xnu-4903.241.1.tar.gz

[apple/xnu.git] / bsd / dev / arm / dtrace_isa.c

/*
 * Copyright (c) 2005-2008 Apple Computer, 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@
 */

#define MACH__POSIX_C_SOURCE_PRIVATE 1  /* pulls in suitable savearea from
                                         * mach/ppc/thread_status.h */
#include <arm/caches_internal.h>
#include <arm/proc_reg.h>

#include <kern/thread.h>
#include <mach/thread_status.h>

#include <stdarg.h>
#include <string.h>
#include <sys/malloc.h>
#include <sys/time.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/proc_internal.h>
#include <sys/kauth.h>
#include <sys/dtrace.h>
#include <sys/dtrace_impl.h>
#include <libkern/OSAtomic.h>
#include <kern/simple_lock.h>
#include <kern/sched_prim.h>            /* for thread_wakeup() */
#include <kern/thread_call.h>
#include <kern/task.h>
#include <miscfs/devfs/devfs.h>
#include <mach/vm_param.h>

extern struct arm_saved_state *find_kern_regs(thread_t);

extern dtrace_id_t      dtrace_probeid_error;   /* special ERROR probe */
typedef arm_saved_state_t savearea_t;

extern lck_attr_t       *dtrace_lck_attr;
extern lck_grp_t        *dtrace_lck_grp;

int dtrace_arm_condition_true(int condition, int cpsr);

/*
 * Atomicity and synchronization
 */
inline void
dtrace_membar_producer(void)
{
#if __ARM_SMP__
        __asm__ volatile("dmb ish" : : : "memory");
#else
        __asm__ volatile("nop" : : : "memory");
#endif
}

inline void
dtrace_membar_consumer(void)
{
#if __ARM_SMP__
        __asm__ volatile("dmb ish" : : : "memory");
#else
        __asm__ volatile("nop" : : : "memory");
#endif
}

/*
 * Interrupt manipulation
 * XXX dtrace_getipl() can be called from probe context.
 */
int
dtrace_getipl(void)
{
        /*
         * XXX Drat, get_interrupt_level is MACH_KERNEL_PRIVATE
         * in osfmk/kern/cpu_data.h
         */
        /* return get_interrupt_level(); */
        return (ml_at_interrupt_context() ? 1 : 0);
}

#if __ARM_SMP__
/*
 * MP coordination
 */

decl_lck_mtx_data(static, dt_xc_lock);
static uint32_t dt_xc_sync;

typedef struct xcArg {
        processorid_t   cpu;
        dtrace_xcall_t  f;
        void           *arg;
} xcArg_t;

static void
xcRemote(void *foo)
{
        xcArg_t *pArg = (xcArg_t *) foo;

        if (pArg->cpu == CPU->cpu_id || pArg->cpu == DTRACE_CPUALL)
                (pArg->f) (pArg->arg);

        if (hw_atomic_sub(&dt_xc_sync, 1) == 0)
                thread_wakeup((event_t) &dt_xc_sync);
}
#endif

/*
 * dtrace_xcall() is not called from probe context.
 */
void
dtrace_xcall(processorid_t cpu, dtrace_xcall_t f, void *arg)
{
#if __ARM_SMP__
        /* Only one dtrace_xcall in flight allowed */
        lck_mtx_lock(&dt_xc_lock);

        xcArg_t xcArg;

        xcArg.cpu = cpu;
        xcArg.f = f;
        xcArg.arg = arg;

        cpu_broadcast_xcall(&dt_xc_sync, TRUE, xcRemote, (void*) &xcArg);

        lck_mtx_unlock(&dt_xc_lock);
        return;
#else
#pragma unused(cpu)
        /* On uniprocessor systems, the cpu should always be either ourselves or all */
        ASSERT(cpu == CPU->cpu_id || cpu == DTRACE_CPUALL);

        (*f)(arg);
        return;
#endif
}

/*
 * Initialization
 */
void
dtrace_isa_init(void)
{
#if __ARM_SMP__
        lck_mtx_init(&dt_xc_lock, dtrace_lck_grp, dtrace_lck_attr);
#endif
        return;
}

/*
 * Runtime and ABI
 */
uint64_t
dtrace_getreg(struct regs * savearea, uint_t reg)
{
        struct arm_saved_state *regs = (struct arm_saved_state *) savearea;
        if (regs == NULL) {
                DTRACE_CPUFLAG_SET(CPU_DTRACE_ILLOP);
                return (0);
        }
        /* beyond register limit? */
        if (reg > ARM_SAVED_STATE32_COUNT - 1) {
                DTRACE_CPUFLAG_SET(CPU_DTRACE_ILLOP);
                return (0);
        }

        return (uint64_t) ((unsigned int *) (&(regs->r)))[reg];
}

#define RETURN_OFFSET 4

static int
dtrace_getustack_common(uint64_t * pcstack, int pcstack_limit, user_addr_t pc,
                        user_addr_t sp)
{
        int ret = 0;
        
