Linux kernel: Difference between revisions

(10 intermediate revisions by 9 users not shown)

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</syntaxHighlight>

nix-repl> :l <nixpkgs>

nix-repl> pkgs = import <nixpkgs> {}

Added 12607 variables.

nix-repl> pkgs.~~linuxPackages~~

nix-repl> pkgs.linuxKernel.packages

pkgs.linuxPackages pkgs.linuxPackages_custom

pkgs.linuxPackages-libre pkgs.linuxPackages_custom_tinyconfig_kernel

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{

boot.kernelPatches = [ {

name = "crashdump-config";

patch = null;

~~extraConfig~~ = ''

structuredExtraConfig = with lib.kernel; {

CRASH_DUMP y

CRASH_DUMP = yes;

DEBUG_INFO y

DEBUG_INFO = yes;

PROC_VMCORE y

PROC_VMCORE = yes;

LOCKUP_DETECTOR y

LOCKUP_DETECTOR = yes;

HARDLOCKUP_DETECTOR y

HARDLOCKUP_DETECTOR = yes;

'';

};

} ];

}

</syntaxhighlight>

Another way is to create an overlay to configure ~~either {{ic|extraConfig}} or~~ {{ic|structuredExtraConfig}}. This allows for more flexibility, since you can basically override any available kernel option<ref>[https://github.com/NixOS/nixpkgs/blob/e6db435973160591fe7348876a5567c729495175/pkgs/os-specific/linux/kernel/generic.nix#L11-L56<tt>pkgs/os-specific/linux/kernel/generic.nix#L11-L56</tt>]</ref>. Using {{ic|structuredExtraConfig}} is recommended as it checks if the configured option are correct. You may also want to set {{ic|ignoreConfigErrors}} to avoid {{ic|error: unused option}} during builds.

Another way is to create an overlay to configure {{ic|structuredExtraConfig}}. This allows for more flexibility, since you can basically override any available kernel option<ref>[https://github.com/NixOS/nixpkgs/blob/e6db435973160591fe7348876a5567c729495175/pkgs/os-specific/linux/kernel/generic.nix#L11-L56<tt>pkgs/os-specific/linux/kernel/generic.nix#L11-L56</tt>]</ref>.

{{file|/etc/nixos/configuration.nix|nix|<nowiki>

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SCHED_MUQSS = yes;

};

ignoreConfigErrors = true;

ignoreConfigErrors = true; # not necessarily a good idea

});

})

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}

</nowiki>}}

If the kernel config fails to build with messages like <code>error: unused option: DRM_I915_GVT</code>, try setting e.g. <code>DRM_I915_GVT = lib.kernel.unset</code>. Setting {{ic|ignoreConfigErrors}} will also silence these errors, at the cost of ignoring potential problems. ([https://github.com/NixOS/nixpkgs/blob/3ab9a9d12ba76f6a544c207e1364da5b3087b77c/pkgs/os-specific/linux/kernel/generate-config.pl generate-config.pl] is responsible for these; they are often produced when [https://github.com/NixOS/nixpkgs/blob/3ab9a9d12ba76f6a544c207e1364da5b3087b77c/pkgs/os-specific/linux/kernel/common-config.nix the default config] doesn't use <code>lib.kernel.option</code> for an option that is implicitly disabled by whatever change you made.)

=== Pinning a kernel version ===

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}

</nowiki>}}

Note that pinning the kernel version will likely require manual recompilation, which may be slow on older hardware. See [https://discourse.nixos.org/t/pin-kernel-version/50630/3 this thread] for a related discussion.

=== Debugging a failed configuration ===

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Please provide a comparison with other distributions' kernel:

~~- arch~~: https://~~github~~.~~com~~/archlinux/~~svntogit-~~packages/~~blob~~/~~packages~~/~~linux~~/~~trunk~~/config

~~- debian~~: https://salsa.debian.org/kernel-team/linux/blob/master/debian/config/config and the ARCH specific ones

* Arch: https://gitlab.archlinux.org/archlinux/packaging/packages/linux/-/blob/main/config

* Debian: https://salsa.debian.org/kernel-team/linux/blob/master/debian/config/config and the ARCH specific ones

== Booting a kernel from a custom source ==

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kernelPatches = [];

~~extraConfig~~ = ''

structuredExtraConfig = with lib.kernel; {

INTEL_SGX y

INTEL_SGX = yes;

'';

};

extraMeta.branch = "5.4";

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owner = "aramg";

repo = "droidcam";

