boot_guard_record.h File Reference

Detailed Description

Platform-neutral record format and policy for the early-boot loop guard (see fl/wdt/boot_guard.h).

Everything is always-inline: platforms call it from startup hooks that run before normal code memory is ready.

Definition in file boot_guard_record.h.

#include "fl/stl/stdint.h"
#include "fl/stl/compiler_control.h"

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Classes
struct	fl::BootGuardDecision
	What the early-boot hook does on this boot. More...
struct	fl::BootGuardRecord
	Reset-persistent boot-guard record. More...

Namespaces
namespace	fl
	Base definition for an LED controller.

Functions
FL_ALWAYS_INLINE fl::u32	fl::bootGuardCheck (fl::u32 image, fl::u32 boots, fl::u32 crashes)
FL_ALWAYS_INLINE fl::u32	fl::bootGuardDecode (const volatile BootGuardRecord &r, fl::u32 image)
	Boot count stored in r, or 0 if r is not a valid record of image.
FL_ALWAYS_INLINE fl::u32	fl::bootGuardDecodeCrashes (const volatile BootGuardRecord &r, fl::u32 image)
	Crash count stored in r, or 0 if r is not a valid record of image.
FL_ALWAYS_INLINE void	fl::bootGuardEncode (volatile BootGuardRecord &r, fl::u32 image, fl::u32 boots)
	Store boots, keeping the crash count (0 if the record is invalid).
FL_ALWAYS_INLINE void	fl::bootGuardEncodeCrashes (volatile BootGuardRecord &r, fl::u32 image, fl::u32 crashes)
	Store crashes, keeping the boot count (0 if the record is invalid).
FL_ALWAYS_INLINE fl::u32	fl::bootGuardHashWords (const volatile fl::u32 *words, fl::u32 count, fl::u32 stride=1)
	FNV-1a over every stride-th of count 32-bit words; platforms hash their firmware image with it to get the record key.
FL_ALWAYS_INLINE BootGuardDecision	fl::bootGuardOnBoot (fl::u32 stored_boots, fl::u32 escape_boots)
	Boot-guard policy.
FL_ALWAYS_INLINE void	fl::bootGuardStore (volatile BootGuardRecord &r, fl::u32 image, fl::u32 boots, fl::u32 crashes)
	Store both counts in r as a valid record of image.
FL_ALWAYS_INLINE bool	fl::bootGuardValid (const volatile BootGuardRecord &r, fl::u32 image)
	True when r holds a valid record written by firmware image.

Variables
constexpr fl::u32	fl::kBootGuardMagic = 0xFA57B008u

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Class Documentation

fl::BootGuardDecision

struct fl::BootGuardDecision

Class Members
u32	boots	count to store before continuing
bool	escape	reboot into the bootloader now

fl::BootGuardRecord

struct fl::BootGuardRecord

Class Members
u32	boots	consecutive boots that never called markBootHealthy()
u32	check	checksum of the fields above, rejects power-on garbage
u32	crashes	consecutive watchdog resets (Watchdog::consecutiveCrashCount())
u32	image	key of the firmware image that wrote the record
u32	magic
u32	reserved[3]