From 6999173410bac7ed473dcb0261a24bb5d50aeea6 Mon Sep 17 00:00:00 2001 From: Doug Rupp Date: Fri, 8 Apr 2022 11:28:48 -0700 Subject: [PATCH] [Ada] arm-qnx-7.1: stack-checking and sigtramp implementation Rewrite and base on VxWorks RTP implementation. gcc/ada/ * sigtramp-arm-qnx.c: Rewrite. --- gcc/ada/sigtramp-arm-qnx.c | 79 +++++++++++++++++++++------------------------- 1 file changed, 36 insertions(+), 43 deletions(-) diff --git a/gcc/ada/sigtramp-arm-qnx.c b/gcc/ada/sigtramp-arm-qnx.c index 4d359d7b290..24a3b64dbf1 100644 --- a/gcc/ada/sigtramp-arm-qnx.c +++ b/gcc/ada/sigtramp-arm-qnx.c @@ -6,7 +6,7 @@ * * * Asm Implementation File * * * - * Copyright (C) 2015-2022, Free Software Foundation, Inc. * + * Copyright (C) 2011-2022, 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- * @@ -33,49 +33,44 @@ * ARM-QNX version of the __gnat_sigtramp service * **************************************************/ +#include #include #include "sigtramp.h" /* See sigtramp.h for a general explanation of functionality. */ -/* ---------------------- - -- General comments -- - ---------------------- +/* ------------------------------------------- + -- Prototypes for our internal asm stubs -- + ------------------------------------------- - Stubs are generated from toplevel asms, - The general idea is to establish CFA as the sigcontext - and state where to find the registers as offsets from there. + Eventhough our symbols will remain local, the prototype claims "extern" + and not "static" to prevent compiler complaints about a symbol used but + never defined. */ - 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. */ +/* sigtramp stub providing ARM unwinding info for common registers. */ -/* ----------------------------------------- - -- Protypes for our internal asm stubs -- - ----------------------------------------- - - The registers are expected to be at SIGCONTEXT + 12 (reference the - sicontext structure in asm/sigcontext.h which describes the first - 3 * 4byte fields.) Even though our symbols will remain local, the - prototype claims "extern" and not "static" to prevent compiler complaints - about a symbol used but never defined. */ +extern void __gnat_sigtramp_common +(int signo, void *siginfo, void *sigcontext, + __sigtramphandler_t * handler, void * sc_pregs); -/* sigtramp stub providing unwind info for common registers. */ +/* ------------------------------------- + -- Common interface implementation -- + ------------------------------------- -extern void __gnat_sigtramp_common - (int signo, void *siginfo, void *sigcontext, - __sigtramphandler_t * handler); + We enforce optimization to minimize the overhead of the extra layer. */ void __gnat_sigtramp (int signo, void *si, void *sc, - __sigtramphandler_t * handler) + __sigtramphandler_t * handler) __attribute__((optimize(2))); -void __gnat_sigtramp (int signo, void *si, void *ucontext, - __sigtramphandler_t * handler) +void __gnat_sigtramp (int signo, void *si, void *sc, + __sigtramphandler_t * handler) { - struct sigcontext *mcontext = &((ucontext_t *) ucontext)->uc_mcontext; + mcontext_t *mcontext = &((ucontext_t *) sc)->uc_mcontext; - __gnat_sigtramp_common (signo, si, mcontext, handler); + /* Pass MCONTEXT in the fifth position so that the assembly code can find + it at the same stack location as SC_PREGS. */ + __gnat_sigtramp_common (signo, si, mcontext, handler, &mcontext->cpu); } /* asm string construction helpers. */ @@ -98,27 +93,25 @@ void __gnat_sigtramp (int signo, void *si, void *ucontext, /* Trampoline body block --------------------- */ +/* The 5 arguments passed to __gnat_sigtramp_common are located in: + - r0-r2: arguments to pass on to the actual handler + - r3: the actual handler + - sp: the address of the reg set to restore + All we have to do then is to instruct the unwinder to restore the registers + from the value in VSP. Unwinder instructions are executed backwards, so we + 1- instruct to pop r2 from the VSP (.save {r2}) + 2- move the VSP to the address pointed to by r2 (.movsp r2) + 3- restore all registers from there. (.save {r0-r15}) + Once the unwinding instructions are set, we just need to call the handler + as r0-r2 are already properly set. +*/ #define SIGTRAMP_BODY \ CR("") \ -TCR("# Allocate frame and also save r2 which is the argument register") \ -TCR("# containing the sigcontext, so that we can restore it during") \ -TCR("# unwinding and thereby load the rest of the desired context.") \ -TCR("stmfd sp!, {r2, r3, lr}") \ -TCR("# The unwinder undo's these operations in reverse order so starting") \ -TCR("# from bottom, restore r2 from the current vsp location, move r2 into") \ -TCR("# the vsp, add 12 bytes to get the start of the register save area") \ -TCR("# then restore the 15 general purpose registers of the frame which") \ -TCR("# raised the signal.") \ TCR(".save {r0-r15}") \ -TCR(".pad #12") \ TCR(".movsp r2") \ TCR(".save {r2}") \ -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("blx r3") \ -TCR("# Restore our callee-saved items, release our frame and return") \ -TCR("# (should never get here!).") \ -TCR("ldmfd sp, {r2, r3, pc}") +TCR("# No return here.") /* Symbol definition block ----------------------- */ -- 2.11.4.GIT