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/*
* This software is part of the SBCL system. See the README file for
* more information.
*
* This software is derived from the CMU CL system, which was
* written at Carnegie Mellon University and released into the
* public domain. The software is in the public domain and is
* provided with absolutely no warranty. See the COPYING and CREDITS
* files for more information.
*/
#include <stdio.h>
#include "sbcl.h"
#include "runtime.h"
#include "globals.h"
#include "validate.h"
#include "os.h"
#include "arch.h"
#include "lispregs.h"
#include "alloc.h"
#include "interrupt.h"
#include "interr.h"
#include "breakpoint.h"
#include "thread.h"
#include "pseudo-atomic.h"
#include "genesis/static-symbols.h"
#include "genesis/symbol.h"
#define BREAKPOINT_INST 0xcc /* INT3 */
#define UD2_INST 0x0b0f /* UD2 */
#ifndef LISP_FEATURE_UD2_BREAKPOINTS
#define BREAKPOINT_WIDTH 1
#else
#define BREAKPOINT_WIDTH 2
#endif
void arch_init(void)
{}
#ifndef LISP_FEATURE_WIN32
os_vm_address_t
arch_get_bad_addr(int sig, siginfo_t *code, os_context_t *context)
{
return (os_vm_address_t)code->si_addr;
}
#endif
/*
* hacking signal contexts
*
* (This depends both on architecture, which determines what we might
* want to get to, and on OS, which determines how we get to it.)
*/
int *
context_eflags_addr(os_context_t *context)
{
#if defined __linux__ || defined __sun
/* KLUDGE: As of kernel 2.2.14 on Red Hat 6.2, there's code in the
* <sys/ucontext.h> file to define symbolic names for offsets into
* gregs[], but it's conditional on __USE_GNU and not defined, so
* we need to do this nasty absolute index magic number thing
* instead. */
return &context->uc_mcontext.gregs[16];
#elif defined(__FreeBSD__) || defined(__DragonFly__)
return &context->uc_mcontext.mc_eflags;
#elif defined __OpenBSD__
return &context->sc_eflags;
#elif defined LISP_FEATURE_DARWIN
return (int *)(&context->uc_mcontext->SS.EFLAGS);
#elif defined __NetBSD__
return &(context->uc_mcontext.__gregs[_REG_EFL]);
#elif defined LISP_FEATURE_WIN32
return (int *)&context->win32_context->EFlags;
#else
#error unsupported OS
#endif
}
void arch_skip_instruction(os_context_t *context)
{
/* Assuming we get here via an INT3 xxx instruction, the PC now
* points to the interrupt code (a Lisp value) so we just move
* past it. Skip the code; after that, if the code is an
* error-trap or cerror-trap then skip the data bytes that follow. */
int vlen;
int code;
/* Get and skip the Lisp interrupt code. */
code = *(char*)(*os_context_pc_addr(context))++;
switch (code)
{
case trap_Error:
case trap_Cerror:
/* Lisp error arg vector length */
vlen = *(char*)(*os_context_pc_addr(context))++;
/* Skip Lisp error arg data bytes. */
while (vlen-- > 0) {
++*os_context_pc_addr(context);
}
break;
case trap_Breakpoint: /* not tested */
case trap_FunEndBreakpoint: /* not tested */
break;
#ifdef LISP_FEATURE_SB_SAFEPOINT
case trap_GlobalSafepoint:
case trap_CspSafepoint:
#endif
case trap_PendingInterrupt:
case trap_Halt:
case trap_SingleStepAround:
case trap_SingleStepBefore:
/* only needed to skip the Code */
break;
default:
fprintf(stderr,"[arch_skip_inst invalid code %d\n]\n",code);
break;
}
FSHOW((stderr,
"/[arch_skip_inst resuming at %x]\n",
*os_context_pc_addr(context)));
}
unsigned char *
arch_internal_error_arguments(os_context_t *context)
{
return 1 + (unsigned char *)(*os_context_pc_addr(context));
}
boolean
arch_pseudo_atomic_atomic(os_context_t *context)
{
return get_pseudo_atomic_atomic(arch_os_get_current_thread());
}
void
arch_set_pseudo_atomic_interrupted(os_context_t *context)
{
struct thread *thread = arch_os_get_current_thread();
set_pseudo_atomic_interrupted(thread);
}
void
arch_clear_pseudo_atomic_interrupted(os_context_t *context)
{
struct thread *thread = arch_os_get_current_thread();
clear_pseudo_atomic_interrupted(thread);
}
/*
* This stuff seems to get called for TRACE and debug activity.
