77 lines
		
	
	
		
			2.1 KiB
		
	
	
	
		
			Nix
		
	
	
	
	
	
			
		
		
	
	
			77 lines
		
	
	
		
			2.1 KiB
		
	
	
	
		
			Nix
		
	
	
	
	
	
{ config, lib, pkgs, ... }:
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with lib;
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let
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  crashdump = config.boot.crashDump;
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  kernelParams = concatStringsSep " " crashdump.kernelParams;
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in
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###### interface
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{
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  options = {
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    boot = {
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      crashDump = {
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        enable = mkOption {
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          type = types.bool;
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          default = false;
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          description = ''
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            If enabled, NixOS will set up a kernel that will
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            boot on crash, and leave the user in systemd rescue
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            to be able to save the crashed kernel dump at
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            /proc/vmcore.
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            It also activates the NMI watchdog.
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          '';
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        };
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        reservedMemory = mkOption {
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          default = "128M";
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          type = types.str;
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          description = ''
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            The amount of memory reserved for the crashdump kernel.
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            If you choose a too high value, dmesg will mention
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            "crashkernel reservation failed".
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          '';
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        };
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        kernelParams = mkOption {
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          type = types.listOf types.str;
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          default = [ "1" "boot.shell_on_fail" ];
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          description = ''
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            Parameters that will be passed to the kernel kexec-ed on crash.
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          '';
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        };
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      };
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    };
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  };
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###### implementation
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  config = mkIf crashdump.enable {
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    boot = {
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      postBootCommands = ''
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        echo "loading crashdump kernel...";
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        ${pkgs.kexectools}/sbin/kexec -p /run/current-system/kernel \
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        --initrd=/run/current-system/initrd \
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        --reset-vga --console-vga \
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        --command-line="systemConfig=$(readlink -f /run/current-system) init=$(readlink -f /run/current-system/init) irqpoll maxcpus=1 reset_devices ${kernelParams}"
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      '';
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      kernelParams = [
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       "crashkernel=${crashdump.reservedMemory}"
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       "nmi_watchdog=panic"
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       "softlockup_panic=1"
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      ];
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      kernelPatches = [ {
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        name = "crashdump-config";
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        patch = null;
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        extraConfig = ''
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                CRASH_DUMP y
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                DEBUG_INFO y
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                PROC_VMCORE y
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                LOCKUP_DETECTOR y
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                HARDLOCKUP_DETECTOR y
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              '';
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        } ];
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    };
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  };
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}
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