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Commit 8dfdd02a authored by David Daney's avatar David Daney Committed by Ralf Baechle
Browse files

MIPS: Don't save/restore OCTEON wide multiplier state on syscalls. 



The ABI allows these to be clobbered on syscalls, so only save and
restore the multiplier state when the temporary registers need to be
preserved.

Signed-off-by: default avatarDavid Daney <david.daney@cavium.com>
Cc: linux-mips@linux-mips.org
Cc: David Daney <david.daney@cavium.com>
Patchwork: https://patchwork.linux-mips.org/patch/5540/


Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent a135a9b5

arch/mips/include/asm/stackframe.h

+14 −15
Original line number Diff line number Diff line
@@ -69,6 +69,14 @@ 
		LONG_S	$24, PT_R24(sp)

#ifndef CONFIG_CPU_HAS_SMARTMIPS

		LONG_S	v1, PT_LO(sp)

#endif

#ifdef CONFIG_CPU_CAVIUM_OCTEON

		/*

		 * The Octeon multiplier state is affected by general

		 * multiply instructions. It must be saved before and

		 * kernel code might corrupt it

		 */

		jal     octeon_mult_save

#endif

		.endm
@@ -220,15 +228,6 @@ 
#ifdef CONFIG_CPU_CAVIUM_OCTEON

		.set    mips64

		pref    0, 0($28)       /* Prefetch the current pointer */

		pref	0, PT_R31(sp)	/* Prefetch the $31(ra) */

		/* The Octeon multiplier state is affected by general multiply

		    instructions. It must be saved before and kernel code might

		    corrupt it */

		jal	octeon_mult_save

		LONG_L	v1, 0($28)  /* Load the current pointer */

			 /* Restore $31(ra) that was changed by the jal */

		LONG_L	ra, PT_R31(sp)

		pref	0, 0(v1)    /* Prefetch the current thread */

#endif

		.set	pop

		.endm
@@ -248,6 +247,10 @@ 
		.endm



		.macro	RESTORE_TEMP

#ifdef CONFIG_CPU_CAVIUM_OCTEON

		/* Restore the Octeon multiplier state */

		jal	octeon_mult_restore

#endif

#ifdef CONFIG_CPU_HAS_SMARTMIPS

		LONG_L	$24, PT_ACX(sp)

		mtlhx	$24
@@ -360,10 +363,6 @@ 
		DVPE	5				# dvpe a1

		jal	mips_ihb

#endif /* CONFIG_MIPS_MT_SMTC */

#ifdef CONFIG_CPU_CAVIUM_OCTEON

		/* Restore the Octeon multiplier state */

		jal	octeon_mult_restore

#endif

		mfc0	a0, CP0_STATUS

		ori	a0, STATMASK

		xori	a0, STATMASK