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authorPeter Zijlstra <peterz@infradead.org>2022-06-28 01:21:17 +0300
committerBorislav Petkov <bp@suse.de>2022-06-29 18:43:41 +0300
commitf43b9876e857c739d407bc56df288b0ebe1a9164 (patch)
tree22fcf2716b615556869c460a71ed3fd9b1393bd6 /arch/x86/Kconfig
parent26aae8ccbc1972233afd08fb3f368947c0314265 (diff)
downloadlinux-f43b9876e857c739d407bc56df288b0ebe1a9164.tar.xz
x86/retbleed: Add fine grained Kconfig knobs
Do fine-grained Kconfig for all the various retbleed parts. NOTE: if your compiler doesn't support return thunks this will silently 'upgrade' your mitigation to IBPB, you might not like this. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de>
Diffstat (limited to 'arch/x86/Kconfig')
-rw-r--r--arch/x86/Kconfig111
1 files changed, 85 insertions, 26 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index e35eecfb74f2..e58798f636d4 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -462,32 +462,6 @@ config GOLDFISH
def_bool y
depends on X86_GOLDFISH
-config RETPOLINE
- bool "Avoid speculative indirect branches in kernel"
- select OBJTOOL if HAVE_OBJTOOL
- default y
- help
- Compile kernel with the retpoline compiler options to guard against
- kernel-to-user data leaks by avoiding speculative indirect
- branches. Requires a compiler with -mindirect-branch=thunk-extern
- support for full protection. The kernel may run slower.
-
-config CC_HAS_SLS
- def_bool $(cc-option,-mharden-sls=all)
-
-config CC_HAS_RETURN_THUNK
- def_bool $(cc-option,-mfunction-return=thunk-extern)
-
-config SLS
- bool "Mitigate Straight-Line-Speculation"
- depends on CC_HAS_SLS && X86_64
- select OBJTOOL if HAVE_OBJTOOL
- default n
- help
- Compile the kernel with straight-line-speculation options to guard
- against straight line speculation. The kernel image might be slightly
- larger.
-
config X86_CPU_RESCTRL
bool "x86 CPU resource control support"
depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
@@ -2456,6 +2430,91 @@ source "kernel/livepatch/Kconfig"
endmenu
+config CC_HAS_SLS
+ def_bool $(cc-option,-mharden-sls=all)
+
+config CC_HAS_RETURN_THUNK
+ def_bool $(cc-option,-mfunction-return=thunk-extern)
+
+menuconfig SPECULATION_MITIGATIONS
+ bool "Mitigations for speculative execution vulnerabilities"
+ default y
+ help
+ Say Y here to enable options which enable mitigations for
+ speculative execution hardware vulnerabilities.
+
+ If you say N, all mitigations will be disabled. You really
+ should know what you are doing to say so.
+
+if SPECULATION_MITIGATIONS
+
+config PAGE_TABLE_ISOLATION
+ bool "Remove the kernel mapping in user mode"
+ default y
+ depends on (X86_64 || X86_PAE)
+ help
+ This feature reduces the number of hardware side channels by
+ ensuring that the majority of kernel addresses are not mapped
+ into userspace.
+
+ See Documentation/x86/pti.rst for more details.
+
+config RETPOLINE
+ bool "Avoid speculative indirect branches in kernel"
+ select OBJTOOL if HAVE_OBJTOOL
+ default y
+ help
+ Compile kernel with the retpoline compiler options to guard against
+ kernel-to-user data leaks by avoiding speculative indirect
+ branches. Requires a compiler with -mindirect-branch=thunk-extern
+ support for full protection. The kernel may run slower.
+
+config RETHUNK
+ bool "Enable return-thunks"
+ depends on RETPOLINE && CC_HAS_RETURN_THUNK
+ select OBJTOOL if HAVE_OBJTOOL
+ default y
+ help
+ Compile the kernel with the return-thunks compiler option to guard
+ against kernel-to-user data leaks by avoiding return speculation.
+ Requires a compiler with -mfunction-return=thunk-extern
+ support for full protection. The kernel may run slower.
+
+config CPU_UNRET_ENTRY
+ bool "Enable UNRET on kernel entry"
+ depends on CPU_SUP_AMD && RETHUNK
+ default y
+ help
+ Compile the kernel with support for the retbleed=unret mitigation.
+
+config CPU_IBPB_ENTRY
+ bool "Enable IBPB on kernel entry"
+ depends on CPU_SUP_AMD
+ default y
+ help
+ Compile the kernel with support for the retbleed=ibpb mitigation.
+
+config CPU_IBRS_ENTRY
+ bool "Enable IBRS on kernel entry"
+ depends on CPU_SUP_INTEL
+ default y
+ help
+ Compile the kernel with support for the spectre_v2=ibrs mitigation.
+ This mitigates both spectre_v2 and retbleed at great cost to
+ performance.
+
+config SLS
+ bool "Mitigate Straight-Line-Speculation"
+ depends on CC_HAS_SLS && X86_64
+ select OBJTOOL if HAVE_OBJTOOL
+ default n
+ help
+ Compile the kernel with straight-line-speculation options to guard
+ against straight line speculation. The kernel image might be slightly
+ larger.
+
+endif
+
config ARCH_HAS_ADD_PAGES
def_bool y
depends on ARCH_ENABLE_MEMORY_HOTPLUG