git: 9313f6b01485 - main - acpi: Add a pseudo-bus for APEI devices to manage resources
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Date: Tue, 07 Jul 2026 19:18:16 UTC
The branch main has been updated by jhb:
URL: https://cgit.FreeBSD.org/src/commit/?id=9313f6b01485ad9a0b7cc59b459f5714533587c3
commit 9313f6b01485ad9a0b7cc59b459f5714533587c3
Author: John Baldwin <jhb@FreeBSD.org>
AuthorDate: 2026-07-07 18:13:51 +0000
Commit: John Baldwin <jhb@FreeBSD.org>
CommitDate: 2026-07-07 18:13:51 +0000
acpi: Add a pseudo-bus for APEI devices to manage resources
Different APEI tables can reuse the same registers (and sometimes
different views of the same register, e.g. 32- vs 64-bit mappings of
the same register). To enable this sharing, apei0 now acts as a bus
device managing a pool of allocated resources and handing out mappings
to child devices which handle individual tables.
Most of the previous apei(4) driver has been moved into a new
hest0 device that is a child of apei0.
Reviewed by: gallatin
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D58024
---
sys/conf/files | 2 +
sys/dev/acpica/acpi_apei.c | 159 ++++-----------
sys/dev/acpica/acpi_apei_bus.c | 435 +++++++++++++++++++++++++++++++++++++++++
sys/dev/acpica/apei_if.m | 49 +++++
sys/dev/acpica/apeivar.h | 54 +++++
5 files changed, 579 insertions(+), 120 deletions(-)
diff --git a/sys/conf/files b/sys/conf/files
index cc18ecbb9301..3635e6474708 100644
--- a/sys/conf/files
+++ b/sys/conf/files
@@ -759,6 +759,7 @@ dev/acpica/Osd/OsdTable.c optional acpi
dev/acpica/acpi.c optional acpi
dev/acpica/acpi_acad.c optional acpi
dev/acpica/acpi_apei.c optional acpi
+dev/acpica/acpi_apei_bus.c optional acpi
dev/acpica/acpi_battery.c optional acpi
dev/acpica/acpi_button.c optional acpi
dev/acpica/acpi_cmbat.c optional acpi
@@ -779,6 +780,7 @@ dev/acpica/acpi_throttle.c optional acpi
dev/acpica/acpi_video.c optional acpi_video acpi
dev/acpica/acpi_dock.c optional acpi_dock acpi
dev/acpica/acpi_spmc.c optional acpi
+dev/acpica/apei_if.m optional acpi
dev/adlink/adlink.c optional adlink
dev/ae/if_ae.c optional ae pci
dev/age/if_age.c optional age pci
diff --git a/sys/dev/acpica/acpi_apei.c b/sys/dev/acpica/acpi_apei.c
index 925558d585bf..09073207c06e 100644
--- a/sys/dev/acpica/acpi_apei.c
+++ b/sys/dev/acpica/acpi_apei.c
@@ -48,6 +48,7 @@
#include <contrib/dev/acpica/include/actables.h>
#include <dev/acpica/acpivar.h>
+#include <dev/acpica/apeivar.h>
#include <dev/pci/pcireg.h>
#include <dev/pci/pcivar.h>
@@ -56,12 +57,8 @@ struct apei_ge {
ACPI_HEST_GENERIC v1;
ACPI_HEST_GENERIC_V2 v2;
};
- int res_type;
- int res_rid;
- struct resource *res;
- int res2_type;
- int res2_rid;
- struct resource *res2;
+ struct resource_map *res;
+ struct resource_map *res2;
uint8_t *buf, *copybuf;
TAILQ_ENTRY(apei_ge) link;
TAILQ_ENTRY(apei_ge) nlink;
@@ -85,7 +82,7 @@ struct apei_pges {
TAILQ_HEAD(, apei_ge) ges;
};
-struct apei_softc {
