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u-boot-brain/drivers/bios_emulator/x86emu/debug.c
Simon Glass b3521f2e49 bios_emulator: Add an option to enable debugging 
At present there are DEBUG options spread around the place. If you enable
one and not another you can end up with an emulator that does not work,
since each file can have a different view of what the registers look like.
To fix this, create a global CONFIG_X86EMU_DEBUG option that keeps
everything consistent.

Signed-off-by: Simon Glass <sjg@chromium.org>
2014-11-25 07:11:17 -07:00

462 lines
10 KiB
C
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/****************************************************************************
*
* Realmode X86 Emulator Library
*
* Copyright (C) 1991-2004 SciTech Software, Inc.
* Copyright (C) David Mosberger-Tang
* Copyright (C) 1999 Egbert Eich
*
* ========================================================================
*
* Permission to use, copy, modify, distribute, and sell this software and
* its documentation for any purpose is hereby granted without fee,
* provided that the above copyright notice appear in all copies and that
* both that copyright notice and this permission notice appear in
* supporting documentation, and that the name of the authors not be used
* in advertising or publicity pertaining to distribution of the software
* without specific, written prior permission. The authors makes no
* representations about the suitability of this software for any purpose.
* It is provided "as is" without express or implied warranty.
*
* THE AUTHORS DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
* EVENT SHALL THE AUTHORS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
* USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
* OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
* PERFORMANCE OF THIS SOFTWARE.
*
* ========================================================================
*
* Language: ANSI C
* Environment: Any
* Developer: Kendall Bennett
*
* Description: This file contains the code to handle debugging of the
* emulator.
*
****************************************************************************/
#include <stdarg.h>
#include <common.h>
#include <linux/ctype.h>
#include "x86emu/x86emui.h"
/*----------------------------- Implementation ----------------------------*/
#ifdef CONFIG_X86EMU_DEBUG
static void print_encoded_bytes(u16 s, u16 o);
static void print_decoded_instruction(void);
static int x86emu_parse_line(char *s, int *ps, int *n);
/* should look something like debug's output. */
void X86EMU_trace_regs(void)
{
if (DEBUG_TRACE()) {
x86emu_dump_regs();
}
if (DEBUG_DECODE() && !DEBUG_DECODE_NOPRINT()) {
printk("%04x:%04x ", M.x86.saved_cs, M.x86.saved_ip);
print_encoded_bytes(M.x86.saved_cs, M.x86.saved_ip);
print_decoded_instruction();
}
}
void X86EMU_trace_xregs(void)
{
if (DEBUG_TRACE()) {
x86emu_dump_xregs();
}
}
void x86emu_just_disassemble(void)
{
/*
* This routine called if the flag DEBUG_DISASSEMBLE is set kind
* of a hack!
*/
printk("%04x:%04x ", M.x86.saved_cs, M.x86.saved_ip);
print_encoded_bytes(M.x86.saved_cs, M.x86.saved_ip);
print_decoded_instruction();
}
static void disassemble_forward(u16 seg, u16 off, int n)
{
X86EMU_sysEnv tregs;
int i;
u8 op1;
/*
* hack, hack, hack. What we do is use the exact machinery set up
* for execution, except that now there is an additional state
* flag associated with the "execution", and we are using a copy
* of the register struct. All the major opcodes, once fully
* decoded, have the following two steps: TRACE_REGS(r,m);
* SINGLE_STEP(r,m); which disappear if DEBUG is not defined to
* the preprocessor. The TRACE_REGS macro expands to:
*
* if (debug&DEBUG_DISASSEMBLE)
* {just_disassemble(); goto EndOfInstruction;}
* if (debug&DEBUG_TRACE) trace_regs(r,m);
*
* ...... and at the last line of the routine.
*
* EndOfInstruction: end_instr();
*
* Up to the point where TRACE_REG is expanded, NO modifications
* are done to any register EXCEPT the IP register, for fetch and
* decoding purposes.
*
* This was done for an entirely different reason, but makes a
* nice way to get the system to help debug codes.
*/
tregs = M;
tregs.x86.R_IP = off;
tregs.x86.R_CS = seg;
/* reset the decoding buffers */
tregs.x86.enc_str_pos = 0;
tregs.x86.enc_pos = 0;
/* turn on the "disassemble only, no execute" flag */
tregs.x86.debug |= DEBUG_DISASSEMBLE_F;
/* DUMP NEXT n instructions to screen in straight_line fashion */
/*
* This looks like the regular instruction fetch stream, except
* that when this occurs, each fetched opcode, upon seeing the
* DEBUG_DISASSEMBLE flag set, exits immediately after decoding
* the instruction. XXX --- CHECK THAT MEM IS NOT AFFECTED!!!
