This is xnu-11215.1.10. See this file in:
/*
* Copyright (c) 2000-2016 Apple Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. The rights granted to you under the License
* may not be used to create, or enable the creation or redistribution of,
* unlawful or unlicensed copies of an Apple operating system, or to
* circumvent, violate, or enable the circumvention or violation of, any
* terms of an Apple operating system software license agreement.
*
* Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
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*/
#include <mach/mach_types.h>
#include <mach/exception_types.h>
#include <arm/exception.h>
#include <arm/pmap.h>
#include <arm64/proc_reg.h>
#include <arm/thread.h>
#include <arm/trap_internal.h>
#include <arm/cpu_data_internal.h>
#include <kdp/kdp_internal.h>
#include <kern/debug.h>
#include <IOKit/IOPlatformExpert.h>
#include <libkern/OSAtomic.h>
#include <vm/vm_map.h>
#include <arm/misc_protos.h>
#if defined(HAS_APPLE_PAC)
#include <ptrauth.h>
#endif
#define KDP_TEST_HARNESS 0
#if KDP_TEST_HARNESS
#define dprintf(x) kprintf x
#else
#define dprintf(x) do {} while (0)
#endif
void halt_all_cpus(boolean_t);
void kdp_call(void);
int kdp_getc(void);
int machine_trace_thread(thread_t thread,
char * tracepos,
char * tracebound,
int nframes,
uint32_t * thread_trace_flags);
int machine_trace_thread64(thread_t thread,
char * tracepos,
char * tracebound,
int nframes,
uint32_t * thread_trace_flags);
void kdp_trap(unsigned int, struct arm_saved_state * saved_state);
extern bool machine_trace_thread_validate_kva(vm_offset_t addr);
#if CONFIG_KDP_INTERACTIVE_DEBUGGING
void
kdp_exception(
unsigned char * pkt, int * len, unsigned short * remote_port, unsigned int exception, unsigned int code, unsigned int subcode)
{
struct {
kdp_exception_t pkt;
kdp_exc_info_t exc;
} aligned_pkt;
kdp_exception_t * rq = (kdp_exception_t *)&aligned_pkt;
bcopy((char *)pkt, (char *)rq, sizeof(*rq));
rq->hdr.request = KDP_EXCEPTION;
rq->hdr.is_reply = 0;
rq->hdr.seq = kdp.exception_seq;
rq->hdr.key = 0;
rq->hdr.len = sizeof(*rq) + sizeof(kdp_exc_info_t);
rq->n_exc_info = 1;
rq->exc_info[0].cpu = 0;
rq->exc_info[0].exception = exception;
rq->exc_info[0].code = code;
rq->exc_info[0].subcode = subcode;
rq->hdr.len += rq->n_exc_info * sizeof(kdp_exc_info_t);
bcopy((char *)rq, (char *)pkt, rq->hdr.len);
kdp.exception_ack_needed = TRUE;
*remote_port = kdp.exception_port;
*len = rq->hdr.len;
}
boolean_t
kdp_exception_ack(unsigned char * pkt, int len)
{
kdp_exception_ack_t aligned_pkt;
kdp_exception_ack_t * rq = (kdp_exception_ack_t *)&aligned_pkt;
if ((unsigned)len < sizeof(*rq)) {
return FALSE;
}
bcopy((char *)pkt, (char *)rq, sizeof(*rq));
if (!rq->hdr.is_reply || rq->hdr.request != KDP_EXCEPTION) {
return FALSE;
}
dprintf(("kdp_exception_ack seq %x %x\n", rq->hdr.seq, kdp.exception_seq));
if (rq->hdr.seq == kdp.exception_seq) {
kdp.exception_ack_needed = FALSE;
kdp.exception_seq++;
}
return TRUE;
}
static void
kdp_getintegerstate(char * out_state)
{
#if defined(__arm64__)
struct arm_thread_state64 thread_state64;
arm_saved_state_t *saved_state;
saved_state = kdp.saved_state;
assert(is_saved_state64(saved_state));
bzero((char *) &thread_state64, sizeof(struct arm_thread_state64));
saved_state_to_thread_state64(saved_state, &thread_state64);
bcopy((char *) &thread_state64, (char *) out_state, sizeof(struct arm_thread_state64));
#else
#error Unknown architecture.
