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// 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
#include <stdint.h>
#include <sys/types.h>
#include <zircon/compiler.h>
#include <optional>
#include <string_view>
#include <fbl/function.h>
// Cmdline is used to build and access the kernel command line.
// The underlying data is stored as a sequence of zero or more C strings followed by a final \0
// (i.e. an empty string).
// It can be accessed using the Get* methods or via data() and size().
// The Get* methods treat later values as overrides for earlier ones.
// For example, an empty command line is [\0], and a command line containing "a=b" is [a=b\0\0].
class Cmdline {
static constexpr uint32_t kCmdlineMax = 4096;
// Append |str| to the command line.
// |str| should contain "key=value" elements, separated by spaces. Repeated spaces in |str| will
// be combined. Invalid characters will be replaced with '.'.
// For example:
// Append("key=value red foo=bar\n");
// will result in [key=value\0red=\0foo=bar.\0\0]
// Append may be called repeatedly. If |kCmdlineMax| is exceeded, will panic.
// The command line will always be properly terminated.
void Append(const char* str);
// Return the last value for |key| or nullptr if not found.
// When |key| is nullptr, the entire command line is returned.
const char* GetString(const char* key) const;
// Return the last value for |key| or |default_value| if not found.
// "0", "false", and "off" are considered false. All other values are considered true.
bool GetBool(const char* key, bool default_value) const;
// Return the last value for |key| or |default_value| if not found.
uint32_t GetUInt32(const char* key, uint32_t default_value) const;
// Return the last value for |key| or |default_value| if not found.
uint64_t GetUInt64(const char* key, uint64_t default_value) const;
// Process and issue callbacks for the reserved RAM entries of the kernel
// command line, fixing up the entries in response to the results of the
// callback.
// A kernel command line may include commands to reserve sections of
// contiguous physical RAM, usually for testing purposes. Reserved sections
// will be contiguous in physical RAM, off limits to the PMM allocator, and
// accessible by usermode software with access to the root resource or an MMIO
// resource with appropriate range. The commands take the following form.
// kernel.ram.reserve.<name>=<size>,0xXXXXXXXXXXXXXXXX
// Note the "0xXXXXXXXXXXXXXXXX". This is a placeholder for a dynamically
// allocated address and needs to be replicated exactly so that the kernel has
// a place to publish the physical address of the reservation to usermode.
// To assist in processing these regions, the Cmdline class provides the
// ProcessRamReservions method. This method will attempt to find all of the
// requested reservation pairs in the system and call the user supplied
// callback for each. If the reservation fails for any reason, the method
// will erase the entry in the cmd line image, replacing it with
// "." characters instead. If the reservation is successful, the method will
// update the base address placeholder with physical address which was reserved.
// Users must supply a callback function/lambda to the ProcessRamReservations
// call. The size and name of each valid reservation will be supplied to the
// callback, which must return the physical address of the successful
// reservation, or std::nullopt in the case that the reservation fails for any
// reason.
using ProcessRamReservationsCbk =
fbl::InlineFunction<std::optional<uintptr_t>(size_t size, std::string_view name),
void ProcessRamReservations(const ProcessRamReservationsCbk& cbk);
// read-only access to the underlying data
const char* data() const { return data_; }
// Return the size of data() including the final \0.
// Guaranteed to be >= 1;
size_t size() const;
// Adds the given character to data_ and updates length_. If the character would cause the buffer
// to exceed kCmdlineMax, panic.
void AddOrAbort(char c);
// Find the key of the explicitly specified length in our list of command line
// arguments.
const char* FindKey(const char* key, size_t key_len) const;
// Zero-initialize to ensure the |gCmdline| instance of this class lives in the BSS rather than
// DATA segment so we don't bloat the kernel.
char data_[kCmdlineMax]{};
// Does not include the final \0.
size_t length_{};
extern Cmdline gCmdline;
// TODO(53594): migrate these to BootOptions.
namespace kernel_option {
static constexpr const char kBufferchainReservePages[] = "kernel.bufferchain.reserve-pages";
static constexpr const char kBypassDebuglog[] = "kernel.bypass-debuglog";
static constexpr const char kDebugUartPoll[] = "kernel.debug_uart_poll";
static constexpr const char kEnableDebuggingSyscalls[] = "kernel.enable-debugging-syscalls";
static constexpr const char kEnableSerialSysaclls[] = "kernel.enable-serial-syscalls";
static constexpr const char kEntropyTestLen[] = "kernel.entropy-test.len";
static constexpr const char kEntropyTestSrc[] = "kernel.entropy-test.src";
static constexpr const char kForceWatchdogDisabled[] = "kernel.force-watchdog-disabled";
static constexpr const char kGfxConsoleEarly[] = "gfxconsole.early";
static constexpr const char kGfxConsoleFont[] = "gfxconsole.font";
static constexpr const char kHaltOnPanic[] = "kernel.halt-on-panic";
static constexpr const char kKtraceBufSize[] = "ktrace.bufsize";
static constexpr const char kKtraceGrpMask[] = "ktrace.grpmask";
static constexpr const char kMemoryLimitDbg[] = "kernel.memory-limit-dbg";
static constexpr const char kMemoryLimitMb[] = "kernel.memory-limit-mb";
static constexpr const char kPageScannerEnableEviction[] = "";
static constexpr const char kPageScannerDiscardableEvictionsPercent[] =
static constexpr const char kPageScannerPageTableEvictionPolicy[] =
static constexpr const char kPageScannerEnableUserPagerEviction[] =
static constexpr const char kPageScannerPromoteNoClones[] = "";
static constexpr const char kPageScannerStartAtBoot[] = "";
static constexpr const char kPageScannerZeroPageScansPerSecond[] =
static constexpr const char kPmmCheckerAction[] = "kernel.pmm-checker.action";
static constexpr const char kPmmCheckerEnable[] = "kernel.pmm-checker.enable";
static constexpr const char kPmmCheckerFillSize[] = "kernel.pmm-checker.fill-size";
static constexpr const char kPortobserverReservePages[] = "kernel.portobserver.reserve-pages";
static constexpr const char kPortPacketReservePages[] = "kernel.portpacket.reserve-pages";
static constexpr const char kRootJobBehavior[] = "kernel.root-job.behavior";
static constexpr const char kRootJobNotice[] = "kernel.root-job.notice";
static constexpr const char kSerial[] = "kernel.serial";
static constexpr const char kShell[] = "";
static constexpr const char kSmpHt[] = "";
static constexpr const char kSmpMaxCpus[] = "kernel.smp.maxcpus";
static constexpr const char kWallclock[] = "kernel.wallclock";
} // namespace kernel_option