kernel/lib/ktrace/ktrace.cpp - zircon/ - Git at Google

 // Copyright 2016 The Fuchsia Authors
 //
 // Use of this source code is governed by a MIT-style
 // license that can be found in the LICENSE file or at
 // https://opensource.org/licenses/MIT

 #include <debug.h>
 #include <err.h>
 #include <platform.h>
 #include <string.h>

 #include <arch/ops.h>
 #include <arch/user_copy.h>
 #include <hypervisor/ktrace.h>
 #include <kernel/cmdline.h>
 #include <lib/ktrace.h>
 #include <lk/init.h>
 #include <object/thread_dispatcher.h>
 #include <vm/vm_aspace.h>
 #include <zircon/thread_annotations.h>

 #define ktrace_timestamp() current_ticks();
 #define ktrace_ticks_per_ms() (ticks_per_second() / 1000)

 // Generated struct that has the syscall index and name.
 static struct ktrace_syscall_info {
     uint32_t id;
     uint32_t nargs;
     const char* name;
 } kt_syscall_info [] = {
     #include <zircon/syscall-ktrace-info.inc>
     {0, 0, nullptr}
 };

 void ktrace_report_syscalls(ktrace_syscall_info* call) {
     size_t ix = 0;
     while (call[ix].name) {
         ktrace_name_etc(TAG_SYSCALL_NAME, call[ix].id, 0, call[ix].name, true);
         ++ix;
     }
 }

 static uint32_t probe_number = 1;

 extern ktrace_probe_info_t* const __start_ktrace_probe[];
 extern ktrace_probe_info_t* const __stop_ktrace_probe[];

 static fbl::Mutex probe_list_lock;
 static ktrace_probe_info_t* probe_list TA_GUARDED(probe_list_lock);

 static ktrace_probe_info_t* ktrace_find_probe(const char* name) TA_REQ(probe_list_lock) {
     ktrace_probe_info_t* probe;
     for (probe = probe_list; probe != nullptr; probe = probe->next) {
         if (!strcmp(name, probe->name)) {
             return probe;
         }
     }
     return nullptr;
 }

 static void ktrace_add_probe(ktrace_probe_info_t* probe) TA_REQ(probe_list_lock) {
     if (probe->num == 0) {
         probe->num = probe_number++;
     }
     probe->next = probe_list;
     probe_list = probe;
     ktrace_name_etc(TAG_PROBE_NAME, probe->num, 0, probe->name, true);
 }

 static void ktrace_report_probes(void) {
     fbl::AutoLock lock(&probe_list_lock);
     ktrace_probe_info_t *probe;
     for (probe = probe_list; probe != nullptr; probe = probe->next) {
         ktrace_name_etc(TAG_PROBE_NAME, probe->num, 0, probe->name, true);
     }
 }

 typedef struct ktrace_state {
     // where the next record will be written
     int offset;

     // mask of groups we allow, 0 == tracing disabled
     int grpmask;

     // total size of the trace buffer
     uint32_t bufsize;

     // offset where tracing was stopped, 0 if tracing active
     uint32_t marker;

     // raw trace buffer
     uint8_t* buffer;
 } ktrace_state_t;

 static ktrace_state_t KTRACE_STATE;

 ssize_t ktrace_read_user(void* ptr, uint32_t off, size_t len) {
     ktrace_state_t* ks = &KTRACE_STATE;

     // Buffer size is limited by the marker if set,
     // otherwise limited by offset (last written point).
     // Offset can end up pointing past the end, so clip
     // it to the actual buffer size to be safe.
     uint32_t max;
     if (ks->marker) {
         max = ks->marker;
     } else {
         max = ks->offset;
         if (max > ks->bufsize) {
             max = ks->bufsize;
         }
     }

     // null read is a query for trace buffer size
     if (ptr == nullptr) {
         return max;
     }

     // constrain read to available buffer
     if (off >= max) {
         return 0;
     }
     if (len > (max - off)) {
         len = max - off;
     }

     if (arch_copy_to_user(ptr, ks->buffer + off, len) != ZX_OK) {
         return ZX_ERR_INVALID_ARGS;
     }
     return len;
 }

