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-rw-r--r--arch/x86/kernel/cpu/Makefile1
-rw-r--r--arch/x86/kernel/cpu/common.c16
-rw-r--r--arch/x86/kernel/cpu/cpuid-deps.c125
-rw-r--r--arch/x86/kernel/fpu/init.c11
-rw-r--r--arch/x86/kernel/fpu/xstate.c43
5 files changed, 167 insertions, 29 deletions
diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile
index e17942c131c8..de260fae1017 100644
--- a/arch/x86/kernel/cpu/Makefile
+++ b/arch/x86/kernel/cpu/Makefile
@@ -22,6 +22,7 @@ obj-y += rdrand.o
obj-y += match.o
obj-y += bugs.o
obj-$(CONFIG_CPU_FREQ) += aperfmperf.o
+obj-y += cpuid-deps.o
obj-$(CONFIG_PROC_FS) += proc.o
obj-$(CONFIG_X86_FEATURE_NAMES) += capflags.o powerflags.o
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index c9176bae7fd8..03bb004bb15e 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1301,18 +1301,16 @@ void print_cpu_info(struct cpuinfo_x86 *c)
pr_cont(")\n");
}
-static __init int setup_disablecpuid(char *arg)
+/*
+ * clearcpuid= was already parsed in fpu__init_parse_early_param.
+ * But we need to keep a dummy __setup around otherwise it would
+ * show up as an environment variable for init.
+ */
+static __init int setup_clearcpuid(char *arg)
{
- int bit;
-
- if (get_option(&arg, &bit) && bit >= 0 && bit < NCAPINTS * 32)
- setup_clear_cpu_cap(bit);
- else
- return 0;
-
return 1;
}
-__setup("clearcpuid=", setup_disablecpuid);
+__setup("clearcpuid=", setup_clearcpuid);
#ifdef CONFIG_X86_64
DEFINE_PER_CPU_FIRST(union irq_stack_union,
diff --git a/arch/x86/kernel/cpu/cpuid-deps.c b/arch/x86/kernel/cpu/cpuid-deps.c
new file mode 100644
index 000000000000..c21f22d836ad
--- /dev/null
+++ b/arch/x86/kernel/cpu/cpuid-deps.c
@@ -0,0 +1,125 @@
+/* Declare dependencies between CPUIDs */
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <asm/cpufeature.h>
+
+struct cpuid_dep {
+ unsigned int feature;
+ unsigned int depends;
+};
+
+/*
+ * Table of CPUID features that depend on others.
+ *
+ * This only includes dependencies that can be usefully disabled, not
+ * features part of the base set (like FPU).
+ *
+ * Note this all is not __init / __initdata because it can be
+ * called from cpu hotplug. It shouldn't do anything in this case,
+ * but it's difficult to tell that to the init reference checker.
+ */
+const static struct cpuid_dep cpuid_deps[] = {
+ { X86_FEATURE_XSAVEOPT, X86_FEATURE_XSAVE },
+ { X86_FEATURE_XSAVEC, X86_FEATURE_XSAVE },
+ { X86_FEATURE_XSAVES, X86_FEATURE_XSAVE },
+ { X86_FEATURE_AVX, X86_FEATURE_XSAVE },
+ { X86_FEATURE_PKU, X86_FEATURE_XSAVE },
+ { X86_FEATURE_MPX, X86_FEATURE_XSAVE },
+ { X86_FEATURE_XGETBV1, X86_FEATURE_XSAVE },
+ { X86_FEATURE_FXSR_OPT, X86_FEATURE_FXSR },
+ { X86_FEATURE_XMM, X86_FEATURE_FXSR },
+ { X86_FEATURE_XMM2, X86_FEATURE_XMM },
+ { X86_FEATURE_XMM3, X86_FEATURE_XMM2 },
+ { X86_FEATURE_XMM4_1, X86_FEATURE_XMM2 },
+ { X86_FEATURE_XMM4_2, X86_FEATURE_XMM2 },
+ { X86_FEATURE_XMM3, X86_FEATURE_XMM2 },
+ { X86_FEATURE_PCLMULQDQ, X86_FEATURE_XMM2 },