* Note the use of a copy of the register structure...
*/
for (i = 0; i < n; i++) {
op1 = (*sys_rdb) (((u32) M.x86.R_CS << 4) + (M.x86.R_IP++));
(x86emu_optab[op1]) (op1);
}
/* end major hack mode. */
}
void x86emu_check_ip_access(void)
{
/* NULL as of now */
}
void x86emu_check_sp_access(void)
{
}
void x86emu_check_mem_access(u32 dummy)
{
/* check bounds, etc */
}
void x86emu_check_data_access(uint dummy1, uint dummy2)
{
/* check bounds, etc */
}
void x86emu_inc_decoded_inst_len(int x)
{
M.x86.enc_pos += x;
}
void x86emu_decode_printf(char *x)
{
sprintf(M.x86.decoded_buf + M.x86.enc_str_pos, "%s", x);
M.x86.enc_str_pos += strlen(x);
}
void x86emu_decode_printf2(char *x, int y)
{
char temp[100];
sprintf(temp, x, y);
sprintf(M.x86.decoded_buf + M.x86.enc_str_pos, "%s", temp);
M.x86.enc_str_pos += strlen(temp);
}
void x86emu_end_instr(void)
{
M.x86.enc_str_pos = 0;
M.x86.enc_pos = 0;
}
static void print_encoded_bytes(u16 s, u16 o)
{
int i;
char buf1[64];
for (i = 0; i < M.x86.enc_pos; i++) {
sprintf(buf1 + 2 * i, "%02x", fetch_data_byte_abs(s, o + i));
}
printk("%-20s", buf1);
}
static void print_decoded_instruction(void)
{
printk("%s", M.x86.decoded_buf);
}
void x86emu_print_int_vect(u16 iv)
{
u16 seg, off;
if (iv > 256)
return;
seg = fetch_data_word_abs(0, iv * 4);
off = fetch_data_word_abs(0, iv * 4 + 2);
printk("%04x:%04x ", seg, off);
}
void X86EMU_dump_memory(u16 seg, u16 off, u32 amt)
{
u32 start = off & 0xfffffff0;
u32 end = (off + 16) & 0xfffffff0;
u32 i;
while (end <= off + amt) {
printk("%04x:%04x ", seg, start);
for (i = start; i < off; i++)
printk(" ");
for (; i < end; i++)
printk("%02x ", fetch_data_byte_abs(seg, i));
printk("\n");
start = end;
end = start + 16;
}
}
void x86emu_single_step(void)
{
char s[1024];
int ps[10];
int ntok;
int cmd;
int done;
int segment;
int offset;
static int breakpoint;
static int noDecode = 1;
if (DEBUG_BREAK()) {
if (M.x86.saved_ip != breakpoint) {
return;
} else {
M.x86.debug &= ~DEBUG_DECODE_NOPRINT_F;
M.x86.debug |= DEBUG_TRACE_F;
M.x86.debug &= ~DEBUG_BREAK_F;
print_decoded_instruction();
X86EMU_trace_regs();
}
}
done = 0;
offset = M.x86.saved_ip;
while (!done) {
printk("-");
ps[1] = 0; /* Avoid dodgy compiler warnings */
ps[2] = 0;
cmd = x86emu_parse_line(s, ps, &ntok);
switch (cmd) {
case 'u':
disassemble_forward(M.x86.saved_cs, (u16) offset, 10);
break;
case 'd':
if (ntok == 2) {
segment = M.x86.saved_cs;
offset = ps[1];
X86EMU_dump_memory(segment, (u16) offset, 16);
offset += 16;
} else if (ntok == 3) {
segment = ps[1];
offset = ps[2];
X86EMU_dump_memory(segment, (u16) offset, 16);
offset += 16;
} else {
segment = M.x86.saved_cs;
X86EMU_dump_memory(segment, (u16) offset, 16);
offset += 16;
}
break;
case 'c':
M.x86.debug ^= DEBUG_TRACECALL_F;
break;
case 's':
M.x86.debug ^=
DEBUG_SVC_F | DEBUG_SYS_F | DEBUG_SYSINT_F;
break;
case 'r':
X86EMU_trace_regs();
break;
case 'x':
X86EMU_trace_xregs();
break;
case 'g':
