From: "Chang S. Bae" <chang.seok.bae@intel.com>
To: bp@suse.de, luto@kernel.org, tglx@linutronix.de,
mingo@kernel.org, x86@kernel.org
Cc: len.brown@intel.com, lenb@kernel.org, dave.hansen@intel.com,
thiago.macieira@intel.com, jing2.liu@intel.com,
ravi.v.shankar@intel.com, linux-kernel@vger.kernel.org,
chang.seok.bae@intel.com
Subject: [PATCH v10 28/28] x86/arch_prctl: ARCH_GET_FEATURES_WITH_KERNEL_ASSISTANCE
Date: Wed, 25 Aug 2021 08:54:13 -0700 [thread overview]
Message-ID: <20210825155413.19673-29-chang.seok.bae@intel.com> (raw)
In-Reply-To: <20210825155413.19673-1-chang.seok.bae@intel.com>
arch_prctl(ARCH_GET_FEATURES_WITH_KERNEL_ASSISTANCE, u64 *bitmask)
Return the bitmask of the kernel-supported features. If XSAVE is
disabled, the bitmask indicates only legacy states.
Suggested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Cc: x86@kernel.org
Cc: linux-kernel@vger.kernel.org
---
Changes from v9:
* Add as a new patch. (Thiago Macieira and Borislav Petkov)
---
arch/x86/include/asm/fpu/xstate.h | 1 +
arch/x86/include/uapi/asm/prctl.h | 23 ++++++++---------
arch/x86/kernel/fpu/xstate.c | 41 +++++++++++++++++++------------
arch/x86/kernel/process.c | 2 ++
4 files changed, 40 insertions(+), 27 deletions(-)
diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h
index 013478c1aa42..4aa7049cc079 100644
--- a/arch/x86/include/asm/fpu/xstate.h
+++ b/arch/x86/include/asm/fpu/xstate.h
@@ -194,6 +194,7 @@ static inline bool dynamic_state_permitted(struct task_struct *tsk, u64 state_ma
}
void reset_dynamic_state_perm(struct task_struct *tsk);
+u64 get_features_mask_uabi(void);
long set_group_state_perm(struct task_struct *tsk, u64 state_perm);
u64 get_group_state_perm(struct task_struct *tsk);
diff --git a/arch/x86/include/uapi/asm/prctl.h b/arch/x86/include/uapi/asm/prctl.h
index c73e141ce90a..6912d5fe85f3 100644
--- a/arch/x86/include/uapi/asm/prctl.h
+++ b/arch/x86/include/uapi/asm/prctl.h
@@ -2,19 +2,20 @@
#ifndef _ASM_X86_PRCTL_H
#define _ASM_X86_PRCTL_H
-#define ARCH_SET_GS 0x1001
-#define ARCH_SET_FS 0x1002
-#define ARCH_GET_FS 0x1003
-#define ARCH_GET_GS 0x1004
+#define ARCH_SET_GS 0x1001
+#define ARCH_SET_FS 0x1002
+#define ARCH_GET_FS 0x1003
+#define ARCH_GET_GS 0x1004
-#define ARCH_GET_CPUID 0x1011
-#define ARCH_SET_CPUID 0x1012
+#define ARCH_GET_CPUID 0x1011
+#define ARCH_SET_CPUID 0x1012
-#define ARCH_SET_STATE_ENABLE 0x1021
-#define ARCH_GET_STATE_ENABLE 0x1022
+#define ARCH_GET_FEATURES_WITH_KERNEL_ASSISTANCE 0x1020
+#define ARCH_SET_STATE_ENABLE 0x1021
+#define ARCH_GET_STATE_ENABLE 0x1022
-#define ARCH_MAP_VDSO_X32 0x2001
-#define ARCH_MAP_VDSO_32 0x2002
-#define ARCH_MAP_VDSO_64 0x2003
+#define ARCH_MAP_VDSO_X32 0x2001
+#define ARCH_MAP_VDSO_32 0x2002
+#define ARCH_MAP_VDSO_64 0x2003
#endif /* _ASM_X86_PRCTL_H */
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 2c62872e4fef..6622366d51ae 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -1297,6 +1297,25 @@ int realloc_xstate_buffer(struct fpu *fpu, u64 mask)
return 0;
}
+/**
+ * get_features_mask_uabi - Get feature list that the kernel supports
+ * Return: A bitmap to indicate which state is available
+ *
+ */
+u64 get_features_mask_uabi(void)
+{
+ if (!cpu_feature_enabled(X86_FEATURE_FPU))
+ return 0;
+
+ if (use_xsave())
+ return xfeatures_mask_uabi();
+
+ if (use_fxsr())
+ return XFEATURE_MASK_FPSSE;
+
+ return XFEATURE_MASK_FP;
+}
+
/**
* set_group_state_perm - Set a per-process permission for dynamic user
* states.
