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authorLinus Torvalds <torvalds@linux-foundation.org>2024-01-10 18:13:44 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2024-01-10 18:13:44 -0800
commitc29901006179c4c87f9335771e50814ec5707239 (patch)
treee406c7796f5545daaa67c4a0eabea547a9cddea8 /Documentation/driver-api
parentMerge tag 'modules-6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux (diff)
parentasm-generic: Fix 32 bit __generic_cmpxchg_local (diff)
downloadwireguard-linux-c29901006179c4c87f9335771e50814ec5707239.tar.xz
wireguard-linux-c29901006179c4c87f9335771e50814ec5707239.zip
Merge tag 'asm-generic-6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic
Pull asm-generic cleanups from Arnd Bergmann: "A series from Baoquan He cleans up the asm-generic/io.h to remove the ioremap_uc() definition from everything except x86, which still needs it for pre-PAT systems. This series notably contains a patch from Jiaxun Yang that converts MIPS to use asm-generic/io.h like every other architecture does, enabling future cleanups. Some of my own patches fix -Wmissing-prototype warnings in architecture specific code across several architectures. This is now needed as the warning is enabled by default. There are still some remaining warnings in minor platforms, but the series should catch most of the widely used ones make them more consistent with one another. David McKay fixes a bug in __generic_cmpxchg_local() when this is used on 64-bit architectures. This could currently only affect parisc64 and sparc64. Additional cleanups address from Linus Walleij, Uwe Kleine-König, Thomas Huth, and Kefeng Wang help reduce unnecessary inconsistencies between architectures" * tag 'asm-generic-6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: asm-generic: Fix 32 bit __generic_cmpxchg_local Hexagon: Make pfn accessors statics inlines ARC: mm: Make virt_to_pfn() a static inline mips: remove extraneous asm-generic/iomap.h include sparc: Use $(kecho) to announce kernel images being ready arm64: vdso32: Define BUILD_VDSO32_64 to correct prototypes csky: fix arch_jump_label_transform_static override arch: add do_page_fault prototypes arch: add missing prepare_ftrace_return() prototypes arch: vdso: consolidate gettime prototypes arch: include linux/cpu.h for trap_init() prototype arch: fix asm-offsets.c building with -Wmissing-prototypes arch: consolidate arch_irq_work_raise prototypes hexagon: Remove CONFIG_HEXAGON_ARCH_VERSION from uapi header asm/io: remove unnecessary xlate_dev_mem_ptr() and unxlate_dev_mem_ptr() mips: io: remove duplicated codes arch/*/io.h: remove ioremap_uc in some architectures mips: add <asm-generic/io.h> including
Diffstat (limited to 'Documentation/driver-api')
-rw-r--r--Documentation/driver-api/device-io.rst9
1 files changed, 5 insertions, 4 deletions
diff --git a/Documentation/driver-api/device-io.rst b/Documentation/driver-api/device-io.rst
index 2c7abd234f4e..d55384b106bd 100644
--- a/Documentation/driver-api/device-io.rst
+++ b/Documentation/driver-api/device-io.rst
@@ -408,11 +408,12 @@ functions for details on the CPU side of things.
ioremap_uc()
------------
-ioremap_uc() behaves like ioremap() except that on the x86 architecture without
-'PAT' mode, it marks memory as uncached even when the MTRR has designated
-it as cacheable, see Documentation/arch/x86/pat.rst.
+ioremap_uc() is only meaningful on old x86-32 systems with the PAT extension,
+and on ia64 with its slightly unconventional ioremap() behavior, everywhere
+elss ioremap_uc() defaults to return NULL.
-Portable drivers should avoid the use of ioremap_uc().
+
+Portable drivers should avoid the use of ioremap_uc(), use ioremap() instead.
ioremap_cache()
---------------