0b1f77e74b
Patch series "mm: ioremap: Convert architectures to take GENERIC_IOREMAP way", v8. Motivation and implementation: ============================== Currently, many architecutres have't taken the standard GENERIC_IOREMAP way to implement ioremap_prot(), iounmap(), and ioremap_xx(), but make these functions specifically under each arch's folder. Those cause many duplicated code of ioremap() and iounmap(). In this patchset, firstly introduce generic_ioremap_prot() and generic_iounmap() to extract the generic code for GENERIC_IOREMAP. By taking GENERIC_IOREMAP method, the generic generic_ioremap_prot(), generic_iounmap(), and their generic wrapper ioremap_prot(), ioremap() and iounmap() are all visible and available to arch. Arch needs to provide wrapper functions to override the generic version if there's arch specific handling in its corresponding ioremap_prot(), ioremap() or iounmap(). With these changes, duplicated ioremap/iounmap() code uder ARCH-es are removed, and the equivalent functioality is kept as before. Background info: ================ 1) The converting more architectures to take GENERIC_IOREMAP way is suggested by Christoph in below discussion: https://lore.kernel.org/all/Yp7h0Jv6vpgt6xdZ@infradead.org/T/#u 2) In the previous v1 to v3, it's basically further action after arm64 has converted to GENERIC_IOREMAP way in below patchset. It's done by adding hook ioremap_allowed() and iounmap_allowed() in ARCH to add ARCH specific handling the middle of ioremap_prot() and iounmap(). [PATCH v5 0/6] arm64: Cleanup ioremap() and support ioremap_prot() https://lore.kernel.org/all/20220607125027.44946-1-wangkefeng.wang@huawei.com/T/#u Later, during v3 reviewing, Christophe Leroy suggested to introduce generic_ioremap_prot() and generic_iounmap() to generic codes, and ARCH can provide wrapper function ioremap_prot(), ioremap() or iounmap() if needed. Christophe made a RFC patchset as below to specially demonstrate his idea. This is what v4 and now v5 is doing. [RFC PATCH 0/8] mm: ioremap: Convert architectures to take GENERIC_IOREMAP way https://lore.kernel.org/all/cover.1665568707.git.christophe.leroy@csgroup.eu/T/#u Testing: ======== In v8, I only applied this patchset onto the latest linus's tree to build and run on arm64 and s390. This patch (of 19): Let's use '#define ioremap_xx' and "#ifdef ioremap_xx" instead. To remove defined ARCH_HAS_IOREMAP_xx macros in <asm/io.h> of each ARCH, the ARCH's own ioremap_wc|wt|np definition need be above "#include <asm-generic/iomap.h>. Otherwise the redefinition error would be seen during compiling. So the relevant adjustments are made to avoid compiling error: loongarch: - doesn't include <asm-generic/iomap.h>, defining ARCH_HAS_IOREMAP_WC is redundant, so simply remove it. m68k: - selected GENERIC_IOMAP, <asm-generic/iomap.h> has been added in <asm-generic/io.h>, and <asm/kmap.h> is included above <asm-generic/iomap.h>, so simply remove ARCH_HAS_IOREMAP_WT defining. mips: - move "#include <asm-generic/iomap.h>" below ioremap_wc definition in <asm/io.h> powerpc: - remove "#include <asm-generic/iomap.h>" in <asm/io.h> because it's duplicated with the one in <asm-generic/io.h>, let's rely on the latter. x86: - selected GENERIC_IOMAP, remove #include <asm-generic/iomap.h> in the middle of <asm/io.h>. Let's rely on <asm-generic/io.h>. Link: https://lkml.kernel.org/r/20230706154520.11257-2-bhe@redhat.com Signed-off-by: Baoquan He <bhe@redhat.com> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: David Laight <David.Laight@ACULAB.COM> Cc: Helge Deller <deller@gmx.de> Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Niklas Schnelle <schnelle@linux.ibm.com> Cc: Stafford Horne <shorne@gmail.com> Cc: Brian Cain <bcain@quicinc.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Chris Zankel <chris@zankel.net> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com> Cc: Jonas Bonn <jonas@southpole.se> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Rich Felker <dalias@libc.org> Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vineet Gupta <vgupta@kernel.org> Cc: Will Deacon <will@kernel.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.