91 lines
2.1 KiB
C++
91 lines
2.1 KiB
C++
/*
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* \brief Thread-environment support common to all programs
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* \author Martin Stein
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* \date 2013-12-13
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*/
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/*
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* Copyright (C) 2013-2017 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU Affero General Public License version 3.
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*/
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/* Genode includes */
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#include <base/stdint.h>
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#include <base/env.h>
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#include <base/log.h>
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#include <linux_syscalls.h>
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using namespace Genode;
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extern addr_t * __initial_sp;
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/*
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* Define 'lx_environ' pointer.
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*/
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char **lx_environ;
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/**
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* Natively aligned memory location used in the lock implementation
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*/
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int main_thread_futex_counter __attribute__((aligned(sizeof(addr_t))));
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/**
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* Signal handler for exceptions like segmentation faults
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*/
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void exception_signal_handler(int signum)
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{
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char const *reason = nullptr;
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switch (signum) {
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case LX_SIGILL: reason = "Illegal instruction"; break;
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case LX_SIGBUS: reason = "Bad memory access"; break;
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case LX_SIGFPE: reason = "Floating point exception"; break;
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case LX_SIGSEGV: reason = "Segmentation fault"; break;
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default: /* unexpected signal */ return;
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}
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raw(reason, " (signum=", signum, "), see Linux kernel log for details");
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/*
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* We reset the signal handler to SIG_DFL and trigger exception again,
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* i.e., terminate the process.
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*/
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lx_sigaction(signum, nullptr, false);
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return;
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}
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void lx_exception_signal_handlers()
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{
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/* use alternate stack in fatal-signal handlers */
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lx_sigaction(LX_SIGILL, exception_signal_handler, true);
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lx_sigaction(LX_SIGBUS, exception_signal_handler, true);
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lx_sigaction(LX_SIGFPE, exception_signal_handler, true);
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lx_sigaction(LX_SIGSEGV, exception_signal_handler, true);
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}
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/*****************************
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** Startup library support **
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*****************************/
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void prepare_init_main_thread()
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{
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/*
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* Initialize the 'lx_environ' pointer
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*
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* environ = &argv[argc + 1]
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* __initial_sp[0] = argc (always 1 in Genode)
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* __initial_sp[1] = argv[0]
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* __initial_sp[2] = NULL
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* __initial_sp[3] = environ
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*/
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lx_environ = (char**)&__initial_sp[3];
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lx_exception_signal_handlers();
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}
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