Add CONFIG_X86_KEYLOCKER to gate whether Key Locker is initialized at boot.
The option is selected by the Key Locker cipher module CRYPTO_AES_KL (to be
added in a later patch).
Add a new command line option "nokeylocker" to optionally override the
default CONFIG_X86_KEYLOCKER=y behavior.
Signed-off-by: Chang S. Bae <chang.seok.bae@xxxxxxxxx>
Reviewed-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: linux-doc@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
Changes from RFC v2:
* Make the option selected by CRYPTO_AES_KL. (Dan Williams)
* Massage the changelog and the config option description.
---
Documentation/admin-guide/kernel-parameters.txt | 2 ++
arch/x86/Kconfig | 3 +++
arch/x86/kernel/cpu/common.c | 16 ++++++++++++++++
3 files changed, 21 insertions(+)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 9725c546a0d4..336495722b12 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3399,6 +3399,8 @@
nohugevmalloc [PPC] Disable kernel huge vmalloc mappings.
+ nokeylocker [X86] Disable Key Locker hardware feature.
+
nosmt [KNL,S390] Disable symmetric multithreading (SMT).
Equivalent to smt=1.
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 5c2ccb85f2ef..191bd4a941eb 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1864,6 +1864,9 @@ config X86_INTEL_MEMORY_PROTECTION_KEYS
If unsure, say y.
+config X86_KEYLOCKER
+ bool
+
choice
prompt "TSX enable mode"
depends on CPU_SUP_INTEL
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 23b4aa437c1e..db1fc9ff0fe3 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -364,6 +364,22 @@ static __always_inline void setup_umip(struct cpuinfo_x86 *c)
/* These bits should not change their value after CPU init is finished. */
static const unsigned long cr4_pinned_mask =
X86_CR4_SMEP | X86_CR4_SMAP | X86_CR4_UMIP | X86_CR4_FSGSBASE;
+
+static __init int x86_nokeylocker_setup(char *arg)
+{
+ /* Expect an exact match without trailing characters. */
+ if (strlen(arg))
+ return 0;
+
+ if (!cpu_feature_enabled(X86_FEATURE_KEYLOCKER))
+ return 1;
+
+ setup_clear_cpu_cap(X86_FEATURE_KEYLOCKER);
+ pr_info("x86/keylocker: Disabled by kernel command line.\n");
+ return 1;
+}
+__setup("nokeylocker", x86_nokeylocker_setup);
+
static DEFINE_STATIC_KEY_FALSE_RO(cr_pinning);
static unsigned long cr4_pinned_bits __ro_after_init;
--
2.17.1