+struct hest_softc {
TAILQ_HEAD(, apei_ge) ges;
struct apei_nges nges;
struct apei_iges iges;
@@ -128,26 +125,6 @@ struct apei_pcie_error {
uint8_t AERInfo[96];
};
-#ifdef __i386__
-static __inline uint64_t
-apei_bus_read_8(struct resource *res, bus_size_t offset)
-{
- return (bus_read_4(res, offset) |
- ((uint64_t)bus_read_4(res, offset + 4)) << 32);
-}
-static __inline void
-apei_bus_write_8(struct resource *res, bus_size_t offset, uint64_t val)
-{
- bus_write_4(res, offset, val);
- bus_write_4(res, offset + 4, val >> 32);
-}
-#define READ8(r, o) apei_bus_read_8((r), (o))
-#define WRITE8(r, o, v) apei_bus_write_8((r), (o), (v))
-#else
-#define READ8(r, o) bus_read_8((r), (o))
-#define WRITE8(r, o, v) bus_write_8((r), (o), (v))
-#endif
-
#define GED_SIZE(ged) ((ged)->Revision >= 0x300 ? \
sizeof(ACPI_HEST_GENERIC_DATA_V300) : sizeof(ACPI_HEST_GENERIC_DATA))
#define GED_DATA(ged) ((uint8_t *)(ged) + GED_SIZE(ged))
@@ -431,10 +408,10 @@ apei_ge_handler(struct apei_ge *ge, bool copy)
ges->BlockStatus = 0;
if (!copy && ge->v1.Header.Type == ACPI_HEST_TYPE_GENERIC_ERROR_V2 &&
ge->res2) {
- uint64_t val = READ8(ge->res2, 0);
+ uint64_t val = bus_read_8(ge->res2, 0);
val &= ge->v2.ReadAckPreserve;
val |= ge->v2.ReadAckWrite;
- WRITE8(ge->res2, 0, val);
+ bus_write_8(ge->res2, 0, val);
}
/* If ACPI told the error is fatal -- make it so. */
@@ -484,10 +461,10 @@ apei_nmi_handler(void)
ges->BlockStatus = 0;
if (ge->v1.Header.Type == ACPI_HEST_TYPE_GENERIC_ERROR_V2 &&
ge->res2) {
- uint64_t val = READ8(ge->res2, 0);
+ uint64_t val = bus_read_8(ge->res2, 0);
val &= ge->v2.ReadAckPreserve;
val |= ge->v2.ReadAckWrite;
- WRITE8(ge->res2, 0, val);
+ bus_write_8(ge->res2, 0, val);
}
handled = 1;
}
@@ -514,7 +491,7 @@ static void
apei_notify_handler(ACPI_HANDLE h, UINT32 notify, void *context)
{
device_t dev = context;
- struct apei_softc *sc = device_get_softc(dev);
+ struct hest_softc *sc = device_get_softc(dev);
struct apei_ge *ge;
TAILQ_FOREACH(ge, &sc->iges.ges, nlink)
@@ -522,7 +499,7 @@ apei_notify_handler(ACPI_HANDLE h, UINT32 notify, void *context)
}
static int
-hest_parse_structure(struct apei_softc *sc, void *addr, int remaining)
+hest_parse_structure(struct hest_softc *sc, void *addr, int remaining)
{
ACPI_HEST_HEADER *hdr = addr;
struct apei_ge *ge;
@@ -582,7 +559,7 @@ hest_parse_structure(struct apei_softc *sc, void *addr, int remaining)
}
static void
-hest_parse_table(ACPI_TABLE_HEST *hest, struct apei_softc *sc)
+hest_parse_table(ACPI_TABLE_HEST *hest, struct hest_softc *sc)
{
char *cp;
int remaining, consumed;
@@ -598,95 +575,43 @@ hest_parse_table(ACPI_TABLE_HEST *hest, struct apei_softc *sc)
}
}
-static char *apei_ids[] = { "PNP0C33", NULL };
-
-static ACPI_STATUS
-apei_find(ACPI_HANDLE handle, UINT32 level, void *context,
- void **status)
-{
- int *found = (int *)status;
- char **ids;
-
- for (ids = apei_ids; *ids != NULL; ids++) {
- if (acpi_MatchHid(handle, *ids)) {
