[PATCH v2 1/2] arch: consolidate CONFIG_STRICT_DEVM in lib/Kconfig.debug
From: Dan Williams
Date: Mon Nov 23 2015 - 19:06:34 EST
Let all the archs that implement devmem_is_allowed() opt-in to a common
definition of CONFIG_STRICT_DEVM in lib/Kconfig.debug.
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Acked-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Acked-by: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
[heiko: drop 'default y' for s390]
Acked-by: Ingo Molnar <mingo@xxxxxxxxxx>
Suggested-by: Arnd Bergmann <arnd@xxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
arch/arm/Kconfig | 1 +
arch/arm/Kconfig.debug | 14 --------------
arch/arm64/Kconfig | 1 +
arch/arm64/Kconfig.debug | 14 --------------
arch/frv/Kconfig | 1 +
arch/m32r/Kconfig | 1 +
arch/powerpc/Kconfig | 1 +
arch/powerpc/Kconfig.debug | 12 ------------
arch/s390/Kconfig | 1 +
arch/s390/Kconfig.debug | 12 ------------
arch/tile/Kconfig | 4 +---
arch/unicore32/Kconfig | 1 +
arch/unicore32/Kconfig.debug | 14 --------------
arch/x86/Kconfig | 1 +
arch/x86/Kconfig.debug | 17 -----------------
lib/Kconfig.debug | 22 ++++++++++++++++++++++
16 files changed, 31 insertions(+), 86 deletions(-)
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 0365cbbc9179..c7d92948bb49 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -2,6 +2,7 @@ config ARM
bool
default y
select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
+ select ARCH_HAS_DEVMEM_IS_ALLOWED
select ARCH_HAS_ELF_RANDOMIZE
select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
select ARCH_HAVE_CUSTOM_GPIO_H
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 b/arch/arm64/Kconfig
index 9ac16a482ff1..4e7bf1d73038 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -3,6 +3,7 @@ config ARM64
select ACPI_CCA_REQUIRED if ACPI
select ACPI_GENERIC_GSI if ACPI
select ACPI_REDUCED_HARDWARE_ONLY if ACPI
+ select ARCH_HAS_DEVMEM_IS_ALLOWED
select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
select ARCH_HAS_ELF_RANDOMIZE
select ARCH_HAS_GCOV_PROFILE_ALL
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/frv/Kconfig b/arch/frv/Kconfig
index 34aa19352dc1..03bfd6bf03e7 100644
--- a/arch/frv/Kconfig
+++ b/arch/frv/Kconfig
@@ -10,6 +10,7 @@ config FRV
select HAVE_DEBUG_BUGVERBOSE
select ARCH_HAVE_NMI_SAFE_CMPXCHG
select GENERIC_CPU_DEVICES
+ select ARCH_HAS_DEVMEM_IS_ALLOWED
select ARCH_WANT_IPC_PARSE_VERSION
select OLD_SIGSUSPEND3
select OLD_SIGACTION
diff --git a/arch/m32r/Kconfig b/arch/m32r/Kconfig
index 9e44bbd8051e..836ac5a963c8 100644
--- a/arch/m32r/Kconfig
+++ b/arch/m32r/Kconfig
@@ -13,6 +13,7 @@ config M32R
select GENERIC_IRQ_PROBE
select GENERIC_IRQ_SHOW
select GENERIC_ATOMIC64
+ select ARCH_HAS_DEVMEM_IS_ALLOWED
select ARCH_USES_GETTIMEOFFSET
select MODULES_USE_ELF_RELA
select HAVE_DEBUG_STACKOVERFLOW
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index db49e0d796b1..85eabc49de61 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -159,6 +159,7 @@ config PPC
select EDAC_SUPPORT
select EDAC_ATOMIC_SCRUB
select ARCH_HAS_DMA_SET_COHERENT_MASK
+ select ARCH_HAS_DEVMEM_IS_ALLOWED
select HAVE_ARCH_SECCOMP_FILTER
config GENERIC_CSUM
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 b/arch/s390/Kconfig
index 3a55f493c7da..779becb895be 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -66,6 +66,7 @@ config S390
def_bool y
select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
select ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
+ select ARCH_HAS_DEVMEM_IS_ALLOWED
select ARCH_HAS_ELF_RANDOMIZE
select ARCH_HAS_GCOV_PROFILE_ALL
select ARCH_HAS_SG_CHAIN
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..cf3116887509 100644
--- a/arch/tile/Kconfig
+++ b/arch/tile/Kconfig
@@ -19,6 +19,7 @@ config TILE
select VIRT_TO_BUS
select SYS_HYPERVISOR
select ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
+ select ARCH_HAS_DEVMEM_IS_ALLOWED
select ARCH_HAVE_NMI_SAFE_CMPXCHG
select GENERIC_CLOCKEVENTS
select MODULES_USE_ELF_RELA
@@ -116,9 +117,6 @@ 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 b/arch/unicore32/Kconfig
index c9faddc61100..5dc4c0a43ccd 100644
--- a/arch/unicore32/Kconfig
+++ b/arch/unicore32/Kconfig
@@ -1,5 +1,6 @@
config UNICORE32
def_bool y
+ select ARCH_HAS_DEVMEM_IS_ALLOWED
select ARCH_MIGHT_HAVE_PC_PARPORT
select ARCH_MIGHT_HAVE_PC_SERIO
select HAVE_MEMBLOCK
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 b/arch/x86/Kconfig
index db3622f22b61..75fba1fc205d 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -24,6 +24,7 @@ config X86
select ARCH_DISCARD_MEMBLOCK
select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
select ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
+ select ARCH_HAS_DEVMEM_IS_ALLOWED
select ARCH_HAS_ELF_RANDOMIZE
select ARCH_HAS_FAST_MULTIPLIER
select ARCH_HAS_GCOV_PROFILE_ALL
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..289dfcbc14eb 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1853,3 +1853,25 @@ source "samples/Kconfig"
source "lib/Kconfig.kgdb"
+config ARCH_HAS_DEVMEM_IS_ALLOWED
+ bool
+
+config STRICT_DEVMEM
+ bool "Filter access to /dev/mem"
+ depends on MMU
+ depends on ARCH_HAS_DEVMEM_IS_ALLOWED
+ default y if TILE || PPC
+ ---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.
--
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