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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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59cbcdb5d8
This is almost a copy/paste of the existing version, with a couple of subtle differences: - Only write to FPEXC once on the save path - Add an isb when enabling VFP access The patch also defines a few sysreg accessors and a __vfp_enabled predicate that test the VFP trapping state. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
68 lines
1.9 KiB
ArmAsm
68 lines
1.9 KiB
ArmAsm
/*
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* Copyright (C) 2012 - Virtual Open Systems and Columbia University
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* Author: Christoffer Dall <c.dall@virtualopensystems.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/linkage.h>
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#include <asm/vfpmacros.h>
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.text
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.pushsection .hyp.text, "ax"
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/* void __vfp_save_state(struct vfp_hard_struct *vfp); */
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ENTRY(__vfp_save_state)
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push {r4, r5}
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VFPFMRX r1, FPEXC
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@ Make sure *really* VFP is enabled so we can touch the registers.
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orr r5, r1, #FPEXC_EN
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tst r5, #FPEXC_EX @ Check for VFP Subarchitecture
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bic r5, r5, #FPEXC_EX @ FPEXC_EX disable
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VFPFMXR FPEXC, r5
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isb
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VFPFMRX r2, FPSCR
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beq 1f
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@ If FPEXC_EX is 0, then FPINST/FPINST2 reads are upredictable, so
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@ we only need to save them if FPEXC_EX is set.
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VFPFMRX r3, FPINST
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tst r5, #FPEXC_FP2V
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VFPFMRX r4, FPINST2, ne @ vmrsne
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1:
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VFPFSTMIA r0, r5 @ Save VFP registers
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stm r0, {r1-r4} @ Save FPEXC, FPSCR, FPINST, FPINST2
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pop {r4, r5}
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bx lr
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ENDPROC(__vfp_save_state)
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/* void __vfp_restore_state(struct vfp_hard_struct *vfp);
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* Assume FPEXC_EN is on and FPEXC_EX is off */
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ENTRY(__vfp_restore_state)
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VFPFLDMIA r0, r1 @ Load VFP registers
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ldm r0, {r0-r3} @ Load FPEXC, FPSCR, FPINST, FPINST2
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VFPFMXR FPSCR, r1
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tst r0, #FPEXC_EX @ Check for VFP Subarchitecture
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beq 1f
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VFPFMXR FPINST, r2
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tst r0, #FPEXC_FP2V
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VFPFMXR FPINST2, r3, ne
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1:
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VFPFMXR FPEXC, r0 @ FPEXC (last, in case !EN)
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bx lr
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ENDPROC(__vfp_restore_state)
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.popsection
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