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Kernel: Introduce the new SysFS

The intention is to add dynamic mechanism for notifying the userspace
about hotplug events. Currently, the DMI (SMBIOS) blobs and ACPI tables
are exposed in the new filesystem.
This commit is contained in:
Liav A 2021-03-13 12:01:44 +02:00 committed by Andreas Kling
parent dc6defa7af
commit 92c0dab5ab
13 changed files with 839 additions and 202 deletions

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@ -1,16 +1,165 @@
/*
* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
* Copyright (c) 2021, Liav A. <liavalb@hotmail.co.il>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/StringView.h>
#include <Kernel/Arch/PC/BIOS.h>
#include <Kernel/FileSystem/FileDescription.h>
#include <Kernel/KBufferBuilder.h>
#include <Kernel/Sections.h>
#include <Kernel/VM/MemoryManager.h>
#include <Kernel/VM/TypedMapping.h>
namespace Kernel {
#define SMBIOS_BASE_SEARCH_ADDR 0xf0000
#define SMBIOS_END_SEARCH_ADDR 0xfffff
#define SMBIOS_SEARCH_AREA_SIZE (SMBIOS_END_SEARCH_ADDR - SMBIOS_BASE_SEARCH_ADDR)
UNMAP_AFTER_INIT NonnullRefPtr<DMIEntryPointExposedBlob> DMIEntryPointExposedBlob::create(PhysicalAddress dmi_entry_point, size_t blob_size)
{
return adopt_ref(*new (nothrow) DMIEntryPointExposedBlob(dmi_entry_point, blob_size));
}
UNMAP_AFTER_INIT BIOSExposedComponent::BIOSExposedComponent(String name)
: SystemExposedComponent(name)
{
}
KResultOr<size_t> BIOSExposedComponent::read_bytes(off_t offset, size_t count, UserOrKernelBuffer& buffer, FileDescription*) const
{
auto blob = try_to_generate_buffer();
if (!blob)
return KResult(EFAULT);
if ((size_t)offset >= blob->size())
return KSuccess;
ssize_t nread = min(static_cast<off_t>(blob->size() - offset), static_cast<off_t>(count));
if (!buffer.write(blob->data() + offset, nread))
return KResult(EFAULT);
return nread;
}
UNMAP_AFTER_INIT DMIEntryPointExposedBlob::DMIEntryPointExposedBlob(PhysicalAddress dmi_entry_point, size_t blob_size)
: BIOSExposedComponent("smbios_entry_point")
, m_dmi_entry_point(dmi_entry_point)
, m_dmi_entry_point_length(blob_size)
{
}
OwnPtr<KBuffer> DMIEntryPointExposedBlob::try_to_generate_buffer() const
{
auto dmi_blob = map_typed<u8>((m_dmi_entry_point), m_dmi_entry_point_length);
return KBuffer::try_create_with_bytes(Span<u8> { dmi_blob.ptr(), m_dmi_entry_point_length });
}
UNMAP_AFTER_INIT NonnullRefPtr<SMBIOSExposedTable> SMBIOSExposedTable::create(PhysicalAddress smbios_structure_table, size_t smbios_structure_table_length)
{
return adopt_ref(*new (nothrow) SMBIOSExposedTable(smbios_structure_table, smbios_structure_table_length));
}
UNMAP_AFTER_INIT SMBIOSExposedTable::SMBIOSExposedTable(PhysicalAddress smbios_structure_table, size_t smbios_structure_table_length)
: BIOSExposedComponent("DMI")
, m_smbios_structure_table(smbios_structure_table)
, m_smbios_structure_table_length(smbios_structure_table_length)
{
}
OwnPtr<KBuffer> SMBIOSExposedTable::try_to_generate_buffer() const
{
auto dmi_blob = map_typed<u8>((m_smbios_structure_table), m_smbios_structure_table_length);
return KBuffer::try_create_with_bytes(Span<u8> { dmi_blob.ptr(), m_smbios_structure_table_length });
