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, 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 v9 13/26] x86/fpu/xstate: Support ptracer-induced XSTATE buffer expansion
Date: Fri, 30 Jul 2021 07:59:44 -0700 [thread overview]
Message-ID: <20210730145957.7927-14-chang.seok.bae@intel.com> (raw)
In-Reply-To: <20210730145957.7927-1-chang.seok.bae@intel.com>
ptrace() may update XSTATE data before the target task has taken an XFD
fault and expanded the XSTATE buffer. Detect this case and allocate a
sufficient buffer to support the request. Also, disable the (now
unnecessary) associated first-use fault.
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Reviewed-by: Len Brown <len.brown@intel.com>
Cc: x86@kernel.org
Cc: linux-kernel@vger.kernel.org
---
Changes from v5:
* Adjusted to use 'tmpbuf' for the new base code.
Changes from v4:
* Improved the condition check for the expansion.
* Simplified the XSTATE_BV retrieval.
* Updated the code comment.
Changes from v3:
* Removed 'no functional changes' in the changelog. (Borislav Petkov)
Changes from v2:
* Updated the changelog with task->fpu removed. (Borislav Petkov)
* Updated the code comments.
---
arch/x86/kernel/fpu/regset.c | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
diff --git a/arch/x86/kernel/fpu/regset.c b/arch/x86/kernel/fpu/regset.c
index 73d7d7b489fe..244e672c3e3d 100644
--- a/arch/x86/kernel/fpu/regset.c
+++ b/arch/x86/kernel/fpu/regset.c
@@ -163,6 +163,30 @@ int xstateregs_set(struct task_struct *target, const struct user_regset *regset,
}
}
+ /*
+ * When a ptracer attempts to write any dynamic user state in the
+ * target buffer but not sufficiently allocated, it dynamically
+ * expands the buffer.
+ *
+ * Check if the expansion is possibly needed.
+ */
+ if (xfeatures_mask_user_dynamic &&
+ ((fpu->state_mask & xfeatures_mask_user_dynamic) != xfeatures_mask_user_dynamic)) {
+ u64 state_mask;
+
+ /* Retrieve XSTATE_BV. */
+ memcpy(&state_mask, (kbuf ?: tmpbuf) + offsetof(struct xregs_state, header),
+ sizeof(u64));
+
+ /* Expand the xstate buffer based on the XSTATE_BV. */
+ state_mask &= xfeatures_mask_user_dynamic;
+ if (state_mask) {
+ ret = alloc_xstate_buffer(fpu, state_mask);
+ if (ret)
+ goto out;
+ }
+ }
+
fpu_force_restore(fpu);
ret = copy_uabi_from_kernel_to_xstate(fpu, kbuf ?: tmpbuf);
--
2.17.1
next prev parent reply other threads:[~2021-07-30 15:06 UTC|newest]
Thread overview: 91+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-30 14:59 [PATCH v9 00/26] x86: Support Intel Advanced Matrix Extensions Chang S. Bae
2021-07-30 14:59 ` [PATCH v9 01/26] x86/fpu/xstate: Modify the initialization helper to handle both static and dynamic buffers Chang S. Bae
2021-07-30 14:59 ` [PATCH v9 02/26] x86/fpu/xstate: Modify state copy helpers " Chang S. Bae
2021-07-30 14:59 ` [PATCH v9 03/26] x86/fpu/xstate: Modify address finders " Chang S. Bae
2021-07-30 14:59 ` [PATCH v9 04/26] x86/fpu/xstate: Add a new variable to indicate dynamic user states Chang S. Bae
2021-07-30 14:59 ` [PATCH v9 05/26] x86/fpu/xstate: Add new variables to indicate dynamic XSTATE buffer size Chang S. Bae
2021-08-12 15:03 ` Borislav Petkov
2021-07-30 14:59 ` [PATCH v9 06/26] x86/fpu/xstate: Calculate and remember dynamic XSTATE buffer sizes Chang S. Bae
2021-08-12 16:36 ` Borislav Petkov
2021-07-30 14:59 ` [PATCH v9 07/26] x86/fpu/xstate: Convert the struct fpu 'state' field to a pointer Chang S. Bae
2021-08-12 17:09 ` Borislav Petkov
2021-07-30 14:59 ` [PATCH v9 08/26] x86/fpu/xstate: Introduce helpers to manage the XSTATE buffer dynamically Chang S. Bae
2021-08-12 19:44 ` Borislav Petkov
2021-08-13 8:04 ` Bae, Chang Seok
2021-08-13 10:04 ` Borislav Petkov
2021-08-13 19:43 ` Bae, Chang Seok
2021-08-18 9:28 ` Borislav Petkov
2021-08-18 19:46 ` Bae, Chang Seok
2021-08-25 16:01 ` Bae, Chang Seok
2021-08-30 17:07 ` Borislav Petkov