- *found = 1;
- break;
- }
- }
- return (AE_OK);
-}
-
static void
-apei_identify(driver_t *driver, device_t parent)
+hest_identify(driver_t *driver, device_t parent)
{
device_t child;
- int found;
ACPI_TABLE_HEADER *hest;
ACPI_STATUS status;
- if (acpi_disabled("apei"))
- return;
-
/* Without HEST table we have nothing to do. */
status = AcpiGetTable(ACPI_SIG_HEST, 0, &hest);
if (ACPI_FAILURE(status))
return;
AcpiPutTable(hest);
- /* Only one APEI device can exist. */
- if (devclass_get_device(devclass_find("apei"), 0))
+ if (device_find_child(parent, "hest", DEVICE_UNIT_ANY) != NULL)
return;
- /* Search for ACPI error device to be used. */
- found = 0;
- AcpiWalkNamespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
- 100, apei_find, NULL, NULL, (void *)&found);
- if (found)
- return;
-
- /* If not found - create a fake one. */
- child = BUS_ADD_CHILD(parent, 2, "apei", 0);
+ child = BUS_ADD_CHILD(parent, 0, "hest", DEVICE_UNIT_ANY);
if (child == NULL)
printf("%s: can't add child\n", __func__);
}
static int
-apei_probe(device_t dev)
+hest_probe(device_t dev)
{
- ACPI_TABLE_HEADER *hest;
- ACPI_STATUS status;
- int rv;
-
- if (acpi_disabled("apei"))
- return (ENXIO);
-
- if (acpi_get_handle(dev) != NULL) {
- rv = ACPI_ID_PROBE(device_get_parent(dev), dev, apei_ids, NULL);
- if (rv > 0)
- return (rv);
- } else
- rv = 0;
-
- /* Without HEST table we have nothing to do. */
- status = AcpiGetTable(ACPI_SIG_HEST, 0, &hest);
- if (ACPI_FAILURE(status))
- return (ENXIO);
- AcpiPutTable(hest);
-
- device_set_desc(dev, "ACPI Platform Error Interface");
- return (rv);
+ device_set_desc(dev, "APEI Hardware Errors");
+ return (BUS_PROBE_NOWILDCARD);
}
static int
-apei_attach(device_t dev)
+hest_attach(device_t dev)
{
- struct apei_softc *sc = device_get_softc(dev);
+ struct hest_softc *sc = device_get_softc(dev);
ACPI_TABLE_HEADER *hest;
struct acpi_softc *acpi_sc;
struct apei_pges *pges;
struct apei_ge *ge;
ACPI_STATUS status;
- int rid;
if (!apei_sysctl_tree) {
/* Install hw.acpi.apei sysctl tree */
@@ -717,21 +642,17 @@ apei_attach(device_t dev)
hest_parse_table((ACPI_TABLE_HEST *)hest, sc);
AcpiPutTable(hest);
- rid = 0;
TAILQ_FOREACH(ge, &sc->ges, link) {
- ge->res_rid = rid++;
- acpi_bus_alloc_gas(dev, &ge->res_type, ge->res_rid,
- &ge->v1.ErrorStatusAddress, &ge->res, 0);
+ ge->res = apei_map_register(dev, &ge->v1.ErrorStatusAddress);
if (ge->res) {
- ge->buf = pmap_mapdev_attr(READ8(ge->res, 0),
+ ge->buf = pmap_mapdev_attr(bus_read_8(ge->res, 0),
ge->v1.ErrorBlockLength, VM_MEMATTR_WRITE_COMBINING);
} else {
device_printf(dev, "Can't allocate status resource.\n");
}
if (ge->v1.Header.Type == ACPI_HEST_TYPE_GENERIC_ERROR_V2) {
- ge->res2_rid = rid++;
- acpi_bus_alloc_gas(dev, &ge->res2_type, ge->res2_rid,
- &ge->v2.ReadAckRegister, &ge->res2, RF_SHAREABLE);
+ ge->res2 = apei_map_register(dev,
+ &ge->v2.ReadAckRegister);
if (ge->res2 == NULL)