}
UNMAP_AFTER_INIT void BIOSExposedFolder::set_dmi_64_bit_entry_initialization_values()
{
dbgln("BIOSExposedFolder: SMBIOS 64bit Entry point @ {}", m_dmi_entry_point);
auto smbios_entry = map_typed<SMBIOS::EntryPoint64bit>(m_dmi_entry_point, SMBIOS_SEARCH_AREA_SIZE);
m_smbios_structure_table = PhysicalAddress(smbios_entry.ptr()->table_ptr);
m_dmi_entry_point_length = smbios_entry.ptr()->length;
m_smbios_structure_table_length = smbios_entry.ptr()->table_maximum_size;
}
UNMAP_AFTER_INIT void BIOSExposedFolder::set_dmi_32_bit_entry_initialization_values()
{
dbgln("BIOSExposedFolder: SMBIOS 32bit Entry point @ {}", m_dmi_entry_point);
auto smbios_entry = map_typed<SMBIOS::EntryPoint32bit>(m_dmi_entry_point, SMBIOS_SEARCH_AREA_SIZE);
m_smbios_structure_table = PhysicalAddress(smbios_entry.ptr()->legacy_structure.smbios_table_ptr);
m_dmi_entry_point_length = smbios_entry.ptr()->length;
m_smbios_structure_table_length = smbios_entry.ptr()->legacy_structure.smboios_table_length;
}
UNMAP_AFTER_INIT void BIOSExposedFolder::initialize()
{
auto bios_folder = adopt_ref(*new (nothrow) BIOSExposedFolder());
SystemRegistrar::the().register_new_component(bios_folder);
bios_folder->create_components();
}
void BIOSExposedFolder::create_components()
{
auto dmi_entry_point = DMIEntryPointExposedBlob::create(m_dmi_entry_point, m_dmi_entry_point_length);
m_components.append(dmi_entry_point);
auto smbios_table = SMBIOSExposedTable::create(m_smbios_structure_table, m_smbios_structure_table_length);
m_components.append(smbios_table);
}
size_t BIOSExposedFolder::dmi_entry_point_length() const
{
return m_dmi_entry_point_length;
}
size_t BIOSExposedFolder::smbios_structure_table_length() const
{
return m_smbios_structure_table_length;
}
UNMAP_AFTER_INIT void BIOSExposedFolder::initialize_dmi_exposer()
{
VERIFY(!(m_dmi_entry_point.is_null()));
if (m_using_64bit_dmi_entry_point) {
set_dmi_64_bit_entry_initialization_values();
} else {
set_dmi_32_bit_entry_initialization_values();
}
dbgln("BIOSExposedFolder: Data table @ {}", m_smbios_structure_table);
}
OwnPtr<KBuffer> BIOSExposedFolder::smbios_structure_table() const
{
auto dmi_blob = map_typed<u8>(m_smbios_structure_table, m_smbios_structure_table_length);
return KBuffer::try_create_with_bytes(Span<u8> { dmi_blob.ptr(), m_smbios_structure_table_length });
}
UNMAP_AFTER_INIT BIOSExposedFolder::BIOSExposedFolder()
: SystemExposedFolder("bios", SystemRegistrar::the().root_folder())
{
auto entry_32bit = find_dmi_entry32bit_point();
m_dmi_entry_point = entry_32bit.value();
auto entry_64bit = find_dmi_entry64bit_point();
if (entry_64bit.has_value()) {
m_dmi_entry_point = entry_64bit.value();
m_using_64bit_dmi_entry_point = true;
}
if (m_dmi_entry_point.is_null())
return;
initialize_dmi_exposer();
}
UNMAP_AFTER_INIT Optional<PhysicalAddress> BIOSExposedFolder::find_dmi_entry64bit_point()
{
return map_bios().find_chunk_starting_with("_SM3_", 16);
}
UNMAP_AFTER_INIT Optional<PhysicalAddress> BIOSExposedFolder::find_dmi_entry32bit_point()
{
return map_bios().find_chunk_starting_with("_SM_", 16);
}
MappedROM map_bios()
{
MappedROM mapping;

