Merge branch 'linus' into x86/memory-corruption-check

[safe/jmp/linux-2.6] / arch / x86 / Kconfig

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 44d4f21..25e2f7a 100644 (file)
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1061,6 +1061,56 @@ config HIGHPTE
          low memory.  Setting this option will put user-space page table
          entries in high memory.
 
+config X86_CHECK_BIOS_CORRUPTION
+        bool "Check for low memory corruption"
+       help
+        Periodically check for memory corruption in low memory, which
+        is suspected to be caused by BIOS.  Even when enabled in the
+        configuration, it is disabled at runtime.  Enable it by
+        setting "memory_corruption_check=1" on the kernel command
+        line.  By default it scans the low 64k of memory every 60
+        seconds; see the memory_corruption_check_size and
+        memory_corruption_check_period parameters in
+        Documentation/kernel-parameters.txt to adjust this.
+
+        When enabled with the default parameters, this option has
+        almost no overhead, as it reserves a relatively small amount
+        of memory and scans it infrequently.  It both detects corruption
+        and prevents it from affecting the running system.
+
+        It is, however, intended as a diagnostic tool; if repeatable
+        BIOS-originated corruption always affects the same memory,
+        you can use memmap= to prevent the kernel from using that
+        memory.
+
+config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
+        bool "Set the default setting of memory_corruption_check"
+       depends on X86_CHECK_BIOS_CORRUPTION
+       default y
+       help
+        Set whether the default state of memory_corruption_check is
+        on or off.
+
+config X86_RESERVE_LOW_64K
+        bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
+       default y
+       help
+        Reserve the first 64K of physical RAM on BIOSes that are known
+        to potentially corrupt that memory range. A numbers of BIOSes are
+        known to utilize this area during suspend/resume, so it must not
+        be used by the kernel.
+
+        Set this to N if you are absolutely sure that you trust the BIOS
+        to get all its memory reservations and usages right.
+
+        If you have doubts about the BIOS (e.g. suspend/resume does not
+        work or there's kernel crashes after certain hardware hotplug
+        events) and it's not AMI or Phoenix, then you might want to enable
+        X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
+        corruption patterns.
+
+        Say Y if unsure.
+
 config MATH_EMULATION
        bool
        prompt "Math emulation" if X86_32