device_printf(dev, "Can't allocate ack resource.\n");
}
@@ -766,9 +687,9 @@ apei_attach(device_t dev)
}
static int
-apei_detach(device_t dev)
+hest_detach(device_t dev)
{
- struct apei_softc *sc = device_get_softc(dev);
+ struct hest_softc *sc = device_get_softc(dev);
struct apei_ge *ge;
apei_nmi = NULL;
@@ -787,12 +708,10 @@ apei_detach(device_t dev)
while ((ge = TAILQ_FIRST(&sc->ges)) != NULL) {
TAILQ_REMOVE(&sc->ges, ge, link);
if (ge->res) {
- bus_release_resource(dev, ge->res_type,
- ge->res_rid, ge->res);
+ apei_unmap_register(dev, ge->res);
}
if (ge->res2) {
- bus_release_resource(dev, ge->res2_type,
- ge->res2_rid, ge->res2);
+ apei_unmap_register(dev, ge->res2);
}
if (ge->v1.Notify.Type == ACPI_HEST_NOTIFY_POLLED) {
TAILQ_REMOVE(&sc->pges[PGE_ID(ge)].ges, ge, nlink);
@@ -812,23 +731,23 @@ apei_detach(device_t dev)
return (0);
}
-static device_method_t apei_methods[] = {
+static device_method_t hest_methods[] = {
/* Device interface */
- DEVMETHOD(device_identify, apei_identify),
- DEVMETHOD(device_probe, apei_probe),
- DEVMETHOD(device_attach, apei_attach),
- DEVMETHOD(device_detach, apei_detach),
+ DEVMETHOD(device_identify, hest_identify),
+ DEVMETHOD(device_probe, hest_probe),
+ DEVMETHOD(device_attach, hest_attach),
+ DEVMETHOD(device_detach, hest_detach),
DEVMETHOD_END
};
-static driver_t apei_driver = {
- "apei",
- apei_methods,
- sizeof(struct apei_softc),
+static driver_t hest_driver = {
+ "hest",
+ hest_methods,
+ sizeof(struct hest_softc),
};
static int
-apei_modevent(struct module *mod __unused, int evt, void *cookie __unused)
+hest_modevent(struct module *mod __unused, int evt, void *cookie __unused)
{
int err = 0;
@@ -845,5 +764,5 @@ apei_modevent(struct module *mod __unused, int evt, void *cookie __unused)
return (err);
}
-DRIVER_MODULE(apei, acpi, apei_driver, apei_modevent, 0);
-MODULE_DEPEND(apei, acpi, 1, 1, 1);
+DRIVER_MODULE(hest, apei, hest_driver, hest_modevent, 0);
+MODULE_DEPEND(hest, acpi, 1, 1, 1);
diff --git a/sys/dev/acpica/acpi_apei_bus.c b/sys/dev/acpica/acpi_apei_bus.c
new file mode 100644
index 000000000000..c6c3a4f11a12
--- /dev/null
+++ b/sys/dev/acpica/acpi_apei_bus.c
@@ -0,0 +1,435 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2020 Alexander Motin <mav@FreeBSD.org>
+ * Copyright (c) 2025-2026 Netflix, Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/types.h>
+#include <sys/bus.h>
+#include <sys/kernel.h>
+#include <sys/malloc.h>
+#include <sys/module.h>
+#include <sys/rman.h>
+
+#include <contrib/dev/acpica/include/acpi.h>
+
+#include <dev/acpica/acpivar.h>
+#include <dev/acpica/apeivar.h>
+
+/*
+ * Different APEI tables can reuse the same registers (and sometimes
+ * different views of the same register, e.g. 32- vs 64-bit mappings
+ * of the same register). To enable this sharing, apei0 acts as a bus
+ * device managing a pool of allocated resources and hands out
+ * mappings to child devices. Child devices handle individual tables.
