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// Copyright 2019 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
#include <align.h>
#include <lib/instrumentation/debugdata.h>
#include <lib/llvm-profdata/llvm-profdata.h>
#include <lib/version.h>
#include <stdint.h>
#include <string.h>
#include <zircon/assert.h>
#include <ktl/byte.h>
#include <ktl/move.h>
#include <ktl/span.h>
#include <ktl/string_view.h>
#include <vm/vm_object_paged.h>
#include "kernel-mapped-vmo.h"
#include "private.h"
#include <ktl/enforce.h>
namespace {
constexpr ktl::string_view kSink = "llvm-profile";
constexpr ktl::string_view kModule = "zircon.elf";
constexpr ktl::string_view kSufix = "profraw";
// This holds the pinned mapping of the live-updated data.
KernelMappedVmo gProfdataLiveData;
} // namespace
InstrumentationDataVmo LlvmProfdataVmo() {
LlvmProfdata profdata;
if (profdata.size_bytes() == 0) {
return {};
// Create a VMO to hold the whole profdata dump.
fbl::RefPtr<VmObjectPaged> vmo;
zx_status_t status = VmObjectPaged::Create(PMM_ALLOC_FLAG_ANY, 0, profdata.size_bytes(),
AttributionObject::GetKernelAttribution(), &vmo);
ZX_ASSERT(status == ZX_OK);
// First fill in just the fixed data, by mapping the whole VMO into the
// kernel address space. Then let the mapping and pinning be cleaned up,
// since we don't need the whole thing mapped into the kernel at runtime.
KernelMappedVmo mapped_vmo;
status = mapped_vmo.Init(vmo, 0, profdata.size_bytes(), "llvm-profdata-setup");
ZX_ASSERT(status == ZX_OK);
ktl::span<ktl::byte> mapped_data{
// Now map in just the pages holding the live data. This mapping will be
// kept alive permanently so the live data can be updated through it.
const uint64_t map_offset =
ROUNDDOWN(ktl::min(profdata.counters_offset(), profdata.bitmap_offset()), PAGE_SIZE);
const size_t map_size =
ROUNDUP_PAGE_SIZE(ktl::max(profdata.counters_offset() + profdata.counters_size_bytes(),
profdata.bitmap_offset() + profdata.bitmap_size_bytes())) -
status = gProfdataLiveData.Init(ktl::move(vmo), map_offset, map_size, "llvm-profdata-live-data");
ZX_ASSERT(status == ZX_OK);
LlvmProfdata::LiveData live_data{
reinterpret_cast<ktl::byte*>(profdata.counters_offset() - map_offset +
reinterpret_cast<ktl::byte*>(profdata.bitmap_offset() - map_offset +
// Live data up to this point have collected in global variable space.
// Copy those data into the mapped VMO data.
// Switch instrumented code over to updating the mapped VMO data in place.
// From this point on, the kernel's VMO mapping is used by all instrumented
// code and must be kept valid and pinned.
// TODO(mcgrathr): We could theoretically decommit the global data pages
// after this to recover that RAM. That part of the kernel's global data
// area should never be accessed again.
auto vmo_name = instrumentation::DebugdataVmoName(kSink, kModule, kSufix, /*is_static=*/false);
return {
.announce = LlvmProfdata::kAnnounce,
.sink_name = LlvmProfdata::kDataSinkName,
.handle = gProfdataLiveData.Publish(ktl::string_view(, vmo_name.size()),