From: kan.liang@linux.intel.com
To: peterz@infradead.org, mingo@redhat.com, acme@kernel.org,
tglx@linutronix.de, bp@alien8.de, x86@kernel.org,
linux-kernel@vger.kernel.org
Cc: mark.rutland@arm.com, alexander.shishkin@linux.intel.com,
jolsa@redhat.com, namhyung@kernel.org, dave.hansen@intel.com,
yu-cheng.yu@intel.com, bigeasy@linutronix.de, gorcunov@gmail.com,
hpa@zytor.com, alexey.budankov@linux.intel.com,
eranian@google.com, ak@linux.intel.com, like.xu@linux.intel.com,
yao.jin@linux.intel.com, wei.w.wang@intel.com,
Kan Liang <kan.liang@linux.intel.com>
Subject: [PATCH V3 21/23] x86/fpu/xstate: Add helpers for LBR dynamic supervisor feature
Date: Fri, 3 Jul 2020 05:49:27 -0700 [thread overview]
Message-ID: <1593780569-62993-22-git-send-email-kan.liang@linux.intel.com> (raw)
In-Reply-To: <1593780569-62993-1-git-send-email-kan.liang@linux.intel.com>
From: Kan Liang <kan.liang@linux.intel.com>
The perf subsystem will only need to save/restore the LBR state.
However, the existing helpers save all supported supervisor states to a
kernel buffer, which will be unnecessary. Two helpers are introduced to
only save/restore requested dynamic supervisor states. The supervisor
features in XFEATURE_MASK_SUPERVISOR_SUPPORTED and
XFEATURE_MASK_SUPERVISOR_UNSUPPORTED mask cannot be saved/restored using
these helpers.
The helpers will be used in the following patch.
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
---
arch/x86/include/asm/fpu/xstate.h | 3 ++
arch/x86/kernel/fpu/xstate.c | 72 +++++++++++++++++++++++++++++++++++++++
2 files changed, 75 insertions(+)
diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h
index 040c4d4..c029fce 100644
--- a/arch/x86/include/asm/fpu/xstate.h
+++ b/arch/x86/include/asm/fpu/xstate.h
@@ -106,6 +106,9 @@ int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned i
int copy_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf);
int copy_user_to_xstate(struct xregs_state *xsave, const void __user *ubuf);
void copy_supervisor_to_kernel(struct xregs_state *xsave);
+void copy_dynamic_supervisor_to_kernel(struct xregs_state *xstate, u64 mask);
+void copy_kernel_to_dynamic_supervisor(struct xregs_state *xstate, u64 mask);
+
/* Validate an xstate header supplied by userspace (ptrace or sigreturn) */
int validate_user_xstate_header(const struct xstate_header *hdr);
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index dcf0624..b0c22b7 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -1361,6 +1361,78 @@ void copy_supervisor_to_kernel(struct xregs_state *xstate)
}
}
+/**
+ * copy_dynamic_supervisor_to_kernel() - Save dynamic supervisor states to
+ * an xsave area
+ * @xstate: A pointer to an xsave area
+ * @mask: Represent the dynamic supervisor features saved into the xsave area
+ *
+ * Only the dynamic supervisor states sets in the mask are saved into the xsave
+ * area (See the comment in XFEATURE_MASK_DYNAMIC for the details of dynamic
+ * supervisor feature). Besides the dynamic supervisor states, the legacy
+ * region and XSAVE header are also saved into the xsave area. The supervisor
+ * features in the XFEATURE_MASK_SUPERVISOR_SUPPORTED and
+ * XFEATURE_MASK_SUPERVISOR_UNSUPPORTED are not saved.
+ *
+ * The xsave area must be 64-bytes aligned.
+ */
+void copy_dynamic_supervisor_to_kernel(struct xregs_state *xstate, u64 mask)
+{
+ u64 dynamic_mask = xfeatures_mask_dynamic() & mask;
+ u32 lmask, hmask;
+ int err;
+
+ if (WARN_ON_FPU(!boot_cpu_has(X86_FEATURE_XSAVES)))
+ return;
+
+ if (WARN_ON_FPU(!dynamic_mask))
+ return;
+
+ lmask = dynamic_mask;
+ hmask = dynamic_mask >> 32;
+
+ XSTATE_OP(XSAVES, xstate, lmask, hmask, err);
+
+ /* Should never fault when copying to a kernel buffer */
+ WARN_ON_FPU(err);
+}
+
+/**
+ * copy_kernel_to_dynamic_supervisor() - Restore dynamic supervisor states from
+ * an xsave area
+ * @xstate: A pointer to an xsave area
+ * @mask: Represent the dynamic supervisor features restored from the xsave area
+ *
+ * Only the dynamic supervisor states sets in the mask are restored from the
+ * xsave area (See the comment in XFEATURE_MASK_DYNAMIC for the details of
+ * dynamic supervisor feature). Besides the dynamic supervisor states, the
+ * legacy region and XSAVE header are also restored from the xsave area. The
+ * supervisor features in the XFEATURE_MASK_SUPERVISOR_SUPPORTED and
+ * XFEATURE_MASK_SUPERVISOR_UNSUPPORTED are not restored.
