Changes

2,010 bytes added ,  22:34, 8 January 2018
Created page with "All elements in the Switch's boot chain up to the kernel have the ability to issue a system panic. Panics are handled by writing a panic code in the '''PMC_SCRATCH200''' regi..."
All elements in the Switch's boot chain up to the kernel have the ability to issue a system panic.

Panics are handled by writing a panic code in the '''PMC_SCRATCH200''' register and requesting a reboot by programming a dedicated hardware watchdog ('''WDT4'''). The bootloaders and the Secure Monitor are able to do this right away, but the kernel must invoke the [[SMC#Panic|Panic SMC]].

When the system reboots, the [[Package1#Section_1|encrypted bootloader]] checks if the reset was requested by the watchdog ('''PMC_RST_STATUS''' register is set to 0x01) and parses the panic code stored in '''PMC_SCRATCH200'''.

If a panic did occur, the Switch will paint the main screen with a solid color and halt execution.

= Structure =
{| class=wikitable
! Bits || Field
|-
| 31-28 || Red value
|-
| 27-24 || Green value
|-
| 23-20 || Blue value
|-
| 19-0 || Description
|}

The red, green and blue values are nibbles which represent the color that will fill the panic screen.
Each nibble is duplicated to form a full byte before writing the final color to the display's MMIO.

== Panic colors ==
{| class=wikitable
! Color || Value || Domain
|-
| 0xFF0000 || Kernel
|-
| 0xFFFF00 || Secure Monitor
|-
| 0xFFAA00 || Hardware?
|-
| 0xFF00AA || Bootloader (general errors)
|-
| 0xAAFFFF || Bootloader (wrong bootloader)
|}

== Panic codes ==
{| class=wikitable
! Value || Description
|-
| 0x0 || No information
|-
| 0x1 || Package2 signature verification failed
|-
| 0x2 || Package2 meta verification failed
|-
| 0x3 || Package2 version check failed
|-
| 0x4 || Package2 payload verification failed
|-
| 0x5 || Unknown SMC
|-
| 0x6 || Unknown Abort
|-
| 0x7 ||
|-
| 0x8 ||
|-
| 0x10 || Unknown exception
|-
| 0x20 || Rebooting into SafeMode
|-
| 0x21 || Rebooting for anti-downgrade
|-
| 0x30 || General bootloader error
|-
| 0x31 || Invalid DRAM ID
|-
| 0x32 || Invalid size
|-
| 0x33 || Invalid argument
|-
| 0x34 || Bad GPT
|-
| 0x35 || Failed to boot SafeMode
|-
| 0x40 || Show error called (kernel panic)
|}