From: Arnd Bergmann <arnd@kernel.org>
To: Richard Weinberger <richard@nod.at>,
Anton Ivanov <anton.ivanov@cambridgegreys.com>,
Johannes Berg <johannes@sipsolutions.net>
Cc: Arnd Bergmann <arnd@arndb.de>,
Nathan Chancellor <nathan@kernel.org>,
Nick Desaulniers <nick.desaulniers+lkml@gmail.com>,
Bill Wendling <morbo@google.com>,
Justin Stitt <justinstitt@google.com>,
Benjamin Berg <benjamin.berg@intel.com>,
Niklas Schnelle <schnelle@linux.ibm.com>,
Masahiro Yamada <masahiroy@kernel.org>,
David Gow <davidgow@google.com>,
Nicolas Schier <nicolas.schier@linux.dev>,
linux-um@lists.infradead.org, linux-kernel@vger.kernel.org,
llvm@lists.linux.dev
Subject: [PATCH] um: stop using PCI port I/O
Date: Fri, 9 May 2025 10:40:52 +0200 [thread overview]
Message-ID: <20250509084125.1488601-1-arnd@kernel.org> (raw)
From: Arnd Bergmann <arnd@arndb.de>
arch/um is one of the last users of CONFIG_GENERIC_IOMAP, but upon
closer look it appears that the PCI host bridge does not register
any port I/O, and the absense of both custom inb/outb functions and
a PCI_IOBASE constant means that actually trying to use port I/O
results on a NULL pointer access.
Build testing with clang confirms this by warning about this exact
problem:
include/asm-generic/io.h:549:31: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic]
549 | val = __raw_readb(PCI_IOBASE + addr);
| ~~~~~~~~~~ ^
Remove all the Kconfig selects that refer to legacy port I/O
and instead just build the normal MMIO path that is emulated
by the virtio PCI host.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
arch/um/Kconfig | 6 ------
arch/um/kernel/Makefile | 1 -
arch/um/kernel/ioport.c | 13 -------------
3 files changed, 20 deletions(-)
delete mode 100644 arch/um/kernel/ioport.c
diff --git a/arch/um/Kconfig b/arch/um/Kconfig
index 79509c7f39de..f08e8a7fac93 100644
--- a/arch/um/Kconfig
+++ b/arch/um/Kconfig
@@ -52,13 +52,7 @@ config NO_IOMEM
config UML_IOMEM_EMULATION
bool
select INDIRECT_IOMEM
- select HAS_IOPORT
select GENERIC_PCI_IOMAP
- select GENERIC_IOMAP
- select NO_GENERIC_PCI_IOPORT_MAP
-
-config NO_IOPORT_MAP
- def_bool !UML_IOMEM_EMULATION
config ISA
bool
diff --git a/arch/um/kernel/Makefile b/arch/um/kernel/Makefile
index 4df1cd0d2017..4669db2aa9be 100644
--- a/arch/um/kernel/Makefile
+++ b/arch/um/kernel/Makefile
@@ -25,7 +25,6 @@ obj-$(CONFIG_GPROF) += gprof_syms.o
obj-$(CONFIG_OF) += dtb.o
obj-$(CONFIG_EARLY_PRINTK) += early_printk.o
obj-$(CONFIG_STACKTRACE) += stacktrace.o
-obj-$(CONFIG_GENERIC_PCI_IOMAP) += ioport.o
USER_OBJS := config.o
diff --git a/arch/um/kernel/ioport.c b/arch/um/kernel/ioport.c
deleted file mode 100644
index 7220615b3beb..000000000000
--- a/arch/um/kernel/ioport.c
+++ /dev/null
@@ -1,13 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * Copyright (C) 2021 Intel Corporation
- * Author: Johannes Berg <johannes@sipsolutions.net>
- */
-#include <asm/iomap.h>
-#include <asm-generic/pci_iomap.h>
-
-void __iomem *__pci_ioport_map(struct pci_dev *dev, unsigned long port,
- unsigned int nr)
-{
- return NULL;
-}
--
2.39.5
reply other threads:[~2025-05-09 9:16 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20250509084125.1488601-1-arnd@kernel.org \
--to=arnd@kernel.org \
--cc=anton.ivanov@cambridgegreys.com \
--cc=arnd@arndb.de \
--cc=benjamin.berg@intel.com \
--cc=davidgow@google.com \
--cc=johannes@sipsolutions.net \
--cc=justinstitt@google.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-um@lists.infradead.org \
--cc=llvm@lists.linux.dev \
--cc=masahiroy@kernel.org \
--cc=morbo@google.com \
--cc=nathan@kernel.org \
--cc=nick.desaulniers+lkml@gmail.com \
--cc=nicolas.schier@linux.dev \
--cc=richard@nod.at \
--cc=schnelle@linux.ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).