#endif
}
kdp_error_t
kdp_machine_read_regs(__unused unsigned int cpu, unsigned int flavor, char * data, int * size)
{
switch (flavor) {
#if defined(__arm64__)
case ARM_THREAD_STATE64:
dprintf(("kdp_readregs THREAD_STATE64\n"));
kdp_getintegerstate(data);
*size = ARM_THREAD_STATE64_COUNT * sizeof(int);
return KDPERR_NO_ERROR;
#endif
case ARM_VFP_STATE:
dprintf(("kdp_readregs THREAD_FPSTATE\n"));
bzero((char *) data, sizeof(struct arm_vfp_state));
*size = ARM_VFP_STATE_COUNT * sizeof(int);
return KDPERR_NO_ERROR;
default:
dprintf(("kdp_readregs bad flavor %d\n"));
return KDPERR_BADFLAVOR;
}
}
static void
kdp_setintegerstate(char * state_in)
{
#if defined(__arm64__)
struct arm_thread_state64 thread_state64;
struct arm_saved_state *saved_state;
bcopy((char *) state_in, (char *) &thread_state64, sizeof(struct arm_thread_state64));
saved_state = kdp.saved_state;
assert(is_saved_state64(saved_state));
/*
* thread_state64_to_saved_state() expects the target thread to be EL0
* state and ignores attempts to change many CPSR bits.
* kdp_setintegerstate() is rarely used and is gated behind significant
* security boundaries. So rather than creating a variant of
* thread_state64_to_saved_state() just for kdp_setintegerstate(), it's
* simpler to reset CPSR.M before converting, then adjust CPSR after
* conversion.
*/
uint32_t cpsr = get_saved_state_cpsr(saved_state);
cpsr &= ~(PSR64_MODE_EL_MASK);
cpsr |= PSR64_MODE_EL0;
set_saved_state_cpsr(saved_state, cpsr);
thread_state64_to_saved_state(&thread_state64, saved_state);
set_saved_state_cpsr(saved_state, thread_state64.cpsr);
#else
#error Unknown architecture.
#endif
}
kdp_error_t
kdp_machine_write_regs(__unused unsigned int cpu, unsigned int flavor, char * data, __unused int * size)
{
switch (flavor) {
#if defined(__arm64__)
case ARM_THREAD_STATE64:
dprintf(("kdp_writeregs THREAD_STATE64\n"));
kdp_setintegerstate(data);
return KDPERR_NO_ERROR;
#endif
case ARM_VFP_STATE:
dprintf(("kdp_writeregs THREAD_FPSTATE\n"));
return KDPERR_NO_ERROR;
default:
dprintf(("kdp_writeregs bad flavor %d\n"));
return KDPERR_BADFLAVOR;
}
}
void
kdp_machine_hostinfo(kdp_hostinfo_t * hostinfo)
{
hostinfo->cpus_mask = 1;
hostinfo->cpu_type = slot_type(0);
hostinfo->cpu_subtype = slot_subtype(0);
}
__attribute__((noreturn))
void
kdp_panic(const char * fmt, ...)
