From 18461960cbf50bf345ef0667d45d5f64de8fb893 Mon Sep 17 00:00:00 2001 From: Paul Mackerras Date: Tue, 10 Sep 2013 20:21:10 +1000 Subject: powerpc: Provide for giveup_fpu/altivec to save state in alternate location This provides a facility which is intended for use by KVM, where the contents of the FP/VSX and VMX (Altivec) registers can be saved away to somewhere other than the thread_struct when kernel code wants to use floating point or VMX instructions. This is done by providing a pointer in the thread_struct to indicate where the state should be saved to. The giveup_fpu() and giveup_altivec() functions test these pointers and save state to the indicated location if they are non-NULL. Note that the MSR_FP/VEC bits in task->thread.regs->msr are still used to indicate whether the CPU register state is live, even when an alternate save location is being used. This also provides load_fp_state() and load_vr_state() functions, which load up FP/VSX and VMX state from memory into the CPU registers, and corresponding store_fp_state() and store_vr_state() functions, which store FP/VSX and VMX state into memory from the CPU registers. Signed-off-by: Paul Mackerras Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/include/asm/processor.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'arch/powerpc/include/asm/processor.h') diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h index afe695e9feb8..ea88e7bd4a34 100644 --- a/arch/powerpc/include/asm/processor.h +++ b/arch/powerpc/include/asm/processor.h @@ -211,6 +211,7 @@ struct thread_struct { #endif #endif struct thread_fp_state fp_state; + struct thread_fp_state *fp_save_area; int fpexc_mode; /* floating-point exception mode */ unsigned int align_ctl; /* alignment handling control */ #ifdef CONFIG_PPC64 @@ -229,6 +230,7 @@ struct thread_struct { unsigned long trap_nr; /* last trap # on this thread */ #ifdef CONFIG_ALTIVEC struct thread_vr_state vr_state; + struct thread_vr_state *vr_save_area; unsigned long vrsave; int used_vr; /* set if process has used altivec */ #endif /* CONFIG_ALTIVEC */ @@ -357,6 +359,11 @@ extern int set_endian(struct task_struct *tsk, unsigned int val); extern int get_unalign_ctl(struct task_struct *tsk, unsigned long adr); extern int set_unalign_ctl(struct task_struct *tsk, unsigned int val); +extern void load_fp_state(struct thread_fp_state *fp); +extern void store_fp_state(struct thread_fp_state *fp); +extern void load_vr_state(struct thread_vr_state *vr); +extern void store_vr_state(struct thread_vr_state *vr); + static inline unsigned int __unpack_fe01(unsigned long msr_bits) { return ((msr_bits & MSR_FE0) >> 10) | ((msr_bits & MSR_FE1) >> 8); -- cgit v1.2.3