*/
unsigned int
arch_install_breakpoint(void *pc)
{
unsigned int result = *(unsigned int*)pc;
#ifndef LISP_FEATURE_UD2_BREAKPOINTS
*(char*)pc = BREAKPOINT_INST; /* x86 INT3 */
*((char*)pc+1) = trap_Breakpoint; /* Lisp trap code */
#else
*(char*)pc = UD2_INST & 0xff;
*((char*)pc+1) = UD2_INST >> 8;
*((char*)pc+2) = trap_Breakpoint;
#endif
return result;
}
void
arch_remove_breakpoint(void *pc, unsigned int orig_inst)
{
*((char *)pc) = orig_inst & 0xff;
*((char *)pc + 1) = (orig_inst & 0xff00) >> 8;
#if BREAKPOINT_WIDTH > 1
*((char *)pc + 2) = (orig_inst & 0xff0000) >> 16;
#endif
}
/* When single stepping, single_stepping holds the original instruction
* PC location. */
unsigned int *single_stepping = NULL;
#ifdef CANNOT_GET_TO_SINGLE_STEP_FLAG
unsigned int single_step_save1;
unsigned int single_step_save2;
unsigned int single_step_save3;
#endif
void
arch_do_displaced_inst(os_context_t *context, unsigned int orig_inst)
{
unsigned int *pc = (unsigned int*)(*os_context_pc_addr(context));
/* Put the original instruction back. */
arch_remove_breakpoint(pc, orig_inst);
#ifdef CANNOT_GET_TO_SINGLE_STEP_FLAG
/* Install helper instructions for the single step:
* pushf; or [esp],0x100; popf. */
single_step_save1 = *(pc-3);
single_step_save2 = *(pc-2);
single_step_save3 = *(pc-1);
*(pc-3) = 0x9c909090;
*(pc-2) = 0x00240c81;
*(pc-1) = 0x9d000001;
#else
*context_eflags_addr(context) |= 0x100;
#endif
single_stepping = pc;
#ifdef CANNOT_GET_TO_SINGLE_STEP_FLAG
*os_context_pc_addr(context) = (os_context_register_t)((char *)pc - 9);
#endif
}
void
restore_breakpoint_from_single_step(os_context_t * context)
{
/* fprintf(stderr,"* single step trap %x\n", single_stepping); */
#ifdef CANNOT_GET_TO_SINGLE_STEP_FLAG
/* Un-install single step helper instructions. */
*(single_stepping-3) = single_step_save1;
*(single_stepping-2) = single_step_save2;
*(single_stepping-1) = single_step_save3;
#else
*context_eflags_addr(context) &= ~0x100;
#endif
/* Re-install the breakpoint if possible. */
if (((char *)*os_context_pc_addr(context) >
(char *)single_stepping) &&
((char *)*os_context_pc_addr(context) <=
(char *)single_stepping + BREAKPOINT_WIDTH)) {
fprintf(stderr, "warning: couldn't reinstall breakpoint\n");
} else {
arch_install_breakpoint(single_stepping);
}
single_stepping = NULL;
return;
}
void
arch_handle_breakpoint(os_context_t *context)
{
*os_context_pc_addr(context) -= BREAKPOINT_WIDTH;
handle_breakpoint(context);
}
void
arch_handle_fun_end_breakpoint(os_context_t *context)
{
*os_context_pc_addr(context) -= BREAKPOINT_WIDTH;
*os_context_pc_addr(context) =
(int)handle_fun_end_breakpoint(context);
}
void
arch_handle_single_step_trap(os_context_t *context, int trap)
{
arch_skip_instruction(context);
/* On x86 the fdefn / function is always in EAX, so we pass 0
* as the register_offset. */
handle_single_step_trap(context, trap, 0);
}
#ifndef LISP_FEATURE_WIN32
void
sigtrap_handler(int signal, siginfo_t *info, os_context_t *context)
{
unsigned int trap;