+ */
+
+struct apei_register {
+ struct resource *res;
+ TAILQ_ENTRY(apei_register) link;
+};
+
+struct apei_register_mapping {
+ struct resource_map map;
+ struct apei_register *reg;
+ TAILQ_ENTRY(apei_register_mapping) link;
+};
+
+struct apei_ivars {
+ TAILQ_HEAD(, apei_register_mapping) mappings;
+};
+
+TAILQ_HEAD(apei_register_list, apei_register);
+
+struct apei_softc {
+ device_t dev;
+ struct apei_register_list mem;
+ struct apei_register_list io;
+};
+
+static char *apei_ids[] = { "PNP0C33", NULL };
+
+static MALLOC_DEFINE(M_APEI, "apei", "ACPI platform error interface");
+
+static ACPI_STATUS
+apei_find(ACPI_HANDLE handle, UINT32 level, void *context,
+ void **status)
+{
+ int *found = (int *)status;
+ char **ids;
+
+ for (ids = apei_ids; *ids != NULL; ids++) {
+ if (acpi_MatchHid(handle, *ids)) {
+ *found = 1;
+ break;
+ }
+ }
+ return (AE_OK);
+}
+
+static void
+apei_identify(driver_t *driver, device_t parent)
+{
+ device_t child;
+ int found;
+
+ if (acpi_disabled("apei"))
+ return;
+
+ /* Only one APEI device can exist. */
+ if (device_find_child(parent, "apei", DEVICE_UNIT_ANY) != NULL)
+ return;
+
+ /* Search for ACPI error device to be used. */
+ found = 0;
+ AcpiWalkNamespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
+ 100, apei_find, NULL, NULL, (void *)&found);
+ if (found)
+ return;
+
+ /* If not found - create a fake one. */
+ child = BUS_ADD_CHILD(parent, 2, "apei", 0);
+ if (child == NULL)
+ printf("%s: can't add child\n", __func__);
+}
+
+static int
+apei_probe(device_t dev)
+{
+ int rv;
+
+ if (acpi_disabled("apei"))
+ return (ENXIO);
+
+ if (acpi_get_handle(dev) != NULL) {
+ rv = ACPI_ID_PROBE(device_get_parent(dev), dev, apei_ids, NULL);
+ if (rv > 0)
+ return (rv);
+ }
+
+ device_set_desc(dev, "ACPI Platform Error Interface");
+ return (0);
+}
+
+static int
+apei_attach(device_t dev)
+{
+ struct apei_softc *sc = device_get_softc(dev);
+
+ sc->dev = dev;
+ TAILQ_INIT(&sc->mem);
+ TAILQ_INIT(&sc->io);
+ bus_identify_children(dev);
+ bus_attach_children(dev);
+ return (0);
+}
+
+static device_t
+apei_add_child(device_t dev, u_int order, const char *name, int unit)
+{
+ struct apei_ivars *ai;
+ device_t child;
+
+ ai = malloc(sizeof(*ai), M_APEI, M_WAITOK);
+ TAILQ_INIT(&ai->mappings);
+ child = device_add_child_ordered(dev, order, name, unit);
+ if (child != NULL)
+ device_set_ivars(child, ai);
+ else
+ free(ai, M_APEI);
+ return (child);
+}
+
+static void
+apei_child_deleted(device_t dev, device_t child)
+{
+ struct apei_ivars *ai = device_get_ivars(child);
+
+ MPASS(TAILQ_EMPTY(&ai->mappings));
+ free(ai, M_APEI);
+}
+
+static void
+apei_child_detached(device_t dev, device_t child)
+{
+ struct apei_ivars *ai = device_get_ivars(child);
+
+ while (!TAILQ_EMPTY(&ai->mappings)) {
+ struct apei_register_mapping *m = TAILQ_FIRST(&ai->mappings);
+
