linux: Remove system->linux-architecture procedure.

* gnu/packages/linux.scm (system->linux-architecture): Remove it.
(make-linux-libre-headers*, make-linux-libre*): Adapt them.
* guix/build-system/linux-module.scm (system->arch): Adapt it.
* gnu/packages/instrumentation.scm (uftrace): Ditto.
* gnu/packages/cross-base.scm (cross-kernel-headers): Ditto.
* gnu/packages/bioinformatics.scm (ncbi-vdb): Ditto.
* doc/guix.texi (Porting to a new platform): Update it.

doc/guix.texi

@@ -40276,20 +40276,22 @@ one:
 guix build --target=armv5tel-linux-gnueabi bootstrap-tarballs
 @end example
 
-For this to work, the @code{glibc-dynamic-linker} procedure in
+For this to work, it is first required to register a new platform as
-@code{(gnu packages bootstrap)} must be augmented to return the right
+defined in the @code{(gnu platform)} module.  A platform is making the
-file name for libc's dynamic linker on that platform; likewise,
+connection between a GNU triplet (@pxref{Specifying Target Triplets, GNU
-@code{system->linux-architecture} in @code{(gnu packages linux)} must be
+configuration triplets,, autoconf, Autoconf}), the equivalent
-taught about the new platform.
+@var{system} in Nix notation, the name of the
+@var{glibc-dynamic-linker}, and the corresponding Linux architecture
+name if applicable.
 
-Once these are built, the @code{(gnu packages bootstrap)} module needs
+Once the bootstrap tarball are built, the @code{(gnu packages
-to be updated to refer to these binaries on the target platform.  That
+bootstrap)} module needs to be updated to refer to these binaries on the
-is, the hashes and URLs of the bootstrap tarballs for the new platform
+target platform.  That is, the hashes and URLs of the bootstrap tarballs
-must be added alongside those of the currently supported platforms.  The
+for the new platform must be added alongside those of the currently
-bootstrap Guile tarball is treated specially: it is expected to be
+supported platforms.  The bootstrap Guile tarball is treated specially:
-available locally, and @file{gnu/local.mk} has rules to download it for
+it is expected to be available locally, and @file{gnu/local.mk} has
-the supported architectures; a rule for the new platform must be added
+rules to download it for the supported architectures; a rule for the new
-as well.
+platform must be added as well.
 
 In practice, there may be some complications.  First, it may be that the
 extended GNU triplet that specifies an ABI (like the @code{eabi} suffix

gnu/packages/bioinformatics.scm

@@ -161,6 +161,7 @@ (define-module (gnu packages bioinformatics)
   #:use-module (gnu packages wget)
   #:use-module (gnu packages xml)
   #:use-module (gnu packages xorg)
+  #:use-module (gnu platform)
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-26)
   #:use-module (ice-9 match))
@@ -6576,10 +6577,12 @@ (define-public ncbi-vdb
              ;; architecture name ("i386") instead of the target system prefix
              ;; ("i686").
              (mkdir (string-append (assoc-ref outputs "out") "/ilib"))
-             (copy-recursively (string-append "build/ncbi-vdb/linux/gcc/"
+             (copy-recursively (string-append
-                                              ,(system->linux-architecture
+                                "build/ncbi-vdb/linux/gcc/"
+                                ,(platform-linux-architecture
+                                  (lookup-platform-by-target-or-system
                                    (or (%current-target-system)
-                                                    (%current-system)))
+                                       (%current-system))))
                                               "/rel/ilib")
                                (string-append (assoc-ref outputs "out")
                                               "/ilib"))

gnu/packages/cross-base.scm

@@ -30,6 +30,7 @@ (define-module (gnu packages cross-base)
   #:use-module (gnu packages linux)
   #:use-module (gnu packages hurd)
   #:use-module (gnu packages mingw)
+  #:use-module (gnu platform)
   #:use-module (guix packages)
   #:use-module (guix download)
   #:use-module (guix utils)
@@ -345,7 +346,8 @@ (define xlinux-headers
           `(modify-phases ,phases
              (replace 'build
                (lambda _
-                 (setenv "ARCH" ,(system->linux-architecture target))
+                 (setenv "ARCH" ,(platform-linux-architecture
+                                  (lookup-platform-by-target target)))
                  (format #t "`ARCH' set to `~a' (cross compiling)~%"
                          (getenv "ARCH"))
 