        ASSERT(pcstack == NULL || pcstack_limit > 0);

        while (pc != 0) {
                ret++;
                if (pcstack != NULL) {
                        *pcstack++ = (uint64_t) pc;
                        pcstack_limit--;
                        if (pcstack_limit <= 0)
                                break;
                }

                if (sp == 0)
                        break;

                pc = dtrace_fuword32((sp + RETURN_OFFSET));
                sp = dtrace_fuword32(sp);
        }

        return (ret);
}

void
dtrace_getupcstack(uint64_t * pcstack, int pcstack_limit)
{
        thread_t        thread = current_thread();
        savearea_t     *regs;
        user_addr_t     pc, sp;
        volatile uint16_t *flags = (volatile uint16_t *) & cpu_core[CPU->cpu_id].cpuc_dtrace_flags;
        int n;

        if (*flags & CPU_DTRACE_FAULT)
                return;

        if (pcstack_limit <= 0)
                return;

        /*
         * If there's no user context we still need to zero the stack.
         */
        if (thread == NULL)
                goto zero;

        regs = (savearea_t *) find_user_regs(thread);
        if (regs == NULL)
                goto zero;

        *pcstack++ = (uint64_t)dtrace_proc_selfpid();
        pcstack_limit--;

        if (pcstack_limit <= 0)
                return;

        pc = regs->pc;
        sp = regs->sp;

        if (DTRACE_CPUFLAG_ISSET(CPU_DTRACE_ENTRY)) {
                *pcstack++ = (uint64_t) pc;
                pcstack_limit--;
                if (pcstack_limit <= 0)
                        return;

                pc = regs->lr;
        }

        n = dtrace_getustack_common(pcstack, pcstack_limit, pc, regs->r[7]);

        ASSERT(n >= 0);
        ASSERT(n <= pcstack_limit);

        pcstack += n;
        pcstack_limit -= n;

zero:
        while (pcstack_limit-- > 0)
                *pcstack++ = 0ULL;
}

int
dtrace_getustackdepth(void)
{
        thread_t        thread = current_thread();
        savearea_t     *regs;
        user_addr_t     pc, sp;
        int             n = 0;

        if (thread == NULL)
                return 0;

        if (DTRACE_CPUFLAG_ISSET(CPU_DTRACE_FAULT))
                return (-1);

        regs = (savearea_t *) find_user_regs(thread);
        if (regs == NULL)
                return 0;

        pc = regs->pc;
        sp = regs->sp;

        if (DTRACE_CPUFLAG_ISSET(CPU_DTRACE_ENTRY)) {
                n++;
                pc = regs->lr;
        }

        /*
         * Note that unlike ppc, the arm code does not use
         * CPU_DTRACE_USTACK_FP. This is because arm always
         * traces from the sp, even in syscall/profile/fbt
         * providers.
         */

        n += dtrace_getustack_common(NULL, 0, pc, regs->r[7]);

        return (n);
}

void
dtrace_getufpstack(uint64_t * pcstack, uint64_t * fpstack, int pcstack_limit)
{
        /* XXX ARMTODO 64vs32 */
        thread_t        thread = current_thread();
        savearea_t      *regs;
        user_addr_t     pc, sp;
        
        volatile        uint16_t  *flags = (volatile uint16_t *) & cpu_core[CPU->cpu_id].cpuc_dtrace_flags;

#if 0
        uintptr_t oldcontext;
        size_t          s1, s2;
#endif

        if (*flags & CPU_DTRACE_FAULT)
                return;

        if (pcstack_limit <= 0)
                return;

        /*
         * If there's no user context we still need to zero the stack.
         */
        if (thread == NULL)
                goto zero;

        regs = (savearea_t *) find_user_regs(thread);
        if (regs == NULL)
                goto zero;
        
        *pcstack++ = (uint64_t)dtrace_proc_selfpid();
        pcstack_limit--;

        if (pcstack_limit <= 0)
                return;
        
        pc = regs->pc;
        sp = regs->sp;

#if 0                           /* XXX signal stack crawl */
        oldcontext = lwp->lwp_oldcontext;

        if (p->p_model == DATAMODEL_NATIVE) {
                s1 = sizeof(struct frame) + 2 * sizeof(long);
                s2 = s1 + sizeof(siginfo_t);
        } else {
                s1 = sizeof(struct frame32) + 3 * sizeof(int);
                s2 = s1 + sizeof(siginfo32_t);
        }
#endif

        if (DTRACE_CPUFLAG_ISSET(CPU_DTRACE_ENTRY)) {
                *pcstack++ = (uint64_t) pc;
                *fpstack++ = 0;
                pcstack_limit--;
                if (pcstack_limit <= 0)
                        return;

                pc = dtrace_fuword32(sp);
        }
        while (pc != 0 && sp != 0) {
                *pcstack++ = (uint64_t) pc;
                *fpstack++ = sp;
                pcstack_limit--;
                if (pcstack_limit <= 0)
                        break;