{
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wformat-nonliteral"
char kdp_fmt[256];
va_list args;
va_start(args, fmt);
(void) snprintf(kdp_fmt, sizeof(kdp_fmt), "kdp panic: %s", fmt);
vprintf(kdp_fmt, args);
va_end(args);
while (1) {
}
;
#pragma clang diagnostic pop
}
int
kdp_intr_disbl(void)
{
return splhigh();
}
void
kdp_intr_enbl(int s)
{
splx(s);
}
void
kdp_us_spin(int usec)
{
delay(usec / 100);
}
void
kdp_call(void)
{
Debugger("inline call to debugger(machine_startup)");
}
int
kdp_getc(void)
{
return console_try_read_char();
}
void
kdp_machine_get_breakinsn(uint8_t * bytes, uint32_t * size)
{
*(uint32_t *)bytes = GDB_TRAP_INSTR1;
*size = sizeof(uint32_t);
}
void
kdp_sync_cache(void)
{
}
int
kdp_machine_ioport_read(kdp_readioport_req_t * rq, caddr_t data, uint16_t lcpu)
{
#pragma unused(rq, data, lcpu)
return 0;
}
int
kdp_machine_ioport_write(kdp_writeioport_req_t * rq, caddr_t data, uint16_t lcpu)
{
#pragma unused(rq, data, lcpu)
return 0;
}
int
kdp_machine_msr64_read(kdp_readmsr64_req_t *rq, caddr_t data, uint16_t lcpu)
{
#pragma unused(rq, data, lcpu)
return 0;
}
int
kdp_machine_msr64_write(kdp_writemsr64_req_t *rq, caddr_t data, uint16_t lcpu)
{
#pragma unused(rq, data, lcpu)
return 0;
}
#endif /* CONFIG_KDP_INTERACTIVE_DEBUGGING */
void
kdp_trap(unsigned int exception, struct arm_saved_state * saved_state)
{
handle_debugger_trap(exception, 0, 0, saved_state);
#if defined(__arm64__)
assert(is_saved_state64(saved_state));
#if HAS_APPLE_PAC
MANIPULATE_SIGNED_THREAD_STATE(saved_state,
"ldr w6, [x1] \n"
"mov w7, %[GDB_TRAP_INSTR1_L] \n"
"movk w7, %[GDB_TRAP_INSTR1_H], lsl #16 \n"
"cmp w6, w7 \n"
"b.eq 1f \n"
"mov w7, %[GDB_TRAP_INSTR2_L] \n"
"movk w7, %[GDB_TRAP_INSTR2_H], lsl #16 \n"
"cmp w6, w7 \n"
"b.ne 0f \n"
"1: \n"
"add x1, x1, #4 \n"
"str x1, [x0, %[SS64_PC]] \n",
[GDB_TRAP_INSTR1_L] "i" (GDB_TRAP_INSTR1 & 0xFFFF),
[GDB_TRAP_INSTR1_H] "i" (GDB_TRAP_INSTR1 >> 16),
[GDB_TRAP_INSTR2_L] "i" (GDB_TRAP_INSTR2 & 0xFFFF),
[GDB_TRAP_INSTR2_H] "i" (GDB_TRAP_INSTR2 >> 16)
);
#else
uint32_t instr = *((uint32_t *)get_saved_state_pc(saved_state));
/*
* As long as we are using the arm32 trap encoding to handling
* traps to the debugger, we should identify both variants and
* increment for both of them.
*/
if ((instr == GDB_TRAP_INSTR1) || (instr == GDB_TRAP_INSTR2)) {
saved_state64(saved_state)->pc += 4;
}
#endif
#else
#error Unknown architecture.
#endif
}
#define ARM32_LR_OFFSET 4
#define ARM64_LR_OFFSET 8
/*
* Since sizeof (struct thread_snapshot) % 4 == 2
* make sure the compiler does not try to use word-aligned
* access to this data, which can result in alignment faults
* that can't be emulated in KDP context.
*/
typedef uint32_t uint32_align2_t __attribute__((aligned(2)));
/*
* @function _was_in_userspace
*
* @abstract Unused function used to indicate that a CPU was in userspace
* before it was IPI'd to enter the Debugger context.
*
* @discussion This function should never actually be called.
*/
void __attribute__((__noreturn__))
_was_in_userspace(void)
{
panic("%s: should not have been invoked.", __FUNCTION__);
}
int
machine_trace_thread64(thread_t thread,
char * tracepos,
char * tracebound,
int nframes,
uint32_t * thread_trace_flags)
{
#if defined(__arm64__)
uint64_t * tracebuf = (uint64_t *)tracepos;
vm_size_t framesize = sizeof(uint64_t);
vm_offset_t stacklimit = 0;
vm_offset_t stacklimit_bottom = 0;
int framecount = 0;
vm_offset_t pc = 0;
vm_offset_t fp = 0;
vm_offset_t sp = 0;
vm_offset_t prevfp = 0;
uint64_t prevlr = 0;
vm_offset_t kern_virt_addr = 0;
nframes = (tracebound > tracepos) ? MIN(nframes, (int)((tracebound - tracepos) / framesize)) : 0;
if (!nframes) {
return 0;
}
framecount = 0;
struct arm_saved_state *state = thread->machine.kpcb;
if (state != NULL) {
fp = state->ss_64.fp;
prevlr = state->ss_64.lr;
pc = state->ss_64.pc;
sp = state->ss_64.sp;
} else {
/* kstackptr may not always be there, so recompute it */
arm_kernel_saved_state_t *kstate = &thread_get_kernel_state(thread)->machine.ss;
fp = kstate->fp;
prevlr = kstate->lr;
pc = kstate->pc_was_in_userspace ? (register_t)ptrauth_strip((void *)&_was_in_userspace, ptrauth_key_function_pointer) : 0;
sp = kstate->sp;
}
stacklimit = VM_MAX_KERNEL_ADDRESS;
stacklimit_bottom = VM_MIN_KERNEL_ADDRESS;
if (!prevlr && !fp && !sp && !pc) {
return 0;
}
prevlr = VM_KERNEL_UNSLIDE(prevlr);
for (; framecount < nframes; framecount++) {
*tracebuf++ = prevlr;
/* Invalid frame */
if (!fp) {
break;
}
/*
* Unaligned frame; given that the stack register must always be
* 16-byte aligned, we are assured 8-byte alignment of the saved
* frame pointer and link register.
