freebsd-dev/sys/x86/xen/pv.c
Dimitry Andric 8e3c56d6b6 xen: Fix warning by adding KERNBASE to modlist_paddr before casting
Clang 13 produces the following warning for hammer_time_xen():

sys/x86/xen/pv.c:183:19: error: the pointer incremented by -2147483648 refers past the last possible element for an array in 64-bit address space containing 256-bit (32-byte) elements (max possible 576460752303423488 elements) [-Werror,-Warray-bounds]
                    (vm_paddr_t)start_info->modlist_paddr + KERNBASE;
                                ^                               ~~~~~~~~
sys/xen/interface/arch-x86/hvm/start_info.h:131:5: note: array 'modlist_paddr' declared here
    uint64_t modlist_paddr;         /* Physical address of an array of           */
    ^

This is because the expression first casts start_info->modlist_paddr to
struct hvm_modlist_entry * (via vmpaddr_t), and *then* adds KERNBASE,
which is then interpreted as KERNBASE * sizeof(struct
hvm_modlist_entry).

Instead, parenthesize the addition to get the intended result, and cast
it to struct hvm_modlist_entry * afterwards. Also remove the cast to
vmpaddr_t since it is not necessary.

Reviewed by:	royger
MFC after:	3 days
Differential Revision: https://reviews.freebsd.org/D31711
2021-08-29 19:43:00 +02:00

