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ddb: allow specifying the exact address of the symtab and strtab

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When the FreeBSD kernel is loaded from Xen the symtab and strtab are
not loaded the same way as the native boot loader. This patch adds
three new global variables to ddb that can be used to specify the
exact position and size of those tables, so they can be directly used
as parameters to db_add_symbol_table. A new helper is introduced, so callers
that used to set ksym_start and ksym_end can use this helper to set the new
variables.

It also adds support for loading them from the Xen PVH port, that was
previously missing those tables.

Sponsored by: Citrix Systems R&D
Reviewed by:	kib

ddb/db_main.c:
 - Add three new global variables: ksymtab, kstrtab, ksymtab_size that
   can be used to specify the position and size of the symtab and
   strtab.
 - Use those new variables in db_init in order to call db_add_symbol_table.
 - Move the logic in db_init to db_fetch_symtab in order to set ksymtab,
   kstrtab, ksymtab_size from ksym_start and ksym_end.

ddb/ddb.h:
 - Add prototype for db_fetch_ksymtab.
 - Declate the extern variables ksymtab, kstrtab and ksymtab_size.

x86/xen/pv.c:
 - Add support for finding the symtab and strtab when booted as a Xen
   PVH guest. Since Xen loads the symtab and strtab as NetBSD expects
   to find them we have to adapt and use the same method.

amd64/amd64/machdep.c:
arm/arm/machdep.c:
i386/i386/machdep.c:
mips/mips/machdep.c:
pc98/pc98/machdep.c:
powerpc/aim/machdep.c:
powerpc/booke/machdep.c:
sparc64/sparc64/machdep.c:
 - Use the newly introduced db_fetch_ksymtab in order to set ksymtab,
   kstrtab and ksymtab_size.
This commit is contained in:
Roger Pau Monné 2014-09-25 08:28:10 +00:00
parent 5af6947046
commit c98a2727cc
11 changed files with 153 additions and 48 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
sys/amd64/amd64/machdep.c
View File

@ -184,9 +184,6 @@ struct init_ops init_ops = {
* the physical address at which the kernel is loaded.
*/
extern char kernphys[];
#ifdef DDB
extern vm_offset_t ksym_start, ksym_end;
#endif
struct msgbuf *msgbufp;
@ -1823,6 +1820,10 @@ static caddr_t
native_parse_preload_data(u_int64_t modulep)
{
caddr_t kmdp;
#ifdef DDB
vm_offset_t ksym_start;
vm_offset_t ksym_end;
#endif
preload_metadata = (caddr_t)(uintptr_t)(modulep + KERNBASE);
preload_bootstrap_relocate(KERNBASE);
@ -1834,6 +1835,7 @@ native_parse_preload_data(u_int64_t modulep)
#ifdef DDB
ksym_start = MD_FETCH(kmdp, MODINFOMD_SSYM, uintptr_t);
ksym_end = MD_FETCH(kmdp, MODINFOMD_ESYM, uintptr_t);
db_fetch_ksymtab(ksym_start, ksym_end);
#endif
return (kmdp);

15
sys/arm/arm/machdep.c
View File

@ -111,6 +111,10 @@ __FBSDID("$FreeBSD$");
#include <dev/ofw/openfirm.h>
#endif
#ifdef DDB
#include <ddb/ddb.h>
#endif
#ifdef DEBUG
#define debugf(fmt, args...) printf(fmt, ##args)
#else
@ -131,9 +135,6 @@ int _min_memcpy_size = 0;
int _min_bzero_size = 0;
extern int *end;
#ifdef DDB
extern vm_offset_t ksym_start, ksym_end;
#endif
#ifdef FDT
/*
@ -817,8 +818,7 @@ fake_preload_metadata(struct arm_boot_params *abp __unused)
lastaddr = *(uint32_t *)(KERNVIRTADDR + 8);
zend = lastaddr;
zstart = *(uint32_t *)(KERNVIRTADDR + 4);
ksym_start = zstart;
ksym_end = zend;
db_fetch_ksymtab(zstart, zend);
} else
#endif
lastaddr = (vm_offset_t)&end;
@ -912,6 +912,10 @@ freebsd_parse_boot_param(struct arm_boot_params *abp)
vm_offset_t lastaddr = 0;
void *mdp;
void *kmdp;
#ifdef DDB
vm_offset_t ksym_start;
vm_offset_t ksym_end;
#endif
/*
* Mask metadata pointer: it is supposed to be on page boundary. If
@ -934,6 +938,7 @@ freebsd_parse_boot_param(struct arm_boot_params *abp)
#ifdef DDB
ksym_start = MD_FETCH(kmdp, MODINFOMD_SSYM, uintptr_t);
ksym_end = MD_FETCH(kmdp, MODINFOMD_ESYM, uintptr_t);
db_fetch_ksymtab(ksym_start, ksym_end);
#endif
preload_addr_relocate = KERNVIRTADDR - abp->abp_physaddr;
return lastaddr;

