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i386/pc386: Add x86 debug register support for hardware break points.

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This commit is contained in:
Chris Johns
2016-05-07 08:18:28 +10:00
parent fc138a1027
commit 8cb397b27d
1 changed files with 157 additions and 1 deletions
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158
c/src/lib/libbsp/i386/shared/comm/i386-stub.c
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@@ -101,9 +101,15 @@
#include <bsp.h>
/*
* Number of debug registers.
*/
#define NUM_DEBUG_REGISTERS 4
/*
* Prototypes we need to avoid warnings but not going into public space.
*/
void bsp_reset(void);
void breakpoint (void);
void set_debug_traps(void);
void set_mem_err(void);
@@ -159,7 +165,6 @@ int i386_gdb_registers[NUMREGS];
int i386_gdb_remcomStack[STACKSIZE / sizeof (int)];
int *i386_gdb_stackPtr = &i386_gdb_remcomStack[STACKSIZE / sizeof (int) - 1];
static int gdb_connected;
/*************************** ASSEMBLY CODE MACROS *************************/
@@ -770,6 +775,65 @@ hexToInt (char **ptr, int *intValue)
return (numChars);
}
/*
* Get/Set the DR registers.
*/
static uint32_t getDR7(void)
{
uint32_t value = 0;
asm volatile (" movl %%dr7, %0;" : "=r" (value) : : );
return value;
}
static void setDR7(uint32_t value)
{
asm volatile (" movl %0, %%dr7;" : : "r" (value) : );
}
static uint32_t getDR(int reg)
{
uint32_t value = 0;
switch (reg)
{
case 0:
asm volatile (" movl %%dr0, %0;" : "=r" (value) : : );
break;
case 1:
asm volatile (" movl %%dr1, %0;" : "=r" (value) : : );
break;
case 2:
asm volatile (" movl %%dr2, %0;" : "=r" (value) : : );
break;
case 3:
asm volatile (" movl %%dr3, %0;" : "=r" (value) : : );
break;
default:
break;
}
return value;
}
static void setDR(int reg, uint32_t addr)
{
switch (reg)
{
case 0:
asm volatile (" movl %0, %%dr0;" : : "r" (addr) : );
break;
case 1:
asm volatile (" movl %0, %%dr1;" : : "r" (addr) : );
break;
case 2:
asm volatile (" movl %0, %%dr2;" : : "r" (addr) : );
break;
case 3:
asm volatile (" movl %0, %%dr3;" : : "r" (addr) : );
break;
default:
break;
}
}
/*
* This function does all command procesing for interfacing to gdb.
*
@@ -939,6 +1003,98 @@ handle_exception (int exceptionVector)
_returnFromException (); /* this is a jump */
break;
case 'Z':
case 'z':
/*
* Z1 = execute (00b)
* Z2 = write (01b)
* Z3 = read (??, need to use 11b))
* Z4 = read/write (11b)
*/
ptr = &remcomInBuffer[1];
reg = *(ptr++);
if (reg == '0')
break;
printk("hbreak\n");
switch ((char) reg)
{
case '1':
reg = 0;
break;
case '2':
reg = 1;
case '3':
case '4':
default:
reg = 3;
break;
}
if (*(ptr++) == ',')
{
bool insert = remcomInBuffer[0] == 'Z';
printk("hbreak type\n", insert);
if (hexToInt (&ptr, &addr))
{
if (*(ptr++) == ',')
{
uint32_t dr7;
int i;
hexToInt(&ptr, &length);
dr7 = getDR7();
for (i = 0; i < NUM_DEBUG_REGISTERS; ++i)
{
if ((dr7 & (2 << (i * 2))) == 0)
{
if (insert)
{
setDR(i, addr);
dr7 |=
((length - 1) << ((i * 2) + 18)) |
(reg << ((i * 2) + 16)) |
(2 << (i * 2));
setDR7(dr7);
printk("set DR%i to %08x\n", i, addr);
break;
}
}
else if (!insert)
{
uint32_t dra = getDR(i);
if (dra == addr)
{
dr7 &= ~(2 << (i * 2));
setDR7(dr7);
printk("clear DR%i\n", i);
break;
}
}
}
if (insert && (i == NUM_DEBUG_REGISTERS))
{
ptr = 0;
}
}
else
{
ptr = 0;
}
}
else
{
ptr = 0;
}
}
else
{
ptr = 0;
}
if (ptr)
strcpy (remcomOutBuffer, "OK");
else
strcpy (remcomOutBuffer, "E1");
break;
/* Detach. */
case 'D':
putpacket (remcomOutBuffer);