 zx_status_t ktrace_control(uint32_t action, uint32_t options, void* ptr) {
     ktrace_state_t* ks = &KTRACE_STATE;
     switch (action) {
     case KTRACE_ACTION_START:
         options = KTRACE_GRP_TO_MASK(options);
         ks->marker = 0;
         atomic_store(&ks->grpmask, options ? options : KTRACE_GRP_TO_MASK(KTRACE_GRP_ALL));
         ktrace_report_live_processes();
         ktrace_report_live_threads();
         break;
     case KTRACE_ACTION_STOP: {
         atomic_store(&ks->grpmask, 0);
         uint32_t n = ks->offset;
         if (n > ks->bufsize) {
             ks->marker = ks->bufsize;
         } else {
             ks->marker = n;
         }
         break;
     }
     case KTRACE_ACTION_REWIND:
         // roll back to just after the metadata
         atomic_store(&ks->offset, KTRACE_RECSIZE * 2);
         ktrace_report_syscalls(kt_syscall_info);
         ktrace_report_probes();
         ktrace_report_vcpu_meta();
         break;
     case KTRACE_ACTION_NEW_PROBE: {
         fbl::AutoLock lock(&probe_list_lock);
         ktrace_probe_info_t* probe;
         if ((probe = ktrace_find_probe((const char*) ptr)) != nullptr) {
             return probe->num;
         }
         probe = (ktrace_probe_info_t*) calloc(sizeof(*probe) + ZX_MAX_NAME_LEN, 1);
         if (probe == nullptr) {
             return ZX_ERR_NO_MEMORY;
         }
         probe->name = (const char*) (probe + 1);
         memcpy(probe + 1, ptr, ZX_MAX_NAME_LEN);
         ktrace_add_probe(probe);
         return probe->num;
     }
     default:
         return ZX_ERR_INVALID_ARGS;
     }
     return ZX_OK;
 }

 int trace_not_ready = 0;

 void ktrace_init(unsigned level) {
     ktrace_state_t* ks = &KTRACE_STATE;

     uint32_t mb = cmdline_get_uint32("ktrace.bufsize", KTRACE_DEFAULT_BUFSIZE);
     uint32_t grpmask = cmdline_get_uint32("ktrace.grpmask", KTRACE_DEFAULT_GRPMASK);

     if (mb == 0) {
         dprintf(INFO, "ktrace: disabled\n");
         return;
     }

     mb *= (1024*1024);

     zx_status_t status;
     VmAspace* aspace = VmAspace::kernel_aspace();
     if ((status = aspace->Alloc("ktrace", mb, (void**)&ks->buffer, 0, VmAspace::VMM_FLAG_COMMIT,
                                 ARCH_MMU_FLAG_PERM_READ | ARCH_MMU_FLAG_PERM_WRITE)) < 0) {
         dprintf(INFO, "ktrace: cannot alloc buffer %d\n", status);
         return;
     }

     // The last packet written can overhang the end of the buffer,
     // so we reduce the reported size by the max size of a record
     ks->bufsize = mb - 256;

     dprintf(INFO, "ktrace: buffer at %p (%u bytes)\n", ks->buffer, mb);

     // register all static probes
     {
         fbl::AutoLock lock(&probe_list_lock);
         for (auto probe = __start_ktrace_probe;
              probe != __stop_ktrace_probe;
              ++probe) {
             ktrace_add_probe(*probe);
         }
     }

     // write metadata to the first two event slots
     uint64_t n = ktrace_ticks_per_ms();
     ktrace_rec_32b_t* rec = (ktrace_rec_32b_t*) ks->buffer;
     rec[0].tag = TAG_VERSION;
     rec[0].a = KTRACE_VERSION;
     rec[1].tag = TAG_TICKS_PER_MS;
     rec[1].a = (uint32_t)n;
     rec[1].b = (uint32_t)(n >> 32);

     // enable tracing
     atomic_store(&ks->offset, KTRACE_RECSIZE * 2);
     ktrace_report_syscalls(kt_syscall_info);
     ktrace_report_probes();
     atomic_store(&ks->grpmask, KTRACE_GRP_TO_MASK(grpmask));

     // report names of existing threads
     ktrace_report_live_threads();

     // report metadata for VCPUs
     ktrace_report_vcpu_meta();

