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[/] [openrisc/] [trunk/] [gnu-dev/] [or1k-gcc/] [gcc/] [ada/] [sigtramp-ppcvxw.c] - Blame information for rev 706

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1 706 jeremybenn
/****************************************************************************
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 *                                                                          *
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 *                         GNAT COMPILER COMPONENTS                         *
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 *                                                                          *
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 *                             S I G T R A M P                              *
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 *                                                                          *
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 *                         Asm Implementation File                          *
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 *                                                                          *
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 *         Copyright (C) 2011-2012, Free Software Foundation, Inc.          *
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 *                                                                          *
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 * GNAT is free software;  you can  redistribute it  and/or modify it under *
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 * terms of the  GNU General Public License as published  by the Free Soft- *
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 * ware  Foundation;  either version 3,  or (at your option) any later ver- *
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 * sion.  GNAT is distributed in the hope that it will be useful, but WITH- *
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 * OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY *
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 * or FITNESS FOR A PARTICULAR PURPOSE.                                     *
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 *                                                                          *
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 * As a special exception under Section 7 of GPL version 3, you are granted *
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 * additional permissions described in the GCC Runtime Library Exception,   *
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 * version 3.1, as published by the Free Software Foundation.               *
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 *                                                                          *
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 * You should have received a copy of the GNU General Public License and    *
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 * a copy of the GCC Runtime Library Exception along with this program;     *
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 * see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    *
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 * <http://www.gnu.org/licenses/>.                                          *
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 *                                                                          *
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 * GNAT was originally developed  by the GNAT team at  New York University. *
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 * Extensive contributions were provided by Ada Core Technologies Inc.      *
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 *                                                                          *
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 ****************************************************************************/
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/**********************************************************
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 * PowerPC-VxWorks version of the __gnat_sigtramp service *
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 **********************************************************/
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#include "sigtramp.h"
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#include <vxWorks.h>
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#include <arch/../regs.h>
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#include <sigLib.h>
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/* ----------------------
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   -- General comments --
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   ----------------------
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   Stubs are generated from toplevel asms and .cfi directives, much simpler
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   to use and check for correctness than manual encodings of CFI byte
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   sequences.  The general idea is to establish CFA as sigcontext->sc_pregs
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   and state where to find the registers as offsets from there.
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   As of today, we support a single stub, providing CFI info for common
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   registers (GPRs, LR, ...). We might need variants with support for floating
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   point or altivec registers as well at some point.
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   Checking which variant should apply and getting at sc_pregs is simpler
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   to express in C (we can't use offsetof in toplevel asms and hardcoding
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   constants is not workable with the flurry of VxWorks variants), so this
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   is the choice for our toplevel interface.
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   Note that the registers we "restore" here are those to which we have
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   direct access through the system sigcontext structure, which includes
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   only a partial set of the non-volatiles ABI-wise.  */
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/* -----------------------------------------
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   -- Protypes for our internal asm stubs --
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   -----------------------------------------
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   SC_PREGS is always expected to be SIGCONTEXT->sc_pregs.  Eventhough our
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   symbols will remain local, the prototype claims "extern" and not
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   "static" to prevent compiler complaints about a symbol used but never
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   defined.  */
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/* sigtramp stub providing CFI info for common registers.  */
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extern void __gnat_sigtramp_common
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(int signo, void *siginfo, void *sigcontext,
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 sighandler_t * handler, void * sc_pregs);
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/* -------------------------------------
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   -- Common interface implementation --
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   -------------------------------------
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   We enforce optimization to minimize the overhead of the extra layer.  */
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void __gnat_sigtramp (int signo, void *si, void *sc,
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                      sighandler_t * handler)
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     __attribute__((optimize(2)));
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void __gnat_sigtramp (int signo, void *si, void *sc,
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                      sighandler_t * handler)
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{
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  struct sigcontext * sctx = (struct sigcontext *) sc;
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  __gnat_sigtramp_common (signo, si, sctx, handler, sctx->sc_pregs);
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}
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/* ---------------------------
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   -- And now the asm stubs --
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   ---------------------------
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   They all have a common structure with blocks of asm sequences queued one
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   after the others.  Typically:
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   SYMBOL_START
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   CFI_DIRECTIVES
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     CFI_DEF_CFA,
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     CFI_COMMON_REGISTERS,
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     ...
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   STUB_BODY
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     asm code to establish frame, setup the cfa reg value,
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     call the real signal handler, ...
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   SYMBOL_END
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*/
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/*--------------------------------
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  -- Misc constants and helpers --
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  -------------------------------- */
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/* REGNO constants, dwarf column numbers for registers of interest.  */
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#define REGNO_LR  65
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#define REGNO_CTR 66
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#define REGNO_CR  70
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#define REGNO_XER 76
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#define REGNO_GR(N) (N)
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#define REGNO_PC  67  /* ARG_POINTER_REGNUM  */
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/* asm string contruction helpers.  */
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#define STR(TEXT) #TEXT
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/* stringify expanded TEXT, surrounding it with double quotes.  */
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#define S(E) STR(E)
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/* stringify E, which will resolve as text but may contain macros
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   still to be expanded.  */
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/* asm (TEXT) outputs <tab>TEXT. These facilitate the output of
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   multine contents:  */
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#define TAB(S) "\t" S
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#define CR(S)  S "\n"
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#undef TCR
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#define TCR(S) TAB(CR(S))
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/*------------------------------
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  -- Stub construction blocks --
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  ------------------------------ */
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/* CFA setup block
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   ---------------
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   Only non-volatile registers are suitable for a CFA base. These are the
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   only ones we can expect to be able retrieve from the unwinding context
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   while walking up the chain, saved by at least the bottom-most exception
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   propagation services.  We use r15 here and set it to the value we need
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   in stub body that follows.  Note that r14 is inappropriate here, even
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   though it is non-volatile according to the ABI, because GCC uses it as
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   an extra SCRATCH on SPE targets.  */
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#define CFA_REG 15
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#define CFI_DEF_CFA \
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CR(".cfi_def_cfa " S(CFA_REG) ", 0")
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/* Register location blocks
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   ------------------------
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   Rules to find registers of interest from the CFA. This should comprise
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   all the non-volatile registers relevant to the interrupted context.
