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head/sys/kern/subr_physmem.c

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/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2014 Ian Lepore <ian@freebsd.org>
* All rights reserved.
*
* 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/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_acpi.h"
#include "opt_ddb.h"
/*
* Routines for describing and initializing anything related to physical memory.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/physmem.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/vm_page.h>
#include <vm/vm_phys.h>
#include <machine/md_var.h>
/*
* These structures are used internally to keep track of regions of physical
* ram, and regions within the physical ram that need to be excluded. An
* exclusion region can be excluded from crash dumps, from the vm pool of pages
* that can be allocated, or both, depending on the exclusion flags associated
* with the region.
*/
#ifdef DEV_ACPI
#define MAX_HWCNT 32 /* ACPI needs more regions */
#define MAX_EXCNT 32
#else
#define MAX_HWCNT 16
#define MAX_EXCNT 16
#endif
#if defined(__arm__)
#define MAX_PHYS_ADDR 0xFFFFFFFFull
#elif defined(__aarch64__) || defined(__riscv)
#define MAX_PHYS_ADDR 0xFFFFFFFFFFFFFFFFull
#endif
struct region {
vm_paddr_t addr;
vm_size_t size;
uint32_t flags;
};
static struct region hwregions[MAX_HWCNT];
static struct region exregions[MAX_EXCNT];
static size_t hwcnt;
static size_t excnt;
/*
* realmem is the total number of hardware pages, excluded or not.
* Maxmem is one greater than the last physical page number.
*/
long realmem;
long Maxmem;
/*
* Print the contents of the physical and excluded region tables using the
* provided printf-like output function (which will be either printf or
* db_printf).
*/
static void
physmem_dump_tables(int (*prfunc)(const char *, ...))
{
int flags, i;
uintmax_t addr, size;
const unsigned int mbyte = 1024 * 1024;
prfunc("Physical memory chunk(s):\n");
for (i = 0; i < hwcnt; ++i) {
addr = hwregions[i].addr;
size = hwregions[i].size;
prfunc(" 0x%08jx - 0x%08jx, %5ju MB (%7ju pages)\n", addr,
addr + size - 1, size / mbyte, size / PAGE_SIZE);
}
prfunc("Excluded memory regions:\n");
for (i = 0; i < excnt; ++i) {
addr = exregions[i].addr;
size = exregions[i].size;
flags = exregions[i].flags;
prfunc(" 0x%08jx - 0x%08jx, %5ju MB (%7ju pages) %s %s\n",
addr, addr + size - 1, size / mbyte, size / PAGE_SIZE,
(flags & EXFLAG_NOALLOC) ? "NoAlloc" : "",
(flags & EXFLAG_NODUMP) ? "NoDump" : "");
}
#ifdef DEBUG
prfunc("Avail lists:\n");
for (i = 0; phys_avail[i] != 0; ++i) {
prfunc(" phys_avail[%d] 0x%08x\n", i, phys_avail[i]);
}
for (i = 0; dump_avail[i] != 0; ++i) {
prfunc(" dump_avail[%d] 0x%08x\n", i, dump_avail[i]);
}
#endif
}
/*
* Print the contents of the static mapping table. Used for bootverbose.
*/
void
physmem_print_tables(void)
{
physmem_dump_tables(printf);
}
/*
* Walk the list of hardware regions, processing it against the list of
* exclusions that contain the given exflags, and generating an "avail list".
*
* Updates the value at *pavail with the sum of all pages in all hw regions.
*
* Returns the number of pages of non-excluded memory added to the avail list.
*/
static size_t
regions_to_avail(vm_paddr_t *avail, uint32_t exflags, size_t maxavail,
long *pavail, long *prealmem)
{
size_t acnt, exi, hwi;
uint64_t end, start, xend, xstart;
long availmem, totalmem;
const struct region *exp, *hwp;
totalmem = 0;
availmem = 0;
acnt = 0;
for (hwi = 0, hwp = hwregions; hwi < hwcnt; ++hwi, ++hwp) {
start = hwp->addr;
end = hwp->size + start;
totalmem += atop((vm_offset_t)(end - start));
for (exi = 0, exp = exregions; exi < excnt; ++exi, ++exp) {
/*
* If the excluded region does not match given flags,
* continue checking with the next excluded region.
*/
if ((exp->flags & exflags) == 0)
continue;
xstart = exp->addr;
xend = exp->size + xstart;
/*
* If the excluded region ends before this hw region,
* continue checking with the next excluded region.
*/
if (xend <= start)
continue;
/*
* If the excluded region begins after this hw region
* we're done because both lists are sorted.
*/
if (xstart >= end)
break;
/*
* If the excluded region completely covers this hw
* region, shrink this hw region to zero size.
*/
if ((start >= xstart) && (end <= xend)) {
start = xend;
end = xend;
break;
}
/*
* If the excluded region falls wholly within this hw
* region without abutting or overlapping the beginning
* or end, create an available entry from the leading
* fragment, then adjust the start of this hw region to
* the end of the excluded region, and continue checking
* the next excluded region because another exclusion
* could affect the remainder of this hw region.
*/
if ((xstart > start) && (xend < end)) {
if (acnt > 0 &&
avail[acnt - 1] == (vm_paddr_t)start) {
avail[acnt - 1] = (vm_paddr_t)xstart;
} else {
avail[acnt++] = (vm_paddr_t)start;
avail[acnt++] = (vm_paddr_t)xstart;
}
availmem += atop((vm_offset_t)(xstart - start));
start = xend;
continue;
}
/*
* We know the excluded region overlaps either the start
* or end of this hardware region (but not both), trim
* the excluded portion off the appropriate end.