     // Report an event for "tracing is all set up now".  This also
     // serves to ensure that there will be at least one static probe
     // entry so that the __{start,stop}_ktrace_probe symbols above
     // will be defined by the linker.
     ktrace_probe0("ktrace_ready");
 }

 void ktrace_tiny(uint32_t tag, uint32_t arg) {
     ktrace_state_t* ks = &KTRACE_STATE;
     if (tag & atomic_load(&ks->grpmask)) {
         tag = (tag & 0xFFFFFFF0) | 2;
         int off;
         if ((off = atomic_add(&ks->offset, KTRACE_HDRSIZE)) >= (int)ks->bufsize) {
             // if we arrive at the end, stop
             atomic_store(&ks->grpmask, 0);
         } else {
             ktrace_header_t* hdr = (ktrace_header_t*) (ks->buffer + off);
             hdr->ts = ktrace_timestamp();
             hdr->tag = tag;
             hdr->tid = arg;
         }
     }
 }

 void* ktrace_open(uint32_t tag) {
     ktrace_state_t* ks = &KTRACE_STATE;
     if (!(tag & atomic_load(&ks->grpmask))) {
         return nullptr;
     }

     int off;
     if ((off = atomic_add(&ks->offset, KTRACE_LEN(tag))) >= (int)ks->bufsize) {
         // if we arrive at the end, stop
         atomic_store(&ks->grpmask, 0);
         return nullptr;
     }

     ktrace_header_t* hdr = (ktrace_header_t*) (ks->buffer + off);
     hdr->ts = ktrace_timestamp();
     hdr->tag = tag;
     hdr->tid = (uint32_t)get_current_thread()->user_tid;
     return hdr + 1;
 }

 void ktrace_name_etc(uint32_t tag, uint32_t id, uint32_t arg, const char* name, bool always) {
     ktrace_state_t* ks = &KTRACE_STATE;
     if ((tag & atomic_load(&ks->grpmask)) || always) {
         uint32_t len = static_cast<uint32_t>(strnlen(name, ZX_MAX_NAME_LEN - 1));

         // set size to: sizeof(hdr) + len + 1, round up to multiple of 8
         tag = (tag & 0xFFFFFFF0) | ((KTRACE_NAMESIZE + len + 1 + 7) >> 3);

         int off;
         if ((off = atomic_add(&ks->offset, KTRACE_LEN(tag))) >= (int)ks->bufsize) {
             // if we arrive at the end, stop
             atomic_store(&ks->grpmask, 0);
         } else {
             ktrace_rec_name_t* rec = (ktrace_rec_name_t*) (ks->buffer + off);
             rec->tag = tag;
             rec->id = id;
             rec->arg = arg;
             memcpy(rec->name, name, len);
             rec->name[len] = 0;
         }
     }
 }

 LK_INIT_HOOK(ktrace, ktrace_init, LK_INIT_LEVEL_USER);
	// Copyright 2016 The Fuchsia Authors
	//
	// Use of this source code is governed by a MIT-style
	// license that can be found in the LICENSE file or at
	// https://opensource.org/licenses/MIT

	#include <debug.h>
	#include <err.h>
	#include <platform.h>
	#include <string.h>

	#include <arch/ops.h>
	#include <arch/user_copy.h>
	#include <hypervisor/ktrace.h>
	#include <kernel/cmdline.h>
	#include <lib/ktrace.h>
	#include <lk/init.h>
	#include <object/thread_dispatcher.h>
	#include <vm/vm_aspace.h>
	#include <zircon/thread_annotations.h>

	#define ktrace_timestamp() current_ticks();
	#define ktrace_ticks_per_ms() (ticks_per_second() / 1000)

	// Generated struct that has the syscall index and name.
	static struct ktrace_syscall_info {
	uint32_t id;
	uint32_t nargs;
	const char* name;
	} kt_syscall_info [] = {
	#include <zircon/syscall-ktrace-info.inc>
	{0, 0, nullptr}
	};

	void ktrace_report_syscalls(ktrace_syscall_info* call) {
	size_t ix = 0;
	while (call[ix].name) {
	ktrace_name_etc(TAG_SYSCALL_NAME, call[ix].id, 0, call[ix].name, true);
	++ix;
	}
	}

	static uint32_t probe_number = 1;

	extern ktrace_probe_info_t* const __start_ktrace_probe[];
	extern ktrace_probe_info_t* const __stop_ktrace_probe[];

	static fbl::Mutex probe_list_lock;
	static ktrace_probe_info_t* probe_list TA_GUARDED(probe_list_lock);

	static ktrace_probe_info_t* ktrace_find_probe(const char* name) TA_REQ(probe_list_lock) {
	ktrace_probe_info_t* probe;
	for (probe = probe_list; probe != nullptr; probe = probe->next) {
	if (!strcmp(name, probe->name)) {
	return probe;
	}
	}
	return nullptr;
	}

	static void ktrace_add_probe(ktrace_probe_info_t* probe) TA_REQ(probe_list_lock) {
	if (probe->num == 0) {
	probe->num = probe_number++;
	}
	probe->next = probe_list;
	probe_list = probe;
	ktrace_name_etc(TAG_PROBE_NAME, probe->num, 0, probe->name, true);
	}

	static void ktrace_report_probes(void) {
	fbl::AutoLock lock(&probe_list_lock);
	ktrace_probe_info_t *probe;
	for (probe = probe_list; probe != nullptr; probe = probe->next) {
	ktrace_name_etc(TAG_PROBE_NAME, probe->num, 0, probe->name, true);
	}
	}

	typedef struct ktrace_state {
	// where the next record will be written
	int offset;

