[RFC PATCH] make CONFIG_STRICT_DEVMEM a core non-debug feature
Leif Lindholm
leif.lindholm at linaro.org
Tue Nov 4 09:23:56 PST 2014
Most, but not all, architectures supporting CONFIG_STRICT_DEVMEM treat
it as a debug feature - although its function is pretty much the
opposite of debug.
This patch deletes all architecture-specific config options and moves
the option to core code, as a non-debug option.
Signed-off-by: Leif Lindholm <leif.lindholm at linaro.org>
---
Apologies for wide distribution, but this is a bit invasive,
if trivial.
arch/Kconfig | 3 +++
arch/arm/Kconfig | 1 +
arch/arm/Kconfig.debug | 14 --------------
arch/arm64/Kconfig | 1 +
arch/arm64/Kconfig.debug | 14 --------------
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 -----------------
drivers/char/Kconfig | 16 ++++++++++++++++
15 files changed, 26 insertions(+), 86 deletions(-)
diff --git a/arch/Kconfig b/arch/Kconfig
index 05d7a8a..e5f4f03 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -484,6 +484,9 @@ config HAVE_IRQ_EXIT_ON_IRQ_STACK
This spares a stack switch and improves cache usage on softirq
processing.
+config HAVE_ARCH_RESTRICTED_DEVMEM
+ bool
+
#
# ABI hall of shame
#
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 89c4b5c..e04910f 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -30,6 +30,7 @@ config ARM
select HAVE_ARCH_AUDITSYSCALL if (AEABI && !OABI_COMPAT)
select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL
select HAVE_ARCH_KGDB
+ select HAVE_ARCH_RESTRICTED_DEVMEM if MMU
select HAVE_ARCH_SECCOMP_FILTER if (AEABI && !OABI_COMPAT)
select HAVE_ARCH_TRACEHOOK
select HAVE_BPF_JIT
diff --git a/arch/arm/Kconfig.debug b/arch/arm/Kconfig.debug
index d8f6a2e..2a02a7d 100644
--- a/arch/arm/Kconfig.debug
+++ b/arch/arm/Kconfig.debug
@@ -14,20 +14,6 @@ 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 9532f8d..90abbb2 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -37,6 +37,7 @@ config ARM64
select HAVE_ARCH_AUDITSYSCALL
select HAVE_ARCH_JUMP_LABEL
select HAVE_ARCH_KGDB
+ select HAVE_ARCH_RESTRICTED_DEVMEM if MMU
select HAVE_ARCH_TRACEHOOK
select HAVE_BPF_JIT
select HAVE_C_RECORDMCOUNT
diff --git a/arch/arm64/Kconfig.debug b/arch/arm64/Kconfig.debug
index 0a12933..d0036dd 100644
--- a/arch/arm64/Kconfig.debug
+++ b/arch/arm64/Kconfig.debug
@@ -6,20 +6,6 @@ config FRAME_POINTER
bool
default y
-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 b/arch/powerpc/Kconfig
index 88eace4..cd35068 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -148,6 +148,7 @@ config PPC
select HAVE_ARCH_AUDITSYSCALL
select ARCH_SUPPORTS_ATOMIC_RMW
select DCACHE_WORD_ACCESS if PPC64 && CPU_LITTLE_ENDIAN
+ select HAVE_ARCH_RESTRICTED_DEVMEM
config GENERIC_CSUM
def_bool CPU_LITTLE_ENDIAN
diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug
index ec2e40f..6f11382 100644
--- a/arch/powerpc/Kconfig.debug
+++ b/arch/powerpc/Kconfig.debug
@@ -334,18 +334,6 @@ 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 f2cf1f9..fe92272 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -109,6 +109,7 @@ config S390
select HAVE_ALIGNED_STRUCT_PAGE if SLUB
select HAVE_ARCH_AUDITSYSCALL
select HAVE_ARCH_JUMP_LABEL if !MARCH_G5
+ select HAVE_ARCH_RESTRICTED_DEVMEM
select HAVE_ARCH_SECCOMP_FILTER
select HAVE_ARCH_TRACEHOOK
select HAVE_ARCH_TRANSPARENT_HUGEPAGE if 64BIT
diff --git a/arch/s390/Kconfig.debug b/arch/s390/Kconfig.debug
index c56878e..26c5d5be 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 7cca418..f881168 100644
--- a/arch/tile/Kconfig
+++ b/arch/tile/Kconfig
@@ -27,6 +27,7 @@ config TILE
select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
select HAVE_DEBUG_STACKOVERFLOW
select ARCH_WANT_FRAME_POINTERS
+ select HAVE_ARCH_RESTRICTED_DEVMEM
# FIXME: investigate whether we need/want these options.
# select HAVE_IOREMAP_PROT
@@ -110,9 +111,6 @@ 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 928237a..574b07f 100644
--- a/arch/unicore32/Kconfig
+++ b/arch/unicore32/Kconfig
@@ -18,6 +18,7 @@ config UNICORE32
select ARCH_WANT_FRAME_POINTERS
select GENERIC_IOMAP
select MODULES_USE_ELF_REL
+ select HAVE_ARCH_RESTRICTED_DEVMEM if MMU
help
UniCore-32 is 32-bit Instruction Set Architecture,
including a series of low-power-consumption RISC chip
diff --git a/arch/unicore32/Kconfig.debug b/arch/unicore32/Kconfig.debug
index 1a36262..f075bbe 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 ded8a67..91392bf 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -137,6 +137,7 @@ config X86
select HAVE_ACPI_APEI_NMI if ACPI
select ACPI_LEGACY_TABLES_LOOKUP if ACPI
select X86_FEATURE_NAMES if PROC_FS
+ select HAVE_ARCH_RESTRICTED_DEVMEM
config INSTRUCTION_DECODER
def_bool y
diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index 61bd2ad..e35d4a1 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/drivers/char/Kconfig b/drivers/char/Kconfig
index efefd12..39f7817 100644
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -6,6 +6,22 @@ menu "Character devices"
source "drivers/tty/Kconfig"
+config STRICT_DEVMEM
+ bool "Reduced access to /dev/mem"
+ depends on HAVE_ARCH_RESTRICTED_DEVMEM
+ default y
+ 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 restricts userspace
+ access to an architecture-specific subset of the physical address
+ space.
+
+ If in doubt, say Y.
+
config DEVKMEM
bool "/dev/kmem virtual device support"
default y
--
1.7.10.4
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