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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: Paul 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: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Paul Burton 2015-07-27 12:58:13 -07:00 committed by Ralf Baechle
parent 397d08b006
commit 689ee8565c
1 changed files with 19 additions and 25 deletions
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44
arch/mips/kernel/signal.c
View File

@ -101,7 +101,14 @@ static int copy_fp_from_sigcontext(struct sigcontext __user *sc)
static int protected_save_fp_context(struct sigcontext __user *sc) static int protected_save_fp_context(struct sigcontext __user *sc)
{ {
int err; 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) { while (1) {
lock_fpu_owner(); lock_fpu_owner();
if (is_fpu_owner()) { if (is_fpu_owner()) {
@ -120,21 +127,22 @@ static int protected_save_fp_context(struct sigcontext __user *sc)
if (err) if (err)
break; /* really bad sigcontext */ 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; return err;
} }
static int protected_restore_fp_context(struct sigcontext __user *sc) static int protected_restore_fp_context(struct sigcontext __user *sc)
{ {
int err, tmp __maybe_unused; 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) { while (1) {
lock_fpu_owner(); lock_fpu_owner();
if (is_fpu_owner()) { if (is_fpu_owner()) {
@ -153,14 +161,7 @@ static int protected_restore_fp_context(struct sigcontext __user *sc)
if (err) if (err)
break; /* really bad sigcontext */ 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; return err;
} }
@ -629,7 +630,6 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
} }
#ifdef CONFIG_SMP #ifdef CONFIG_SMP
#ifndef CONFIG_EVA
static int smp_save_fp_context(struct sigcontext __user *sc) static int smp_save_fp_context(struct sigcontext __user *sc)
{ {
return raw_cpu_has_fpu return raw_cpu_has_fpu
@ -643,12 +643,10 @@ static int smp_restore_fp_context(struct sigcontext __user *sc)
? _restore_fp_context(sc) ? _restore_fp_context(sc)
: copy_fp_from_sigcontext(sc); : copy_fp_from_sigcontext(sc);
} }
#endif /* CONFIG_EVA */
#endif #endif
static int signal_setup(void) static int signal_setup(void)
{ {
#ifndef CONFIG_EVA
#ifdef CONFIG_SMP #ifdef CONFIG_SMP
/* For now just do the cpu_has_fpu check when the functions are invoked */ /* For now just do the cpu_has_fpu check when the functions are invoked */
save_fp_context = smp_save_fp_context; save_fp_context = smp_save_fp_context;
@ -662,10 +660,6 @@ static int signal_setup(void)
restore_fp_context = copy_fp_from_sigcontext; restore_fp_context = copy_fp_from_sigcontext;
} }
#endif /* CONFIG_SMP */ #endif /* CONFIG_SMP */
#else
save_fp_context = copy_fp_to_sigcontext;
restore_fp_context = copy_fp_from_sigcontext;
#endif
return 0; return 0;
} }