#if 0                           /* XXX signal stack crawl */
                if (oldcontext == sp + s1 || oldcontext == sp + s2) {
                        if (p->p_model == DATAMODEL_NATIVE) {
                                ucontext_t     *ucp = (ucontext_t *) oldcontext;
                                greg_t         *gregs = ucp->uc_mcontext.gregs;

                                sp = dtrace_fulword(&gregs[REG_FP]);
                                pc = dtrace_fulword(&gregs[REG_PC]);

                                oldcontext = dtrace_fulword(&ucp->uc_link);
                        } else {
                                ucontext_t     *ucp = (ucontext_t *) oldcontext;
                                greg_t         *gregs = ucp->uc_mcontext.gregs;

                                sp = dtrace_fuword32(&gregs[EBP]);
                                pc = dtrace_fuword32(&gregs[EIP]);

                                oldcontext = dtrace_fuword32(&ucp->uc_link);
                        }
                } else
#endif
                {
                        pc = dtrace_fuword32((sp + RETURN_OFFSET));
                        sp = dtrace_fuword32(sp);
                }

#if 0
                /* XXX ARMTODO*/
                /*
                 * This is totally bogus:  if we faulted, we're going to clear
                 * the fault and break.  This is to deal with the apparently
                 * broken Java stacks on x86.
                 */
                if (*flags & CPU_DTRACE_FAULT) {
                        *flags &= ~CPU_DTRACE_FAULT;
                        break;
                }
#endif
        }

zero:
        while (pcstack_limit-- > 0)
                *pcstack++ = 0ULL;
}

void
dtrace_getpcstack(pc_t * pcstack, int pcstack_limit, int aframes,
                  uint32_t * intrpc)
{
        struct frame   *fp = (struct frame *) __builtin_frame_address(0);
        struct frame   *nextfp, *minfp, *stacktop;
        int             depth = 0;
        int             on_intr;
        int             last = 0;
        uintptr_t       pc;
        uintptr_t       caller = CPU->cpu_dtrace_caller;

        if ((on_intr = CPU_ON_INTR(CPU)) != 0)
                stacktop = (struct frame *) dtrace_get_cpu_int_stack_top();
        else
                stacktop = (struct frame *) (dtrace_get_kernel_stack(current_thread()) + kernel_stack_size);

        minfp = fp;

        aframes++;

        if (intrpc != NULL && depth < pcstack_limit)
                pcstack[depth++] = (pc_t) intrpc;

        while (depth < pcstack_limit) {
                nextfp = *(struct frame **) fp;
                pc = *(uintptr_t *) (((uint32_t) fp) + RETURN_OFFSET);

                if (nextfp <= minfp || nextfp >= stacktop) {
                        if (on_intr) {
                                /*
                                 * Hop from interrupt stack to thread stack.
                                 */
                                arm_saved_state_t *arm_kern_regs = (arm_saved_state_t *) find_kern_regs(current_thread());
                                if (arm_kern_regs) {
                                        nextfp = (struct frame *)arm_kern_regs->r[7];

                                        vm_offset_t kstack_base = dtrace_get_kernel_stack(current_thread());

                                        minfp = (struct frame *)kstack_base;
                                        stacktop = (struct frame *)(kstack_base + kernel_stack_size);

                                        on_intr = 0;

                                        if (nextfp <= minfp || nextfp >= stacktop) {
                                                last = 1;
                                        }
                                } else {
                                        /*
                                         * If this thread was on the interrupt stack, but did not
                                         * take an interrupt (i.e, the idle thread), there is no
                                         * explicit saved state for us to use.
                                         */
                                        last = 1;
                                }
                        } else {
                                /*
                                 * This is the last frame we can process; indicate
                                 * that we should return after processing this frame.
                                 */
                                last = 1;
                        }
                }
                if (aframes > 0) {
                        if (--aframes == 0 && caller != (uintptr_t)NULL) {
                                /*
                                 * We've just run out of artificial frames,
                                 * and we have a valid caller -- fill it in
                                 * now.
                                 */
                                ASSERT(depth < pcstack_limit);
                                pcstack[depth++] = (pc_t) caller;
                                caller = (uintptr_t)NULL;
                        }
                } else {
                        if (depth < pcstack_limit)
                                pcstack[depth++] = (pc_t) pc;
                }

