Date: Wed, 15 Jan 2003 01:30:14 +0100 From: Thomas Moestl <tmoestl@gmx.net> To: John Polstra <jdp@polstra.com> Cc: sparc@freebsd.org Subject: Re: Sparc64 floating point questions Message-ID: <20030115003013.GA3536@crow.dom2ip.de> In-Reply-To: <XFMail.20030114144825.jdp@polstra.com> References: <XFMail.20030114144825.jdp@polstra.com>
next in thread | previous in thread | raw e-mail | index | archive | help
--tKW2IUtsqtDRztdT Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Tue, 2003/01/14 at 14:48:25 -0800, John Polstra wrote: > I think that the CVSup failure one person reported was caused by the > fact that I'm not currently saving/restoring the floating point state > on thread context switches. Hmmm, how do you switch contexts? If it's voluntary in some form (i.e. using a function call like longjmp()), you do not need to save, as the floating-point registers are not preserved across function calls (so the compiler should save and reload them across calls as needed, unless that's different for m3). When switching by signals in some form, sendsig() should save the registers in the signal context, so this should be safe when restoring the context by returning from the signal handler. However, this saving is not currently done, which is a bug. The attached patch should fix this (it also implements getcontext() and setcontext(), setcontext() will not work for ucontexts from signals and some optimizing remains to be done though). > I need to find out how to do that. It > looks like if I save and restore the FSR and the FPRS and %q0 through > %q60, that will do it. Am I missing anything? Yes, that should do it. > What is the most straightforward way to save all of the %qN registers? > Like this? > > stq %q0, ... > stq %q4, ... > stq %q8, ... > [...] > stq %q60, ... Yes, unless you want to use UltraSPARC specific instructions. Then, you could do: wr %g0, ASI_BLK_P, %asi stda %f0, [...] %asi stda %f16, [...] %asi stda %f32, [...] %asi stda %f48, [...] %asi This stores 16 floating-point registers at a time, i.e. 64 bytes, which is a complete 2nd-level-cache line, so it should be faster. - Thomas -- Thomas Moestl <tmoestl@gmx.net> http://www.tu-bs.de/~y0015675/ <tmm@FreeBSD.org> http://people.FreeBSD.org/~tmm/ PGP fingerprint: 1C97 A604 2BD0 E492 51D0 9C0F 1FE6 4F1D 419C 776C --tKW2IUtsqtDRztdT Content-Type: text/plain; charset=us-ascii Content-Disposition: attachment; filename="ctx2.diff" Index: include/cache.h =================================================================== RCS file: /ncvs/src/sys/sparc64/include/cache.h,v retrieving revision 1.6 diff -u -r1.6 cache.h --- include/cache.h 20 May 2002 16:30:46 -0000 1.6 +++ include/cache.h 9 Jan 2003 23:10:53 -0000 @@ -99,8 +99,8 @@ void dcache_inval(pmap_t, vm_offset_t, vm_offset_t); void dcache_inval_phys(vm_offset_t, vm_offset_t); void dcache_blast(void); -void