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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, jing2.liu@intel.com,
	ravi.v.shankar@intel.com, linux-kernel@vger.kernel.org,
	chang.seok.bae@intel.com, linux-kselftest@vger.kernel.org
Subject: [PATCH v3 20/21] x86/fpu/xstate: Support dynamic user state in the signal handling path
Date: Wed, 23 Dec 2020 07:57:16 -0800	[thread overview]
Message-ID: <20201223155717.19556-21-chang.seok.bae@intel.com> (raw)
In-Reply-To: <20201223155717.19556-1-chang.seok.bae@intel.com>

Entering a signal handler, the kernel saves the XSAVE buffer. The dynamic
user state is better to be saved only when used. fpu->state_mask can help
to exclude unused states.

Returning from a signal handler, XRSTOR re-initializes the excluded state
components.

Add a test case to verify in the signal handler that the signal frame
excludes AMX data when the signaled thread has initialized AMX state.

No functional change until the kernel supports the dynamic user states.

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
Cc: linux-kselftest@vger.kernel.org
---
Changes from v1:
* Made it revertible (moved close to the end of the series).
* Included the test case.
---
 arch/x86/include/asm/fpu/internal.h |  2 +-
 tools/testing/selftests/x86/amx.c   | 66 +++++++++++++++++++++++++++++
 2 files changed, 67 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h
index 5eba9a466249..202874bb79da 100644
--- a/arch/x86/include/asm/fpu/internal.h
+++ b/arch/x86/include/asm/fpu/internal.h
@@ -369,7 +369,7 @@ static inline void copy_kernel_to_xregs(struct xregs_state *xstate, u64 mask)
  */
 static inline int copy_xregs_to_user(struct xregs_state __user *buf)
 {
-	u64 mask = xfeatures_mask_user();
+	u64 mask = current->thread.fpu.state_mask;
 	u32 lmask = mask;
 	u32 hmask = mask >> 32;
 	int err;
diff --git a/tools/testing/selftests/x86/amx.c b/tools/testing/selftests/x86/amx.c
index f4ecdfd27ae9..a7386b886532 100644
--- a/tools/testing/selftests/x86/amx.c
+++ b/tools/testing/selftests/x86/amx.c
@@ -650,6 +650,71 @@ static void test_ptrace(void)
 	test_tile_state_write(ptracee_loads_tiles);
 }
 
+/* Signal handling test */
+
+static int sigtrapped;
+struct tile_data sig_tiles, sighdl_tiles;
+
+static void handle_sigtrap(int sig, siginfo_t *info, void *ctx_void)
+{
+	ucontext_t *uctxt = (ucontext_t *)ctx_void;
+	struct xsave_data xdata;
+	struct tile_config cfg;
+	struct tile_data tiles;
+	u64 header;
+
+	header = __get_xsave_xstate_bv((void *)uctxt->uc_mcontext.fpregs);
+
+	if (header & (1 << XFEATURE_XTILE_DATA))
+		printf("[FAIL]\ttile data was written in sigframe\n");
+	else
+		printf("[OK]\ttile data was skipped in sigframe\n");
+
+	set_tilecfg(&cfg);
+	load_tilecfg(&cfg);
+	init_xdata(&xdata);
+
+	make_tiles(&tiles);
+	copy_tiles_to_xdata(&xdata, &tiles);
+	restore_xdata(&xdata);
+
+	save_xdata(&xdata);
+	if (compare_xdata_tiles(&xdata, &tiles))
+		err(1, "tile load file");
+
+	printf("\tsignal handler: load tile data\n");
+
+	sigtrapped = sig;
+}
+
+static void test_signal_handling(void)
+{
+	struct xsave_data xdata = { 0 };
+	struct tile_data tiles = { 0 };
+
+	sethandler(SIGTRAP, handle_sigtrap, 0);
+	sigtrapped = 0;
+
+	printf("[RUN]\tCheck tile state management in handling signal\n");
+
+	printf("\tbefore signal: initial tile data state\n");
+
+	raise(SIGTRAP);
+
+	if (sigtrapped == 0)
+		err(1, "sigtrap");
+
+	save_xdata(&xdata);
+	if (compare_xdata_tiles(&xdata, &tiles)) {
+		printf("[FAIL]\ttile data was not loaded at sigreturn\n");
+		nerrs++;
+	} else {
+		printf("[OK]\ttile data was re-initialized at sigreturn\n");
+	}
+
+	clearhandler(SIGTRAP);
+}
+
 int main(void)
 {
 	/* Check hardware availability at first */
@@ -672,6 +737,7 @@ int main(void)
 	test_fork();
 	test_context_switch();
 	test_ptrace();
+	test_signal_handling();
 
 	return nerrs ? 1 : 0;
 }
-- 
2.17.1


  parent reply	other threads:[~2020-12-23 16:02 UTC|newest]

