[PATCH v4 09/13] x86/cpu: Add a configuration and command line option for Key Locker
From: Chang S. Bae <hidden>
Date: 2021-12-14 01:00:09
Also in:
linux-doc, lkml
Subsystem:
documentation, the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Jonathan Corbet, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
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 <redacted> Reviewed-by: Dan Williams <redacted> Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org --- 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