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freebsd-dev/sys/x86/xen/pv.c
Ian Lepore 69dcb7e771 Make the 'env' directive described in config(5) work on all architectures, 
providing compiled-in static environment data that is used instead of any
data passed in from a boot loader.

Previously 'env' worked only on i386 and arm xscale systems, because it
required the MD startup code to examine the global envmode variable and
decide whether to use static_env or an environment obtained from the boot
loader, and set the global kern_envp accordingly.  Most startup code wasn't
doing so.  Making things even more complex, some mips startup code uses an
alternate scheme that involves calling init_static_kenv() to pass an empty
buffer and its size, then uses a series of kern_setenv() calls to populate
that buffer.

Now all MD startup code calls init_static_kenv(), and that routine provides
a single point where envmode is checked and the decision is made whether to
use the compiled-in static_kenv or the values provided by the MD code.

The routine also continues to serve its original purpose for mips; if a
non-zero buffer size is passed the routine installs the empty buffer ready
to accept kern_setenv() values.  Now if the size is zero, the provided buffer
full of existing env data is installed.  A NULL pointer can be passed if the
boot loader provides no env data; this allows the static env to be installed
if envmode is set to do so.

Most of the work here is a near-mechanical change to call the init function
instead of directly setting kern_envp.  A notable exception is in xen/pv.c;
that code was originally installing a buffer full of preformatted env data
along with its non-zero size (like mips code does), which would have allowed
kern_setenv() calls to wipe out the preformatted data.  Now it passes a zero
for the size so that the buffer of data it installs is treated as
non-writeable.
2016-01-02 02:53:48 +00:00

