git: e6cf1a0826c9 - main - physmem: add ram0 pseudo-driver
Date: Wed, 08 Feb 2023 20:52:24 UTC
The branch main has been updated by mhorne: URL: https://cgit.FreeBSD.org/src/commit/?id=e6cf1a0826c9d7f229e41224ec7b783501636528 commit e6cf1a0826c9d7f229e41224ec7b783501636528 Author: Mitchell Horne <mhorne@FreeBSD.org> AuthorDate: 2021-05-27 14:27:40 +0000 Commit: Mitchell Horne <mhorne@FreeBSD.org> CommitDate: 2023-02-08 20:50:46 +0000 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 --- sys/kern/subr_physmem.c | 100 +++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 99 insertions(+), 1 deletion(-) diff --git a/sys/kern/subr_physmem.c b/sys/kern/subr_physmem.c index 498ad2440f40..bb6af5a580aa 100644 --- a/sys/kern/subr_physmem.c +++ b/sys/kern/subr_physmem.c @@ -40,7 +40,9 @@ __FBSDID("$FreeBSD$"); #include <sys/param.h> #include <sys/systm.h> +#include <sys/bus.h> #include <sys/kernel.h> +#include <sys/module.h> #include <sys/physmem.h> #ifdef _KERNEL @@ -49,7 +51,9 @@ __FBSDID("$FreeBSD$"); #include <vm/vm_page.h> #include <vm/vm_phys.h> #include <vm/vm_dumpset.h> + #include <machine/md_var.h> +#include <machine/resource.h> #else #include <stdarg.h> #include <stdio.h> @@ -524,7 +528,6 @@ physmem_init_kernel_globals(void) panic("No memory entries in phys_avail"); Maxmem = atop(phys_avail[nextidx - 1]); } -#endif #ifdef DDB #include <ddb/ddb.h> @@ -536,3 +539,98 @@ DB_SHOW_COMMAND_FLAGS(physmem, db_show_physmem, DB_CMD_MEMSAFE) } #endif /* DDB */ + +/* + * ram pseudo driver - this reserves I/O space resources corresponding to physical + * memory regions. + */ + +static void +ram_identify(driver_t *driver, device_t parent) +{ + + if (resource_disabled("ram", 0)) + return; + if (BUS_ADD_CHILD(parent, 0, "ram", 0) == NULL) + panic("ram_identify"); +} + +static int +ram_probe(device_t dev) +{ + + device_quiet(dev); + device_set_desc(dev, "System RAM"); + return (BUS_PROBE_SPECIFIC); +} + +static int +ram_attach(device_t dev) +{ + vm_paddr_t avail_list[PHYS_AVAIL_COUNT]; + rman_res_t start, end; + struct region *hwp; + int rid, i; + + rid = 0; + + /* Get the avail list. */ + bzero(avail_list, sizeof(avail_list)); + regions_to_avail(avail_list, EXFLAG_NOALLOC | EXFLAG_NODUMP, + PHYS_AVAIL_COUNT, 0, NULL, NULL); + + /* Reserve all memory regions. */ + for (i = 0; avail_list[i + 1] != 0; i += 2) { + start = avail_list[i]; + end = avail_list[i + 1]; + + if (bootverbose) + device_printf(dev, + "reserving memory region: %jx-%jx\n", + (uintmax_t)start, (uintmax_t)end); + + if (bus_alloc_resource(dev, SYS_RES_MEMORY, &rid, start, end, + end - start, 0) == NULL) + panic("ram_attach: resource %d failed to attach", rid); + rid++; + } + + /* Now, reserve the excluded memory regions. */ + for (i = 0, hwp = exregions; i < excnt; i++, hwp++) { + start = hwp->addr; + end = hwp->addr + hwp->size; + + if (bootverbose) + device_printf(dev, + "reserving excluded region: %jx-%jx\n", + (uintmax_t)start, (uintmax_t)(end - 1)); + + /* + * Best-effort attempt to reserve the range. This may fail, as + * sometimes the excluded ranges provided by the device tree + * will cover or overlap some I/O range. + */ + if (bus_alloc_resource(dev, SYS_RES_MEMORY, &rid, start, end, + end - start, 0) == NULL) { + if (bootverbose) + device_printf(dev, "failed to reserve region\n"); + continue; + } + rid++; + } + + return (0); +} + +static device_method_t ram_methods[] = { + /* Device interface */ + DEVMETHOD(device_identify, ram_identify), + DEVMETHOD(device_probe, ram_probe), + DEVMETHOD(device_attach, ram_attach), + + DEVMETHOD_END +}; + +DEFINE_CLASS_0(ram, ram_driver, ram_methods, /* no softc */ 1); +DRIVER_MODULE(ram, nexus, ram_driver, 0, 0); +#endif /* _KERNEL */