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@ -1,16 +1,123 @@
/*
* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
* Copyright (c) 2021, Liav A. <liavalb@hotmail.co.il>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Types.h>
#include <AK/Vector.h>
#include <Kernel/FileSystem/SysFS.h>
#include <Kernel/KBuffer.h>
#include <Kernel/PhysicalAddress.h>
#include <Kernel/VM/MappedROM.h>
#include <Kernel/VM/Region.h>
#include <Kernel/VirtualAddress.h>
namespace Kernel::SMBIOS {
struct [[gnu::packed]] LegacyEntryPoint32bit {
char legacy_sig[5];
u8 checksum2;
u16 smboios_table_length;
u32 smbios_table_ptr;
u16 smbios_tables_count;
u8 smbios_bcd_revision;
};
struct [[gnu::packed]] EntryPoint32bit {
char sig[4];
u8 checksum;
u8 length;
u8 major_version;
u8 minor_version;
u16 maximum_structure_size;
u8 implementation_revision;
char formatted_area[5];
LegacyEntryPoint32bit legacy_structure;
};
struct [[gnu::packed]] EntryPoint64bit {
char sig[5];
u8 checksum;
u8 length;
u8 major_version;
u8 minor_version;
u8 document_revision;
u8 revision;
u8 reserved;
u32 table_maximum_size;
u64 table_ptr;
};
}
namespace Kernel {
MappedROM map_bios();
MappedROM map_ebda();
class BIOSExposedComponent : public SystemExposedComponent {
public:
virtual KResultOr<size_t> read_bytes(off_t, size_t, UserOrKernelBuffer&, FileDescription*) const override;
protected:
virtual OwnPtr<KBuffer> try_to_generate_buffer() const = 0;
explicit BIOSExposedComponent(String name);
};
class DMIEntryPointExposedBlob : public BIOSExposedComponent {
public:
static NonnullRefPtr<DMIEntryPointExposedBlob> create(PhysicalAddress dmi_entry_point, size_t blob_size);
virtual size_t size() const override { return m_dmi_entry_point_length; }
private:
DMIEntryPointExposedBlob(PhysicalAddress dmi_entry_point, size_t blob_size);
virtual OwnPtr<KBuffer> try_to_generate_buffer() const override;
PhysicalAddress m_dmi_entry_point;
size_t m_dmi_entry_point_length;
};
class SMBIOSExposedTable : public BIOSExposedComponent {
public:
static NonnullRefPtr<SMBIOSExposedTable> create(PhysicalAddress, size_t blob_size);
virtual size_t size() const override { return m_smbios_structure_table_length; }
private:
SMBIOSExposedTable(PhysicalAddress dmi_entry_point, size_t blob_size);
virtual OwnPtr<KBuffer> try_to_generate_buffer() const override;
PhysicalAddress m_smbios_structure_table;
size_t m_smbios_structure_table_length;
};
class BIOSExposedFolder : public SystemExposedFolder {
public:
static void initialize();
void create_components();
private:
OwnPtr<KBuffer> dmi_entry_point() const;
OwnPtr<KBuffer> smbios_structure_table() const;
size_t dmi_entry_point_length() const;
size_t smbios_structure_table_length() const;
BIOSExposedFolder();
void set_dmi_64_bit_entry_initialization_values();
void set_dmi_32_bit_entry_initialization_values();
void initialize_dmi_exposer();
Optional<PhysicalAddress> find_dmi_entry64bit_point();
Optional<PhysicalAddress> find_dmi_entry32bit_point();
PhysicalAddress m_dmi_entry_point;
PhysicalAddress m_smbios_structure_table;
bool m_using_64bit_dmi_entry_point { false };
size_t m_smbios_structure_table_length { 0 };
size_t m_dmi_entry_point_length { 0 };
};
}