46374a6932
On Genode/Fiasco.OC, when an unresolved page fault occurs, only the IP and SP registers are valid in the thread state read by GDB monitor. This was not taken into account so far and the other (possibly outdated) register values got reported to the client, too. With this patch, only IP and SP get reported to the client in the page fault case. Fixes #1063.
157 lines
6.8 KiB
C++
157 lines
6.8 KiB
C++
/*
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* \brief Fiasco.OC(x86_32)-specific helper functions for GDB server
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* \author Christian Prochaska
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* \date 2011-05-06
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*/
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/*
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* Copyright (C) 2011-2013 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 General Public License version 2.
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*/
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extern "C" {
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#define private _private
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#include "genode-low.h"
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#define _private private
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}
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#include <base/printf.h>
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#include "i386.h"
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#include "cpu_session_component.h"
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#include "gdbserver_platform_helper.h"
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#include "gdb_stub_thread.h"
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#undef PDBG
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#define PDBG(...)
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using namespace Genode;
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static bool in_syscall(Thread_state const &thread_state)
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{
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/* looking for syscall pattern:
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* EIP-7: 55 push %ebp
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* EIP-6: ff 93 call ...
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* EIP: 5d pop %ebp
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*/
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if ((genode_read_memory_byte((void*)(thread_state.ip)) == 0x5d) &&
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(genode_read_memory_byte((void*)(thread_state.ip - 5)) == 0x93) &&
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(genode_read_memory_byte((void*)(thread_state.ip - 6)) == 0xff) &&
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(genode_read_memory_byte((void*)(thread_state.ip - 7)) == 0x55))
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return true;
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return false;
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}
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extern "C" int genode_fetch_register(int regno, unsigned long *reg_content)
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{
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Thread_state thread_state;
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try { thread_state = get_current_thread_state(); }
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catch (...) { return 0; }
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if (in_syscall(thread_state) || thread_state.unresolved_page_fault) {
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switch((enum reg_index)regno)
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{
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case EAX: PDBG("cannot determine contents of register EAX"); return -1;
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case ECX: PDBG("cannot determine contents of register ECX"); return -1;
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case EDX: PDBG("cannot determine contents of register EDX"); return -1;
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case EBX:
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if (in_syscall(thread_state)) {
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/* When in a syscall, the user EBX has been pushed onto the stack at address ESP+4 */
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*reg_content = genode_read_memory_byte((void*)(thread_state.sp + 4)) +
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(genode_read_memory_byte((void*)(thread_state.sp + 5)) << 8) +
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(genode_read_memory_byte((void*)(thread_state.sp + 6)) << 16) +
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(genode_read_memory_byte((void*)(thread_state.sp + 7)) << 24);
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PDBG("EBX = %8lx", *reg_content);
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return 0;
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} else {
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PDBG("cannot determine contents of register EBX"); return -1;
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}
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case UESP: *reg_content = thread_state.sp; PDBG("ESP = %8lx", *reg_content); return 0;
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case EBP:
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if (in_syscall(thread_state)) {
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/* When in a syscall, the user EBP has been pushed onto the stack at address ESP+0 */
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*reg_content = genode_read_memory_byte((void*)(thread_state.sp + 0)) +
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(genode_read_memory_byte((void*)(thread_state.sp + 1)) << 8) +
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(genode_read_memory_byte((void*)(thread_state.sp + 2)) << 16) +
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(genode_read_memory_byte((void*)(thread_state.sp + 3)) << 24);
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PDBG("EBP = %8lx", *reg_content);
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return 0;
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} else {
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PDBG("cannot determine contents of register EBP"); return -1;
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}
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case ESI: PDBG("cannot determine contents of register ESI"); return -1;
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case EDI: PDBG("cannot determine contents of register EDI"); return -1;
