alternate_debugger.c [plain text]
#if ALTERNATE_DEBUGGER
#include <arm64/alternate_debugger.h>
#include <kern/kalloc.h>
#include <arm64/lowglobals.h>
#include <arm/caches_internal.h>
#include <kern/cpu_data.h>
#include <arm/pmap.h>
#include <pexpert/pexpert.h>
#include <vm/vm_map.h>
#include <vm/vm_kern.h>
#include <libkern/version.h>
void kprintf(const char *fmt, ...);
static mach_vm_address_t alt_code;
static mach_vm_size_t alt_size;
static mach_vm_address_t alt_pages;
static mach_vm_size_t alt_pages_size;
typedef void (*t_putc_fn)(char c);
typedef void (*t_call_altdbg_fn)(mach_vm_size_t size, mach_vm_address_t pages, mach_vm_size_t pages_size, t_putc_fn putc_address );
extern void alternate_debugger_just_return(__unused mach_vm_size_t size, __unused mach_vm_address_t pages, __unused mach_vm_size_t pages_size, t_putc_fn putc_address);
extern void *alternate_debugger_just_return_end;
void alternate_debugger_enter(void)
{
if ( alt_code != 0 ) {
disable_preemption();
printf("########## Going to call ALTERNATE DEBUGGER\n");
assert((alt_size & 0xFFFFFFFF00000000) == 0);
flush_dcache(alt_code, (unsigned int)alt_size, 0);
pmap_protect(kernel_map->pmap, alt_code, alt_code+alt_size, VM_PROT_READ|VM_PROT_EXECUTE);
if ( *osversion ) {
memcpy(osversion, "ALT", 3); } else {
strncpy(osversion, "ALT - Version Not Set Yet", OSVERSIZE);
}
kprintf("########## Calling ALTERNATE DEBUGGER (size %lld, pages 0x%llx, pages_size 0x%llx, putc %p\n", alt_size, alt_pages, alt_pages_size, &consdebug_putc_unbuffered);
((t_call_altdbg_fn)alt_code)(alt_size, alt_pages, alt_pages_size, &consdebug_putc_unbuffered);
kprintf("########## Returned from calling ALTERNATE DEBUGGER\n");
enable_preemption();
}
}
void alternate_debugger_init(void)
{
if( PE_parse_boot_argn("alternate_debugger_init", (void*)&alt_size, sizeof(alt_size)) )
{
vm_offset_t alt_va = 0;
kprintf("########## ALTERNATE_DEBUGGER\n");
PE_parse_boot_argn("alternate_debugger_init_pages", (void*)&alt_pages_size, sizeof(alt_pages_size));
alt_size = vm_map_round_page(alt_size,
VM_MAP_PAGE_MASK(kernel_map));
alt_pages_size = vm_map_round_page(alt_pages_size,
VM_MAP_PAGE_MASK(kernel_map));
kern_return_t kr = KERN_SUCCESS;
kr = kmem_alloc_contig(kernel_map, &alt_va, alt_size, VM_MAP_PAGE_MASK(kernel_map), 0, 0, KMA_NOPAGEWAIT | KMA_KOBJECT | KMA_LOMEM, VM_KERN_MEMORY_DIAG);
if( kr != KERN_SUCCESS)
{
kprintf("########## ALTERNATE_DEBUGGER FAILED kmem_alloc_contig with %d\n", kr);
alt_va = 0;
}
else {
if ( alt_pages_size ) {
alt_pages = (vm_offset_t) kalloc((vm_size_t) alt_pages_size);
}
}
kprintf("########## Initializing ALTERNATE DEBUGGER : [alloc size 0x%llx @0x%lx] [pages_size 0x%llx @0x%llx] -- lowmem pointer at %p\n",
alt_size, alt_va, alt_pages_size, alt_pages, &lowGlo.lgAltDebugger );
if ( alt_va ) {
uintptr_t just_return_size = (uintptr_t)&alternate_debugger_just_return_end - (uintptr_t)&alternate_debugger_just_return;
assert(just_return_size <= alt_size); memcpy((void*)alt_va, &alternate_debugger_just_return, just_return_size);
lowGlo.lgAltDebugger = alt_code = alt_va;
#if 1
unsigned int alt_init_test;
if(PE_parse_boot_argn("alternate_debugger_pause_for_load_at_boot", &alt_init_test, sizeof(alt_init_test)) ) {
kprintf("########## Waiting for ALTERNATE DEBUGGER to load (in file %s).... to continue, set register to 1", __FILE__ );
volatile int ii = 0;
while(!ii)
;
kprintf("\n");
alternate_debugger_enter();
}
#endif
}
}
}
#endif