physmem: add ram0 pseudo-driver
Its purpose is to reserve all I/O space belonging to physical memory from nexus, preventing it from being handed out by bus_alloc_resource() to callers such as xenpv_alloc_physmem(), which looks for the first available free range it can get. This mimics the existing pseudo-driver on x86. If needed, the device can be disabled with hint.ram.0.disabled="1" in /boot/device.hints. Reviewed by: imp MFC after: 1 month Differential Revision: https://reviews.freebsd.org/D32343
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@ -40,7 +40,9 @@ __FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/bus.h>
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#include <sys/kernel.h>
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#include <sys/module.h>
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#include <sys/physmem.h>
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#ifdef _KERNEL
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@ -49,7 +51,9 @@ __FBSDID("$FreeBSD$");
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#include <vm/vm_page.h>
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#include <vm/vm_phys.h>
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#include <vm/vm_dumpset.h>
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#include <machine/md_var.h>
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#include <machine/resource.h>
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#else
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#include <stdarg.h>
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#include <stdio.h>
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@ -524,7 +528,6 @@ physmem_init_kernel_globals(void)
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panic("No memory entries in phys_avail");
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Maxmem = atop(phys_avail[nextidx - 1]);
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}
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#endif
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#ifdef DDB
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#include <ddb/ddb.h>
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@ -536,3 +539,98 @@ DB_SHOW_COMMAND_FLAGS(physmem, db_show_physmem, DB_CMD_MEMSAFE)
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}
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#endif /* DDB */
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/*
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* ram pseudo driver - this reserves I/O space resources corresponding to physical
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* memory regions.
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*/
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static void
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ram_identify(driver_t *driver, device_t parent)
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{
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if (resource_disabled("ram", 0))
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return;
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if (BUS_ADD_CHILD(parent, 0, "ram", 0) == NULL)
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panic("ram_identify");
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}
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static int
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ram_probe(device_t dev)
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{
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device_quiet(dev);
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device_set_desc(dev, "System RAM");
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return (BUS_PROBE_SPECIFIC);
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}
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static int
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ram_attach(device_t dev)
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{
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vm_paddr_t avail_list[PHYS_AVAIL_COUNT];
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rman_res_t start, end;
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struct region *hwp;
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int rid, i;
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rid = 0;
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/* Get the avail list. */
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bzero(avail_list, sizeof(avail_list));
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regions_to_avail(avail_list, EXFLAG_NOALLOC | EXFLAG_NODUMP,
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PHYS_AVAIL_COUNT, 0, NULL, NULL);
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/* Reserve all memory regions. */
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for (i = 0; avail_list[i + 1] != 0; i += 2) {
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start = avail_list[i];
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end = avail_list[i + 1];
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if (bootverbose)
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device_printf(dev,
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"reserving memory region: %jx-%jx\n",
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(uintmax_t)start, (uintmax_t)end);
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if (bus_alloc_resource(dev, SYS_RES_MEMORY, &rid, start, end,
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end - start, 0) == NULL)
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panic("ram_attach: resource %d failed to attach", rid);
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rid++;
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}
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/* Now, reserve the excluded memory regions. */
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for (i = 0, hwp = exregions; i < excnt; i++, hwp++) {
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start = hwp->addr;
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end = hwp->addr + hwp->size;
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if (bootverbose)
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device_printf(dev,
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"reserving excluded region: %jx-%jx\n",
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(uintmax_t)start, (uintmax_t)(end - 1));
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/*
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* Best-effort attempt to reserve the range. This may fail, as
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* sometimes the excluded ranges provided by the device tree
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* will cover or overlap some I/O range.
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*/
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if (bus_alloc_resource(dev, SYS_RES_MEMORY, &rid, start, end,
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end - start, 0) == NULL) {
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if (bootverbose)
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device_printf(dev, "failed to reserve region\n");
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continue;
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}
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rid++;
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}
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return (0);
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}
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static device_method_t ram_methods[] = {
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/* Device interface */
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DEVMETHOD(device_identify, ram_identify),
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DEVMETHOD(device_probe, ram_probe),
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DEVMETHOD(device_attach, ram_attach),
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DEVMETHOD_END
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};
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DEFINE_CLASS_0(ram, ram_driver, ram_methods, /* no softc */ 1);
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DRIVER_MODULE(ram, nexus, ram_driver, 0, 0);
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#endif /* _KERNEL */
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