	// mask of groups we allow, 0 == tracing disabled
	int grpmask;

	// total size of the trace buffer
	uint32_t bufsize;

	// offset where tracing was stopped, 0 if tracing active
	uint32_t marker;

	// raw trace buffer
	uint8_t* buffer;
	} ktrace_state_t;

	static ktrace_state_t KTRACE_STATE;

	ssize_t ktrace_read_user(void* ptr, uint32_t off, size_t len) {
	ktrace_state_t* ks = &KTRACE_STATE;

	// Buffer size is limited by the marker if set,
	// otherwise limited by offset (last written point).
	// Offset can end up pointing past the end, so clip
	// it to the actual buffer size to be safe.
	uint32_t max;
	if (ks->marker) {
	max = ks->marker;
	} else {
	max = ks->offset;
	if (max > ks->bufsize) {
	max = ks->bufsize;
	}
	}

	// null read is a query for trace buffer size
	if (ptr == nullptr) {
	return max;
	}

	// constrain read to available buffer
	if (off >= max) {
	return 0;
	}
	if (len > (max - off)) {
	len = max - off;
	}

	if (arch_copy_to_user(ptr, ks->buffer + off, len) != ZX_OK) {
	return ZX_ERR_INVALID_ARGS;
	}
	return len;
	}

	zx_status_t ktrace_control(uint32_t action, uint32_t options, void* ptr) {
	ktrace_state_t* ks = &KTRACE_STATE;
	switch (action) {
	case KTRACE_ACTION_START:
	options = KTRACE_GRP_TO_MASK(options);
	ks->marker = 0;
	atomic_store(&ks->grpmask, options ? options : KTRACE_GRP_TO_MASK(KTRACE_GRP_ALL));
	ktrace_report_live_processes();
	ktrace_report_live_threads();
	break;
	case KTRACE_ACTION_STOP: {
	atomic_store(&ks->grpmask, 0);
	uint32_t n = ks->offset;
	if (n > ks->bufsize) {
	ks->marker = ks->bufsize;
	} else {
	ks->marker = n;
	}
	break;
	}
	case KTRACE_ACTION_REWIND:
	// roll back to just after the metadata
	atomic_store(&ks->offset, KTRACE_RECSIZE * 2);
	ktrace_report_syscalls(kt_syscall_info);
	ktrace_report_probes();
	ktrace_report_vcpu_meta();
	break;
	case KTRACE_ACTION_NEW_PROBE: {
	fbl::AutoLock lock(&probe_list_lock);
	ktrace_probe_info_t* probe;
	if ((probe = ktrace_find_probe((const char*) ptr)) != nullptr) {
	return probe->num;
	}
	probe = (ktrace_probe_info_t) calloc(sizeof(probe) + ZX_MAX_NAME_LEN, 1);
	if (probe == nullptr) {
	return ZX_ERR_NO_MEMORY;
	}
	probe->name = (const char*) (probe + 1);
	memcpy(probe + 1, ptr, ZX_MAX_NAME_LEN);
	ktrace_add_probe(probe);
	return probe->num;
	}
	default:
	return ZX_ERR_INVALID_ARGS;
	}
	return ZX_OK;
	}

	int trace_not_ready = 0;

	void ktrace_init(unsigned level) {
	ktrace_state_t* ks = &KTRACE_STATE;

	uint32_t mb = cmdline_get_uint32("ktrace.bufsize", KTRACE_DEFAULT_BUFSIZE);
	uint32_t grpmask = cmdline_get_uint32("ktrace.grpmask", KTRACE_DEFAULT_GRPMASK);

	if (mb == 0) {
	dprintf(INFO, "ktrace: disabled\n");
	return;
	}

	mb = (10241024);

	zx_status_t status;
	VmAspace* aspace = VmAspace::kernel_aspace();
	if ((status = aspace->Alloc("ktrace", mb, (void**)&ks->buffer, 0, VmAspace::VMM_FLAG_COMMIT,
	ARCH_MMU_FLAG_PERM_READ \| ARCH_MMU_FLAG_PERM_WRITE)) < 0) {
	dprintf(INFO, "ktrace: cannot alloc buffer %d\n", status);
	return;
	}

