From: Palmer Dabbelt <palmer@dabbelt.com>
To: zong.li@sifive.com, linux-riscv@lists.infradead.org, rppt@linux.ibm.com
Cc: linux@armlinux.org.uk, catalin.marinas@arm.com, will@kernel.org,
Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
aou@eecs.berkeley.edu, gxt@pku.edu.cn,
Arnd Bergmann <arnd@arndb.de>,
linus.walleij@linaro.org, akpm@linux-foundation.org,
mchehab+samsung@kernel.org, gregory.0xf0@gmail.com,
masahiroy@kernel.org, Nick Desaulniers <ndesaulniers@google.com>,
bgolaszewski@baylibre.com, steve@sk2.org, tglx@linutronix.de,
keescook@chromium.org, alex@ghiti.fr, mcgrof@kernel.org,
mark.rutland@arm.com, james.morse@arm.com,
alex.shi@linux.alibaba.com, andriy.shevchenko@linux.intel.com,
broonie@kernel.org, rdunlap@infradead.org, davem@davemloft.net,
rostedt@goodmis.org, dan.j.williams@intel.com,
mhiramat@kernel.org, krzk@kernel.org, zaslonko@linux.ibm.com,
matti.vaittinen@fi.rohmeurope.com, uwe@kleine-koenig.org,
clabbe@baylibre.com, changbin.du@intel.com,
Greg KH <gregkh@linuxfoundation.org>,
paulmck@kernel.org, pmladek@suse.com, brendanhiggins@google.com,
glider@google.com, elver@google.com, davidgow@google.com,
ardb@kernel.org, takahiro.akashi@linaro.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org,
linux-arch@vger.kernel.org, kernel-team@android.com,
Palmer Dabbelt <palmerdabbelt@google.com>
Subject: [PATCH v2 1/5] lib: Add a generic version of devmem_is_allowed()
Date: Thu, 9 Jul 2020 14:19:21 -0700 [thread overview]
Message-ID: <20200709211925.1926557-2-palmer@dabbelt.com> (raw)
In-Reply-To: <20200709211925.1926557-1-palmer@dabbelt.com>
From: Palmer Dabbelt <palmerdabbelt@google.com>
As part of adding support for STRICT_DEVMEM to the RISC-V port, Zong
provided a devmem_is_allowed() implementation that's exactly the same as
all the others I checked. Instead I'm adding a generic version, which
will soon be used.
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
---
include/asm-generic/io.h | 4 ++++
lib/Kconfig | 3 +++
lib/Kconfig.debug | 2 +-
lib/Makefile | 2 ++
lib/devmem_is_allowed.c | 27 +++++++++++++++++++++++++++
5 files changed, 37 insertions(+), 1 deletion(-)
create mode 100644 lib/devmem_is_allowed.c
diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
index 8b1e020e9a03..69e3db65fba0 100644
--- a/include/asm-generic/io.h
+++ b/include/asm-generic/io.h
@@ -1122,6 +1122,10 @@ static inline void memcpy_toio(volatile void __iomem *addr, const void *buffer,
}
#endif
+#ifndef CONFIG_GENERIC_DEVMEM_IS_ALLOWED
+extern int devmem_is_allowed(unsigned long pfn);
+#endif
+
#endif /* __KERNEL__ */
#endif /* __ASM_GENERIC_IO_H */
diff --git a/lib/Kconfig b/lib/Kconfig
index df3f3da95990..610c16ecbb7c 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -676,3 +676,6 @@ config GENERIC_LIB_CMPDI2
config GENERIC_LIB_UCMPDI2
bool
+
+config GENERIC_LIB_DEVMEM_IS_ALLOWED
+ bool
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 9ad9210d70a1..e095bd631ba1 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1577,7 +1577,7 @@ config ARCH_HAS_DEVMEM_IS_ALLOWED
config STRICT_DEVMEM
bool "Filter access to /dev/mem"
depends on MMU && DEVMEM
- depends on ARCH_HAS_DEVMEM_IS_ALLOWED
+ depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
default y if PPC || X86 || ARM64
help
If this option is disabled, you allow userspace (root) access to all
diff --git a/lib/Makefile b/lib/Makefile
index b1c42c10073b..554ef14f9be5 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -318,3 +318,5 @@ obj-$(CONFIG_OBJAGG) += objagg.o
# KUnit tests
obj-$(CONFIG_LIST_KUNIT_TEST) += list-test.o
obj-$(CONFIG_LINEAR_RANGES_TEST) += test_linear_ranges.o
+
+obj-$(CONFIG_GENERIC_LIB_DEVMEM_IS_ALLOWED) += devmem_is_allowed.o
diff --git a/lib/devmem_is_allowed.c b/lib/devmem_is_allowed.c
new file mode 100644
index 000000000000..c0d67c541849
--- /dev/null
+++ b/lib/devmem_is_allowed.c
@@ -0,0 +1,27 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * A generic version of devmem_is_allowed.