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   Note that we include r1 in this set, unlike the libgcc unwinding
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   fallbacks.  This is useful for fallbacks to allow the use of r1 in CFI
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   expressions and the absence of rule for r1 gets compensated by using the
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   target CFA instead.  We don't need the expression facility here and
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   setup a fake CFA to allow very simple offset expressions, so having a
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   rule for r1 is the proper thing to do.  We for sure have observed
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   crashes in some cases without it.  */
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#define COMMON_CFI(REG) \
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  ".cfi_offset " S(REGNO_##REG) "," S(REG_SET_##REG)
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#define CFI_COMMON_REGS \
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CR("# CFI for common registers\n") \
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TCR(COMMON_CFI(GR(1)))  \
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TCR(COMMON_CFI(GR(2)))  \
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TCR(COMMON_CFI(GR(3)))  \
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TCR(COMMON_CFI(GR(4)))  \
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TCR(COMMON_CFI(GR(5)))  \
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TCR(COMMON_CFI(GR(6)))  \
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TCR(COMMON_CFI(GR(7)))  \
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TCR(COMMON_CFI(GR(8)))  \
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TCR(COMMON_CFI(GR(9)))  \
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TCR(COMMON_CFI(GR(10)))  \
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TCR(COMMON_CFI(GR(11)))  \
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TCR(COMMON_CFI(GR(12)))  \
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TCR(COMMON_CFI(GR(13)))  \
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TCR(COMMON_CFI(GR(14))) \
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TCR(COMMON_CFI(GR(15))) \
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TCR(COMMON_CFI(GR(16))) \
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TCR(COMMON_CFI(GR(17))) \
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TCR(COMMON_CFI(GR(18))) \
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TCR(COMMON_CFI(GR(19))) \
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TCR(COMMON_CFI(GR(20))) \
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TCR(COMMON_CFI(GR(21))) \
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TCR(COMMON_CFI(GR(22))) \
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TCR(COMMON_CFI(GR(23))) \
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TCR(COMMON_CFI(GR(24))) \
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TCR(COMMON_CFI(GR(25))) \
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TCR(COMMON_CFI(GR(26))) \
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TCR(COMMON_CFI(GR(27))) \
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TCR(COMMON_CFI(GR(28))) \
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TCR(COMMON_CFI(GR(29))) \
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TCR(COMMON_CFI(GR(30))) \
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TCR(COMMON_CFI(GR(31))) \
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TCR(COMMON_CFI(LR)) \
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TCR(COMMON_CFI(CR)) \
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TCR(COMMON_CFI(CTR)) \
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TCR(COMMON_CFI(XER)) \
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TCR(COMMON_CFI(PC)) \
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TCR(".cfi_return_column " S(REGNO_PC))
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/* Trampoline body block
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   ---------------------  */
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#define SIGTRAMP_BODY \
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CR("") \
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TCR("# Allocate frame and save the non-volatile") \
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TCR("# registers we're going to modify") \
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TCR("stwu %r1,-16(%r1)")  \
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TCR("mflr %r0") \
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TCR("stw %r0,20(%r1)")  \
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TCR("stw %r" S(CFA_REG) ",8(%r1)")      \
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TCR("")                 \
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TCR("# Setup CFA_REG = sc_pregs, that we'll retrieve as our CFA value") \
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TCR("mr %r" S(CFA_REG) ", %r7") \
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TCR("")                 \
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TCR("# Call the real handler. The signo, siginfo and sigcontext") \
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TCR("# arguments are the same as those we received in r3, r4 and r5") \
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TCR("mtctr %r6") \
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TCR("bctrl")    \
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TCR("")         \
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TCR("# Restore our callee-saved items, release our frame and return") \
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TCR("lwz %r" S(CFA_REG) ",8(%r1)")      \
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TCR("lwz %r0,20(%r1)")  \
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TCR("mtlr %r0")         \
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TCR("")                 \
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TCR("addi %r1,%r1,16")  \
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TCR("blr")
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/* Symbol definition block
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   -----------------------  */
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#define SIGTRAMP_START(SYM) \
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CR("# " S(SYM) " cfi trampoline") \
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TCR(".type " S(SYM) ", @function") \
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CR("") \
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CR(S(SYM) ":") \
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TCR(".cfi_startproc") \
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TCR(".cfi_signal_frame")
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/* Symbol termination block
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   ------------------------  */
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#define SIGTRAMP_END(SYM) \
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CR(".cfi_endproc") \
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TCR(".size " S(SYM) ", .-" S(SYM))
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/*----------------------------
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  -- And now, the real code --
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  ---------------------------- */
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/* Text section start.  The compiler isn't aware of that switch.  */
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278
asm (".text\n"
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     TCR(".align 2"));
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/* sigtramp stub for common registers.  */
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#define TRAMP_COMMON __gnat_sigtramp_common
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asm (SIGTRAMP_START(TRAMP_COMMON));
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asm (CFI_DEF_CFA);
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asm (CFI_COMMON_REGS);
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asm (SIGTRAMP_BODY);
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asm (SIGTRAMP_END(TRAMP_COMMON));
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