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/* $OpenBSD: acpihve.c,v 1.2 2018/04/28 15:44:59 jasper Exp $ */
/*
* Copyright (c) 2017 Jonathan Gray <jsg@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <dev/acpi/acpireg.h>
#include <dev/acpi/acpivar.h>
#include <dev/rndvar.h>
int acpihve_match(struct device *, void *, void *);
void acpihve_attach(struct device *, struct device *, void *);
struct acpi_oem0 {
struct acpi_table_header hdr;
uint32_t entropy[16];
} __packed;
struct acpihve_softc {
struct device sc_dev;
};
struct cfattach acpihve_ca = {
sizeof(struct acpihve_softc), acpihve_match, acpihve_attach
};
struct cfdriver acpihve_cd = {
NULL, "acpihve", DV_DULL
};
int acpihve_attached;
int
acpihve_match(struct device *parent, void *match, void *aux)
{
struct acpi_attach_args *aaa = aux;
struct acpi_table_header *hdr;
/*
* If we do not have a table, it is not us; attach only once
*/
if (acpihve_attached || aaa->aaa_table == NULL)
return (0);
hdr = (struct acpi_table_header *)aaa->aaa_table;
if (memcmp(hdr->signature, "OEM0", 4) != 0 ||
memcmp(hdr->oemid, "VRTUAL", 6) != 0 ||
memcmp(hdr->oemtableid, "MICROSFT", 8) != 0)
return (0);
return (1);
}
void
acpihve_attach(struct device *parent, struct device *self, void *aux)
{
struct acpi_attach_args *aaa = aux;
struct acpi_oem0 *oem0 = (struct acpi_oem0 *)aaa->aaa_table;
int i;
acpihve_attached++;
if (oem0->hdr.length != sizeof(*oem0)) {
printf(": unexpected table length %u\n", oem0->hdr.length);
return;
}
/* 64 bytes of entropy from OEM0 table */
for (i = 0; i < nitems(oem0->entropy); i++)
enqueue_randomness(oem0->entropy[i]);
printf("\n");
}
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