diff mbox

[1/2] arch: consolidate CONFIG_STRICT_DEVM in lib/Kconfig.debug

Message ID 20151122035702.9313.52457.stgit@dwillia2-desk3.jf.intel.com (mailing list archive)
State Superseded
Headers show

Commit Message

Dan Williams Nov. 22, 2015, 3:57 a.m. UTC
Let all the archs that implement CONFIG_STRICT_DEVM use a common
definition in lib/Kconfig.debug.

Note, the 'depends on !SPARC' is due to sparc not implementing
devmem_is_allowed().

Cc: Kees Cook <keescook@chromium.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "David S. Miller" <davem@davemloft.net>
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 arch/arm/Kconfig.debug       |   14 --------------
 arch/arm64/Kconfig.debug     |   14 --------------
 arch/powerpc/Kconfig.debug   |   12 ------------
 arch/s390/Kconfig.debug      |   12 ------------
 arch/tile/Kconfig            |    3 ---
 arch/unicore32/Kconfig.debug |   14 --------------
 arch/x86/Kconfig.debug       |   17 -----------------
 lib/Kconfig.debug            |   19 +++++++++++++++++++
 8 files changed, 19 insertions(+), 86 deletions(-)

Comments

Ingo Molnar Nov. 23, 2015, 8:12 a.m. UTC | #1
* Dan Williams <dan.j.williams@intel.com> wrote:

> Let all the archs that implement CONFIG_STRICT_DEVM use a common
> definition in lib/Kconfig.debug.

For the x86 bit:

Acked-by: Ingo Molnar <mingo@kernel.org>

> Note, the 'depends on !SPARC' is due to sparc not implementing
> devmem_is_allowed().

Maybe that should be converted into a helper Kconfig switch for architectures to 
opt in to /dev/mem restrictions?

Thanks,

	Ingo
Dan Williams Nov. 23, 2015, 5:09 p.m. UTC | #2
On Mon, Nov 23, 2015 at 1:53 AM, Heiko Carstens
<heiko.carstens@de.ibm.com> wrote:
> On Sat, Nov 21, 2015 at 07:57:02PM -0800, Dan Williams wrote:
>> Let all the archs that implement CONFIG_STRICT_DEVM use a common
>> definition in lib/Kconfig.debug.
>>
>> Note, the 'depends on !SPARC' is due to sparc not implementing
>> devmem_is_allowed().
>>
>> Cc: Kees Cook <keescook@chromium.org>
>> Cc: Russell King <linux@arm.linux.org.uk>
>> Cc: Catalin Marinas <catalin.marinas@arm.com>
>> Cc: Will Deacon <will.deacon@arm.com>
>> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
>> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
>> Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
>> Cc: Thomas Gleixner <tglx@linutronix.de>
>> Cc: Ingo Molnar <mingo@redhat.com>
>> Cc: "H. Peter Anvin" <hpa@zytor.com>
>> Cc: Andrew Morton <akpm@linux-foundation.org>
>> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>> Cc: "David S. Miller" <davem@davemloft.net>
>> Suggested-by: Arnd Bergmann <arnd@arndb.de>
>> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
>> ---
>>  arch/arm/Kconfig.debug       |   14 --------------
>>  arch/arm64/Kconfig.debug     |   14 --------------
>>  arch/powerpc/Kconfig.debug   |   12 ------------
>>  arch/s390/Kconfig.debug      |   12 ------------
>>  arch/tile/Kconfig            |    3 ---
>>  arch/unicore32/Kconfig.debug |   14 --------------
>>  arch/x86/Kconfig.debug       |   17 -----------------
>>  lib/Kconfig.debug            |   19 +++++++++++++++++++
>>  8 files changed, 19 insertions(+), 86 deletions(-)
>
> For s390
>
> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
>
>> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
>> index 8c15b29d5adc..ad85145d0047 100644
>> --- a/lib/Kconfig.debug
>> +++ b/lib/Kconfig.debug
>> @@ -1853,3 +1853,22 @@ source "samples/Kconfig"
>>
>>  source "lib/Kconfig.kgdb"
>>
>> +config STRICT_DEVMEM
>> +     bool "Filter access to /dev/mem"
>> +     depends on MMU
>> +     depends on !SPARC
>> +     default y if TILE || PPC || S390
>
> I wouldn't mind if you would remove s390 from this list.
>

Will do. Thanks.
Dan Williams Nov. 23, 2015, 5:12 p.m. UTC | #3
On Mon, Nov 23, 2015 at 12:12 AM, Ingo Molnar <mingo@kernel.org> wrote:
>
> * Dan Williams <dan.j.williams@intel.com> wrote:
>
>> Let all the archs that implement CONFIG_STRICT_DEVM use a common
>> definition in lib/Kconfig.debug.
>
> For the x86 bit:
>
> Acked-by: Ingo Molnar <mingo@kernel.org>
>
>> Note, the 'depends on !SPARC' is due to sparc not implementing
>> devmem_is_allowed().
>
> Maybe that should be converted into a helper Kconfig switch for architectures to
> opt in to /dev/mem restrictions?

