/*
* Copyright (c) 2019 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,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
#ifdef MACH_BSD
#include <mach_ldebug.h>
#include <mach/kern_return.h>
#include <mach/mach_traps.h>
#include <mach/vm_param.h>
#include <kern/bits.h>
#include <kern/cpu_data.h>
#include <arm/cpu_data_internal.h>
#include <kern/mach_param.h>
#include <kern/task.h>
#include <kern/thread.h>
#include <kern/sched_prim.h>
#include <kern/misc_protos.h>
#include <kern/assert.h>
#include <kern/spl.h>
#include <kern/syscall_sw.h>
#include <ipc/ipc_port.h>
#include <vm/vm_kern.h>
#include <mach/thread_status.h>
#include <vm/pmap.h>
#include <sys/kdebug.h>
#include <sys/syscall.h>
#if CONFIG_MACF
#include <security/mac_mach_internal.h>
#endif
extern void throttle_lowpri_io(int);
extern arm_debug_state64_t *find_or_allocate_debug_state64(thread_t thread);
void mach_syscall(struct arm_saved_state*);
typedef kern_return_t (*mach_call_t)(void *);
struct mach_call_args {
syscall_arg_t arg1;
syscall_arg_t arg2;
syscall_arg_t arg3;
syscall_arg_t arg4;
syscall_arg_t arg5;
syscall_arg_t arg6;
syscall_arg_t arg7;
syscall_arg_t arg8;
syscall_arg_t arg9;
};
static void
arm_set_mach_syscall_ret(struct arm_saved_state *state, int retval)
{
if (is_saved_state32(state)) {
saved_state32(state)->r[0] = retval;
} else {
saved_state64(state)->x[0] = retval;
}
}
static kern_return_t
arm_get_mach_syscall_args(struct arm_saved_state *state, struct mach_call_args *dest, const mach_trap_t *trapp)
{
uint32_t reg_count;
if (is_saved_state32(state)) {
/* The trap table entry defines the number of 32-bit words to be copied in from userspace. */
reg_count = trapp->mach_trap_u32_words;
/*
* We get 7 contiguous words; r0-r6, hop over r7
* (frame pointer), optionally r8
*/
if (reg_count <= 7) {
bcopy((char*)saved_state32(state), (char*)dest, sizeof(uint32_t) * reg_count);
} else if (reg_count <= 9) {
bcopy((char*)saved_state32(state), (char*)dest, sizeof(uint32_t) * 7);
bcopy((char*)&saved_state32(state)->r[8], ((char*)dest) + sizeof(uint32_t) * 7,
reg_count - 7);
} else {
panic("Trap with %d words of args? We only support 9.", reg_count);
}
#if CONFIG_REQUIRES_U32_MUNGING
trapp->mach_trap_arg_munge32(dest);
#else
#error U32 mach traps on ARM64 kernel requires munging
#endif
} else {
assert(is_saved_state64(state));
bcopy((char*)saved_state64(state), (char*)dest, trapp->mach_trap_arg_count * sizeof(uint64_t));
}
return KERN_SUCCESS;
}
/**
* Marks or unmarks the given thread to be single stepped such
* that it executes exactly one instruction and then takes an exception to
* prevent further execution.
*
* @param thread 64 bit thread to be single stepped
* @param on boolean value representing whether the thread should be
* single stepped (on is true) or not (on is false)
*
* @returns KERN_SUCCESS if the status is successfully set or KERN_FAILURE if
* it fails for any reason.
