diff options
Diffstat (limited to 'arch/x86/Kconfig')
| -rw-r--r-- | arch/x86/Kconfig | 71 |
1 files changed, 52 insertions, 19 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 96d058a87100..db3622f22b61 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1123,8 +1123,10 @@ config X86_REBOOTFIXUPS Say N otherwise. config MICROCODE - tristate "CPU microcode loading support" + bool "CPU microcode loading support" + default y depends on CPU_SUP_AMD || CPU_SUP_INTEL + depends on BLK_DEV_INITRD select FW_LOADER ---help--- @@ -1166,24 +1168,6 @@ config MICROCODE_OLD_INTERFACE def_bool y depends on MICROCODE -config MICROCODE_INTEL_EARLY - bool - -config MICROCODE_AMD_EARLY - bool - -config MICROCODE_EARLY - bool "Early load microcode" - depends on MICROCODE=y && BLK_DEV_INITRD - select MICROCODE_INTEL_EARLY if MICROCODE_INTEL - select MICROCODE_AMD_EARLY if MICROCODE_AMD - default y - help - This option provides functionality to read additional microcode data - at the beginning of initrd image. The data tells kernel to load - microcode to CPU's as early as possible. No functional change if no - microcode data is glued to the initrd, therefore it's safe to say Y. - config X86_MSR tristate "/dev/cpu/*/msr - Model-specific register support" ---help--- @@ -2043,6 +2027,55 @@ config COMPAT_VDSO If unsure, say N: if you are compiling your own kernel, you are unlikely to be using a buggy version of glibc. +choice + prompt "vsyscall table for legacy applications" + depends on X86_64 + default LEGACY_VSYSCALL_EMULATE + help + Legacy user code that does not know how to find the vDSO expects + to be able to issue three syscalls by calling fixed addresses in + kernel space. Since this location is not randomized with ASLR, + it can be used to assist security vulnerability exploitation. + + This setting can be changed at boot time via the kernel command + line parameter vsyscall=[native|emulate|none]. + + On a system with recent enough glibc (2.14 or newer) and no + static binaries, you can say None without a performance penalty + to improve security. + + If unsure, select "Emulate". + + config LEGACY_VSYSCALL_NATIVE + bool "Native" + help + Actual executable code is located in the fixed vsyscall + address mapping, implementing time() efficiently. Since + this makes the mapping executable, it can be used during + security vulnerability exploitation (traditionally as + ROP gadgets). This configuration is not recommended. + + config LEGACY_VSYSCALL_EMULATE + bool "Emulate" + help + The kernel traps and emulates calls into the fixed + vsyscall address mapping. This makes the mapping + non-executable, but it still contains known contents, + which could be used in certain rare security vulnerability + exploits. This configuration is recommended when userspace + still uses the vsyscall area. + + config LEGACY_VSYSCALL_NONE + bool "None" + help + There will be no vsyscall mapping at all. This will + eliminate any risk of ASLR bypass due to the vsyscall + fixed address mapping. Attempts to use the vsyscalls + will be reported to dmesg, so that either old or + malicious userspace programs can be identified. + +endchoice + config CMDLINE_BOOL bool "Built-in kernel command line" ---help--- |