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Query the media and vfp feature registers to determine what our default

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mode should be and what bits in the fpscr can be changed.
Print what features are supported:
vfp0 at cpu0: NEON MPE (VFP 3.0+), rounding, NaN propogation, denormals
This commit is contained in:
matt 2014-03-03 08:45:18 +00:00
parent 5daa42d650
commit 82ca37398f
2 changed files with 38 additions and 15 deletions
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7
sys/arch/arm/arm32/sys_machdep.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: sys_machdep.c,v 1.19 2013/08/23 14:39:50 matt Exp $ */
/* $NetBSD: sys_machdep.c,v 1.20 2014/03/03 08:45:18 matt Exp $ */
/*
* Copyright (c) 1995-1997 Mark Brinicombe.
@ -41,7 +41,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: sys_machdep.c,v 1.19 2013/08/23 14:39:50 matt Exp $");
__KERNEL_RCSID(0, "$NetBSD: sys_machdep.c,v 1.20 2014/03/03 08:45:18 matt Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@ -106,11 +106,12 @@ arm32_vfp_fpscr(struct lwp *l, const void *uap, register_t *retval)
retval[0] = pcb->pcb_vfp.vfp_fpscr;
if (uap) {
extern uint32_t vfp_fpscr_changable;
struct arm_vfp_fpscr_args ua;
int error;
if ((error = copyin(uap, &ua, sizeof(ua))) != 0)
return (error);
if (((ua.fpscr_clear|ua.fpscr_set) & ~VFP_FPSCR_RMODE) != 0)
if ((ua.fpscr_clear|ua.fpscr_set) & ~vfp_fpscr_changable)
return EINVAL;
pcb->pcb_vfp.vfp_fpscr &= ~ua.fpscr_clear;
pcb->pcb_vfp.vfp_fpscr |= ua.fpscr_set;

46
sys/arch/arm/vfp/vfp_init.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: vfp_init.c,v 1.33 2014/01/25 17:30:56 skrll Exp $ */
/* $NetBSD: vfp_init.c,v 1.34 2014/03/03 08:45:18 matt Exp $ */
/*
* Copyright (c) 2008 ARM Ltd
@ -148,6 +148,11 @@ struct evcnt vfpevent_use;
struct evcnt vfpevent_reuse;
struct evcnt vfpevent_fpe;
/* determine what bits can be changed */
uint32_t vfp_fpscr_changable = VFP_FPSCR_CSUM;
/* default to run fast */
uint32_t vfp_fpscr_default = (VFP_FPSCR_DN | VFP_FPSCR_FZ | VFP_FPSCR_RN);
/*
* Used to test for a VFP. The following function is installed as a coproc10
* handler on the undefined instruction vector and then we issue a VFP
@ -208,10 +213,8 @@ vfp_fpscr_handler(u_int address, u_int insn, trapframe_t *frame, int fault_code)
if (insn & 0x00100000) {
*regp = pcb->pcb_vfp.vfp_fpscr;
} else {
register_t tmp = *regp;
if (!(cpu_media_and_vfp_features[0] & ARM_MVFR0_EXCEPT_MASK))
tmp &= ~VFP_FPSCR_ESUM;
pcb->pcb_vfp.vfp_fpscr = tmp;
pcb->pcb_vfp.vfp_fpscr &= ~vfp_fpscr_changable;
pcb->pcb_vfp.vfp_fpscr |= *regp & vfp_fpscr_changable;
}
vfp_fpscr_ev.ev_count++;
@ -345,14 +348,34 @@ vfp_attach(void)
cpu_media_and_vfp_features[0] = armreg_mvfr0_read();
cpu_media_and_vfp_features[1] = armreg_mvfr1_read();
if (fpsid != 0) {
aprint_normal("vfp%d at %s: %s\n",
uint32_t f0 = armreg_mvfr0_read();
uint32_t f1 = armreg_mvfr0_read();
aprint_normal("vfp%d at %s: %s%s%s%s%s\n",
device_unit(curcpu()->ci_dev),
device_xname(curcpu()->ci_dev),
model);
model,
((f0 & ARM_MVFR0_ROUNDING_MASK) ? ", rounding" : ""),
((f0 & ARM_MVFR0_EXCEPT_MASK) ? ", exceptions" : ""),
((f1 & ARM_MVFR1_D_NAN_MASK) ? ", NaN propogation" : ""),
((f1 & ARM_MVFR1_FTZ_MASK) ? ", denormals" : ""));
aprint_verbose("vfp%d: mvfr: [0]=%#x [1]=%#x\n",
device_unit(curcpu()->ci_dev),
cpu_media_and_vfp_features[0],
cpu_media_and_vfp_features[1]);
device_unit(curcpu()->ci_dev), f0, f1);
if (cpu_media_and_vfp_features[0] & ARM_MVFR0_ROUNDING_MASK) {
vfp_fpscr_changable |= VFP_FPSCR_RMODE;
}
if (cpu_media_and_vfp_features[0] & ARM_MVFR0_EXCEPT_MASK) {
vfp_fpscr_changable |= VFP_FPSCR_ESUM;
}
// If hardware supports propogation of NaNs, select it.
if (cpu_media_and_vfp_features[1] & ARM_MVFR1_D_NAN_MASK) {
vfp_fpscr_default &= ~VFP_FPSCR_DN;
vfp_fpscr_changable |= VFP_FPSCR_DN;
}
// If hardware supports denormalized numbers, use it.
if (cpu_media_and_vfp_features[1] & ARM_MVFR1_FTZ_MASK) {
vfp_fpscr_default &= ~VFP_FPSCR_FZ;
vfp_fpscr_changable |= VFP_FPSCR_FZ;
}
}
evcnt_attach_dynamic(&vfpevent_use, EVCNT_TYPE_MISC, NULL,
"VFP", "coproc use");
@ -505,8 +528,7 @@ vfp_state_load(lwp_t *l, u_int flags)
if (__predict_false((flags & PCU_LOADED) == 0)) {
KASSERT(flags & PCU_RELOAD);
vfpevent_use.ev_count++;
pcb->pcb_vfp.vfp_fpscr =
(VFP_FPSCR_DN | VFP_FPSCR_FZ | VFP_FPSCR_RN); /* Runfast */
pcb->pcb_vfp.vfp_fpscr = vfp_fpscr_default;
} else {
vfpevent_reuse.ev_count++;
}