x86: introduce /dev/mem restrictions with a config option

[linux-2.6-omap-h63xx.git] / arch / x86 / Kconfig.debug

diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index 2e1e3af28c3a2d5c455b048a330b720a74d1f8bf..0c1890c41279735b68931f2aefe0b54be06638d8 100644 (file)
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -5,6 +5,18 @@ config TRACE_IRQFLAGS_SUPPORT
 
 source "lib/Kconfig.debug"
 
+config NONPROMISC_DEVMEM
+       bool "Disable promiscuous /dev/mem"
+       default y
+       help
+         The /dev/mem file by default 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. With this config
+         option, you allow userspace access to all of memory, including
+         kernel and userspace memory. Accidental access to this is
+         obviously disasterous, but specific access can be used by people
+         debugging the kernel.
+
 config EARLY_PRINTK
        bool "Early printk" if EMBEDDED
        default y
@@ -34,13 +46,9 @@ config DEBUG_STACK_USAGE
 
          This option will slow down process creation somewhat.
 
-comment "Page alloc debug is incompatible with Software Suspend on i386"
-       depends on DEBUG_KERNEL && HIBERNATION
-       depends on X86_32
-
 config DEBUG_PAGEALLOC
        bool "Debug page memory allocations"
-       depends on DEBUG_KERNEL && X86_32
+       depends on DEBUG_KERNEL
        help
          Unmap pages from the kernel linear mapping after free_pages().
          This results in a large slowdown, but helps to find certain types
@@ -58,6 +66,18 @@ config DEBUG_PER_CPU_MAPS
 
          Say N if unsure.
 
+config X86_PTDUMP
+       bool "Export kernel pagetable layout to userspace via debugfs"
+       depends on DEBUG_KERNEL
+       select DEBUG_FS
+       help
+         Say Y here if you want to show the kernel pagetable layout in a
+         debugfs file. This information is only useful for kernel developers
+         who are working in architecture specific areas of the kernel.
+         It is probably not a good idea to enable this feature in a production
+         kernel.
+         If in doubt, say "N"
+
 config DEBUG_RODATA
        bool "Write protect kernel read-only data structures"
        default y
@@ -68,6 +88,18 @@ config DEBUG_RODATA
          data. This is recommended so that we can catch kernel bugs sooner.
          If in doubt, say "Y".
 
+config DIRECT_GBPAGES
+       bool "Enable gbpages-mapped kernel pagetables"
+       depends on DEBUG_KERNEL && EXPERIMENTAL && X86_64
+       help
+         Enable gigabyte pages support (if the CPU supports it). This can
+         improve the kernel's performance a tiny bit by reducing TLB
+         pressure.
+
+         This is experimental code.
+
+         If in doubt, say "N".
+
 config DEBUG_RODATA_TEST
        bool "Testcase for the DEBUG_RODATA feature"
        depends on DEBUG_RODATA
@@ -86,8 +118,8 @@ config DEBUG_NX_TEST
 
 config 4KSTACKS
        bool "Use 4Kb for kernel stacks instead of 8Kb"
-       depends on DEBUG_KERNEL
        depends on X86_32
+       default y
        help
          If you say Y here the kernel will use a 4Kb stacksize for the
          kernel stack attached to each process/thread. This facilitates
@@ -160,7 +192,7 @@ config IO_DELAY_TYPE_NONE
 
 choice
        prompt "IO delay type"
-       default IO_DELAY_0XED
+       default IO_DELAY_0X80
 
 config IO_DELAY_0X80
        bool "port 0x80 based port-IO delay [recommended]"
@@ -220,9 +252,9 @@ config DEBUG_BOOT_PARAMS
          This option will cause struct boot_params to be exported via debugfs.
 
 config CPA_DEBUG
-       bool "CPA self test code"
+       bool "CPA self-test code"
        depends on DEBUG_KERNEL
        help
-         Do change_page_attr self tests at boot.
+         Do change_page_attr() self-tests every 30 seconds.
 
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