+ { X86_FEATURE_SSSE3, X86_FEATURE_XMM2, },
+ { X86_FEATURE_F16C, X86_FEATURE_XMM2, },
+ { X86_FEATURE_AES, X86_FEATURE_XMM2 },
+ { X86_FEATURE_SHA_NI, X86_FEATURE_XMM2 },
+ { X86_FEATURE_FMA, X86_FEATURE_AVX },
+ { X86_FEATURE_AVX2, X86_FEATURE_AVX, },
+ { X86_FEATURE_AVX512F, X86_FEATURE_AVX, },
+ { X86_FEATURE_AVX512IFMA, X86_FEATURE_AVX512F },
+ { X86_FEATURE_AVX512PF, X86_FEATURE_AVX512F },
+ { X86_FEATURE_AVX512ER, X86_FEATURE_AVX512F },
+ { X86_FEATURE_AVX512CD, X86_FEATURE_AVX512F },
+ { X86_FEATURE_AVX512DQ, X86_FEATURE_AVX512F },
+ { X86_FEATURE_AVX512BW, X86_FEATURE_AVX512F },
+ { X86_FEATURE_AVX512VL, X86_FEATURE_AVX512F },
+ { X86_FEATURE_AVX512VBMI, X86_FEATURE_AVX512F },
+ { X86_FEATURE_AVX512_VBMI2, X86_FEATURE_AVX512VL },
+ { X86_FEATURE_GFNI, X86_FEATURE_AVX512VL },
+ { X86_FEATURE_VAES, X86_FEATURE_AVX512VL },
+ { X86_FEATURE_VPCLMULQDQ, X86_FEATURE_AVX512VL },
+ { X86_FEATURE_AVX512_VNNI, X86_FEATURE_AVX512VL },
+ { X86_FEATURE_AVX512_BITALG, X86_FEATURE_AVX512VL },
+ { X86_FEATURE_AVX512_4VNNIW, X86_FEATURE_AVX512F },
+ { X86_FEATURE_AVX512_4FMAPS, X86_FEATURE_AVX512F },
+ { X86_FEATURE_AVX512_VPOPCNTDQ, X86_FEATURE_AVX512F },
+ {}
+};
+
+static inline void __clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int bit)
+{
+ clear_bit32(bit, c->x86_capability);
+}
+
+static inline void __setup_clear_cpu_cap(unsigned int bit)
+{
+ clear_cpu_cap(&boot_cpu_data, bit);
+ set_bit32(bit, cpu_caps_cleared);
+}
+
+static inline void clear_feature(struct cpuinfo_x86 *c, unsigned int feature)
+{
+ if (!c)
+ __setup_clear_cpu_cap(feature);
+ else
+ __clear_cpu_cap(c, feature);
+}
+
+/* Take the capabilities and the BUG bits into account */
+#define MAX_FEATURE_BITS ((NCAPINTS + NBUGINTS) * sizeof(u32) * 8)
+
+static void do_clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int feature)
+{
+ DECLARE_BITMAP(disable, MAX_FEATURE_BITS);
+ const struct cpuid_dep *d;
+ bool changed;
+
+ if (WARN_ON(feature >= MAX_FEATURE_BITS))
+ return;
+
+ clear_feature(c, feature);
+
+ /* Collect all features to disable, handling dependencies */
+ memset(disable, 0, sizeof(disable));
+ __set_bit(feature, disable);
+
+ /* Loop until we get a stable state. */
+ do {
+ changed = false;
+ for (d = cpuid_deps; d->feature; d++) {
+ if (!test_bit(d->depends, disable))
+ continue;
+ if (__test_and_set_bit(d->feature, disable))
+ continue;
+
+ changed = true;
+ clear_feature(c, d->feature);
+ }
+ } while (changed);
+}
+
+void clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int feature)
+{
+ do_clear_cpu_cap(c, feature);
+}
+
+void setup_clear_cpu_cap(unsigned int feature)
+{
+ do_clear_cpu_cap(NULL, feature);
+}
diff --git a/arch/x86/kernel/fpu/init.c b/arch/x86/kernel/fpu/init.c
index 7affb7e3d9a5..6abd83572b01 100644
--- a/arch/x86/kernel/fpu/init.c
+++ b/arch/x86/kernel/fpu/init.c
@@ -249,6 +249,10 @@ static void __init fpu__init_system_ctx_switch(void)
*/
static void __init fpu__init_parse_early_param(void)
{