                if (last) {
                        while (depth < pcstack_limit)
                                pcstack[depth++] = (pc_t) NULL;
                        return;
                }
                fp = nextfp;
                minfp = fp;
        }
}

int
dtrace_instr_size(uint32_t instr, int thumb_mode)
{
        if (thumb_mode) {
                uint16_t instr16 = *(uint16_t*) &instr;
                if (((instr16 >> 11) & 0x1F) > 0x1C)
                        return 4;
                else
                        return 2;
        } else {
                return 4;
        }
}

uint64_t
dtrace_getarg(int arg, int aframes, dtrace_mstate_t *mstate, dtrace_vstate_t *vstate)
{
#pragma unused(arg, aframes, mstate, vstate)
#if 0
        /* XXX ARMTODO */
        uint64_t val;
        uintptr_t *fp = (uintptr_t *)__builtin_frame_address(0);
        uintptr_t *stack;
        uintptr_t pc;
        int i;

        for (i = 1; i <= aframes; i++) {
                fp = fp[0];
                pc = fp[1];

                if (dtrace_invop_callsite_pre != NULL
                        && pc  >  (uintptr_t)dtrace_invop_callsite_pre
                        && pc  <= (uintptr_t)dtrace_invop_callsite_post) {
                        /*
                         * If we pass through the invalid op handler, we will
                         * use the pointer that it passed to the stack as the
                         * second argument to dtrace_invop() as the pointer to
                         * the frame we're hunting for.
                         */

                        stack = (uintptr_t *)&fp[1]; /* Find marshalled arguments */
                        fp = (struct frame *)stack[1]; /* Grab *second* argument */
                        stack = (uintptr_t *)&fp[1]; /* Find marshalled arguments */
                        DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT);
                        val = (uint64_t)(stack[arg]);
                        DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT);
                        return val;
                }
        }

        /*
         * Arrive here when provider has called dtrace_probe directly.
         */
        stack = (uintptr_t *)&fp[1]; /* Find marshalled arguments */
        stack++; /* Advance past probeID */

        DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT);
        val = *(((uint64_t *)stack) + arg); /* dtrace_probe arguments arg0 .. arg4 are 64bits wide */
        DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT);
        return (val);
#endif
        return 0xfeedfacedeafbeadLL;
}

void
dtrace_probe_error(dtrace_state_t *state, dtrace_epid_t epid, int which,
                int fltoffs, int fault, uint64_t illval)
{
        /* XXX ARMTODO */
        /*
         * For the case of the error probe firing lets
         * stash away "illval" here, and special-case retrieving it in DIF_VARIABLE_ARG.
         */
        state->dts_arg_error_illval = illval;
        dtrace_probe( dtrace_probeid_error, (uint64_t)(uintptr_t)state, epid, which, fltoffs, fault );
}

void
dtrace_toxic_ranges(void (*func)(uintptr_t base, uintptr_t limit))
{
        /* XXX ARMTODO check copied from ppc/x86*/
        /*
         * "base" is the smallest toxic address in the range, "limit" is the first
         * VALID address greater than "base".
         */ 
        func(0x0, VM_MIN_KERNEL_ADDRESS);
        if (VM_MAX_KERNEL_ADDRESS < ~(uintptr_t)0)
                        func(VM_MAX_KERNEL_ADDRESS + 1, ~(uintptr_t)0);
}

int
dtrace_arm_condition_true(int cond, int cpsr)
{
        int taken = 0;
        int zf = (cpsr & PSR_ZF) ? 1 : 0,
            nf = (cpsr & PSR_NF) ? 1 : 0,
            cf = (cpsr & PSR_CF) ? 1 : 0,
            vf = (cpsr & PSR_VF) ? 1 : 0;

        switch(cond) {
                case 0: taken = zf; break;
                case 1: taken = !zf; break;
                case 2: taken = cf; break;
                case 3: taken = !cf; break;
                case 4: taken = nf; break;
                case 5: taken = !nf; break;
                case 6: taken = vf; break;
                case 7: taken = !vf; break;
                case 8: taken = (cf && !zf); break;
                case 9: taken = (!cf || zf); break;
                case 10: taken = (nf == vf); break;
                case 11: taken = (nf != vf); break;
                case 12: taken = (!zf && (nf == vf)); break;
                case 13: taken = (zf || (nf != vf)); break;
                case 14: taken = 1; break;
                case 15: taken = 1; break; /* always "true" for ARM, unpredictable for THUMB. */
        }

        return taken;
}

void dtrace_flush_caches(void)
{
        /* TODO There were some problems with flushing just the cache line that had been modified.
         * For now, we'll flush the entire cache, until we figure out how to flush just the patched block.
         */
        FlushPoU_Dcache();
        InvalidatePoU_Icache();
}