gnu/packages/instrumentation.scm

@@ -42,6 +42,7 @@ (define-module (gnu packages instrumentation)
   #:use-module (gnu packages swig)
   #:use-module (gnu packages tbb)
   #:use-module (gnu packages xml)
+  #:use-module (gnu platform)
   #:use-module (guix build-system cmake)
   #:use-module (guix build-system copy)
   #:use-module (guix build-system gnu)
@@ -312,9 +313,10 @@ (define-public uftrace
        (modify-phases %standard-phases
          (replace 'configure
            (lambda* (#:key outputs target #:allow-other-keys)
-             (let ((arch ,(system->linux-architecture
+             (let ((arch ,(platform-linux-architecture
+                           (lookup-platform-by-target-or-system
                             (or (%current-target-system)
-                               (%current-system)))))
+                                (%current-system))))))
                (setenv "ARCH"
                        (cond
                         ((string=? arch "arm64") "aarch64")

gnu/packages/linux.scm

@@ -158,6 +158,7 @@ (define-module (gnu packages linux)
   #:use-module (gnu packages groff)
   #:use-module (gnu packages selinux)
   #:use-module (gnu packages swig)
+  #:use-module (gnu platform)
   #:use-module (guix build-system cmake)
   #:use-module (guix build-system copy)
   #:use-module (guix build-system gnu)
@@ -181,20 +182,6 @@ (define-module (gnu packages linux)
   #:use-module (ice-9 match)
   #:use-module (ice-9 regex))
 
-(define-public (system->linux-architecture arch)
-  "Return the Linux architecture name for ARCH, a Guix system name such as
-\"x86_64-linux\" or a target triplet such as \"arm-linux-gnueabihf\"."
-  (let ((arch (car (string-split arch #\-))))
-    (cond ((string=? arch "i686") "i386")
-          ((string-prefix? "mips" arch) "mips")
-          ((string-prefix? "arm" arch) "arm")
-          ((string-prefix? "aarch64" arch) "arm64")
-          ((string-prefix? "alpha" arch) "alpha")
-          ((string-prefix? "powerpc" arch) "powerpc") ;including "powerpc64le"
-          ((string-prefix? "s390" arch) "s390")
-          ((string-prefix? "riscv" arch) "riscv")
-          (else arch))))
-
 (define-public (system->defconfig system)
   "Some systems (notably powerpc-linux) require a special target for kernel
 defconfig.  Return the appropriate make target if applicable, otherwise return
@@ -567,9 +554,10 @@ (define (make-linux-libre-headers* version gnu-revision source)
          (delete 'configure)
          (replace 'build
            (lambda _
-             (let ((arch ,(system->linux-architecture
+             (let ((arch ,(platform-linux-architecture
+                           (lookup-platform-by-target-or-system
                             (or (%current-target-system)
-                              (%current-system))))
+                                (%current-system)))))
                    (defconfig ,(system->defconfig
                                 (or (%current-target-system)
                                     (%current-system))))
@@ -807,8 +795,9 @@ (define* (make-linux-libre* version gnu-revision source supported-systems
 
        ,@(match (and configuration-file
                      (configuration-file
-                      (system->linux-architecture
+                      (platform-linux-architecture
-                       (or (%current-target-system) (%current-system)))
+                       (lookup-platform-by-target-or-system
+                        (or (%current-target-system) (%current-system))))
                       #:variant (version-major+minor version)))
            (#f                                    ;no config for this platform
             '())
@@ -839,9 +828,10 @@ (define* (make-linux-libre* version gnu-revision source supported-systems
                    (setenv "KBUILD_BUILD_HOST" "guix")
 
                    ;; Set ARCH and CROSS_COMPILE.
-                   (let ((arch #$(system->linux-architecture
+                   (let ((arch #$(platform-linux-architecture
+                                  (lookup-platform-by-target-or-system
                                    (or (%current-target-system)
-                                      (%current-system)))))
+                                       (%current-system))))))
                      (setenv "ARCH" arch)
                      (format #t "`ARCH' set to `~a'~%" (getenv "ARCH"))
 

guix/build-system/linux-module.scm

@@ -50,8 +50,8 @@ (define (default-linux)
     (module-ref module 'linux-libre)))
 
 (define (system->arch system)
-  (let ((module (resolve-interface '(gnu packages linux))))
+  (let ((module (resolve-interface '(gnu platform))))
-    ((module-ref module 'system->linux-architecture) system)))
+    ((module-ref module 'lookup-platform-by-target-or-system) system)))
 
 (define (make-linux-module-builder linux)
   (package