68b34588e2
System call entry and particularly exit code is beyond the limit of what is reasonable to implement in asm. This conversion moves all conditional branches out of the asm code, except for the case that all GPRs should be restored at exit. Null syscall test is about 5% faster after this patch, because the exit work is handled under local_irq_disable, and the hard mask and pending interrupt replay is handled after that, which avoids games with MSR. mpe: Includes subsequent fixes from Nick: This fixes 4 issues caught by TM selftests. First was a tm-syscall bug that hit due to tabort_syscall being called after interrupts were reconciled (in a subsequent patch), which led to interrupts being enabled before tabort_syscall was called. Rather than going through an un-reconciling interrupts for the return, I just go back to putting the test early in asm, the C-ification of that wasn't a big win anyway. Second is the syscall return _TIF_USER_WORK_MASK check would go into an infinite loop if _TIF_RESTORE_TM became set. The asm code uses _TIF_USER_WORK_MASK to brach to slowpath which includes restore_tm_state. Third is system call return was not calling restore_tm_state, I missed this completely (alhtough it's in the return from interrupt C conversion because when the asm syscall code encountered problems it would branch to the interrupt return code. Fourth is MSR_VEC missing from restore_math, which was caught by tm-unavailable selftest taking an unexpected facility unavailable interrupt when testing VSX unavailble exception with MSR.FP=1 MSR.VEC=1. Fourth case also has a fixup in a subsequent patch. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michal Suchanek <msuchanek@suse.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200225173541.1549955-26-npiggin@gmail.com
104 lines
2.7 KiB
C
104 lines
2.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (C) 1999 Cort Dougan <cort@cs.nmt.edu>
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*/
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#ifndef _ASM_POWERPC_SWITCH_TO_H
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#define _ASM_POWERPC_SWITCH_TO_H
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#include <linux/sched.h>
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#include <asm/reg.h>
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struct thread_struct;
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struct task_struct;
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struct pt_regs;
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extern struct task_struct *__switch_to(struct task_struct *,
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struct task_struct *);
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#define switch_to(prev, next, last) ((last) = __switch_to((prev), (next)))
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extern struct task_struct *_switch(struct thread_struct *prev,
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struct thread_struct *next);
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extern void switch_booke_debug_regs(struct debug_reg *new_debug);
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extern int emulate_altivec(struct pt_regs *);
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void restore_math(struct pt_regs *regs);
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void restore_tm_state(struct pt_regs *regs);
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extern void flush_all_to_thread(struct task_struct *);
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extern void giveup_all(struct task_struct *);
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#ifdef CONFIG_PPC_FPU
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extern void enable_kernel_fp(void);
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extern void flush_fp_to_thread(struct task_struct *);
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extern void giveup_fpu(struct task_struct *);
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extern void save_fpu(struct task_struct *);
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static inline void disable_kernel_fp(void)
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{
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msr_check_and_clear(MSR_FP);
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}
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#else
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static inline void save_fpu(struct task_struct *t) { }
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static inline void flush_fp_to_thread(struct task_struct *t) { }
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#endif
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#ifdef CONFIG_ALTIVEC
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extern void enable_kernel_altivec(void);
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extern void flush_altivec_to_thread(struct task_struct *);
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extern void giveup_altivec(struct task_struct *);
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extern void save_altivec(struct task_struct *);
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static inline void disable_kernel_altivec(void)
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{
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msr_check_and_clear(MSR_VEC);
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}
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#else
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static inline void save_altivec(struct task_struct *t) { }
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static inline void __giveup_altivec(struct task_struct *t) { }
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#endif
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#ifdef CONFIG_VSX
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extern void enable_kernel_vsx(void);
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extern void flush_vsx_to_thread(struct task_struct *);
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static inline void disable_kernel_vsx(void)
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{
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msr_check_and_clear(MSR_FP|MSR_VEC|MSR_VSX);
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}
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#endif
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#ifdef CONFIG_SPE
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extern void enable_kernel_spe(void);
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extern void flush_spe_to_thread(struct task_struct *);
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extern void giveup_spe(struct task_struct *);
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extern void __giveup_spe(struct task_struct *);
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static inline void disable_kernel_spe(void)
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{
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msr_check_and_clear(MSR_SPE);
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}
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#else
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static inline void __giveup_spe(struct task_struct *t) { }
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#endif
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static inline void clear_task_ebb(struct task_struct *t)
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{
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#ifdef CONFIG_PPC_BOOK3S_64
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/* EBB perf events are not inherited, so clear all EBB state. */
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t->thread.ebbrr = 0;
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t->thread.ebbhr = 0;
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t->thread.bescr = 0;
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t->thread.mmcr2 = 0;
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t->thread.mmcr0 = 0;
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t->thread.siar = 0;
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t->thread.sdar = 0;
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t->thread.sier = 0;
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t->thread.used_ebb = 0;
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#endif
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}
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extern int set_thread_uses_vas(void);
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extern int set_thread_tidr(struct task_struct *t);
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#endif /* _ASM_POWERPC_SWITCH_TO_H */
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