arch: consolidate CONFIG_STRICT_DEVM in lib/Kconfig.debug

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 <[email protected]> Cc: Russell King <[email protected]> Cc: Will Deacon <[email protected]> Cc: Benjamin Herrenschmidt <[email protected]> Cc: Martin Schwidefsky <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> Cc: "David S. Miller" <[email protected]> Acked-by: Catalin Marinas <[email protected]> Acked-by: Heiko Carstens <[email protected]> [heiko: drop 'default y' for s390] Acked-by: Ingo Molnar <[email protected]> Suggested-by: Arnd Bergmann <[email protected]> Signed-off-by: Dan Williams <[email protected]>
josf · Jan 9, 2016 · 21266be · 21266be
1 parent 9f9499a
commit 21266be
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Showing 16 changed files with 31 additions and 86 deletions.
diff --git 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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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.