From: Fenghua Yu <fenghua.yu@intel.com>
To: "Thomas Gleixner" <tglx@linutronix.de>,
"Ingo Molnar" <mingo@redhat.com>,
"Borislav Petkov" <bp@alien8.de>, "H Peter Anvin" <hpa@zytor.com>,
"Dave Hansen" <dave.hansen@intel.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Ashok Raj" <ashok.raj@intel.com>,
"Peter Zijlstra" <peterz@infradead.org>,
"Kalle Valo" <kvalo@codeaurora.org>,
"Xiaoyao Li " <xiaoyao.li@intel.com>,
"Michael Chan" <michael.chan@broadcom.com>,
"Ravi V Shankar" <ravi.v.shankar@intel.com>
Cc: "linux-kernel" <linux-kernel@vger.kernel.org>,
"x86" <x86@kernel.org>,
linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
kvm@vger.kernel.org, Fenghua Yu <fenghua.yu@intel.com>
Subject: [PATCH v6 17/20] x86/clearcpuid: Support feature flag string in kernel option clearcpuid
Date: Wed, 3 Apr 2019 14:22:03 -0700 [thread overview]
Message-ID: <1554326526-172295-18-git-send-email-fenghua.yu@intel.com> (raw)
In-Reply-To: <1554326526-172295-1-git-send-email-fenghua.yu@intel.com>
The kernel option clearcpuid currently only takes feature bit which
can be changed from kernel to kernel.
Extend clearcpuid to use cap flag string, which is defined in
x86_cap_flags[] and won't be changed from kernel to kernel.
And user can easily get the cap flag string from /proc/cpuinfo.
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
---
arch/x86/include/asm/cpufeature.h | 1 +
arch/x86/kernel/cpu/cpuid-deps.c | 26 ++++++++++++++++++++++++++
arch/x86/kernel/fpu/init.c | 3 ++-
3 files changed, 29 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index 0e56ff7e4848..823c4ab82e12 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -133,6 +133,7 @@ extern const char * const x86_bug_flags[NBUGINTS*32];
extern void setup_clear_cpu_cap(unsigned int bit);
extern void clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int bit);
+bool find_cpu_cap(char *cap_flag, unsigned int *pfeature);
#define setup_force_cpu_cap(bit) do { \
set_cpu_cap(&boot_cpu_data, bit); \
diff --git a/arch/x86/kernel/cpu/cpuid-deps.c b/arch/x86/kernel/cpu/cpuid-deps.c
index 3d633f67fbd7..1a71434f7b46 100644
--- a/arch/x86/kernel/cpu/cpuid-deps.c
+++ b/arch/x86/kernel/cpu/cpuid-deps.c
@@ -120,3 +120,29 @@ void setup_clear_cpu_cap(unsigned int feature)
{
do_clear_cpu_cap(NULL, feature);
}
+
+/**
+ * find_cpu_cap - Given a cap flag string, find its corresponding feature bit.
+ * @cap_flag: cap flag string as defined in x86_cap_flags[]
+ * @pfeature: feature bit
+ *
+ * Return: true if the feature is found. false if not found
+ */
+bool find_cpu_cap(char *cap_flag, unsigned int *pfeature)
+{
+#ifdef CONFIG_X86_FEATURE_NAMES
+ unsigned int feature;
+
+ for (feature = 0; feature < NCAPINTS * 32; feature++) {
+ if (!x86_cap_flags[feature])
+ continue;
+
+ if (strcmp(cap_flag, x86_cap_flags[feature]) == 0) {
+ *pfeature = feature;
+
+ return true;
+ }
+ }
+#endif
+ return false;
+}
diff --git a/arch/x86/kernel/fpu/init.c b/arch/x86/kernel/fpu/init.c
index 88bbba7ee96a..99b895eea166 100644
--- a/arch/x86/kernel/fpu/init.c
+++ b/arch/x86/kernel/fpu/init.c
@@ -256,7 +256,8 @@ static void __init clear_cpuid(void)
/* Chang command line range for next search. */
cmdline_size = option_pos - boot_command_line + 1;
argptr = arg;
- if (get_option(&argptr, &bit) &&
+ /* cpu cap can be specified by either feature bit or string */
+ if ((get_option(&argptr, &bit) || find_cpu_cap(arg, &bit)) &&