+ device_printf(dev, "child leaked mapping of %s %#jx-%#jx\n",
+ rman_get_type(m->reg->res) == SYS_RES_MEMORY ? "iomem" :
+ "port", rman_get_start(m->reg->res),
+ rman_get_end(m->reg->res));
+
+ (void) apei_unmap_register(child, &m->map);
+ }
+}
+
+static int
+apei_read_ivar(device_t dev, device_t child, int index, uintptr_t *result)
+{
+ switch (index) {
+ case ACPI_IVAR_HANDLE:
+ *(ACPI_HANDLE *)result = acpi_get_handle(dev);
+ break;
+ default:
+ return (ENOENT);
+ }
+
+ return (0);
+}
+
+static struct apei_register *
+apei_alloc_register(struct apei_softc *sc, int type, rman_res_t start,
+ rman_res_t count)
+{
+ struct apei_register_list *list;
+ struct apei_register *reg, *prev;
+ rman_res_t end;
+ const char *descr;
+ int error, next_rid;
+
+ switch (type) {
+ case SYS_RES_MEMORY:
+ list = &sc->mem;
+ descr = "iomem";
+ break;
+ case SYS_RES_IOPORT:
+ list = &sc->io;
+ descr = "port";
+ break;
+ default:
+ return (NULL);
+ }
+
+ end = start + (count - 1);
+
+ /* First, look for an existing resource. */
+ prev = NULL;
+ TAILQ_FOREACH(reg, list, link) {
+ /* Does the existing register overlap with this request? */
+ if (start > rman_get_end(reg->res) ||
+ end < rman_get_start(reg->res)) {
+
+ /* prev will be the location of the first free rid */
+ if (prev == NULL)
+ next_rid = 0;
+ else
+ next_rid = rman_get_rid(prev->res) + 1;
+ if (rman_get_rid(reg->res) == next_rid)
+ prev = reg;
+ continue;
+ }
+
+ /* Do we need to extend the existing register? */
+ if (start < rman_get_start(reg->res) ||
+ end > rman_get_end(reg->res)) {
+ rman_res_t new_end, new_start;
+
+ new_start = rman_get_start(reg->res);
+ if (start < new_start)
+ new_start = start;
+ new_end = rman_get_end(reg->res);
+ if (end > new_end)
+ new_end = end;
+ error = bus_adjust_resource(sc->dev, reg->res,
+ new_start, new_end);
+ if (error != 0) {
+ if (bootverbose)
+ device_printf(sc->dev,
+ "failed to grow %s %#jx-%#jx for %#jx-%#jx: %d\n",
+ descr, rman_get_start(reg->res),
+ rman_get_end(reg->res), start, end,
+ error);
+ return (NULL);
+ }
+ }
+
+ return (reg);
+ }
+
+ /* Allocate a new resource. */
+ if (prev == NULL)
+ next_rid = 0;
+ else
+ next_rid = rman_get_rid(prev->res) + 1;
+ error = bus_set_resource(sc->dev, type, next_rid, start, count);
+ if (error != 0) {
+ if (bootverbose)
+ device_printf(sc->dev,
+ "failed to add %s %#jx-%#jx: %d\n", descr, start,
+ end, error);
+ return (NULL);
+ }
+
+ reg = malloc(sizeof(*reg), M_APEI, M_WAITOK);
+ reg->res = bus_alloc_resource_any(sc->dev, type, next_rid, RF_ACTIVE |
+ RF_UNMAPPED);
+ if (reg->res == NULL) {
+ if (bootverbose)
+ device_printf(sc->dev,
+ "failed to allocate %s %#jx-%#jx\n", descr, start,
+ end);
+ free(reg, M_APEI);
+ bus_delete_resource(sc->dev, type, next_rid);
+ return (NULL);
+ }
+
+ if (prev == NULL)
+ TAILQ_INSERT_HEAD(list, reg, link);
+ else
+ TAILQ_INSERT_AFTER(list, prev, reg, link);