@@ -1306,16 +1325,7 @@ int realloc_xstate_buffer(struct fpu *fpu, u64 mask)
*/
long set_group_state_perm(struct task_struct *tsk, u64 state_perm)
{
- u64 features_mask;
-
- if (!cpu_feature_enabled(X86_FEATURE_FPU))
- features_mask = 0;
- else if (use_xsave())
- features_mask = xfeatures_mask_uabi();
- else if (use_fxsr())
- features_mask = XFEATURE_MASK_FPSSE;
- else
- features_mask = XFEATURE_MASK_FP;
+ u64 features_mask = get_features_mask_uabi();
if (state_perm & ~features_mask)
return -EINVAL;
@@ -1365,17 +1375,16 @@ void reset_dynamic_state_perm(struct task_struct *tsk)
*/
u64 get_group_state_perm(struct task_struct *tsk)
{
+ u64 mask = get_features_mask_uabi();
+
if (!cpu_feature_enabled(X86_FEATURE_FPU))
return 0;
if (use_xsave())
- return (xfeatures_mask_uabi() & ~xfeatures_mask_user_dynamic) |
+ return (mask & ~xfeatures_mask_user_dynamic) |
get_group_dynamic_state_perm(tsk);
-
- if (use_fxsr())
- return XFEATURE_MASK_FPSSE;
-
- return XFEATURE_MASK_FP;
+ else
+ return mask;
}
static void copy_feature(bool from_xstate, struct membuf *to, void *xstate,
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index beab1bf76d1a..544b0c4f3aed 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -1023,6 +1023,8 @@ long do_arch_prctl_common(struct task_struct *task, int option,
return get_cpuid_mode();
case ARCH_SET_CPUID:
return set_cpuid_mode(task, arg2);
+ case ARCH_GET_FEATURES_WITH_KERNEL_ASSISTANCE:
+ return put_user(get_features_mask_uabi(), (unsigned long __user *)arg2);
case ARCH_SET_STATE_ENABLE:
return set_group_state_perm(task, arg2);
case ARCH_GET_STATE_ENABLE:
--
2.17.1
next prev parent reply other threads:[~2021-08-25 16:02 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-25 15:53 [PATCH v10 00/28] x86: Support Intel Advanced Matrix Extensions Chang S. Bae
2021-08-25 15:53 ` [PATCH v10 01/28] x86/fpu/xstate: Fix the state copy function to the XSTATE buffer Chang S. Bae
2021-10-01 12:44 ` Thomas Gleixner
2021-10-03 22:34 ` Bae, Chang Seok
2021-08-25 15:53 ` [PATCH v10 02/28] x86/fpu/xstate: Modify the initialization helper to handle both static and dynamic buffers Chang S. Bae
2021-10-01 12:45 ` Thomas Gleixner
2021-10-03 22:35 ` Bae, Chang Seok
2021-08-25 15:53 ` [PATCH v10 03/28] x86/fpu/xstate: Modify state copy helpers " Chang S. Bae
2021-10-01 12:47 ` Thomas Gleixner
2021-10-03 22:42 ` Bae, Chang Seok
2021-08-25 15:53 ` [PATCH v10 04/28] x86/fpu/xstate: Modify address finders " Chang S. Bae
2021-10-01 13:15 ` Thomas Gleixner
2021-10-03 22:35 ` Bae, Chang Seok
2021-10-04 12:54 ` Thomas Gleixner
2021-08-25 15:53 ` [PATCH v10 05/28] x86/fpu/xstate: Add a new variable to indicate dynamic user states Chang S. Bae
2021-10-01 13:16 ` Thomas Gleixner
2021-10-03 22:35 ` Bae, Chang Seok
2021-10-04 12:57 ` Thomas Gleixner
2021-08-25 15:53 ` [PATCH v10 06/28] x86/fpu/xstate: Add new variables to indicate dynamic XSTATE buffer size Chang S. Bae
2021-10-01 13:32 ` Thomas Gleixner
2021-10-03 22:36 ` Bae, Chang Seok
2021-08-25 15:53 ` [PATCH v10 07/28] x86/fpu/xstate: Calculate and remember dynamic XSTATE buffer sizes Chang S. Bae