bit >= 0 && bit < NCAPINTS * 32)
setup_clear_cpu_cap(bit);
}
--
2.19.1
next prev parent reply other threads:[~2019-04-03 21:32 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-03 21:21 [PATCH v6 00/20] x86/split_lock: Enable split locked accesses detection Fenghua Yu
2019-04-03 21:21 ` [PATCH v6 01/20] x86/common: Align cpu_caps_cleared and cpu_caps_set to unsigned long Fenghua Yu
2019-04-04 14:39 ` Borislav Petkov
2019-04-04 15:54 ` Fenghua Yu
2019-04-03 21:21 ` [PATCH v6 02/20] drivers/net/b44: Align pwol_mask to unsigned long for better performance Fenghua Yu
2019-04-03 21:21 ` [PATCH v6 03/20] wlcore: simplify/fix/optimize reg_ch_conf_pending operations Fenghua Yu
2019-04-03 21:21 ` [PATCH v6 04/20] x86/split_lock: Align x86_capability to unsigned long to avoid split locked access Fenghua Yu
2019-04-04 14:44 ` David Laight
2019-04-04 16:24 ` David Laight
2019-04-04 16:35 ` Sean Christopherson
2019-04-04 16:52 ` Thomas Gleixner
2019-04-04 17:29 ` Paolo Bonzini
2019-04-04 18:11 ` Thomas Gleixner
2019-04-05 9:23 ` David Laight
2019-04-03 21:21 ` [PATCH v6 05/20] x86/msr-index: Define MSR_IA32_CORE_CAPABILITY and split lock detection bit Fenghua Yu
2019-04-03 21:21 ` [PATCH v6 06/20] x86/cpufeatures: Enumerate MSR_IA32_CORE_CAPABILITY Fenghua Yu
2019-04-03 21:21 ` [PATCH v6 07/20] x86/split_lock: Enumerate split lock detection by MSR_IA32_CORE_CAPABILITY Fenghua Yu
2019-04-03 21:21 ` [PATCH v6 08/20] x86/split_lock: Enumerate split lock detection on Icelake mobile processor Fenghua Yu
2019-04-03 21:21 ` [PATCH v6 09/20] x86/split_lock: Define MSR_TEST_CTL register Fenghua Yu
2019-04-03 21:21 ` [PATCH v6 10/20] x86/split_lock: Handle #AC exception for split lock Fenghua Yu
2019-04-04 17:31 ` Thomas Gleixner
2019-04-04 22:49 ` Fenghua Yu
2019-04-03 21:21 ` [PATCH v6 11/20] kvm/x86: Emulate MSR IA32_CORE_CAPABILITY Fenghua Yu
2019-04-05 12:00 ` Thomas Gleixner
2019-04-09 6:03 ` Xiaoyao Li
2019-04-03 21:21 ` [PATCH v6 12/20] kvm/vmx: Emulate MSR TEST_CTL Fenghua Yu
2019-04-04 14:44 ` Sean Christopherson
2019-04-08 8:54 ` Xiaoyao Li
2019-04-05 12:30 ` Thomas Gleixner
2019-04-08 9:54 ` Xiaoyao Li
2019-04-08 17:48 ` Sean Christopherson
2019-04-10 5:03 ` Xiaoyao Li
2019-04-03 21:21 ` [PATCH v6 13/20] x86/split_lock: Enable split lock detection by default Fenghua Yu
2019-04-04 18:07 ` Thomas Gleixner
2019-04-04 18:14 ` Thomas Gleixner
2019-04-04 19:23 ` Fenghua Yu
2019-04-04 19:44 ` Thomas Gleixner
2019-04-10 0:02 ` Fenghua Yu
2019-04-10 6:31 ` Thomas Gleixner
2019-04-10 12:35 ` Fenghua Yu
2019-04-10 8:50 ` David Laight
2019-04-03 21:22 ` [PATCH v6 14/20] x86/split_lock: Add a sysfs interface to enable/disable split lock detection during run time Fenghua Yu
2019-04-04 19:11 ` Thomas Gleixner
2019-04-03 21:22 ` [PATCH v6 15/20] x86/split_lock: Document the new sysfs file for split lock detection Fenghua Yu
2019-04-03 21:22 ` [PATCH v6 16/20] x86/clearcpuid: Support multiple clearcpuid options Fenghua Yu
2019-04-03 21:22 ` Fenghua Yu [this message]
2019-04-03 21:22 ` [PATCH v6 18/20] x86/clearcpuid: Apply cleared feature bits that are forced set before Fenghua Yu
2019-04-03 21:22 ` [PATCH v6 19/20] x86/clearcpuid: Clear CPUID bit in CPUID faulting Fenghua Yu
2019-04-03 21:22 ` [PATCH v6 20/20] x86/clearcpuid: Change document for kernel option clearcpuid Fenghua Yu
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