCR("sub fp, ip, #4") \ +TCR("blx r3") \ +TCR("# Restore our callee-saved items, release our frame and return") \ +TCR("ldmfd sp, {r"S(CFA_REG)", fp, sp, pc}") + + +/* Symbol definition block + ----------------------- */ + +#define SIGTRAMP_START(SYM) \ +CR("# " S(SYM) " cfi trampoline") \ +TCR(".type " S(SYM) ", %function") \ +CR("") \ +CR(S(SYM) ":") \ +TCR(".cfi_startproc") \ +TCR(".cfi_signal_frame") + +/* Symbol termination block + ------------------------ */ + +#define SIGTRAMP_END(SYM) \ +CR(".cfi_endproc") \ +TCR(".size " S(SYM) ", .-" S(SYM)) + +/*---------------------------- + -- And now, the real code -- + ---------------------------- */ + +/* Text section start. The compiler isn't aware of that switch. */ + +asm (".text\n" + TCR(".align 2")); + +/* sigtramp stub for common registers. */ + +#define TRAMP_COMMON __gnat_sigtramp_common + +asm (SIGTRAMP_START(TRAMP_COMMON)); +asm (CFI_DEF_CFA); +asm (CFI_COMMON_REGS); +asm (SIGTRAMP_BODY); +asm (SIGTRAMP_END(TRAMP_COMMON)); + + |