*/
if (xstart <= start)
start = xend;
else
end = xstart;
}
/*
* If the trimming actions above left a non-zero size, create an
* available entry for it.
*/
if (end > start) {
if (acnt > 0 && avail[acnt - 1] == (vm_paddr_t)start) {
avail[acnt - 1] = (vm_paddr_t)end;
} else {
avail[acnt++] = (vm_paddr_t)start;
avail[acnt++] = (vm_paddr_t)end;
}
availmem += atop((vm_offset_t)(end - start));
}
if (acnt >= maxavail)
panic("Not enough space in the dump/phys_avail arrays");
}
if (pavail != NULL)
*pavail = availmem;
if (prealmem != NULL)
*prealmem = totalmem;
return (acnt);
}
/*
* Insertion-sort a new entry into a regions list; sorted by start address.
*/
static size_t
insert_region(struct region *regions, size_t rcnt, vm_paddr_t addr,
vm_size_t size, uint32_t flags)
{
size_t i;
struct region *ep, *rp;
ep = regions + rcnt;
for (i = 0, rp = regions; i < rcnt; ++i, ++rp) {
if (rp->addr == addr && rp->size == size) /* Pure dup. */
return (rcnt);
if (flags == rp->flags) {
if (addr + size == rp->addr) {
rp->addr = addr;
rp->size += size;
return (rcnt);
} else if (rp->addr + rp->size == addr) {
rp->size += size;
return (rcnt);
}
}
if (addr < rp->addr) {
bcopy(rp, rp + 1, (ep - rp) * sizeof(*rp));
break;
}
}
rp->addr = addr;
rp->size = size;
rp->flags = flags;
rcnt++;
return (rcnt);
}
/*
* Add a hardware memory region.
*/
void
physmem_hardware_region(uint64_t pa, uint64_t sz)
{
vm_offset_t adj;
/*
* Filter out the page at PA 0x00000000. The VM can't handle it, as
* pmap_extract() == 0 means failure.
*/
if (pa == 0) {
if (sz <= PAGE_SIZE)
return;
pa = PAGE_SIZE;
sz -= PAGE_SIZE;
} else if (pa > MAX_PHYS_ADDR) {
/* This range is past usable memory, ignore it */
return;
}
/*
* Also filter out the page at the end of the physical address space --
* if addr is non-zero and addr+size is zero we wrapped to the next byte
* beyond what vm_paddr_t can express. That leads to a NULL pointer
* deref early in startup; work around it by leaving the last page out.
*
* XXX This just in: subtract out a whole megabyte, not just 1 page.
* Reducing the size by anything less than 1MB results in the NULL
* pointer deref in _vm_map_lock_read(). Better to give up a megabyte
* than leave some folks with an unusable system while we investigate.
*/
if ((pa + sz) > (MAX_PHYS_ADDR - 1024 * 1024)) {
sz = MAX_PHYS_ADDR - pa + 1;
if (sz <= 1024 * 1024)
return;
sz -= 1024 * 1024;
}
/*
* Round the starting address up to a page boundary, and truncate the
* ending page down to a page boundary.
*/
adj = round_page(pa) - pa;
pa = round_page(pa);
sz = trunc_page(sz - adj);
if (sz > 0 && hwcnt < nitems(hwregions))
hwcnt = insert_region(hwregions, hwcnt, pa, sz, 0);
}
/*
* Add an exclusion region.
*/
void
physmem_exclude_region(vm_paddr_t pa, vm_size_t sz, uint32_t exflags)
{
vm_offset_t adj;
/*
* Truncate the starting address down to a page boundary, and round the
* ending page up to a page boundary.
*/
adj = pa - trunc_page(pa);
pa = trunc_page(pa);
sz = round_page(sz + adj);
if (excnt >= nitems(exregions))
panic("failed to exclude region %#jx-%#jx", (uintmax_t)pa,
(uintmax_t)(pa + sz));
excnt = insert_region(exregions, excnt, pa, sz, exflags);
}
size_t
physmem_avail(vm_paddr_t *avail, size_t maxavail)
{
return (regions_to_avail(avail, EXFLAG_NOALLOC, maxavail, NULL, NULL));
}
/*
* Process all the regions added earlier into the global avail lists.
*
* Updates the kernel global 'physmem' with the number of physical pages
* available for use (all pages not in any exclusion region).
*
* Updates the kernel global 'Maxmem' with the page number one greater then the
* last page of physical memory in the system.
*/
void
physmem_init_kernel_globals(void)
{
size_t nextidx;
regions_to_avail(dump_avail, EXFLAG_NODUMP, PHYS_AVAIL_ENTRIES, NULL,
NULL);
nextidx = regions_to_avail(phys_avail, EXFLAG_NOALLOC,
PHYS_AVAIL_ENTRIES, &physmem, &realmem);
if (nextidx == 0)
panic("No memory entries in phys_avail");
Maxmem = atop(phys_avail[nextidx - 1]);
}
#ifdef DDB
#include <ddb/ddb.h>
DB_SHOW_COMMAND(physmem, db_show_physmem)
{
physmem_dump_tables(db_printf);
}
#endif /* DDB */