	// The last packet written can overhang the end of the buffer,
	// so we reduce the reported size by the max size of a record
	ks->bufsize = mb - 256;

	dprintf(INFO, "ktrace: buffer at %p (%u bytes)\n", ks->buffer, mb);

	// register all static probes
	{
	fbl::AutoLock lock(&probe_list_lock);
	for (auto probe = __start_ktrace_probe;
	probe != __stop_ktrace_probe;
	++probe) {
	ktrace_add_probe(*probe);
	}
	}

	// write metadata to the first two event slots
	uint64_t n = ktrace_ticks_per_ms();
	ktrace_rec_32b_t* rec = (ktrace_rec_32b_t*) ks->buffer;
	rec[0].tag = TAG_VERSION;
	rec[0].a = KTRACE_VERSION;
	rec[1].tag = TAG_TICKS_PER_MS;
	rec[1].a = (uint32_t)n;
	rec[1].b = (uint32_t)(n >> 32);

	// enable tracing
	atomic_store(&ks->offset, KTRACE_RECSIZE * 2);
	ktrace_report_syscalls(kt_syscall_info);
	ktrace_report_probes();
	atomic_store(&ks->grpmask, KTRACE_GRP_TO_MASK(grpmask));

	// report names of existing threads
	ktrace_report_live_threads();

	// report metadata for VCPUs
	ktrace_report_vcpu_meta();

	// Report an event for "tracing is all set up now". This also
	// serves to ensure that there will be at least one static probe
	// entry so that the __{start,stop}_ktrace_probe symbols above
	// will be defined by the linker.
	ktrace_probe0("ktrace_ready");
	}

	void ktrace_tiny(uint32_t tag, uint32_t arg) {
	ktrace_state_t* ks = &KTRACE_STATE;
	if (tag & atomic_load(&ks->grpmask)) {
	tag = (tag & 0xFFFFFFF0) \| 2;
	int off;
	if ((off = atomic_add(&ks->offset, KTRACE_HDRSIZE)) >= (int)ks->bufsize) {
	// if we arrive at the end, stop
	atomic_store(&ks->grpmask, 0);
	} else {
	ktrace_header_t* hdr = (ktrace_header_t*) (ks->buffer + off);
	hdr->ts = ktrace_timestamp();
	hdr->tag = tag;
	hdr->tid = arg;
	}
	}
	}

	void* ktrace_open(uint32_t tag) {
	ktrace_state_t* ks = &KTRACE_STATE;
	if (!(tag & atomic_load(&ks->grpmask))) {
	return nullptr;
	}

	int off;
	if ((off = atomic_add(&ks->offset, KTRACE_LEN(tag))) >= (int)ks->bufsize) {
	// if we arrive at the end, stop
	atomic_store(&ks->grpmask, 0);
	return nullptr;
	}

	ktrace_header_t* hdr = (ktrace_header_t*) (ks->buffer + off);
	hdr->ts = ktrace_timestamp();
	hdr->tag = tag;
	hdr->tid = (uint32_t)get_current_thread()->user_tid;
	return hdr + 1;
	}

	void ktrace_name_etc(uint32_t tag, uint32_t id, uint32_t arg, const char* name, bool always) {
	ktrace_state_t* ks = &KTRACE_STATE;
	if ((tag & atomic_load(&ks->grpmask)) \|\| always) {
	uint32_t len = static_cast<uint32_t>(strnlen(name, ZX_MAX_NAME_LEN - 1));

	// set size to: sizeof(hdr) + len + 1, round up to multiple of 8
	tag = (tag & 0xFFFFFFF0) \| ((KTRACE_NAMESIZE + len + 1 + 7) >> 3);

	int off;
	if ((off = atomic_add(&ks->offset, KTRACE_LEN(tag))) >= (int)ks->bufsize) {
	// if we arrive at the end, stop
	atomic_store(&ks->grpmask, 0);
	} else {
	ktrace_rec_name_t* rec = (ktrace_rec_name_t*) (ks->buffer + off);
	rec->tag = tag;
	rec->id = id;
	rec->arg = arg;
	memcpy(rec->name, name, len);
	rec->name[len] = 0;
	}
	}
	}

	LK_INIT_HOOK(ktrace, ktrace_init, LK_INIT_LEVEL_USER);