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case EIP: *reg_content = thread_state.ip; PDBG("EIP = %8lx", *reg_content); return 0;
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case EFL: PDBG("cannot determine contents of register EFLAGS"); return -1;
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case CS: PDBG("cannot determine contents of register CS"); return -1;
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case SS: PDBG("cannot determine contents of register SS"); return -1;
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case DS: PDBG("cannot determine contents of register DS"); return -1;
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case ES: PDBG("cannot determine contents of register ES"); return -1;
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case FS: PDBG("cannot determine contents of register FS"); return -1;
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case GS: PDBG("cannot determine contents of register GS"); return -1;
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}
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} else {
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switch((enum reg_index)regno)
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{
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case EAX: *reg_content = thread_state.eax; PDBG("EAX = %8lx", *reg_content); return 0;
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case ECX: *reg_content = thread_state.ecx; PDBG("ECX = %8lx", *reg_content); return 0;
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case EDX: *reg_content = thread_state.edx; PDBG("EDX = %8lx", *reg_content); return 0;
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case EBX: *reg_content = thread_state.ebx; PDBG("EBX = %8lx", *reg_content); return 0;
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case UESP: *reg_content = thread_state.sp; PDBG("ESP = %8lx", *reg_content); return 0;
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case EBP: *reg_content = thread_state.ebp; PDBG("EBP = %8lx", *reg_content); return 0;
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case ESI: *reg_content = thread_state.esi; PDBG("ESI = %8lx", *reg_content); return 0;
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case EDI: *reg_content = thread_state.edi; PDBG("EDI = %8lx", *reg_content); return 0;
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case EIP: *reg_content = thread_state.ip; PDBG("EIP = %8lx", *reg_content); return 0;
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case EFL: *reg_content = thread_state.eflags; PDBG("EFLAGS = %8lx", *reg_content); return 0;
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case CS: PDBG("cannot determine contents of register CS"); return -1;
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case SS: PDBG("cannot determine contents of register SS"); return -1;
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case DS: PDBG("cannot determine contents of register DS"); return -1;
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case ES: PDBG("cannot determine contents of register ES"); return -1;
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case FS: *reg_content = thread_state.fs; PDBG("FS = %8lx", *reg_content); return 0;
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case GS: *reg_content = thread_state.gs; PDBG("GS = %8lx", *reg_content); return 0;
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}
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}
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return -1;
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}
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extern "C" void genode_store_register(int regno, unsigned long reg_content)
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{
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Thread_state thread_state;
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try { thread_state = get_current_thread_state(); }
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catch (...) { return; }
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if (in_syscall(thread_state)) {
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PDBG("cannot set registers while thread is in syscall");
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return;
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}
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switch((enum reg_index)regno)
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{
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case EAX: thread_state.eax = reg_content; PDBG("EAX = %8lx", reg_content); break;
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case ECX: thread_state.ecx = reg_content; PDBG("ECX = %8lx", reg_content); break;
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case EDX: thread_state.edx = reg_content; PDBG("EDX = %8lx", reg_content); break;
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case EBX: thread_state.ebx = reg_content; PDBG("EBX = %8lx", reg_content); break;
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case UESP: thread_state.sp = reg_content; PDBG("ESP = %8lx", reg_content); break;
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case EBP: thread_state.ebp = reg_content; PDBG("EBP = %8lx", reg_content); break;
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case ESI: thread_state.esi = reg_content; PDBG("ESI = %8lx", reg_content); break;
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case EDI: thread_state.edi = reg_content; PDBG("EDI = %8lx", reg_content); break;
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case EIP: thread_state.ip = reg_content; PDBG("EIP = %8lx", reg_content); break;
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case EFL: thread_state.eflags = reg_content; PDBG("EFL = %8lx", reg_content); break;
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case CS: PDBG("cannot set contents of register CS"); PDBG(" CS = %8lx", reg_content); break;
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case SS: PDBG("cannot set contents of register SS"); PDBG(" SS = %8lx", reg_content); break;
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case DS: PDBG("cannot set contents of register DS"); PDBG(" DS = %8lx", reg_content); break;
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case ES: PDBG("cannot set contents of register ES"); PDBG(" ES = %8lx", reg_content); break;
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case FS: thread_state.fs = reg_content; PDBG(" FS = %8lx", reg_content); break;
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case GS: thread_state.gs = reg_content; PDBG(" GS = %8lx", reg_content); break;
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}
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set_current_thread_state(thread_state);
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}
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