ecache_flush(vm_offset_t, vm_offset_t); #if 0 +void ecache_flush(vm_offset_t, vm_offset_t); void ecache_inval_phys(vm_offset_t, vm_offset_t); #endif Index: include/fp.h =================================================================== RCS file: /ncvs/src/sys/sparc64/include/fp.h,v retrieving revision 1.8 diff -u -r1.8 fp.h --- include/fp.h 8 Jun 2002 07:17:18 -0000 1.8 +++ include/fp.h 9 Jan 2003 23:27:22 -0000 @@ -45,8 +45,8 @@ * Note: The pointers passed to the next two functions must be aligned on * 64 byte boundaries. */ -void savefpctx(struct fpstate *); -void restorefpctx(struct fpstate *); +void savefpregs(struct fpstate *); +void savefpctx(struct thread *); #endif /* _KERNEL */ #endif /* !_MACHINE_FP_H_ */ Index: include/pcb.h =================================================================== RCS file: /ncvs/src/sys/sparc64/include/pcb.h,v retrieving revision 1.12 diff -u -r1.12 pcb.h --- include/pcb.h 19 Oct 2002 15:54:34 -0000 1.12 +++ include/pcb.h 9 Jan 2003 23:00:31 -0000 @@ -37,6 +37,7 @@ /* NOTE: pcb_fpstate must be aligned on a 64 byte boundary. */ struct pcb { struct fpstate pcb_fpstate; + u_long pcb_fpsaved; u_long pcb_fp; u_long pcb_pc; u_long pcb_nsaved; Index: include/ucontext.h =================================================================== RCS file: /ncvs/src/sys/sparc64/include/ucontext.h,v retrieving revision 1.8 diff -u -r1.8 ucontext.h --- include/ucontext.h 10 Jan 2003 00:04:56 -0000 1.8 +++ include/ucontext.h 14 Jan 2003 23:47:40 -0000 @@ -42,16 +42,24 @@ typedef struct __mcontext mcontext_t; +/* Common. */ #define mc_flags mc_global[0] -#define mc_sp mc_out[6] -#define mc_fprs mc_local[0] -#define mc_fsr mc_local[1] -#define mc_gsr mc_local[2] -#define mc_tnpc mc_in[0] -#define mc_tpc mc_in[1] -#define mc_tstate mc_in[2] -#define mc_y mc_in[4] -#define mc_wstate mc_in[5] +#define mc_sp mc_out[6] + +/* Signal contexts only. */ +#define mcs_fprs mc_local[0] +#define mcs_fsr mc_local[1] +#define mcs_gsr mc_local[2] +#define mcs_tnpc mc_in[0] +#define mcs_tpc mc_in[1] +#define mcs_tstate mc_in[2] +#define mcs_y mc_in[4] +#define mcs_wstate mc_in[5] + +/* Regular user contexts only. */ +#define mcu_tpc mc_out[0] +#define mcu_tnpc mc_out[1] +#define mcu_pc mc_out[7] #define _MC_VERSION_SHIFT 0 #define _MC_VERSION_BITS 32 @@ -60,5 +68,6 @@ #define _MC_FLAGS_SHIFT 32 #define _MC_FLAGS_BITS 32 #define _MC_VOLUNTARY ((1L << 0) << _MC_FLAGS_SHIFT) +#define _MC_FP ((1L << 1) << _MC_FLAGS_SHIFT) #endif /* !