414 lines
12 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-NetBSD
*
* Copyright (c) 2004 Christian Limpach.
* Copyright (c) 2004-2006,2008 Kip Macy
* Copyright (c) 2008 The NetBSD Foundation, Inc.
* Copyright (c) 2013 Roger Pau Monné <roger.pau@citrix.com>
* 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_ddb.h"
#include "opt_kstack_pages.h"
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/reboot.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/linker.h>
#include <sys/lock.h>
#include <sys/rwlock.h>
#include <sys/boot.h>
#include <sys/ctype.h>
#include <sys/mutex.h>
#include <sys/smp.h>
#include <sys/efi.h>
#include <vm/vm.h>
#include <vm/vm_extern.h>
#include <vm/vm_kern.h>
#include <vm/vm_page.h>
#include <vm/vm_map.h>
#include <vm/vm_object.h>
#include <vm/vm_pager.h>
#include <vm/vm_param.h>
#include <machine/_inttypes.h>
#include <machine/intr_machdep.h>
#include <x86/apicvar.h>
#include <x86/init.h>
#include <machine/pc/bios.h>
#include <machine/smp.h>
#include <machine/intr_machdep.h>
#include <machine/md_var.h>
#include <machine/metadata.h>
#include <xen/xen-os.h>
#include <xen/hvm.h>
#include <xen/hypervisor.h>
#include <xen/xenstore/xenstorevar.h>
#include <xen/xen_pv.h>
#include <xen/interface/arch-x86/hvm/start_info.h>
#include <xen/interface/vcpu.h>
#include <dev/xen/timer/timer.h>
#ifdef DDB
#include <ddb/ddb.h>
#endif
/* Native initial function */
extern u_int64_t hammer_time(u_int64_t, u_int64_t);
/* Xen initial function */
uint64_t hammer_time_xen(vm_paddr_t);
#define MAX_E820_ENTRIES 128
/*--------------------------- Forward Declarations ---------------------------*/
static caddr_t xen_pvh_parse_preload_data(uint64_t);
static void xen_pvh_parse_memmap(caddr_t, vm_paddr_t *, int *);
/*---------------------------- Extern Declarations ---------------------------*/
/*
* Placed by the linker at the end of the bss section, which is the last
* section loaded by Xen before loading the symtab and strtab.
*/
extern uint32_t end;
/*-------------------------------- Global Data -------------------------------*/
struct init_ops xen_pvh_init_ops = {
.parse_preload_data = xen_pvh_parse_preload_data,
.early_clock_source_init = xen_clock_init,
.early_delay = xen_delay,
.parse_memmap = xen_pvh_parse_memmap,
};
static struct bios_smap xen_smap[MAX_E820_ENTRIES];
static struct hvm_start_info *start_info;
/*-------------------------------- Xen PV init -------------------------------*/
uint64_t
hammer_time_xen(vm_paddr_t start_info_paddr)
{
struct hvm_modlist_entry *mod;
struct xen_add_to_physmap xatp;
uint64_t physfree;
char *kenv;
int rc;
xen_domain_type = XEN_HVM_DOMAIN;
vm_guest = VM_GUEST_XEN;
rc = xen_hvm_init_hypercall_stubs(XEN_HVM_INIT_EARLY);
if (rc) {
xc_printf("ERROR: failed to initialize hypercall page: %d\n",
rc);
HYPERVISOR_shutdown(SHUTDOWN_crash);
}
start_info = (struct hvm_start_info *)(start_info_paddr + KERNBASE);
if (start_info->magic != XEN_HVM_START_MAGIC_VALUE) {
xc_printf("Unknown magic value in start_info struct: %#x\n",
start_info->magic);
HYPERVISOR_shutdown(SHUTDOWN_crash);
}
/*
* The hvm_start_into structure is always appended after loading
* the kernel and modules.
*/
physfree = roundup2(start_info_paddr + PAGE_SIZE, PAGE_SIZE);
xatp.domid = DOMID_SELF;
xatp.idx = 0;
xatp.space = XENMAPSPACE_shared_info;
xatp.gpfn = atop(physfree);
if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp)) {
xc_printf("ERROR: failed to setup shared_info page\n");
HYPERVISOR_shutdown(SHUTDOWN_crash);
}
HYPERVISOR_shared_info = (shared_info_t *)(physfree + KERNBASE);
physfree += PAGE_SIZE;
/*
* Init a static kenv using a free page. The contents will be filled
* from the parse_preload_data hook.
*/
kenv = (void *)(physfree + KERNBASE);
physfree += PAGE_SIZE;
bzero_early(kenv, PAGE_SIZE);
init_static_kenv(kenv, PAGE_SIZE);
if (start_info->modlist_paddr != 0) {
if (start_info->modlist_paddr >= physfree) {
xc_printf(
"ERROR: unexpected module list memory address\n");
HYPERVISOR_shutdown(SHUTDOWN_crash);
}
if (start_info->nr_modules == 0) {
xc_printf(
"ERROR: modlist_paddr != 0 but nr_modules == 0\n");
HYPERVISOR_shutdown(SHUTDOWN_crash);
}
mod = (struct hvm_modlist_entry *)
(start_info->modlist_paddr + KERNBASE);
if (mod[0].paddr >= physfree) {
xc_printf("ERROR: unexpected module memory address\n");
HYPERVISOR_shutdown(SHUTDOWN_crash);
}
}
/* Set the hooks for early functions that diverge from bare metal */
init_ops = xen_pvh_init_ops;
hvm_start_flags = start_info->flags;
/* Now we can jump into the native init function */
return (hammer_time(0, physfree));
}
/*-------------------------------- PV specific -------------------------------*/
/*
* When booted as a PVH guest FreeBSD needs to avoid using the RSDP address
* hint provided by the loader because it points to the native set of ACPI
* tables instead of the ones crafted by Xen. The acpi.rsdp env variable is
* removed from kenv if present, and a new acpi.rsdp is added to kenv that