~~rev~~ = "v${version}";

tag = "v${version}";

hash = "1d9qpnmqa3pfwsrpjnxdz76ipk4w37bbxyrazchh4vslnfc886fx";

};

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$ nix-shell

# to configure

$ # to configure

$ nix-shell> make $makeFlags defconfig -j $(nproc)

# to build

$ # to build

$ nix-shell> make $makeFlags -j $(nproc)

</syntaxHighlight>

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$ nix-shell

# to configure

$ # to configure

$ nix-shell> make $makeFlags defconfig -j $(nproc)

# to build

$ # to build

$ nix-shell> make $makeFlags -j $(nproc)

</syntaxHighlight>

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=== Overriding kernel packages ===

In order to override <code>linuxPackages</code>, use the <code>extend</code> attribute. Example:

In order to override <code>linuxPackages</code>, an alias of <code>linuxKernel.packages</code>, use the <code>extend</code> attribute. Example:

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})

];

</syntaxHighlight>

You can also use <code>kernelPackagesExtensions</code> in a similar fashion to override <code>linuxKernel.packages</code>:

nixpkgs.overlays = [

(_: prev: {

kernelPackagesExtensions = prev.kernelPackagesExtensions ++ [

(_: linuxPrev: {

digimend = linuxPrev.digimend.overrideAttrs (prevAttrs: {

postPatch = prevAttrs.postPatch or "" + ''

substituteInPlace "hid-uclogic-core.c" \

--replace-fail "del_timer_sync" "timer_shutdown_sync"

'';

});

})

];

})

];