_MACHINE_UCONTEXT_H_ */ Index: sparc64/cache.c =================================================================== RCS file: /ncvs/src/sys/sparc64/sparc64/cache.c,v retrieving revision 1.14 diff -u -r1.14 cache.c --- sparc64/cache.c 5 Jan 2003 05:30:40 -0000 1.14 +++ sparc64/cache.c 10 Jan 2003 17:11:24 -0000 @@ -430,6 +430,7 @@ stxa_sync(dca, ASI_DCACHE_TAG, 0); } +#if 0 /* Flush an E$ physical range using block commit stores. */ void ecache_flush(vm_offset_t start, vm_offset_t end) @@ -439,8 +440,8 @@ if (!cache.c_enabled) return; - /* XXX: not needed in all cases, provide a wrapper in fp.c */ - savefpctx(&curthread->td_pcb->pcb_fpstate); + critical_enter(); + savefpctx(curthread); wr(fprs, 0, FPRS_FEF); for (addr = start & ~(cache.ec_linesize - 1); addr <= end; @@ -451,10 +452,10 @@ } membar(Sync); - restorefpctx(&curthread->td_pcb->pcb_fpstate); + wr(fprs, 0, 0); + critical_enter(); } -#if 0 /* * Invalidate an E$ range using diagnostic accesses. * This is disabled: it suffers from the same races as dcache_blast() and Index: sparc64/exception.S =================================================================== RCS file: /ncvs/src/sys/sparc64/sparc64/exception.S,v retrieving revision 1.57 diff -u -r1.57 exception.S --- sparc64/exception.S 29 Dec 2002 00:23:48 -0000 1.57 +++ sparc64/exception.S 10 Jan 2003 18:02:02 -0000 @@ -458,16 +458,21 @@ .endm .macro tl0_fp_restore - wr %g0, FPRS_FEF, %fprs + ba %xcc, tl0_fp_restore + wr %g0, FPRS_FEF, %fprs + .align 32 + .endm + +ENTRY(tl0_fp_restore) wr %g0, ASI_BLK_S, %asi ldda [PCB_REG + PCB_FPSTATE + FP_FB0] %asi, %f0 ldda [PCB_REG + PCB_FPSTATE + FP_FB1] %asi, %f16 ldda [PCB_REG + PCB_FPSTATE + FP_FB2] %asi, %f32 ldda [PCB_REG + PCB_FPSTATE + FP_FB3] %asi, %f48 membar #Sync + stx %g0, [PCB_REG + PCB_FPSAVED] done - .align 32 - .endm +END(tl0_fp_restore) .macro tl0_insn_excptn wrpr %g0, PSTATE_ALT, %pstate Index: sparc64/genassym.c =================================================================== RCS file: /ncvs/src/sys/sparc64/sparc64/genassym.c,v retrieving revision 1.45 diff -u -r1.45 genassym.c --- sparc64/genassym.c 28 Dec 2002 23:58:18 -0000 1.45 +++ sparc64/genassym.c 9 Jan 2003 22:57:15 -0000 @@ -250,6 +250,7 @@ ASSYM(PCB_NSAVED, offsetof(struct pcb, pcb_nsaved)); ASSYM(PCB_RWSP, offsetof(struct pcb, pcb_rwsp)); ASSYM(PCB_RW, offsetof(struct pcb, pcb_rw)); +ASSYM(PCB_FPSAVED, offsetof(struct pcb, pcb_fpsaved)); ASSYM(VM_PMAP, offsetof(struct vmspace, vm_pmap)); ASSYM(PM_ACTIVE, offsetof(struct pmap, pm_active)); Index: sparc64/machdep.c =================================================================== RCS file: /ncvs/src/sys/sparc64/sparc64/machdep.c,v retrieving revision 1.75 diff -u -r1.75 machdep.c --- sparc64/machdep.c 10 Jan 2003 00:04:56 -0000 1.75 +++ sparc64/machdep.c 15 Jan 2003 00:06:37 -0000 @@ -92,6 +92,7 @@ #include <machine/clock.h> #include <machine/cpu.h> #include <machine/fp.h> +#include <machine/fsr.h> #include <machine/intr_machdep.h> #include <machine/md_var.h> #include <machine/metadata.h> @@ -365,6 +366,7 @@ struct sigframe *sfp; struct sigacts *psp; struct sigframe sf; + mcontext_t *mcp; struct thread *td; struct frame *fp; struct proc *p; @@ -399,7 +401,16 @@ sf.sf_uc.uc_stack = p->p_sigstk; sf.sf_uc.uc_stack.ss_flags = (p->p_flag & P_ALTSTACK) ? ((oonstack) ? SS_ONSTACK : 0) : SS_DISABLE; - bcopy(tf, &sf.sf_uc.uc_mcontext, sizeof(*tf)); + + savefpctx(td); + mcp = &sf.sf_uc.uc_mcontext; + mcp->mc_flags = 0; + bcopy(tf, mcp, sizeof(*tf)); + if (td->td_pcb->pcb_fpsaved) { + bcopy(&td->td_pcb->pcb_fpstate, &mcp->mc_fp, + sizeof(mcp->mc_fp)); + mcp->mc_flags |= _MC_FP; + } /* Allocate and validate space for the signal handler context. */ if ((p->p_flag & P_ALTSTACK) != 0 && !oonstack && @@ -455,6 +466,28 @@ }; #endif +static int +set_sigmcontext(struct thread *td, const mcontext_t *mcp) +{ + uint64_t wstate; + int error; + + if ((error = rwindow_save(td)) != 0) + return (error); + + if (!TSTATE_SECURE(mcp->mcs_tstate)) + return (EINVAL); + wstate = td->td_frame->tf_wstate; + bcopy(mcp, td->td_frame, sizeof(*td->td_frame)); + td->td_frame->tf_wstate = wstate; + if ((mcp->mc_flags & _MC_FP) != 0) { + td->td_frame->tf_fprs &= ~FPRS_FEF; + bcopy(&mcp->mc_fp, &td->td_pcb->pcb_fpstate, + sizeof(td->td_pcb->pcb_fpstate)); + } + return (0); +} + /* * MPSAFE */ @@ -463,14 +496,11 @@ { struct trapframe *tf; struct proc *p; - mcontext_t *mc; ucontext_t uc; + int error; p = td->td_proc; - if (rwindow_save(td)) { - PROC_LOCK(p); - sigexit(td, SIGILL); - } + tf = td->td_frame; CTR2(KTR_SIG, "sigreturn: td=%p ucp=%p", td, uap->sigcntxp); if (copyin(uap->sigcntxp, &uc, sizeof(uc)) != 0) { @@ -478,12 +508,8 @@ return (EFAULT); } - mc = &uc.uc_mcontext; - tf = td->td_frame; - if (!TSTATE_SECURE(mc->mc_tstate)) - return (EINVAL); - mc->mc_wstate = tf->tf_wstate; - bcopy(mc, tf, sizeof(*tf)); + if ((error = set_sigmcontext(td, &uc.uc_mcontext)) != 0) + return (error); PROC_LOCK(p); p->p_sigmask = uc.uc_sigmask; @@ -508,15 +534,49 @@ int get_mcontext(struct thread *td, mcontext_t *mcp) { + struct trapframe *tf; + struct frame *f; + int error; - return (ENOSYS); + /* + * Need to save the ins and locals of the caller; gcc does not know + * that getcontext() is magic and will not discard them after the call. + */ + tf = td->td_frame; + f = (struct frame *)(uintptr_t)(tf->tf_sp + SPOFF); + if ((error = rwindow_save(td)) != 0 || + (error = copyin(&f->fr_local, &mcp->mc_local, + sizeof(f->fr_local) + sizeof(f->fr_in)) != 0)) + return (error); + mcp->mc_sp = tf->tf_sp; + mcp->mcu_pc = tf->tf_out[7]; + mcp->mcu_tpc = tf->tf_tpc; + mcp->mcu_tnpc = tf->tf_tnpc; + mcp->mc_flags = _MC_VOLUNTARY; + return (0); } int set_mcontext(struct thread *td, const mcontext_t *mcp) { + struct trapframe *tf; + struct frame *f; + int error; - return (ENOSYS); + /* Handle return from signal. */ + if ((mcp->mc_flags & _MC_VOLUNTARY) == 0) + return (set_sigmcontext(td, mcp)); + tf = td->td_frame; + f = (struct frame *)(uintptr_t)(mcp->mc_sp + SPOFF); + if ((error = rwindow_save(td)) != 0 || + (error = copyout(&mcp->mc_local, &f->fr_local, + sizeof(f->fr_local) + sizeof(f->fr_in)) != 0)) + return (error); + tf->tf_sp = mcp->mc_sp; + tf->tf_out[7] = mcp->mcu_pc; + tf->tf_tpc = mcp->mcu_tpc; + tf->tf_tnpc = mcp->mcu_tnpc; + return (0); } /* @@ -696,4 +756,18 @@ tf->tf_fsr = fpregs->fr_fsr; tf->tf_gsr = fpregs->fr_gsr; return (0); +} + +void +savefpctx(struct thread *td) +{ + struct pcb *pcb = td->td_pcb; + + critical_enter(); + if ((td->td_frame->tf_fprs & FPRS_FEF) != 0) { + savefpregs(&pcb->pcb_fpstate); + pcb->pcb_fpsaved = 1; + td->td_frame->tf_fprs &= ~FPRS_FEF; + } + critical_exit(); } Index: sparc64/swtch.S =================================================================== RCS file: /ncvs/src/sys/sparc64/sparc64/swtch.S,v retrieving revision 1.22 diff -u -r1.22 swtch.S --- sparc64/swtch.S 22 Oct 2002 18:03:15 -0000 1.22 +++ sparc64/swtch.S 9 Jan 2003 23:27:51 -0000 @@ -74,6 +74,7 @@ stda %f48, [%l1 + PCB_FPSTATE + FP_FB3] %asi membar #Sync wr %g0, 0, %fprs + stx %l3, [%l1 + PCB_FPSAVED] andn %l3, FPRS_FEF, %l3 stx %l3, [%l2 + TF_FPRS] @@ -269,8 +270,8 @@ ENTRY(savectx) save %sp, -CCFSZ, %sp flushw - call savefpctx - mov %i0, %o0 + call savefpregs + add %i0, PCB_FPSTATE, %o0 stx %fp, [%i0 + PCB_FP] stx %i7, [%i0 + PCB_PC] ret @@ -280,29 +281,14 @@ /* * void savefpctx(struct fpstate *); */ -ENTRY(savefpctx) +ENTRY(savefpregs) wr %g0, FPRS_FEF, %fprs wr %g0, ASI_BLK_S, %asi - stda %f0, [%o0 + PCB_FPSTATE + FP_FB0] %asi - stda %f16, [%o0 + PCB_FPSTATE + FP_FB1] %asi - stda %f32, [%o0 + PCB_FPSTATE + FP_FB2] %asi - stda %f48, [%o0 + PCB_FPSTATE + FP_FB3] %asi + stda %f0, [%o0 + FP_FB0] %asi + stda %f16, [%o0 + FP_FB1] %asi + stda %f32, [%o0 + FP_FB2] %asi + stda %f48, [%o0 + FP_FB3] %asi membar #Sync retl wr %g0, 0, %fprs -END(savefpctx) - -/* - * void restorefpctx(struct fpstate *); - */ -ENTRY(restorefpctx) - wr %g0, FPRS_FEF, %fprs - wr %g0, ASI_BLK_S, %asi - ldda [%o0 + PCB_FPSTATE + FP_FB0] %asi, %f0 - ldda [%o0 + PCB_FPSTATE + FP_FB1] %asi, %f16 - ldda [%o0 + PCB_FPSTATE + FP_FB2] %asi, %f32 - ldda [%o0 + PCB_FPSTATE + FP_FB3] %asi, %f48 - membar #Sync - retl - wr %g0, 0, %fprs -END(restorefpctx) +END(savefpregs) Index: sparc64/vm_machdep.c =================================================================== RCS file: /ncvs/src/sys/sparc64/sparc64/vm_machdep.c,v retrieving revision 1.32 diff -u -r1.32 vm_machdep.c --- sparc64/vm_machdep.c 5 Jan 2003 05:30:40 -0000 1.32 +++ sparc64/vm_machdep.c 9 Jan 2003 23:14:32 -0000 @@ -181,11 +181,7 @@ /* * Ensure that p1's pcb is up to date. */ - if ((td1->td_frame->tf_fprs & FPRS_FEF) != 0) { - mtx_lock_spin(&sched_lock); - savefpctx(&pcb1->pcb_fpstate); - mtx_unlock_spin(&sched_lock); - } + savefpctx(td1); /* Make sure the copied windows are spilled. */ flushw(); /* Copy the pcb (this will copy the windows saved in the pcb, too). */ --tKW2IUtsqtDRztdT-- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-sparc" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20030115003013.GA3536>