+ char arg[32];
+ char *argptr = arg;
+ int bit;
+
if (cmdline_find_option_bool(boot_command_line, "no387"))
setup_clear_cpu_cap(X86_FEATURE_FPU);
@@ -266,6 +270,13 @@ static void __init fpu__init_parse_early_param(void)
if (cmdline_find_option_bool(boot_command_line, "noxsaves"))
setup_clear_cpu_cap(X86_FEATURE_XSAVES);
+
+ if (cmdline_find_option(boot_command_line, "clearcpuid", arg,
+ sizeof(arg)) &&
+ get_option(&argptr, &bit) &&
+ bit >= 0 &&
+ bit < NCAPINTS * 32)
+ setup_clear_cpu_cap(bit);
}
/*
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index f1d5476c9022..87a57b7642d3 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -15,6 +15,7 @@
#include <asm/fpu/xstate.h>
#include <asm/tlbflush.h>
+#include <asm/cpufeature.h>
/*
* Although we spell it out in here, the Processor Trace
@@ -36,6 +37,19 @@ static const char *xfeature_names[] =
"unknown xstate feature" ,
};
+static short xsave_cpuid_features[] __initdata = {
+ X86_FEATURE_FPU,
+ X86_FEATURE_XMM,
+ X86_FEATURE_AVX,
+ X86_FEATURE_MPX,
+ X86_FEATURE_MPX,
+ X86_FEATURE_AVX512F,
+ X86_FEATURE_AVX512F,
+ X86_FEATURE_AVX512F,
+ X86_FEATURE_INTEL_PT,
+ X86_FEATURE_PKU,
+};
+
/*
* Mask of xstate features supported by the CPU and the kernel:
*/
@@ -59,26 +73,6 @@ unsigned int fpu_user_xstate_size;
void fpu__xstate_clear_all_cpu_caps(void)
{
setup_clear_cpu_cap(X86_FEATURE_XSAVE);
- setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT);
- setup_clear_cpu_cap(X86_FEATURE_XSAVEC);
- setup_clear_cpu_cap(X86_FEATURE_XSAVES);
- setup_clear_cpu_cap(X86_FEATURE_AVX);
- setup_clear_cpu_cap(X86_FEATURE_AVX2);
- setup_clear_cpu_cap(X86_FEATURE_AVX512F);
- setup_clear_cpu_cap(X86_FEATURE_AVX512IFMA);
- setup_clear_cpu_cap(X86_FEATURE_AVX512PF);
- setup_clear_cpu_cap(X86_FEATURE_AVX512ER);
- setup_clear_cpu_cap(X86_FEATURE_AVX512CD);
- setup_clear_cpu_cap(X86_FEATURE_AVX512DQ);
- setup_clear_cpu_cap(X86_FEATURE_AVX512BW);
- setup_clear_cpu_cap(X86_FEATURE_AVX512VL);
- setup_clear_cpu_cap(X86_FEATURE_MPX);
- setup_clear_cpu_cap(X86_FEATURE_XGETBV1);
- setup_clear_cpu_cap(X86_FEATURE_AVX512VBMI);
- setup_clear_cpu_cap(X86_FEATURE_PKU);
- setup_clear_cpu_cap(X86_FEATURE_AVX512_4VNNIW);
- setup_clear_cpu_cap(X86_FEATURE_AVX512_4FMAPS);
- setup_clear_cpu_cap(X86_FEATURE_AVX512_VPOPCNTDQ);
}
/*
@@ -726,6 +720,7 @@ void __init fpu__init_system_xstate(void)
unsigned int eax, ebx, ecx, edx;
static int on_boot_cpu __initdata = 1;
int err;
+ int i;
WARN_ON_FPU(!on_boot_cpu);
on_boot_cpu = 0;
@@ -759,6 +754,14 @@ void __init fpu__init_system_xstate(void)
goto out_disable;
}
+ /*
+ * Clear XSAVE features that are disabled in the normal CPUID.
+ */
+ for (i = 0; i < ARRAY_SIZE(xsave_cpuid_features); i++) {
+ if (!boot_cpu_has(xsave_cpuid_features[i]))
+ xfeatures_mask &= ~BIT(i);
+ }
+
xfeatures_mask &= fpu__get_supported_xfeatures_mask();
/* Enable xstate instructions to be able to continue with initialization: */
generated by cgit v1.2.3 (git 2.39.1) at 2025-01-20 12:57:59 +0100