if (ntok == 2) {
breakpoint = ps[1];
if (noDecode) {
M.x86.debug |= DEBUG_DECODE_NOPRINT_F;
} else {
M.x86.debug &= ~DEBUG_DECODE_NOPRINT_F;
}
M.x86.debug &= ~DEBUG_TRACE_F;
M.x86.debug |= DEBUG_BREAK_F;
done = 1;
}
break;
case 'q':
M.x86.debug |= DEBUG_EXIT;
return;
case 'P':
noDecode = (noDecode) ? 0 : 1;
printk("Toggled decoding to %s\n",
(noDecode) ? "false" : "true");
break;
case 't':
case 0:
done = 1;
break;
}
}
}
int X86EMU_trace_on(void)
{
return M.x86.debug |= DEBUG_STEP_F | DEBUG_DECODE_F | DEBUG_TRACE_F;
}
int X86EMU_trace_off(void)
{
return M.x86.debug &= ~(DEBUG_STEP_F | DEBUG_DECODE_F | DEBUG_TRACE_F);
}
static int x86emu_parse_line(char *s, int *ps, int *n)
{
int cmd;
*n = 0;
while (isblank(*s))
s++;
ps[*n] = *s;
switch (*s) {
case '\n':
*n += 1;
return 0;
default:
cmd = *s;
*n += 1;
}
while (1) {
while (!isblank(*s) && *s != '\n')
s++;
if (*s == '\n')
return cmd;
while (isblank(*s))
s++;
*n += 1;
}
}
#endif /* DEBUG */
void x86emu_dump_regs(void)
{
printk("\tAX=%04x ", M.x86.R_AX);
printk("BX=%04x ", M.x86.R_BX);
printk("CX=%04x ", M.x86.R_CX);
printk("DX=%04x ", M.x86.R_DX);
printk("SP=%04x ", M.x86.R_SP);
printk("BP=%04x ", M.x86.R_BP);
printk("SI=%04x ", M.x86.R_SI);
printk("DI=%04x\n", M.x86.R_DI);
printk("\tDS=%04x ", M.x86.R_DS);
printk("ES=%04x ", M.x86.R_ES);
printk("SS=%04x ", M.x86.R_SS);
printk("CS=%04x ", M.x86.R_CS);
printk("IP=%04x ", M.x86.R_IP);
if (ACCESS_FLAG(F_OF))
printk("OV "); /* CHECKED... */
else
printk("NV ");
if (ACCESS_FLAG(F_DF))
printk("DN ");
else
printk("UP ");
if (ACCESS_FLAG(F_IF))
printk("EI ");
else
printk("DI ");
if (ACCESS_FLAG(F_SF))
printk("NG ");
else
printk("PL ");
if (ACCESS_FLAG(F_ZF))
printk("ZR ");
else
printk("NZ ");
if (ACCESS_FLAG(F_AF))
printk("AC ");
else
printk("NA ");
if (ACCESS_FLAG(F_PF))
printk("PE ");
else
printk("PO ");
if (ACCESS_FLAG(F_CF))
printk("CY ");
else
printk("NC ");
printk("\n");
}
void x86emu_dump_xregs(void)
{
printk("\tEAX=%08x ", M.x86.R_EAX);
printk("EBX=%08x ", M.x86.R_EBX);
printk("ECX=%08x ", M.x86.R_ECX);
printk("EDX=%08x \n", M.x86.R_EDX);
printk("\tESP=%08x ", M.x86.R_ESP);
printk("EBP=%08x ", M.x86.R_EBP);
printk("ESI=%08x ", M.x86.R_ESI);
printk("EDI=%08x\n", M.x86.R_EDI);
printk("\tDS=%04x ", M.x86.R_DS);
printk("ES=%04x ", M.x86.R_ES);
printk("SS=%04x ", M.x86.R_SS);
printk("CS=%04x ", M.x86.R_CS);
printk("EIP=%08x\n\t", M.x86.R_EIP);
if (ACCESS_FLAG(F_OF))
printk("OV "); /* CHECKED... */
else
printk("NV ");
if (ACCESS_FLAG(F_DF))
printk("DN ");
else
printk("UP ");
if (ACCESS_FLAG(F_IF))
printk("EI ");
else
printk("DI ");
if (ACCESS_FLAG(F_SF))
printk("NG ");
else
printk("PL ");
if (ACCESS_FLAG(F_ZF))
printk("ZR ");
else
printk("NZ ");
if (ACCESS_FLAG(F_AF))
printk("AC ");
else
printk("NA ");
if (ACCESS_FLAG(F_PF))
printk("PE ");
else
printk("PO ");
if (ACCESS_FLAG(F_CF))
printk("CY ");
else
printk("NC ");
printk("\n");
}
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