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From: Ben Hutchings <ben@decadent.org.uk>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: akpm@linux-foundation.org, "Arnd Bergmann" <arnd@arndb.de>,
	linux-mips@linux-mips.org, "Ralf Baechle" <ralf@linux-mips.org>,
	"Paul Burton" <paul.burton@imgtec.com>
Subject: [PATCH 3.16 04/19] MIPS: preserve scalar FP CSR when switching vector context
Date: Sat, 01 Apr 2017 14:17:50 +0100	[thread overview]
Message-ID: <lsq.1491052670.80726452@decadent.org.uk> (raw)
In-Reply-To: <lsq.1491052670.319419763@decadent.org.uk>

3.16.43-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Paul Burton <paul.burton@imgtec.com>

commit b83406735a4ae0aff4b614664d6a64a0fd6b9917 upstream.

Switching the vector context implicitly saves & restores the state of
the aliased scalar FP data registers, however the scalar FP control
& status register is distinct from the MSA control & status register.
In order to allow scalar FP to function correctly in programs using
MSA, the scalar CSR needs to be saved & restored along with the MSA
vector context.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7301/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
---
 arch/mips/kernel/r4k_switch.S | 4 +++-
 arch/mips/kernel/traps.c      | 5 +++++
 2 files changed, 8 insertions(+), 1 deletion(-)

--- a/arch/mips/kernel/r4k_switch.S
+++ b/arch/mips/kernel/r4k_switch.S
@@ -64,8 +64,10 @@
 	/* Check whether we're saving scalar or vector context. */
 	bgtz	a3, 1f
 
-	/* Save 128b MSA vector context. */
+	/* Save 128b MSA vector context + scalar FP control & status. */
+	cfc1	t1, fcr31
 	msa_save_all	a0
+	sw	t1, THREAD_FCR31(a0)
 	b	2f
 
 1:	/* Save 32b/64b scalar FP context. */
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -1159,6 +1159,11 @@ static int enable_restore_fp_context(int
 
 	/* We need to restore the vector context. */
 	restore_msa(current);
+
+	/* Restore the scalar FP control & status register */
+	if (!was_fpu_owner)
+		asm volatile("ctc1 %0, $31" : : "r"(current->thread.fpu.fcr31));
+
 	return 0;
 }
 

  parent reply	other threads:[~2017-04-01 13:25 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-01 13:17 [PATCH 3.16 00/19] 3.16.43-rc1 review Ben Hutchings
2017-04-01 13:17 ` [PATCH 3.16 05/19] MIPS: save/disable MSA in lose_fpu Ben Hutchings
2017-04-01 13:17 ` [PATCH 3.16 14/19] MIPS: Zero variable read by get_user / __get_user in case of an error Ben Hutchings
2017-04-01 13:17 ` Ben Hutchings [this message]
2017-04-01 13:17 ` [PATCH 3.16 15/19] HID: hid-input: Add parentheses to quell gcc warning Ben Hutchings
2017-04-01 13:17 ` [PATCH 3.16 18/19] aio: mark AIO pseudo-fs noexec Ben Hutchings
2017-04-01 13:17 ` [PATCH 3.16 17/19] vfs: Commit to never having exectuables on proc and sysfs Ben Hutchings
2017-04-01 13:17 ` [PATCH 3.16 12/19] serial: samsung: Use %pa to print 'resource_size_t' type Ben Hutchings
2017-04-01 13:17 ` [PATCH 3.16 16/19] netlink: remove mmapped netlink support Ben Hutchings
2017-04-01 13:17 ` [PATCH 3.16 11/19] mmc: sunxi: avoid invalid pointer calculation Ben Hutchings
2017-04-01 18:45   ` David Lanzendörfer
2017-04-01 19:53     ` Ben Hutchings
2017-04-01 13:17 ` [PATCH 3.16 08/19] atm: iphase: fix misleading indention Ben Hutchings
2017-04-01 13:17 ` [PATCH 3.16 19/19] keys: Guard against null match function in keyring_search_aux() Ben Hutchings
2017-04-01 13:17 ` [PATCH 3.16 10/19] fs/nfs: fix new compiler warning about boolean in switch Ben Hutchings
2017-04-01 13:17 ` [PATCH 3.16 13/19] MIPS: ralink: Cosmetic change to prom_init() Ben Hutchings
2017-04-01 13:17 ` [PATCH 3.16 06/19] MIPS: init upper 64b of vector registers when MSA is first used Ben Hutchings
2017-04-01 13:17 ` [PATCH 3.16 02/19] blk: rq_data_dir() should not return a boolean Ben Hutchings
2017-04-01 13:17 ` [PATCH 3.16 09/19] crypto: improve gcc optimization flags for serpent and wp512 Ben Hutchings
2017-04-01 13:17 ` [PATCH 3.16 03/19] MIPS: save/restore MSACSR register on context switch Ben Hutchings
2017-04-01 13:17 ` [PATCH 3.16 01/19] fs: namespace: suppress 'may be used uninitialized' warnings Ben Hutchings
2017-04-01 13:17 ` [PATCH 3.16 07/19] MIPS: Fix build with binutils 2.24.51+ Ben Hutchings
2017-04-01 17:43 ` [PATCH 3.16 00/19] 3.16.43-rc1 review Guenter Roeck
2017-04-01 22:40   ` Ben Hutchings
2017-04-02  2:21     ` Guenter Roeck
2017-04-02  2:48     ` Ben Hutchings
2017-04-02  3:04 ` [PATCH 3.16 00/26] 3.16.43-rc2 review Ben Hutchings
2017-04-02  3:04   ` [PATCH 3.16 22/26] MIPS: traps: Fix inline asm ctc1 missing .set hardfloat Ben Hutchings
2017-04-02  3:04   ` [PATCH 3.16 23/26] MIPS: Push .set mips64r* into the functions needing it Ben Hutchings
2017-04-02  3:04   ` [PATCH 3.16 24/26] MIPS: assume at as source/dest of MSA copy/insert instructions Ben Hutchings
2017-04-02  3:04   ` [PATCH 3.16 20/26] MIPS: allow msa.h to be included in assembly files Ben Hutchings
2017-04-02  3:04   ` [PATCH 3.16 26/26] MIPS: wrap cfcmsa & ctcmsa accesses for toolchains with MSA support Ben Hutchings
2017-04-02  3:04   ` [PATCH 3.16 21/26] MIPS: mipsregs.h: Add write_32bit_cp1_register() Ben Hutchings
2017-04-02  3:04   ` [PATCH 3.16 25/26] MIPS: remove MSA macro recursion Ben Hutchings
2017-04-02  3:15   ` [PATCH 3.16 00/26] 3.16.43-rc2 review Ben Hutchings

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