Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
powerpc: Fix bug causing FP registers corruption on UP + preempt
This fixes a bug noticed by Paolo Galtieri and fixed for ARCH=ppc in
the previous commit (ppc: fix floating point register corruption).
This fixes the arch/powerpc code by adding preempt_disable/enable,
and also cleans it up a bit by pulling out the code that discards
any lazily-switched CPU register state into a new function, rather
than having that code repeated in three places.
Signed-off-by: Paul Mackerras <paulus@samba.org>
+25
-37
arch/powerpc/kernel/process.c
+25
-37
arch/powerpc/kernel/process.c
···
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}
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#endif /* CONFIG_SPE */
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+
/*
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* If we are doing lazy switching of CPU state (FP, altivec or SPE),
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* and the current task has some state, discard it.
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*/
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static inline void discard_lazy_cpu_state(void)
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{
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#ifndef CONFIG_SMP
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preempt_disable();
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if (last_task_used_math == current)
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+
last_task_used_math = NULL;
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+
#ifdef CONFIG_ALTIVEC
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if (last_task_used_altivec == current)
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last_task_used_altivec = NULL;
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+
#endif /* CONFIG_ALTIVEC */
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+
#ifdef CONFIG_SPE
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if (last_task_used_spe == current)
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last_task_used_spe = NULL;
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+
#endif
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preempt_enable();
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+
#endif /* CONFIG_SMP */
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}
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+
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int set_dabr(unsigned long dabr)
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{
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if (ppc_md.set_dabr)
···
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void exit_thread(void)
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{
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kprobe_flush_task(current);
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-
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-
#ifndef CONFIG_SMP
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-
if (last_task_used_math == current)
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-
last_task_used_math = NULL;
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-
#ifdef CONFIG_ALTIVEC
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-
if (last_task_used_altivec == current)
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-
last_task_used_altivec = NULL;
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-
#endif /* CONFIG_ALTIVEC */
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-
#ifdef CONFIG_SPE
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-
if (last_task_used_spe == current)
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-
last_task_used_spe = NULL;
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-
#endif
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-
#endif /* CONFIG_SMP */
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+
discard_lazy_cpu_state();
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}
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void flush_thread(void)
···
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t->flags ^= (_TIF_ABI_PENDING | _TIF_32BIT);
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#endif
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-
#ifndef CONFIG_SMP
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-
if (last_task_used_math == current)
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-
last_task_used_math = NULL;
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-
#ifdef CONFIG_ALTIVEC
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-
if (last_task_used_altivec == current)
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-
last_task_used_altivec = NULL;
477
-
#endif /* CONFIG_ALTIVEC */
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-
#ifdef CONFIG_SPE
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-
if (last_task_used_spe == current)
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-
last_task_used_spe = NULL;
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-
#endif
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-
#endif /* CONFIG_SMP */
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+
discard_lazy_cpu_state();
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#ifdef CONFIG_PPC64 /* for now */
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if (current->thread.dabr) {
···
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}
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#endif
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-
#ifndef CONFIG_SMP
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-
if (last_task_used_math == current)
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-
last_task_used_math = NULL;
640
-
#ifdef CONFIG_ALTIVEC
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-
if (last_task_used_altivec == current)
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-
last_task_used_altivec = NULL;
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-
#endif
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-
#ifdef CONFIG_SPE
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-
if (last_task_used_spe == current)
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-
last_task_used_spe = NULL;
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-
#endif
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-
#endif /* CONFIG_SMP */
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+
discard_lazy_cpu_state();
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memset(current->thread.fpr, 0, sizeof(current->thread.fpr));
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current->thread.fpscr.val = 0;
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#ifdef CONFIG_ALTIVEC