if (single_stepping) {
restore_breakpoint_from_single_step(context);
return;
}
/* This is just for info in case the monitor wants to print an
* approximation. */
access_control_stack_pointer(arch_os_get_current_thread()) =
(lispobj *)*os_context_sp_addr(context);
#ifdef LISP_FEATURE_SUNOS
/* For some reason the breakpoints that :ENCAPSULATE NIL tracing sets up
* cause a trace trap (i.e. processor single-stepping trap) on the following
* instruction on Solaris 10/x86. -- JES, 2006-04-07
*/
if (info->si_code == TRAP_TRACE) {
lose("foo");
return;
}
#endif
/* On entry %eip points just after the INT3 byte and aims at the
* 'kind' value (eg trap_Cerror). For error-trap and Cerror-trap a
* number of bytes will follow, the first is the length of the byte
* arguments to follow. */
trap = *(unsigned char *)(*os_context_pc_addr(context));
handle_trap(context, trap);
}
void
sigill_handler(int signal, siginfo_t *siginfo, os_context_t *context) {
/* Triggering SIGTRAP using int3 is unreliable on OS X/x86, so
* we need to use illegal instructions for traps.
*/
#if defined(LISP_FEATURE_UD2_BREAKPOINTS) && !defined(LISP_FEATURE_MACH_EXCEPTION_HANDLER)
if (*((unsigned short *)*os_context_pc_addr(context)) == UD2_INST) {
*os_context_pc_addr(context) += 2;
return sigtrap_handler(signal, siginfo, context);
}
#endif
fake_foreign_function_call(context);
lose("Unhandled SIGILL");
}
#endif /* not LISP_FEATURE_WIN32 */
void
arch_install_interrupt_handlers()
{
SHOW("entering arch_install_interrupt_handlers()");
/* Note: The old CMU CL code here used sigtrap_handler() to handle
* SIGILL as well as SIGTRAP. I couldn't see any reason to do
* things that way. So, I changed to separate handlers when
* debugging a problem on OpenBSD, where SBCL wasn't catching
* SIGILL properly, but was instead letting the process be
* terminated with an "Illegal instruction" output. If this change
* turns out to break something (maybe breakpoint handling on some
* OS I haven't tested on?) and we have to go back to the old CMU
* CL way, I hope there will at least be a comment to explain
* why.. -- WHN 2001-06-07 */
#if !defined(LISP_FEATURE_WIN32) && !defined(LISP_FEATURE_MACH_EXCEPTION_HANDLER)
undoably_install_low_level_interrupt_handler(SIGILL , sigill_handler);
undoably_install_low_level_interrupt_handler(SIGTRAP, sigtrap_handler);
#endif
SHOW("returning from arch_install_interrupt_handlers()");
}
#ifdef LISP_FEATURE_LINKAGE_TABLE
/* FIXME: It might be cleaner to generate these from the lisp side of
* things.
*/
void
arch_write_linkage_table_jmp(char * reloc, void * fun)
{
/* Make JMP to function entry. JMP offset is calculated from next
* instruction.
*/
long offset = (char *)fun - (reloc + 5);
int i;
*reloc++ = 0xe9; /* opcode for JMP rel32 */
for (i = 0; i < 4; i++) {
*reloc++ = offset & 0xff;
offset >>= 8;
}
/* write a nop for good measure. */
*reloc = 0x90;
}
void
arch_write_linkage_table_ref(void * reloc, void * data)
{
*(unsigned long *)reloc = (unsigned long)data;
}
#endif