</syntaxHighlight>

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}

</syntaxhighlight>

~~== Troubleshooting ==~~

~~=== Build fails ===~~

~~==== Too high ram usage ====~~

~~turn off <code>DEBUG_INFO_BTF</code>~~

== See also ==

@@ Line 24: / Line 24: @@
 </syntaxHighlight>
 <syntaxhighlight lang="nix">
-nix-repl> :l <nixpkgs>
+nix-repl> pkgs = import <nixpkgs> {}
 Added 12607 variables.
-nix-repl> pkgs.linuxPackages
+nix-repl> pkgs.linuxKernel.packages
 pkgs.linuxPackages                           pkgs.linuxPackages_custom
 pkgs.linuxPackages-libre                     pkgs.linuxPackages_custom_tinyconfig_kernel
@@ Line 127: / Line 127: @@
 <syntaxhighlight lang=nix>
 {
-      boot.kernelPatches = [ {
+  boot.kernelPatches = [ {
-        name = "crashdump-config";
+    name = "crashdump-config";
-        patch = null;
+    patch = null;
-        extraConfig = ''
+    structuredExtraConfig = with lib.kernel; {
-                CRASH_DUMP y
+      CRASH_DUMP = yes;
-                DEBUG_INFO y
+      DEBUG_INFO = yes;
-                PROC_VMCORE y
+      PROC_VMCORE = yes;
-                LOCKUP_DETECTOR y
+      LOCKUP_DETECTOR = yes;
-                HARDLOCKUP_DETECTOR y
+      HARDLOCKUP_DETECTOR = yes;
-              '';
+    };
-        } ];
+  } ];
 }
 </syntaxhighlight>
-Another way is to create an overlay to configure either {{ic|extraConfig}} or {{ic|structuredExtraConfig}}. This allows for more flexibility, since you can basically override any available kernel option<ref>[https://github.com/NixOS/nixpkgs/blob/e6db435973160591fe7348876a5567c729495175/pkgs/os-specific/linux/kernel/generic.nix#L11-L56<tt>pkgs/os-specific/linux/kernel/generic.nix#L11-L56</tt>]</ref>. Using {{ic|structuredExtraConfig}} is recommended as it checks if the configured option are correct. You may also want to set {{ic|ignoreConfigErrors}} to avoid {{ic|error: unused option}} during builds.
+Another way is to create an overlay to configure {{ic|structuredExtraConfig}}. This allows for more flexibility, since you can basically override any available kernel option<ref>[https://github.com/NixOS/nixpkgs/blob/e6db435973160591fe7348876a5567c729495175/pkgs/os-specific/linux/kernel/generic.nix#L11-L56<tt>pkgs/os-specific/linux/kernel/generic.nix#L11-L56</tt>]</ref>.
 {{file|/etc/nixos/configuration.nix|nix|<nowiki>
@@ Line 152: / Line 153: @@
              SCHED_MUQSS = yes;
            };
-           ignoreConfigErrors = true;
+           ignoreConfigErrors = true; # not necessarily a good idea
          });
        })
@@ Line 159: / Line 160: @@
 }
 </nowiki>}}
+If the kernel config fails to build with messages like <code>error: unused option: DRM_I915_GVT</code>, try setting e.g. <code>DRM_I915_GVT = lib.kernel.unset</code>. Setting {{ic|ignoreConfigErrors}} will also silence these errors, at the cost of ignoring potential problems. ([https://github.com/NixOS/nixpkgs/blob/3ab9a9d12ba76f6a544c207e1364da5b3087b77c/pkgs/os-specific/linux/kernel/generate-config.pl generate-config.pl] is responsible for these; they are often produced when [https://github.com/NixOS/nixpkgs/blob/3ab9a9d12ba76f6a544c207e1364da5b3087b77c/pkgs/os-specific/linux/kernel/common-config.nix the default config] doesn't use <code>lib.kernel.option</code> for an option that is implicitly disabled by whatever change you made.)
 === Pinning a kernel version ===
@@ Line 176: / Line 179: @@
 }
 </nowiki>}}
+Note that pinning the kernel version will likely require manual recompilation, which may be slow on older hardware. See [https://discourse.nixos.org/t/pin-kernel-version/50630/3 this thread] for a related discussion.
 === Debugging a failed configuration  ===
@@ Line 236: / Line 241: @@
 Please provide a comparison with other distributions' kernel:
-- arch: https://github.com/archlinux/svntogit-packages/blob/packages/linux/trunk/config
-- debian: https://salsa.debian.org/kernel-team/linux/blob/master/debian/config/config and the ARCH specific ones
+* Arch: https://gitlab.archlinux.org/archlinux/packaging/packages/linux/-/blob/main/config
+* Debian: https://salsa.debian.org/kernel-team/linux/blob/master/debian/config/config and the ARCH specific ones
 == Booting a kernel from a custom source ==
@@ Line 261: / Line 267: @@
            kernelPatches = [];
-           extraConfig = ''
+           structuredExtraConfig = with lib.kernel; {
-             INTEL_SGX y
+             INTEL_SGX = yes;
-           '';
+           };
            extraMeta.branch = "5.4";
@@ Line 286: / Line 292: @@
      owner = "aramg";
      repo = "droidcam";
-     rev = "v${version}";
+     tag = "v${version}";
      hash = "1d9qpnmqa3pfwsrpjnxdz76ipk4w37bbxyrazchh4vslnfc886fx";
    };
@@ Line 440: / Line 446: @@
 <syntaxHighlight lang=console>
 $ nix-shell
-# to configure
+$ # to configure
 $ nix-shell> make $makeFlags defconfig -j $(nproc)
-# to build
+$ # to build
 $ nix-shell> make $makeFlags -j $(nproc)
 </syntaxHighlight>
@@ Line 461: / Line 467: @@
 <syntaxHighlight lang=console>
 $ nix-shell
-# to configure
+$ # to configure
 $ nix-shell> make $makeFlags defconfig -j $(nproc)
-# to build
+$ # to build
 $ nix-shell> make $makeFlags -j $(nproc)
 </syntaxHighlight>
@@ Line 469: / Line 475: @@
 === Overriding kernel packages ===
-In order to override <code>linuxPackages</code>, use the <code>extend</code> attribute. Example:
+In order to override <code>linuxPackages</code>, an alias of <code>linuxKernel.packages</code>, use the <code>extend</code> attribute. Example:
 <syntaxHighlight lang=nix>
@@ Line 493: / Line 499: @@
      })
    ];
+</syntaxHighlight>
+You can also use <code>kernelPackagesExtensions</code> in a similar fashion to override <code>linuxKernel.packages</code>:
+<syntaxHighlight lang=nix>
+nixpkgs.overlays = [
+  (_: prev: {
+    kernelPackagesExtensions = prev.kernelPackagesExtensions ++ [
+      (_: linuxPrev: {
+        digimend = linuxPrev.digimend.overrideAttrs (prevAttrs: {
+          postPatch = prevAttrs.postPatch or "" + ''
+            substituteInPlace "hid-uclogic-core.c" \
+              --replace-fail "del_timer_sync" "timer_shutdown_sync"
+          '';
+        });
+      })
+    ];
+  })
+];
 </syntaxHighlight>
@@ Line 589: / Line 614: @@
 }
 </syntaxhighlight>
-== Troubleshooting ==
-=== Build fails ===
-==== Too high ram usage ====
-turn off <code>DEBUG_INFO_BTF</code>
 == See also ==