*/
kern_return_t
thread_setsinglestep(thread_t thread, int on)
{
arm_debug_state64_t *thread_state = find_or_allocate_debug_state64(thread);
if (thread_state == NULL) {
return KERN_FAILURE;
}
if (on) {
thread_state->mdscr_el1 |= MDSCR_SS;
} else {
thread_state->mdscr_el1 &= ~MDSCR_SS;
}
if (thread == current_thread()) {
arm_debug_set64(thread->machine.DebugData);
}
return KERN_SUCCESS;
}
#if CONFIG_DTRACE
vm_offset_t dtrace_get_cpu_int_stack_top(void);
vm_offset_t
dtrace_get_cpu_int_stack_top(void)
{
return getCpuDatap()->intstack_top;
}
#endif /* CONFIG_DTRACE */
/* ARM64_TODO: remove this. still TODO?*/
extern struct proc* current_proc(void);
extern int proc_pid(struct proc*);
#if CONFIG_DEBUG_SYSCALL_REJECTION
extern int debug_syscall_rejection_mode;
extern bool debug_syscall_rejection_handle(int syscall_mach_trap_number);
#endif /* CONFIG_DEBUG_SYSCALL_REJECTION */
void
mach_syscall(struct arm_saved_state *state)
{
kern_return_t retval;
mach_call_t mach_call;
struct mach_call_args args = {
.arg1 = 0,
.arg2 = 0,
.arg3 = 0,
.arg4 = 0,
.arg5 = 0,
.arg6 = 0,
.arg7 = 0,
.arg8 = 0,
.arg9 = 0
};
int call_number = get_saved_state_svc_number(state);
int64_t exc_code;
int argc;
struct uthread *ut = get_bsdthread_info(current_thread());
uthread_reset_proc_refcount(ut);
assert(call_number < 0); /* Otherwise it would be a Unix syscall */
call_number = -call_number;
if (call_number >= MACH_TRAP_TABLE_COUNT) {
goto bad;
}
DEBUG_KPRINT_SYSCALL_MACH(
"mach_syscall: code=%d(%s) (pid %d, tid %lld)\n",
call_number, mach_syscall_name_table[call_number],
proc_pid(current_proc()), thread_tid(current_thread()));
#if DEBUG_TRACE
kprintf("mach_syscall(0x%08x) code=%d\n", state, call_number);
#endif
mach_call = (mach_call_t)mach_trap_table[call_number].mach_trap_function;
if (mach_call == (mach_call_t)kern_invalid) {
DEBUG_KPRINT_SYSCALL_MACH(
"mach_syscall: kern_invalid 0x%x\n", call_number);
goto bad;
}
argc = mach_trap_table[call_number].mach_trap_arg_count;
if (argc) {
retval = arm_get_mach_syscall_args(state, &args, &mach_trap_table[call_number]);
if (retval != KERN_SUCCESS) {
arm_set_mach_syscall_ret(state, retval);
DEBUG_KPRINT_SYSCALL_MACH(
"mach_syscall: retval=0x%x\n", retval);
return;
}
}
KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE,
MACHDBG_CODE(DBG_MACH_EXCP_SC, (call_number)) | DBG_FUNC_START,
args.arg1, args.arg2, args.arg3, args.arg4, 0);
#if CONFIG_MACF
/*
* Check syscall filter mask, if exists.
*
* Not all mach traps are filtered. e.g., mach_absolute_time() and
* mach_continuous_time(). See handle_svc().
*/
thread_ro_t tro = current_thread_ro();
task_t task = tro->tro_task;
struct proc *proc = tro->tro_proc;
uint8_t *filter_mask = task_get_mach_trap_filter_mask(task);
if (__improbable(filter_mask != NULL &&
!bitstr_test(filter_mask, call_number) &&
mac_task_mach_trap_evaluate != NULL)) {
retval = mac_task_mach_trap_evaluate(proc, call_number);
if (retval != KERN_SUCCESS) {
if (mach_trap_table[call_number].mach_trap_returns_port) {
retval = MACH_PORT_NULL;
}
goto skip_machcall;
}
}
#endif /* CONFIG_MACF */
#if CONFIG_DEBUG_SYSCALL_REJECTION
bitmap_t const *rejection_mask = uthread_get_syscall_rejection_mask(ut);
if (__improbable(rejection_mask != NULL &&
uthread_syscall_rejection_is_enabled(ut)) &&
!bitmap_test(rejection_mask, call_number)) {
if (debug_syscall_rejection_handle(-call_number)) {
if (mach_trap_table[call_number].mach_trap_returns_port) {
retval = MACH_PORT_NULL;
} else {
retval = KERN_DENIED;
}
goto skip_machcall;
}
}
#endif /* CONFIG_DEBUG_SYSCALL_REJECTION */
retval = mach_call(&args);
skip_machcall:
DEBUG_KPRINT_SYSCALL_MACH("mach_syscall: retval=0x%x (pid %d, tid %lld)\n", retval,
proc_pid(current_proc()), thread_tid(current_thread()));
KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE,
MACHDBG_CODE(DBG_MACH_EXCP_SC, (call_number)) | DBG_FUNC_END,
retval, 0, 0, 0, 0);
arm_set_mach_syscall_ret(state, retval);
throttle_lowpri_io(1);
#if DEBUG || DEVELOPMENT
kern_allocation_name_t
prior __assert_only = thread_get_kernel_state(current_thread())->allocation_name;
assertf(prior == NULL, "thread_set_allocation_name(\"%s\") not cleared", kern_allocation_get_name(prior));
#endif /* DEBUG || DEVELOPMENT */
uthread_assert_zero_proc_refcount(ut);
return;
bad:
exc_code = call_number;
exception_triage(EXC_SYSCALL, &exc_code, 1);
/* NOTREACHED */
panic("Returned from exception_triage()?");
}
#endif /* MACH_BSD */