*/
if (fp & 0x0000007) {
break;
}
/* Frame is out of range, maybe a user FP while doing kernel BT */
if (fp > stacklimit) {
break;
}
if (fp < stacklimit_bottom) {
break;
}
/* Stack grows downward */
if (fp < prevfp) {
bool switched_stacks = false;
/*
* As a special case, sometimes we are backtracing out of an interrupt
* handler, and the stack jumps downward because of the memory allocation
* pattern during early boot due to KASLR.
*/
int cpu;
int max_cpu = ml_get_max_cpu_number();
for (cpu = 0; cpu <= max_cpu; cpu++) {
cpu_data_t *target_cpu_datap;
target_cpu_datap = (cpu_data_t *)CpuDataEntries[cpu].cpu_data_vaddr;
if (target_cpu_datap == (cpu_data_t *)NULL) {
continue;
}
if (prevfp >= (target_cpu_datap->intstack_top - INTSTACK_SIZE) && prevfp < target_cpu_datap->intstack_top) {
switched_stacks = true;
break;
}
#if defined(__arm64__)
if (prevfp >= (target_cpu_datap->excepstack_top - EXCEPSTACK_SIZE) && prevfp < target_cpu_datap->excepstack_top) {
switched_stacks = true;
break;
}
#endif
}
/**
* The stack could be "growing upwards" because this frame is
* stitching two different stacks together. There can be more than
* one non-XNU stack so if both frames are in non-XNU stacks but it
* looks like the stack is growing upward, then assume that we've
* switched from one non-XNU stack to another.
*/
if ((ml_addr_in_non_xnu_stack(prevfp) != ml_addr_in_non_xnu_stack(fp)) ||
(ml_addr_in_non_xnu_stack(prevfp) && ml_addr_in_non_xnu_stack(fp))) {
switched_stacks = true;
}
if (!switched_stacks) {
/* Corrupt frame pointer? */
break;
}
}
/* Assume there's a saved link register, and read it */
kern_virt_addr = fp + ARM64_LR_OFFSET;
bool ok = machine_trace_thread_validate_kva(kern_virt_addr);
if (!ok) {
if (thread_trace_flags != NULL) {
*thread_trace_flags |= kThreadTruncatedBT;
}
break;
}
prevlr = *(uint64_t *)kern_virt_addr;
#if defined(HAS_APPLE_PAC)
/* return addresses on stack signed by arm64e ABI */
prevlr = (uint64_t) ptrauth_strip((void *)prevlr, ptrauth_key_return_address);
#endif
prevlr = VM_KERNEL_UNSLIDE(prevlr);
prevfp = fp;
/* Next frame */
kern_virt_addr = fp;
ok = machine_trace_thread_validate_kva(kern_virt_addr);
if (!ok) {
if (thread_trace_flags != NULL) {
*thread_trace_flags |= kThreadTruncatedBT;
}
fp = 0;
break;
}
fp = *(uint64_t *)kern_virt_addr;
#if defined(HAS_APPLE_PAC)
/* frame pointers on stack signed by arm64e ABI */
fp = (uint64_t) ptrauth_strip((void *)fp, ptrauth_key_frame_pointer);
#endif
}
return (int)(((char *)tracebuf) - tracepos);
#else
#error Unknown architecture.
#endif
}
void
kdp_ml_enter_debugger(void)
{
__asm__ volatile (".long 0xe7ffdefe");
}