Sure, easy enough to add a ARCH_HAS_DEVMEM_IS_ALLOWED opt-in.
Ingo Molnar Nov. 24, 2015, 8:27 a.m. UTC | #4
* Kees Cook <keescook@chromium.org> wrote:

> On Mon, Nov 23, 2015 at 9:12 AM, Dan Williams <dan.j.williams@intel.com> wrote:
> > On Mon, Nov 23, 2015 at 12:12 AM, Ingo Molnar <mingo@kernel.org> wrote:
> >>
> >> * Dan Williams <dan.j.williams@intel.com> wrote:
> >>
> >>> Let all the archs that implement CONFIG_STRICT_DEVM use a common
> >>> definition in lib/Kconfig.debug.
> >>
> >> For the x86 bit:
> >>
> >> Acked-by: Ingo Molnar <mingo@kernel.org>
> >>
> >>> Note, the 'depends on !SPARC' is due to sparc not implementing
> >>> devmem_is_allowed().
> >>
> >> Maybe that should be converted into a helper Kconfig switch for architectures to
> >> opt in to /dev/mem restrictions?
> >
> > Sure, easy enough to add a ARCH_HAS_DEVMEM_IS_ALLOWED opt-in.
> 
> Is there some hidden meaning about the difference between ARCH_HAS_...
> and HAVE_ARCH_... and HAVE_... ?

There's also the double underscore variants such as __HAVE_ARCH_STRNCASECMP! ;-)

It's all just nonsensical historic muck: because no-one ever was confronted with 
the messy global picture.

Today you can run Documentation/features/list-arch.sh and wonder at the zoo of 
options ;-)

Thanks,

	Ingo
diff mbox

Patch

diff --git a/arch/arm/Kconfig.debug b/arch/arm/Kconfig.debug
index 259c0ca9c99a..e356357d86bb 100644
--- a/arch/arm/Kconfig.debug
+++ b/arch/arm/Kconfig.debug
@@ -15,20 +15,6 @@  config ARM_PTDUMP
 	  kernel.
 	  If in doubt, say "N"
 
-config STRICT_DEVMEM
-	bool "Filter access to /dev/mem"
-	depends on MMU
-	---help---
-	  If this option is disabled, you allow userspace (root) access to all
-	  of memory, including kernel and userspace memory. Accidental
-	  access to this is obviously disastrous, but specific access can
-	  be used by people debugging the kernel.
-
-	  If this option is switched on, the /dev/mem file only allows
-	  userspace access to memory mapped peripherals.
-
-          If in doubt, say Y.
-
 # RMK wants arm kernels compiled with frame pointers or stack unwinding.
 # If you know what you are doing and are willing to live without stack
 # traces, you can get a slightly smaller kernel by setting this option to
diff --git a/arch/arm64/Kconfig.debug b/arch/arm64/Kconfig.debug
index 04fb73b973f1..e13c4bf84d9e 100644
--- a/arch/arm64/Kconfig.debug
+++ b/arch/arm64/Kconfig.debug
@@ -14,20 +14,6 @@  config ARM64_PTDUMP
 	  kernel.
 	  If in doubt, say "N"
 
-config STRICT_DEVMEM
-	bool "Filter access to /dev/mem"
-	depends on MMU
-	help
-	  If this option is disabled, you allow userspace (root) access to all
-	  of memory, including kernel and userspace memory. Accidental
-	  access to this is obviously disastrous, but specific access can
-	  be used by people debugging the kernel.
-
-	  If this option is switched on, the /dev/mem file only allows
-	  userspace access to memory mapped peripherals.
-
-	  If in doubt, say Y.
-
 config PID_IN_CONTEXTIDR
 	bool "Write the current PID to the CONTEXTIDR register"
 	help
diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug
index 3a510f4a6b68..a0e44a9c456f 100644
--- a/arch/powerpc/Kconfig.debug
+++ b/arch/powerpc/Kconfig.debug
@@ -335,18 +335,6 @@  config PPC_EARLY_DEBUG_CPM_ADDR
 	  platform probing is done, all platforms selected must
 	  share the same address.
 