* points to the address of the Xen crafted RSDP.
*/
static bool reject_option(const char *option)
{
static const char *reject[] = {
"acpi.rsdp",
};
unsigned int i;
for (i = 0; i < nitems(reject); i++)
if (strncmp(option, reject[i], strlen(reject[i])) == 0)
return (true);
return (false);
}
static void
xen_pvh_set_env(char *env, bool (*filter)(const char *))
{
char *option;
if (env == NULL)
return;
option = env;
while (*option != 0) {
char *value;
if (filter != NULL && filter(option)) {
option += strlen(option) + 1;
continue;
}
value = option;
option = strsep(&value, "=");
if (kern_setenv(option, value) != 0)
xc_printf("unable to add kenv %s=%s\n", option, value);
option = value + strlen(value) + 1;
}
}
#ifdef DDB
/*
* The way Xen loads the symtab is different from the native boot loader,
* because it's tailored for NetBSD. So we have to adapt and use the same
* method as NetBSD. Portions of the code below have been picked from NetBSD:
* sys/kern/kern_ksyms.c CVS Revision 1.71.
*/
static void
xen_pvh_parse_symtab(void)
{
Elf_Ehdr *ehdr;
Elf_Shdr *shdr;
uint32_t size;
int i, j;
size = end;
ehdr = (Elf_Ehdr *)(&end + 1);
if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG) ||
ehdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
ehdr->e_version > 1) {
xc_printf("Unable to load ELF symtab: invalid symbol table\n");
return;
}
shdr = (Elf_Shdr *)((uint8_t *)ehdr + ehdr->e_shoff);
/* Find the symbol table and the corresponding string table. */
for (i = 1; i < ehdr->e_shnum; i++) {
if (shdr[i].sh_type != SHT_SYMTAB)
continue;
if (shdr[i].sh_offset == 0)
continue;
ksymtab = (uintptr_t)((uint8_t *)ehdr + shdr[i].sh_offset);
ksymtab_size = shdr[i].sh_size;
j = shdr[i].sh_link;
if (shdr[j].sh_offset == 0)
continue; /* Can this happen? */
kstrtab = (uintptr_t)((uint8_t *)ehdr + shdr[j].sh_offset);
break;
}
if (ksymtab == 0 || kstrtab == 0)
xc_printf(
"Unable to load ELF symtab: could not find symtab or strtab\n");
}
#endif
static caddr_t
xen_pvh_parse_preload_data(uint64_t modulep)
{
caddr_t kmdp;
vm_ooffset_t off;
vm_paddr_t metadata;
char *envp;
char acpi_rsdp[19];
if (start_info->modlist_paddr != 0) {
struct hvm_modlist_entry *mod;
const char *cmdline;
mod = (struct hvm_modlist_entry *)
(start_info->modlist_paddr + KERNBASE);
cmdline = mod[0].cmdline_paddr ?
(const char *)(mod[0].cmdline_paddr + KERNBASE) : NULL;
if (strcmp(cmdline, "header") == 0) {
struct xen_header *header;
header = (struct xen_header *)(mod[0].paddr + KERNBASE);
if ((header->flags & XENHEADER_HAS_MODULEP_OFFSET) !=
XENHEADER_HAS_MODULEP_OFFSET) {
xc_printf("Unable to load module metadata\n");
HYPERVISOR_shutdown(SHUTDOWN_crash);
}
preload_metadata = (caddr_t)(mod[0].paddr +
header->modulep_offset + KERNBASE);
kmdp = preload_search_by_type("elf kernel");
if (kmdp == NULL)
kmdp = preload_search_by_type("elf64 kernel");
if (kmdp == NULL) {
xc_printf("Unable to find kernel\n");
HYPERVISOR_shutdown(SHUTDOWN_crash);
}
/*
* Xen has relocated the metadata and the modules, so
* we need to recalculate it's position. This is done
* by saving the original modulep address and then
* calculating the offset from the real modulep
* position.
*/
metadata = MD_FETCH(kmdp, MODINFOMD_MODULEP,
vm_paddr_t);
off = mod[0].paddr + header->modulep_offset - metadata +
KERNBASE;
} else {
preload_metadata = (caddr_t)(mod[0].paddr + KERNBASE);
kmdp = preload_search_by_type("elf kernel");
if (kmdp == NULL)
kmdp = preload_search_by_type("elf64 kernel");
if (kmdp == NULL) {
xc_printf("Unable to find kernel\n");
HYPERVISOR_shutdown(SHUTDOWN_crash);
}
metadata = MD_FETCH(kmdp, MODINFOMD_MODULEP, vm_paddr_t);
off = mod[0].paddr + KERNBASE - metadata;
}
preload_bootstrap_relocate(off);
boothowto = MD_FETCH(kmdp, MODINFOMD_HOWTO, int);
envp = MD_FETCH(kmdp, MODINFOMD_ENVP, char *);
if (envp != NULL)
envp += off;
xen_pvh_set_env(envp, reject_option);
if (MD_FETCH(kmdp, MODINFOMD_EFI_MAP, void *) != NULL)
strlcpy(bootmethod, "UEFI", sizeof(bootmethod));
else
strlcpy(bootmethod, "BIOS", sizeof(bootmethod));
} else {
/* Parse the extra boot information given by Xen */
if (start_info->cmdline_paddr != 0)
boot_parse_cmdline_delim(
(char *)(start_info->cmdline_paddr + KERNBASE),
",");
kmdp = NULL;
strlcpy(bootmethod, "XEN", sizeof(bootmethod));
}
boothowto |= boot_env_to_howto();
snprintf(acpi_rsdp, sizeof(acpi_rsdp), "%#" PRIx64,
start_info->rsdp_paddr);
kern_setenv("acpi.rsdp", acpi_rsdp);
#ifdef DDB
xen_pvh_parse_symtab();
#endif
return (kmdp);
}
static void
xen_pvh_parse_memmap(caddr_t kmdp, vm_paddr_t *physmap, int *physmap_idx)
{
struct xen_memory_map memmap;
u_int32_t size;
int rc;
/* Fetch the E820 map from Xen */
memmap.nr_entries = MAX_E820_ENTRIES;
set_xen_guest_handle(memmap.buffer, xen_smap);
rc = HYPERVISOR_memory_op(XENMEM_memory_map, &memmap);
if (rc) {
xc_printf("ERROR: unable to fetch Xen E820 memory map: %d\n",
rc);
HYPERVISOR_shutdown(SHUTDOWN_crash);
}
size = memmap.nr_entries * sizeof(xen_smap[0]);
bios_add_smap_entries(xen_smap, size, physmap, physmap_idx);
}