/*
* patch the call to do_debug inside debug interrupt handler
*/
int patch_do_debug(void)
{
int i, call_found = 0;
unsigned int rip_offset;
unsigned char *ptr = (unsigned char *)get_idt_handler(1);
for (i = 0; i < 128; i++) {
if (call_found == 2) {
patched_addr = (unsigned int *)ptr;
old_rip_off = *patched_addr;
rip_offset = (unsigned long)my_do_debug - (unsigned long)patched_addr - 4;
clear_CR0_WP();
*patched_addr = rip_offset;
set_CR0_WP();
return 0;
} else if (ptr[0] == 0xe8) {
call_found++;
}
ptr++;
}
return -1;
}
/*
* x86_get_kernel_syms: get syscall table addr
* ia32 addrs are not mandatory (CONFIG_IA32_EMULATION=n ?)
*/
int x86_get_kernel_syms(void)
{
int ret = 0;
/* die chain */
ksyms.die_chain = (void *)x86_get_die_chain_addr();
/*
* ia32 emulation via sysenter (not used ?)
*/
rdmsrl(MSR_IA32_SYSENTER_EIP, ksyms.ia32_sysenter);
if (ksyms.ia32_sysenter) {
ret = __get_sycall_addrs(ksyms.ia32_sysenter,
&ksyms.ia32_sys_call_table,
&ksyms.ia32_sysenter_sys_call_table_call);
if (ret)
goto exit;
}
/*
* ia32 emulation via syscall
*/
ksyms.ia32_syscall = get_idt_handler(0x80);
if (ksyms.ia32_syscall) {
ret = __get_sycall_addrs(ksyms.ia32_syscall,
&ksyms.ia32_sys_call_table,
&ksyms.ia32_syscall_sys_call_table_call);
if (ret)
goto exit;
}
/*
* x86_64
*/
rdmsrl(MSR_LSTAR, ksyms.system_call);
if (ksyms.system_call)
ret = __get_sycall_addrs(ksyms.system_call,
&ksyms.sys_call_table,
&ksyms.sys_call_table_call);
else
ret = -1;
exit:
pr_debug("%s: ia32_sysenter=%lx ia32_sysenter_sys_call_table_call=%lx\n",
__func__, ksyms.ia32_sysenter, ksyms.ia32_sysenter_sys_call_table_call);
pr_debug("%s: ia32_syscall=%lx ia32_syscall_sys_call_table_call=%lx\n",
__func__, ksyms.ia32_syscall, ksyms.ia32_syscall_sys_call_table_call);
pr_debug("%s: ia32_sys_call_table=%lx\n", __func__, ksyms.ia32_sys_call_table);
pr_debug("%s: die_chain=%p\n", __func__, ksyms.die_chain);
return ret;
}