+ return (reg);
+}
+
+static struct resource_map *
+apei_map_register_method(device_t dev, device_t child, int type,
+ rman_res_t start, rman_res_t count)
+{
+ struct apei_softc *sc = device_get_softc(dev);
+ struct apei_ivars *ai = device_get_ivars(child);
+ struct apei_register_mapping *m;
+ struct apei_register *reg;
+ struct resource_map_request req;
+ int error;
+
+ reg = apei_alloc_register(sc, type, start, count);
+ if (reg == NULL)
+ return (NULL);
+
+ m = malloc(sizeof(*m), M_APEI, M_WAITOK | M_ZERO);
+ m->reg = reg;
+ resource_init_map_request(&req);
+ req.offset = start - rman_get_start(reg->res);
+ req.length = count;
+ error = bus_map_resource(dev, reg->res, &req, &m->map);
+ if (error != 0) {
+ if (bootverbose)
+ device_printf(dev, "failed to map %s %#jx-%#jx: %d\n",
+ type == SYS_RES_MEMORY ? "iomem" : "port",
+ start,
+ start + (count - 1), error);
+ free(m, M_APEI);
+ return (NULL);
+ }
+ TAILQ_INSERT_TAIL(&ai->mappings, m, link);
+ return (&m->map);
+}
+
+static int
+apei_unmap_register_method(device_t dev, device_t child,
+ struct resource_map *map)
+{
+ struct apei_ivars *ai = device_get_ivars(child);
+ struct apei_register_mapping *m;
+ int error;
+
+ if (map == NULL)
+ return (0);
+
+ TAILQ_FOREACH(m, &ai->mappings, link) {
+ if (&m->map == map)
+ break;
+ }
+
+ if (m == NULL)
+ return (EINVAL);
+
+ TAILQ_REMOVE(&ai->mappings, m, link);
+ error = bus_unmap_resource(dev, m->reg->res, &m->map);
+ if (error != 0 && bootverbose)
+ device_printf(dev, "failed to unmap %s %#jx-%#jx: %d\n",
+ rman_get_type(m->reg->res) == SYS_RES_MEMORY ? "iomem" :
+ "port", rman_get_start(m->reg->res),
+ rman_get_end(m->reg->res), error);
+ free(m, M_APEI);
+ return (0);
+}
+
+struct resource_map *
+apei_map_register(device_t dev, ACPI_GENERIC_ADDRESS *gas)
+{
+ int type;
+
+ if (gas->Address == 0 || gas->BitWidth == 0 || gas->BitWidth % 8 != 0)
+ return (NULL);
+
+ switch (gas->SpaceId) {
+ case ACPI_ADR_SPACE_SYSTEM_MEMORY:
+ type = SYS_RES_MEMORY;
+ break;
+ case ACPI_ADR_SPACE_SYSTEM_IO:
+ type = SYS_RES_IOPORT;
+ break;
+ default:
+ return (NULL);
+ }
+
+ return (APEI_MAP_REGISTER(device_get_parent(dev), dev, type,
+ gas->Address, gas->BitWidth / 8));
+}
+
+struct resource_map *
+apei_map_memory(device_t dev, rman_res_t start, rman_res_t count)
+{
+ return (APEI_MAP_REGISTER(device_get_parent(dev), dev, SYS_RES_MEMORY,
+ start, count));
+}
+
+int
+apei_unmap_register(device_t dev, struct resource_map *map)
+{
+ return (APEI_UNMAP_REGISTER(device_get_parent(dev), dev, map));
+}
+
+static device_method_t apei_methods[] = {
+ /* Device interface */
+ DEVMETHOD(device_identify, apei_identify),
+ DEVMETHOD(device_probe, apei_probe),
+ DEVMETHOD(device_attach, apei_attach),
+
+ /* Bus interface */
+ DEVMETHOD(bus_add_child, apei_add_child),
+ DEVMETHOD(bus_print_child, bus_generic_print_child),