-config STRICT_DEVMEM
-	def_bool y
-	prompt "Filter access to /dev/mem"
-	help
-	  This option restricts access to /dev/mem.  If this option is
-	  disabled, you allow userspace access to all memory, including
-	  kernel and userspace memory. Accidental memory access is likely
-	  to be disastrous.
-	  Memory access is required for experts who want to debug the kernel.
-
-	  If you are unsure, say Y.
-
 config FAIL_IOMMU
 	bool "Fault-injection capability for IOMMU"
 	depends on FAULT_INJECTION
diff --git a/arch/s390/Kconfig.debug b/arch/s390/Kconfig.debug
index c56878e1245f..26c5d5beb4be 100644
--- a/arch/s390/Kconfig.debug
+++ b/arch/s390/Kconfig.debug
@@ -5,18 +5,6 @@  config TRACE_IRQFLAGS_SUPPORT
 
 source "lib/Kconfig.debug"
 
-config STRICT_DEVMEM
-	def_bool y
-	prompt "Filter access to /dev/mem"
-	---help---
-	  This option restricts access to /dev/mem.  If this option is
-	  disabled, you allow userspace access to all memory, including
-	  kernel and userspace memory. Accidental memory access is likely
-	  to be disastrous.
-	  Memory access is required for experts who want to debug the kernel.
-
-	  If you are unsure, say Y.
-
 config S390_PTDUMP
 	bool "Export kernel pagetable layout to userspace via debugfs"
 	depends on DEBUG_KERNEL
diff --git a/arch/tile/Kconfig b/arch/tile/Kconfig
index 106c21bd7f44..7b2d40db11fa 100644
--- a/arch/tile/Kconfig
+++ b/arch/tile/Kconfig
@@ -116,9 +116,6 @@  config ARCH_DISCONTIGMEM_DEFAULT
 config TRACE_IRQFLAGS_SUPPORT
 	def_bool y
 
-config STRICT_DEVMEM
-	def_bool y
-
 # SMP is required for Tilera Linux.
 config SMP
 	def_bool y
diff --git a/arch/unicore32/Kconfig.debug b/arch/unicore32/Kconfig.debug
index 1a3626239843..f075bbe1d46f 100644
--- a/arch/unicore32/Kconfig.debug
+++ b/arch/unicore32/Kconfig.debug
@@ -2,20 +2,6 @@  menu "Kernel hacking"
 
 source "lib/Kconfig.debug"
 
-config STRICT_DEVMEM
-	bool "Filter access to /dev/mem"
-	depends on MMU
-	---help---
-	  If this option is disabled, you allow userspace (root) access to all
-	  of memory, including kernel and userspace memory. Accidental
-	  access to this is obviously disastrous, but specific access can
-	  be used by people debugging the kernel.
-
-	  If this option is switched on, the /dev/mem file only allows
-	  userspace access to memory mapped peripherals.
-
-          If in doubt, say Y.
-
 config EARLY_PRINTK
 	def_bool DEBUG_OCD
 	help
diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index 137dfa96aa14..1116452fcfc2 100644
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -5,23 +5,6 @@  config TRACE_IRQFLAGS_SUPPORT
 
 source "lib/Kconfig.debug"
 
-config STRICT_DEVMEM
-	bool "Filter access to /dev/mem"
-	---help---
-	  If this option is disabled, you allow userspace (root) access to all
-	  of memory, including kernel and userspace memory. Accidental
-	  access to this is obviously disastrous, but specific access can
-	  be used by people debugging the kernel. Note that with PAT support
-	  enabled, even in this case there are restrictions on /dev/mem
-	  use due to the cache aliasing requirements.
-
-	  If this option is switched on, the /dev/mem file only allows
-	  userspace access to PCI space and the BIOS code and data regions.
-	  This is sufficient for dosemu and X and all common users of
-	  /dev/mem.
-
-	  If in doubt, say Y.
-
 config X86_VERBOSE_BOOTUP
 	bool "Enable verbose x86 bootup info messages"
 	default y
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 8c15b29d5adc..ad85145d0047 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1853,3 +1853,22 @@  source "samples/Kconfig"
 
 source "lib/Kconfig.kgdb"
 
+config STRICT_DEVMEM
+	bool "Filter access to /dev/mem"
+	depends on MMU
+	depends on !SPARC
+	default y if TILE || PPC || S390
+	---help---
+	  If this option is disabled, you allow userspace (root) access to all
+	  of memory, including kernel and userspace memory. Accidental
+	  access to this is obviously disastrous, but specific access can
+	  be used by people debugging the kernel. Note that with PAT support
+	  enabled, even in this case there are restrictions on /dev/mem
+	  use due to the cache aliasing requirements.
+
+	  If this option is switched on, the /dev/mem file only allows
+	  userspace access to PCI space and the BIOS code and data regions.
+	  This is sufficient for dosemu and X and all common users of
+	  /dev/mem.
+
+	  If in doubt, say Y.