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Commit 33c771ba authored by Paul Burton's avatar Paul Burton Committed by Ralf Baechle
Browse files

MIPS: save/disable MSA in lose_fpu 



The kernel depends upon MSA never being enabled when the FPU is not, a
condition which is currently violated in a few places (whilst saving
sigcontext, following mips_cpu_save). Catch all the problem cases by
disabling MSA in lose_fpu, after saving context if necessary.

Signed-off-by: default avatarPaul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7302/


Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent b8340673

arch/mips/include/asm/fpu.h

+12 −3
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 
#include <asm/hazards.h>

#include <asm/processor.h>

#include <asm/current.h>

#include <asm/msa.h>



#ifdef CONFIG_MIPS_MT_FPAFF

#include <asm/mips_mt.h>
@@ -141,13 +142,21 @@ static inline int own_fpu(int restore) 
static inline void lose_fpu(int save)

{

	preempt_disable();

	if (is_fpu_owner()) {

	if (is_msa_enabled()) {

		if (save) {

			save_msa(current);

			asm volatile("cfc1 %0, $31"

				: "=r"(current->thread.fpu.fcr31));

		}

		disable_msa();

		clear_thread_flag(TIF_USEDMSA);

	} else if (is_fpu_owner()) {

		if (save)

			_save_fp(current);

		KSTK_STATUS(current) &= ~ST0_CU1;

		clear_thread_flag(TIF_USEDFPU);

		__disable_fpu();

	}

	KSTK_STATUS(current) &= ~ST0_CU1;

	clear_thread_flag(TIF_USEDFPU);

	preempt_enable();

}