Thread overview: 64+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-23 15:56 [PATCH v3 00/21] x86: Support Intel Advanced Matrix Extensions Chang S. Bae
2020-12-23 15:56 ` [PATCH v3 01/21] x86/fpu/xstate: Modify initialization helper to handle both static and dynamic buffers Chang S. Bae
2021-01-15 12:40   ` Borislav Petkov
2020-12-23 15:56 ` [PATCH v3 02/21] x86/fpu/xstate: Modify state copy helpers " Chang S. Bae
2021-01-15 12:50   ` Borislav Petkov
2021-01-19 18:50     ` Bae, Chang Seok
2021-01-20 20:53       ` Borislav Petkov
2021-01-20 21:12         ` Bae, Chang Seok
2020-12-23 15:56 ` [PATCH v3 03/21] x86/fpu/xstate: Modify address finders " Chang S. Bae
2021-01-15 13:06   ` Borislav Petkov
2020-12-23 15:57 ` [PATCH v3 04/21] x86/fpu/xstate: Modify context switch helpers " Chang S. Bae
2021-01-15 13:18   ` Borislav Petkov
2021-01-19 18:49     ` Bae, Chang Seok
2020-12-23 15:57 ` [PATCH v3 05/21] x86/fpu/xstate: Add a new variable to indicate dynamic user states Chang S. Bae
2021-01-15 13:39   ` Borislav Petkov
2021-01-15 19:47     ` Bae, Chang Seok
2021-01-19 15:57       ` Borislav Petkov
2021-01-19 18:57         ` Bae, Chang Seok
2021-01-22 10:56           ` Borislav Petkov
2021-01-27  1:23             ` Bae, Chang Seok
2020-12-23 15:57 ` [PATCH v3 06/21] x86/fpu/xstate: Calculate and remember dynamic xstate buffer sizes Chang S. Bae
2021-01-22 11:44   ` Borislav Petkov
2021-01-27  1:23     ` Bae, Chang Seok
2021-01-27  9:38       ` Borislav Petkov
2021-02-03  2:54         ` Bae, Chang Seok
2020-12-23 15:57 ` [PATCH v3 07/21] x86/fpu/xstate: Introduce helpers to manage dynamic xstate buffers Chang S. Bae
2021-01-26 20:17   ` Borislav Petkov
2021-01-27  1:23     ` Bae, Chang Seok
2021-01-27 10:41       ` Borislav Petkov
2021-02-03  4:10         ` Bae, Chang Seok
2021-02-04 13:10           ` Borislav Petkov
2021-02-03  4:10     ` Bae, Chang Seok
2020-12-23 15:57 ` [PATCH v3 08/21] x86/fpu/xstate: Define the scope of the initial xstate data Chang S. Bae
2021-02-08 12:33   ` Borislav Petkov
2021-02-08 18:53     ` Bae, Chang Seok
2021-02-09 12:49       ` Borislav Petkov
2021-02-09 15:38         ` Bae, Chang Seok
2020-12-23 15:57 ` [PATCH v3 09/21] x86/fpu/xstate: Introduce wrapper functions to organize xstate buffer access Chang S. Bae
2021-02-08 12:33   ` Borislav Petkov
2021-02-09 15:50     ` Bae, Chang Seok
2020-12-23 15:57 ` [PATCH v3 10/21] x86/fpu/xstate: Update xstate save function to support dynamic xstate Chang S. Bae
2021-01-07  8:41   ` Liu, Jing2
2021-01-07 18:40     ` Bae, Chang Seok
2021-01-12  2:52       ` Liu, Jing2
2021-01-15  4:59         ` Bae, Chang Seok
2021-01-15  5:45           ` Liu, Jing2
2021-02-08 12:33   ` Borislav Petkov
2021-02-09 15:48     ` Bae, Chang Seok
2020-12-23 15:57 ` [PATCH v3 11/21] x86/fpu/xstate: Update xstate buffer address finder " Chang S. Bae
2021-02-19 15:00   ` Borislav Petkov
2021-02-19 19:19     ` Bae, Chang Seok
2020-12-23 15:57 ` [PATCH v3 12/21] x86/fpu/xstate: Update xstate context copy function to support dynamic buffer Chang S. Bae
2020-12-23 15:57 ` [PATCH v3 13/21] x86/fpu/xstate: Expand dynamic context switch buffer on first use Chang S. Bae
2020-12-23 15:57 ` [PATCH v3 14/21] x86/fpu/xstate: Support ptracer-induced xstate buffer expansion Chang S. Bae
2020-12-23 15:57 ` [PATCH v3 15/21] x86/fpu/xstate: Extend the table to map xstate components with features Chang S. Bae
2020-12-23 15:57 ` [PATCH v3 16/21] x86/cpufeatures/amx: Enumerate Advanced Matrix Extension (AMX) feature bits Chang S. Bae
2020-12-23 15:57 ` [PATCH v3 17/21] x86/fpu/amx: Define AMX state components and have it used for boot-time checks Chang S. Bae
2020-12-23 15:57 ` [PATCH v3 18/21] x86/fpu/amx: Enable the AMX feature in 64-bit mode Chang S. Bae
2020-12-23 15:57 ` [PATCH v3 19/21] selftest/x86/amx: Include test cases for the AMX state management Chang S. Bae
2020-12-23 15:57 ` Chang S. Bae [this message]
2020-12-23 15:57 ` [PATCH v3 21/21] x86/fpu/xstate: Introduce boot-parameters to control some state component support Chang S. Bae
2020-12-23 18:37   ` Randy Dunlap
2021-01-14 21:31     ` Bae, Chang Seok
2021-01-14 21:31 ` [PATCH v3 00/21] x86: Support Intel Advanced Matrix Extensions Bae, Chang Seok

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