+ *
+ * Based on arch/arm64/mm/mmap.c
+ *
+ * Copyright (C) 2020 Google, Inc.
+ * Copyright (C) 2012 ARM Ltd.
+ */
+
+#include <linux/mm.h>
+#include <linux/ioport.h>
+
+/*
+ * devmem_is_allowed() checks to see if /dev/mem access to a certain address
+ * is valid. The argument is a physical page number. We mimic x86 here by
+ * disallowing access to system RAM as well as device-exclusive MMIO regions.
+ * This effectively disable read()/write() on /dev/mem.
+ */
+int devmem_is_allowed(unsigned long pfn)
+{
+ if (iomem_is_exclusive(pfn << PAGE_SHIFT))
+ return 0;
+ if (!page_is_ram(pfn))
+ return 1;
+ return 0;
+}
--
2.27.0.383.g050319c2ae-goog
next prev parent reply other threads:[~2020-07-09 21:20 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-09 21:19 Add and use a generic version of devmem_is_allowed() Palmer Dabbelt
2020-07-09 21:19 ` Palmer Dabbelt [this message]
2020-07-09 21:19 ` [PATCH v2 2/5] RISC-V: Use the new generic devmem_is_allowed() Palmer Dabbelt
2020-07-09 21:19 ` [PATCH v2 3/5] arm: Use the " Palmer Dabbelt
2020-07-09 21:19 ` [PATCH v2 4/5] arm64: " Palmer Dabbelt
2020-07-14 18:14 ` Catalin Marinas
2020-07-09 21:19 ` [PATCH v2 5/5] unicore32: " Palmer Dabbelt
2020-07-12 6:09 ` Add and use a generic version of devmem_is_allowed() Mike Rapoport
2020-07-29 0:00 ` Luis Chamberlain
2020-12-11 20:32 ` Palmer Dabbelt
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=20200709211925.1926557-2-palmer@dabbelt.com \
--to=palmer@dabbelt.com \
--cc=akpm@linux-foundation.org \
--cc=alex.shi@linux.alibaba.com \
--cc=alex@ghiti.fr \
--cc=andriy.shevchenko@linux.intel.com \
--cc=aou@eecs.berkeley.edu \
--cc=ardb@kernel.org \
--cc=arnd@arndb.de \
--cc=bgolaszewski@baylibre.com \
--cc=brendanhiggins@google.com \
--cc=broonie@kernel.org \
--cc=catalin.marinas@arm.com \
--cc=changbin.du@intel.com \
--cc=clabbe@baylibre.com \
--cc=dan.j.williams@intel.com \
--cc=davem@davemloft.net \
--cc=davidgow@google.com \
--cc=elver@google.com \
--cc=glider@google.com \
--cc=gregkh@linuxfoundation.org \
--cc=gregory.0xf0@gmail.com \
--cc=gxt@pku.edu.cn \
--cc=james.morse@arm.com \
--cc=keescook@chromium.org \
--cc=kernel-team@android.com \
--cc=krzk@kernel.org \
--cc=linus.walleij@linaro.org \
--cc=linux-arch@vger.kernel.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-riscv@lists.infradead.org \
--cc=linux@armlinux.org.uk \
--cc=mark.rutland@arm.com \
--cc=masahiroy@kernel.org \
--cc=matti.vaittinen@fi.rohmeurope.com \
--cc=mcgrof@kernel.org \
--cc=mchehab+samsung@kernel.org \
--cc=mhiramat@kernel.org \
--cc=ndesaulniers@google.com \
--cc=palmerdabbelt@google.com \
--cc=paul.walmsley@sifive.com \
--cc=paulmck@kernel.org \
--cc=pmladek@suse.com \
--cc=rdunlap@infradead.org \
--cc=rostedt@goodmis.org \
--cc=rppt@linux.ibm.com \
--cc=steve@sk2.org \
--cc=takahiro.akashi@linaro.org \
--cc=tglx@linutronix.de \
--cc=uwe@kleine-koenig.org \
--cc=will@kernel.org \
--cc=zaslonko@linux.ibm.com \
--cc=zong.li@sifive.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).