+ DEVMETHOD(bus_child_deleted, apei_child_deleted),
+ DEVMETHOD(bus_child_detached, apei_child_detached),
+ DEVMETHOD(bus_read_ivar, apei_read_ivar),
+
+ /* APEI interface */
+ DEVMETHOD(apei_map_register, apei_map_register_method),
+ DEVMETHOD(apei_unmap_register, apei_unmap_register_method),
+
+ DEVMETHOD_END
+};
+
+static driver_t apei_driver = {
+ "apei",
+ apei_methods,
+ sizeof(struct apei_softc),
+};
+
+DRIVER_MODULE(apei, acpi, apei_driver, NULL, NULL);
+MODULE_DEPEND(apei, acpi, 1, 1, 1);
diff --git a/sys/dev/acpica/apei_if.m b/sys/dev/acpica/apei_if.m
new file mode 100644
index 000000000000..1975fbde962f
--- /dev/null
+++ b/sys/dev/acpica/apei_if.m
@@ -0,0 +1,49 @@
+#-
+# SPDX-License-Identifier: BSD-2-Clause
+#
+# Copyright (c) 2025 Netflix, Inc.
+# Written by: John Baldwin <jhb@FreeBSD.org>
+#
+
+#include <sys/bus.h>
+
+#include <contrib/dev/acpica/include/acpi.h>
+
+/**
+ * @defgroup APEI apei - KObj methods for ACPI platform error interface drivers
+ * @brief A pair of methods to allocate/deallocate registers for APEI
+ * @{
+ */
+INTERFACE apei;
+
+/**
+ * @brief Allocate a mapping for a resource.
+ *
+ * @param _bus parent device
+ * @param _dev device requesting the mapping
+ * @param _type resource type
+ * @param _start start address
+ * @param _count length
+ *
+ * @returns resource mapping on success, or @c NULL on failure
+ */
+METHOD struct resource_map * map_register {
+ device_t _bus;
+ device_t _child;
+ int _type;
+ rman_res_t _start;
+ rman_res_t _count;
+};
+
+/**
+ * @brief Deallocate a mapping for a resource.
+ *
+ * @param _bus parent device
+ * @param _dev device releasing the mapping
+ * @param _map resource map
+ */
+METHOD int unmap_register {
+ device_t _bus;
+ device_t _child;
+ struct resource_map *_map;
+};
diff --git a/sys/dev/acpica/apeivar.h b/sys/dev/acpica/apeivar.h
new file mode 100644
index 000000000000..7820641aef1f
--- /dev/null
+++ b/sys/dev/acpica/apeivar.h
@@ -0,0 +1,54 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2020 Alexander Motin <mav@FreeBSD.org>
+ * Copyright (c) 2025 Netflix, Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef __APEIVAR_H__
+#define __APEIVAR_H__
+
+#include "apei_if.h"
+
+struct resource_map *apei_map_register(device_t dev, ACPI_GENERIC_ADDRESS *gas);
+struct resource_map *apei_map_memory(device_t dev, rman_res_t start,
+ rman_res_t len);
+int apei_unmap_register(device_t dev, struct resource_map *map);
+
+#ifdef __i386__
+static __inline uint64_t
+bus_read_8(struct resource_map *res, bus_size_t offset)
+{
+ return (bus_read_4(res, offset) |
+ ((uint64_t)bus_read_4(res, offset + 4)) << 32);
+}
+static __inline void
+bus_write_8(struct resource_map *res, bus_size_t offset, uint64_t val)
+{
+ bus_write_4(res, offset, val);
+ bus_write_4(res, offset + 4, val >> 32);
+}
+#endif
+
+#endif /* !__APEIVAR_H__ */