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Commit 689ee856 authored by Paul Burton's avatar Paul Burton Committed by Ralf Baechle
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MIPS: Simplify EVA FP context handling code 



The protected_{save,restore}_fp_context functions had effectively
different implementations for EVA. Simplify & unify the code somewhat
such that EVA configurations simply guarantee the FPU-not-owned path
through the standard code path.

Signed-off-by: default avatarPaul Burton <paul.burton@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Matthew Fortune <matthew.fortune@imgtec.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linux-kernel@vger.kernel.org
Cc: Richard Weinberger <richard@nod.at>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Maciej W. Rozycki <macro@codesourcery.com>
Patchwork: https://patchwork.linux-mips.org/patch/10787/


Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent 397d08b0

arch/mips/kernel/signal.c

+19 −25
Original line number Diff line number Diff line
@@ -101,7 +101,14 @@ static int copy_fp_from_sigcontext(struct sigcontext __user *sc) 
static int protected_save_fp_context(struct sigcontext __user *sc)

{

	int err;

#ifndef CONFIG_EVA



	/*

	 * EVA does not have userland equivalents of ldc1 or sdc1, so

	 * save to the kernel FP context & copy that to userland below.

	 */

	if (config_enabled(CONFIG_EVA))

		lose_fpu(1);



	while (1) {

		lock_fpu_owner();

		if (is_fpu_owner()) {
@@ -120,21 +127,22 @@ static int protected_save_fp_context(struct sigcontext __user *sc) 
		if (err)

			break;	/* really bad sigcontext */

	}

#else

	/*

	 * EVA does not have FPU EVA instructions so saving fpu context directly

	 * does not work.

	 */

	lose_fpu(1);

	err = save_fp_context(sc); /* this might fail */

#endif



	return err;

}



static int protected_restore_fp_context(struct sigcontext __user *sc)

{

	int err, tmp __maybe_unused;

#ifndef CONFIG_EVA



	/*

	 * EVA does not have userland equivalents of ldc1 or sdc1, so we

	 * disable the FPU here such that the code below simply copies to

	 * the kernel FP context.

	 */

	if (config_enabled(CONFIG_EVA))

		lose_fpu(0);



	while (1) {

		lock_fpu_owner();

		if (is_fpu_owner()) {
@@ -153,14 +161,7 @@ static int protected_restore_fp_context(struct sigcontext __user *sc) 
		if (err)

			break;	/* really bad sigcontext */

	}

#else

	/*

	 * EVA does not have FPU EVA instructions so restoring fpu context

	 * directly does not work.

	 */

	lose_fpu(0);

	err = restore_fp_context(sc); /* this might fail */

#endif



	return err;

}
@@ -629,7 +630,6 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused, 
}



#ifdef CONFIG_SMP

#ifndef CONFIG_EVA

static int smp_save_fp_context(struct sigcontext __user *sc)

{

	return raw_cpu_has_fpu
@@ -643,12 +643,10 @@ static int smp_restore_fp_context(struct sigcontext __user *sc) 
	       ? _restore_fp_context(sc)

	       : copy_fp_from_sigcontext(sc);

}

#endif /* CONFIG_EVA */

#endif



static int signal_setup(void)

{

#ifndef CONFIG_EVA

#ifdef CONFIG_SMP

	/* For now just do the cpu_has_fpu check when the functions are invoked */

	save_fp_context = smp_save_fp_context;
@@ -662,10 +660,6 @@ static int signal_setup(void) 
		restore_fp_context = copy_fp_from_sigcontext;

	}

#endif /* CONFIG_SMP */

#else

	save_fp_context = copy_fp_to_sigcontext;

	restore_fp_context = copy_fp_from_sigcontext;

#endif



	return 0;

}