2021-08-25 15:53 ` [PATCH v10 08/28] x86/fpu/xstate: Convert the struct fpu 'state' field to a pointer Chang S. Bae
2021-08-25 15:53 ` [PATCH v10 09/28] x86/fpu/xstate: Introduce helpers to manage the XSTATE buffer dynamically Chang S. Bae
2021-10-01 14:20 ` Thomas Gleixner
2021-10-03 22:36 ` Bae, Chang Seok
2021-08-25 15:53 ` [PATCH v10 10/28] x86/fpu/xstate: Update the XSTATE save function to support dynamic states Chang S. Bae
2021-10-01 15:41 ` Thomas Gleixner
2021-10-02 21:31 ` Thomas Gleixner
2021-10-02 22:54 ` Bae, Chang Seok
2021-10-05 8:16 ` Paolo Bonzini
2021-10-05 7:50 ` Paolo Bonzini
2021-10-05 9:55 ` Thomas Gleixner
2021-08-25 15:53 ` [PATCH v10 11/28] x86/fpu/xstate: Update the XSTATE buffer address finder " Chang S. Bae
2021-08-25 15:53 ` [PATCH v10 12/28] x86/fpu/xstate: Update the XSTATE context copy function " Chang S. Bae
2021-08-25 15:53 ` [PATCH v10 13/28] x86/fpu/xstate: Use feature disable (XFD) to protect dynamic user state Chang S. Bae
2021-10-01 15:02 ` Thomas Gleixner
2021-10-01 15:10 ` Thomas Gleixner
2021-10-03 22:38 ` Bae, Chang Seok
2021-10-04 12:35 ` Thomas Gleixner
2021-10-01 20:20 ` Thomas Gleixner
2021-10-03 22:39 ` Bae, Chang Seok
2021-10-04 19:03 ` Thomas Gleixner
2021-10-03 22:41 ` Bae, Chang Seok
2021-08-25 15:53 ` [PATCH v10 14/28] x86/fpu/xstate: Support ptracer-induced XSTATE buffer expansion Chang S. Bae
2021-08-25 15:54 ` [PATCH v10 15/28] x86/arch_prctl: Create ARCH_SET_STATE_ENABLE/ARCH_GET_STATE_ENABLE Chang S. Bae
2021-08-25 16:36 ` Bae, Chang Seok
2021-08-25 15:54 ` [PATCH v10 16/28] x86/fpu/xstate: Support both legacy and expanded signal XSTATE size Chang S. Bae
2021-08-25 15:54 ` [PATCH v10 17/28] x86/fpu/xstate: Adjust the XSAVE feature table to address gaps in state component numbers Chang S. Bae
2021-08-25 15:54 ` [PATCH v10 18/28] x86/fpu/xstate: Disable XSTATE support if an inconsistent state is detected Chang S. Bae
2021-08-25 15:54 ` [PATCH v10 19/28] x86/cpufeatures/amx: Enumerate Advanced Matrix Extension (AMX) feature bits Chang S. Bae
2021-08-25 15:54 ` [PATCH v10 20/28] x86/fpu/amx: Define AMX state components and have it used for boot-time checks Chang S. Bae
2021-08-25 15:54 ` [PATCH v10 21/28] x86/fpu/amx: Initialize child's AMX state Chang S. Bae
2021-08-25 15:54 ` [PATCH v10 22/28] x86/fpu/amx: Enable the AMX feature in 64-bit mode Chang S. Bae
2021-08-25 15:54 ` [PATCH v10 23/28] x86/fpu/xstate: Skip writing zeros to signal frame for dynamic user states if in INIT-state Chang S. Bae
2021-08-25 15:54 ` [PATCH v10 24/28] selftest/x86/amx: Test cases for the AMX state management Chang S. Bae
2021-08-25 15:54 ` [PATCH v10 25/28] x86/insn/amx: Add TILERELEASE instruction to the opcode map Chang S. Bae
2021-08-25 15:54 ` [PATCH v10 26/28] intel_idle/amx: Add SPR support with XTILEDATA capability Chang S. Bae
2021-08-25 15:54 ` [PATCH v10 27/28] x86/fpu/xstate: Add a sanity check for XFD state when saving XSTATE Chang S. Bae
2021-08-25 15:54 ` Chang S. Bae [this message]
2021-09-30 21:12 ` [PATCH v10 00/28] x86: Support Intel Advanced Matrix Extensions Len Brown
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