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/*
* 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 <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/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/metadata.h>
#include <xen/xen-os.h>
#include <xen/hypervisor.h>
#include <xen/xenstore/xenstorevar.h>
#include <xen/xen_pv.h>
#include <xen/xen_msi.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(start_info_t *, uint64_t);
#define MAX_E820_ENTRIES 128
/*--------------------------- Forward Declarations ---------------------------*/
static caddr_t xen_pv_parse_preload_data(u_int64_t);
static void xen_pv_parse_memmap(caddr_t, vm_paddr_t *, int *);
#ifdef SMP
static int xen_pv_start_all_aps(void);
#endif
/*---------------------------- Extern Declarations ---------------------------*/
#ifdef SMP
/* Variables used by amd64 mp_machdep to start APs */
extern char *doublefault_stack;
extern char *nmi_stack;
#endif
/*
* 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 -------------------------------*/
/* Xen init_ops implementation. */
struct init_ops xen_init_ops = {
.parse_preload_data = xen_pv_parse_preload_data,
.early_clock_source_init = xen_clock_init,
.early_delay = xen_delay,
.parse_memmap = xen_pv_parse_memmap,
#ifdef SMP
.start_all_aps = xen_pv_start_all_aps,
#endif
.msi_init = xen_msi_init,
};
static struct bios_smap xen_smap[MAX_E820_ENTRIES];
/*-------------------------------- Xen PV init -------------------------------*/
/*
* First function called by the Xen PVH boot sequence.
*
* Set some Xen global variables and prepare the environment so it is
* as similar as possible to what native FreeBSD init function expects.
*/
uint64_t
hammer_time_xen(start_info_t *si, uint64_t xenstack)
{
uint64_t physfree;
uint64_t *PT4 = (u_int64_t *)xenstack;
uint64_t *PT3 = (u_int64_t *)(xenstack + PAGE_SIZE);
uint64_t *PT2 = (u_int64_t *)(xenstack + 2 * PAGE_SIZE);
int i;
xen_domain_type = XEN_PV_DOMAIN;
vm_guest = VM_GUEST_XEN;
if ((si == NULL) || (xenstack == 0)) {
xc_printf("ERROR: invalid start_info or xen stack, halting\n");
HYPERVISOR_shutdown(SHUTDOWN_crash);
}
xc_printf("FreeBSD PVH running on %s\n", si->magic);
/* We use 3 pages of xen stack for the boot pagetables */
physfree = xenstack + 3 * PAGE_SIZE - KERNBASE;
/* Setup Xen global variables */
HYPERVISOR_start_info = si;
HYPERVISOR_shared_info =
(shared_info_t *)(si->shared_info + KERNBASE);
/*
* Setup some misc global variables for Xen devices
*
* XXX: Devices that need these specific variables should
* be rewritten to fetch this info by themselves from the
* start_info page.
*/
xen_store = (struct xenstore_domain_interface *)
(ptoa(si->store_mfn) + KERNBASE);
console_page = (char *)(ptoa(si->console.domU.mfn) + KERNBASE);
/*
* Use the stack Xen gives us to build the page tables
* as native FreeBSD expects to find them (created
* by the boot trampoline).
*/
for (i = 0; i < (PAGE_SIZE / sizeof(uint64_t)); i++) {
/*
* Each slot of the level 4 pages points
* to the same level 3 page
*/
PT4[i] = ((uint64_t)&PT3[0]) - KERNBASE;
PT4[i] |= PG_V | PG_RW | PG_U;
/*
* Each slot of the level 3 pages points
* to the same level 2 page
*/
PT3[i] = ((uint64_t)&PT2[0]) - KERNBASE;
PT3[i] |= PG_V | PG_RW | PG_U;
/*
* The level 2 page slots are mapped with
* 2MB pages for 1GB.
*/
PT2[i] = i * (2 * 1024 * 1024);
PT2[i] |= PG_V | PG_RW | PG_PS | PG_U;
}
load_cr3(((uint64_t)&PT4[0]) - KERNBASE);
/* Set the hooks for early functions that diverge from bare metal */
init_ops = xen_init_ops;
apic_ops = xen_apic_ops;
/* Now we can jump into the native init function */
return (hammer_time(0, physfree));
}
/*-------------------------------- PV specific -------------------------------*/
#ifdef SMP
static bool
start_xen_ap(int cpu)
{
struct vcpu_guest_context *ctxt;
int ms, cpus = mp_naps;
const size_t stacksize = kstack_pages * PAGE_SIZE;
/* allocate and set up an idle stack data page */
bootstacks[cpu] =
(void *)kmem_malloc(kernel_arena, stacksize, M_WAITOK | M_ZERO);
doublefault_stack =
(char *)kmem_malloc(kernel_arena, PAGE_SIZE, M_WAITOK | M_ZERO);
nmi_stack =
(char *)kmem_malloc(kernel_arena, PAGE_SIZE, M_WAITOK | M_ZERO);
dpcpu =
(void *)kmem_malloc(kernel_arena, DPCPU_SIZE, M_WAITOK | M_ZERO);
bootSTK = (char *)bootstacks[cpu] + kstack_pages * PAGE_SIZE - 8;
bootAP = cpu;
ctxt = malloc(sizeof(*ctxt), M_TEMP, M_WAITOK | M_ZERO);
if (ctxt == NULL)
panic("unable to allocate memory");
ctxt->flags = VGCF_IN_KERNEL;
ctxt->user_regs.rip = (unsigned long) init_secondary;
ctxt->user_regs.rsp = (unsigned long) bootSTK;
/* Set the AP to use the same page tables */
ctxt->ctrlreg[3] = KPML4phys;
if (HYPERVISOR_vcpu_op(VCPUOP_initialise, cpu, ctxt))
panic("unable to initialize AP#%d", cpu);
free(ctxt, M_TEMP);
/* Launch the vCPU */
if (HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL))
panic("unable to start AP#%d", cpu);
/* Wait up to 5 seconds for it to start. */
for (ms = 0; ms < 5000; ms++) {
if (mp_naps > cpus)
return (true);
DELAY(1000);
}
return (false);
}
static int
xen_pv_start_all_aps(void)
{
int cpu;
mtx_init(&ap_boot_mtx, "ap boot", NULL, MTX_SPIN);
for (cpu = 1; cpu < mp_ncpus; cpu++) {
/* attempt to start the Application Processor */
if (!start_xen_ap(cpu))
panic("AP #%d failed to start!", cpu);
CPU_SET(cpu, &all_cpus); /* record AP in CPU map */
}
return (mp_naps);
}
#endif /* SMP */
/*
* Functions to convert the "extra" parameters passed by Xen
* into FreeBSD boot options.
*/
static void
xen_pv_set_env(void)
{
char *cmd_line_next, *cmd_line;
size_t env_size;
cmd_line = HYPERVISOR_start_info->cmd_line;
env_size = sizeof(HYPERVISOR_start_info->cmd_line);
/* Skip leading spaces */
for (; isspace(*cmd_line) && (env_size != 0); cmd_line++)
env_size--;
/* Replace ',' with '\0' */
for (cmd_line_next = cmd_line; strsep(&cmd_line_next, ",") != NULL;)
;
init_static_kenv(cmd_line, 0);
}
static void
xen_pv_set_boothowto(void)
{
int i;
char *env;
/* get equivalents from the environment */
for (i = 0; howto_names[i].ev != NULL; i++) {
if ((env = kern_getenv(howto_names[i].ev)) != NULL) {
boothowto |= howto_names[i].mask;
freeenv(env);
}
}
}
#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_pv_parse_symtab(void)
{
Elf_Ehdr *ehdr;
Elf_Shdr *shdr;
vm_offset_t sym_end;
uint32_t size;
int i, j;
size = end;
sym_end = HYPERVISOR_start_info->mod_start != 0 ?
HYPERVISOR_start_info->mod_start :
HYPERVISOR_start_info->mfn_list;
/*
* Make sure the size is right headed, sym_end is just a
* high boundary, but at least allows us to fail earlier.
*/
if ((vm_offset_t)&end + size > sym_end) {
xc_printf("Unable to load ELF symtab: size mismatch\n");
return;
}
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");
return;
}
}
#endif
static caddr_t
xen_pv_parse_preload_data(u_int64_t modulep)
{
caddr_t kmdp;
vm_ooffset_t off;
vm_paddr_t metadata;
char *envp;
if (HYPERVISOR_start_info->mod_start != 0) {
preload_metadata = (caddr_t)(HYPERVISOR_start_info->mod_start);
kmdp = preload_search_by_type("elf kernel");
if (kmdp == NULL)
kmdp = preload_search_by_type("elf64 kernel");
KASSERT(kmdp != NULL, ("unable to find kernel"));
/*
* 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 with mod_start,
* which contains the relocated modulep address.
*/
metadata = MD_FETCH(kmdp, MODINFOMD_MODULEP, vm_paddr_t);
off = HYPERVISOR_start_info->mod_start - metadata;
preload_bootstrap_relocate(off);
boothowto = MD_FETCH(kmdp, MODINFOMD_HOWTO, int);
envp = MD_FETCH(kmdp, MODINFOMD_ENVP, char *);
if (envp != NULL)
envp += off;
init_static_kenv(envp, 0);
} else {
/* Parse the extra boot information given by Xen */
xen_pv_set_env();
xen_pv_set_boothowto();
kmdp = NULL;
}
#ifdef DDB
xen_pv_parse_symtab();
#endif
return (kmdp);
}
static void
xen_pv_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)
panic("unable to fetch Xen E820 memory map");
size = memmap.nr_entries * sizeof(xen_smap[0]);
bios_add_smap_entries(xen_smap, size, physmap, physmap_idx);
}
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