+ *
+ * The xsave area must be 64-bytes aligned.
+ */
+void copy_kernel_to_dynamic_supervisor(struct xregs_state *xstate, u64 mask)
+{
+ u64 dynamic_mask = xfeatures_mask_dynamic() & mask;
+ u32 lmask, hmask;
+ int err;
+
+ if (WARN_ON_FPU(!boot_cpu_has(X86_FEATURE_XSAVES)))
+ return;
+
+ if (WARN_ON_FPU(!dynamic_mask))
+ return;
+
+ lmask = dynamic_mask;
+ hmask = dynamic_mask >> 32;
+
+ XSTATE_OP(XRSTORS, xstate, lmask, hmask, err);
+
+ /* Should never fault when copying from a kernel buffer */
+ WARN_ON_FPU(err);
+}
+
#ifdef CONFIG_PROC_PID_ARCH_STATUS
/*
* Report the amount of time elapsed in millisecond since last AVX512
--
2.7.4
next prev parent reply other threads:[~2020-07-03 12:54 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-03 12:49 [PATCH V3 00/23] Support Architectural LBR kan.liang
2020-07-03 12:49 ` [PATCH V3 01/23] x86/cpufeatures: Add Architectural LBRs feature bit kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-09 23:00 ` Dave Hansen
2020-07-10 9:51 ` Peter Zijlstra
2020-07-10 14:09 ` Liang, Kan
2020-07-03 12:49 ` [PATCH V3 02/23] perf/x86/intel/lbr: Add a function pointer for LBR reset kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 03/23] perf/x86/intel/lbr: Add a function pointer for LBR read kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 04/23] perf/x86/intel/lbr: Add the function pointers for LBR save and restore kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 05/23] perf/x86/intel/lbr: Factor out a new struct for generic optimization kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 06/23] perf/x86/intel/lbr: Use dynamic data structure for task_ctx kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 07/23] x86/msr-index: Add bunch of MSRs for Arch LBR kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 08/23] perf/x86: Expose CPUID enumeration bits for arch LBR kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 09/23] perf/x86/intel/lbr: Support LBR_CTL kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 10/23] perf/x86/intel/lbr: Unify the stored format of LBR information kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 11/23] perf/x86/intel/lbr: Mark the {rd,wr}lbr_{to,from} wrappers __always_inline kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 12/23] perf/x86/intel/lbr: Factor out rdlbr_all() and wrlbr_all() kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 13/23] perf/x86/intel/lbr: Factor out intel_pmu_store_lbr kan.liang
2020-07-03 19:50 ` Peter Zijlstra
2020-07-03 20:59 ` Liang, Kan
2020-07-06 10:25 ` Peter Zijlstra
2020-07-06 13:32 ` Liang, Kan
2020-07-06 14:25 ` Peter Zijlstra
2020-07-06 22:29 ` Liang, Kan
2020-07-07 7:40 ` Peter Zijlstra
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 14/23] perf/x86/intel/lbr: Support Architectural LBR kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 15/23] perf/core: Factor out functions to allocate/free the task_ctx_data kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 16/23] perf/core: Use kmem_cache to allocate the PMU specific data kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 17/23] perf/x86/intel/lbr: Create kmem_cache for the LBR context data kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 18/23] perf/x86: Remove task_ctx_size kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 19/23] x86/fpu: Use proper mask to replace full instruction mask kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 20/23] x86/fpu/xstate: Support dynamic supervisor feature for LBR kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2021-05-27 22:15 ` Thomas Gleixner
2020-07-03 12:49 ` kan.liang [this message]
2020-07-08 9:51 ` [tip: perf/core] x86/fpu/xstate: Add helpers for LBR dynamic supervisor feature tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 22/23] perf/x86/intel/lbr: Support XSAVES/XRSTORS for LBR context switch kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 23/23] perf/x86/intel/lbr: Support XSAVES for arch LBR read kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 19:34 ` [PATCH V3 00/23] Support Architectural LBR Peter Zijlstra
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