2021-08-30 23:39 ` Bae, Chang Seok
2021-08-16 18:33 ` Bae, Chang Seok
2021-08-16 18:53 ` Borislav Petkov
2021-08-30 17:45 ` Dave Hansen
2021-08-30 23:39 ` Bae, Chang Seok
2021-07-30 14:59 ` [PATCH v9 09/26] x86/fpu/xstate: Update the XSTATE save function to support dynamic states Chang S. Bae
2021-07-30 14:59 ` [PATCH v9 10/26] x86/fpu/xstate: Update the XSTATE buffer address finder " Chang S. Bae
2021-08-18 11:33 ` Borislav Petkov
2021-08-18 19:47 ` Bae, Chang Seok
2021-08-30 17:18 ` Borislav Petkov
2021-08-30 23:38 ` Bae, Chang Seok
2021-07-30 14:59 ` [PATCH v9 11/26] x86/fpu/xstate: Update the XSTATE context copy function " Chang S. Bae
2021-08-18 12:03 ` Borislav Petkov
2021-08-18 19:47 ` Bae, Chang Seok
2021-07-30 14:59 ` [PATCH v9 12/26] x86/fpu/xstate: Use feature disable (XFD) to protect dynamic user state Chang S. Bae
2021-08-18 16:24 ` Borislav Petkov
2021-08-18 17:20 ` Thiago Macieira
2021-08-18 17:46 ` Borislav Petkov
2021-08-18 17:58 ` Thiago Macieira
2021-08-18 18:10 ` Borislav Petkov
2021-08-24 22:51 ` Len Brown
2021-08-18 20:43 ` Bae, Chang Seok
2021-08-18 21:04 ` Thiago Macieira
2021-08-18 21:12 ` Bae, Chang Seok
2021-08-18 22:27 ` Thiago Macieira
2021-08-19 1:21 ` Andy Lutomirski
2021-08-19 16:06 ` Thiago Macieira
2021-08-18 21:17 ` Borislav Petkov
2021-08-18 21:37 ` Bae, Chang Seok
2021-08-19 8:00 ` Borislav Petkov
2021-08-19 15:24 ` Bae, Chang Seok
2021-08-24 23:22 ` Len Brown
2021-08-30 17:31 ` Borislav Petkov
2021-09-17 3:48 ` Len Brown
2021-08-18 19:47 ` Bae, Chang Seok
2021-08-24 22:21 ` Len Brown
2021-08-30 17:41 ` Borislav Petkov
2021-08-31 21:44 ` Len Brown
2021-08-24 23:17 ` Len Brown
2021-08-30 17:53 ` Borislav Petkov
2021-08-31 22:07 ` Len Brown
2021-08-31 22:11 ` Dave Hansen
2021-08-30 18:04 ` Dave Hansen
2021-08-31 22:15 ` Len Brown
2021-08-31 22:16 ` Len Brown
2021-08-31 22:39 ` Thiago Macieira
2021-08-31 22:44 ` Len Brown
2021-07-30 14:59 ` Chang S. Bae [this message]
2021-07-30 14:59 ` [PATCH v9 14/26] x86/arch_prctl: Create ARCH_SET_STATE_ENABLE/ARCH_GET_STATE_ENABLE Chang S. Bae
2021-08-06 16:46 ` Thiago Macieira
2021-08-09 22:08 ` Bae, Chang Seok
2021-08-09 23:42 ` Thiago Macieira
2021-08-10 0:57 ` Bae, Chang Seok
2021-08-13 19:44 ` Bae, Chang Seok
2021-07-30 14:59 ` [PATCH v9 15/26] x86/fpu/xstate: Support both legacy and expanded signal XSTATE size Chang S. Bae
2021-07-30 14:59 ` [PATCH v9 16/26] x86/fpu/xstate: Adjust the XSAVE feature table to address gaps in state component numbers Chang S. Bae
2021-07-30 14:59 ` [PATCH v9 17/26] x86/fpu/xstate: Disable XSTATE support if an inconsistent state is detected Chang S. Bae
2021-07-30 14:59 ` [PATCH v9 18/26] x86/cpufeatures/amx: Enumerate Advanced Matrix Extension (AMX) feature bits Chang S. Bae
2021-07-30 14:59 ` [PATCH v9 19/26] x86/fpu/amx: Define AMX state components and have it used for boot-time checks Chang S. Bae
2021-07-30 14:59 ` [PATCH v9 20/26] x86/fpu/amx: Initialize child's AMX state Chang S. Bae
2021-07-30 14:59 ` [PATCH v9 21/26] x86/fpu/amx: Enable the AMX feature in 64-bit mode Chang S. Bae
2021-07-30 14:59 ` [PATCH v9 22/26] x86/fpu/xstate: Skip writing zeros to signal frame for dynamic user states if in INIT-state Chang S. Bae
2021-07-30 14:59 ` [PATCH v9 23/26] selftest/x86/amx: Test cases for the AMX state management Chang S. Bae
2021-07-30 14:59 ` [PATCH v9 24/26] x86/insn/amx: Add TILERELEASE instruction to the opcode map Chang S. Bae
2021-07-30 14:59 ` [PATCH v9 25/26] intel_idle/amx: Add SPR support with XTILEDATA capability Chang S. Bae
2021-07-30 18:41 ` Dave Hansen
2021-08-03 21:32 ` Bae, Chang Seok
2021-08-03 21:38 ` Dave Hansen
2021-08-03 21:43 ` Brown, Len
2021-07-30 20:15 ` Dave Hansen
2021-07-30 14:59 ` [PATCH v9 26/26] x86/fpu/xstate: Add a sanity check for XFD state when saving XSTATE Chang S. Bae
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