48
sys/ddb/db_main.c
View File

@ -56,7 +56,12 @@ static dbbe_trace_thread_f db_trace_thread_wrapper;
KDB_BACKEND(ddb, db_init, db_trace_self_wrapper, db_trace_thread_wrapper,
db_trap);
vm_offset_t ksym_start, ksym_end;
/*
* Symbols can be loaded by specifying the exact addresses of
* the symtab and strtab in memory. This is used when loaded from
* boot loaders different than the native one (like Xen).
*/
vm_offset_t ksymtab, kstrtab, ksymtab_size;
boolean_t
X_db_line_at_pc(db_symtab_t *symtab, c_db_sym_t sym, char **file, int *line,
@ -168,24 +173,39 @@ X_db_symbol_values(db_symtab_t *symtab, c_db_sym_t sym, const char **namep,
}
}
int
db_fetch_ksymtab(vm_offset_t ksym_start, vm_offset_t ksym_end)
{
Elf_Size strsz;
if (ksym_end > ksym_start && ksym_start != 0) {
ksymtab = ksym_start;
ksymtab_size = *(Elf_Size*)ksymtab;
ksymtab += sizeof(Elf_Size);
kstrtab = ksymtab + ksymtab_size;
strsz = *(Elf_Size*)kstrtab;
kstrtab += sizeof(Elf_Size);
if (kstrtab + strsz > ksym_end) {
/* Sizes doesn't match, unset everything. */
ksymtab = ksymtab_size = kstrtab = 0;
}
}
if (ksymtab == 0 || ksymtab_size == 0 || kstrtab == 0)
return (-1);
return (0);
}
static int
db_init(void)
{
uintptr_t symtab, strtab;
Elf_Size tabsz, strsz;
db_command_init();
if (ksym_end > ksym_start && ksym_start != 0) {
symtab = ksym_start;
tabsz = *((Elf_Size*)symtab);
symtab += sizeof(Elf_Size);
strtab = symtab + tabsz;
strsz = *((Elf_Size*)strtab);
strtab += sizeof(Elf_Size);
if (strtab + strsz <= ksym_end) {
db_add_symbol_table((char *)symtab,
(char *)(symtab + tabsz), "elf", (char *)strtab);
}
if (ksymtab != 0 && kstrtab != 0 && ksymtab_size != 0) {
db_add_symbol_table((char *)ksymtab,
(char *)(ksymtab + ksymtab_size), "elf", (char *)kstrtab);
}
db_add_symbol_table(NULL, NULL, "kld", NULL);
return (1); /* We're the default debugger. */

8
sys/ddb/ddb.h
View File

@ -76,6 +76,13 @@ SYSCTL_DECL(_debug_ddb);
int DB_CALL(db_expr_t, db_expr_t *, int, db_expr_t[]);
#endif
/*
* Extern variables to set the address and size of the symtab and strtab.
* Most users should use db_fetch_symtab in order to set them from the
* boot loader provided values.
*/
extern vm_offset_t ksymtab, kstrtab, ksymtab_size;
/*
* There are three "command tables":
* - One for simple commands; a list of these is displayed
@ -218,6 +225,7 @@ int db_value_of_name_vnet(const char *name, db_expr_t *valuep);
int db_write_bytes(vm_offset_t addr, size_t size, char *data);
void db_command_register(struct command_table *, struct command *);
void db_command_unregister(struct command_table *, struct command *);
int db_fetch_ksymtab(vm_offset_t ksym_start, vm_offset_t ksym_end);
db_cmdfcn_t db_breakpoint_cmd;
db_cmdfcn_t db_capture_cmd;

10
sys/i386/i386/machdep.c
View File

@ -197,10 +197,6 @@ static void fill_fpregs_xmm(struct savexmm *, struct save87 *);
#endif /* CPU_ENABLE_SSE */
SYSINIT(cpu, SI_SUB_CPU, SI_ORDER_FIRST, cpu_startup, NULL);
#ifdef DDB
extern vm_offset_t ksym_start, ksym_end;
#endif
/* Intel ICH registers */
#define ICH_PMBASE 0x400
#define ICH_SMI_EN ICH_PMBASE + 0x30
@ -2736,8 +2732,7 @@ init386(first)
#endif
#ifdef DDB
ksym_start = bootinfo.bi_symtab;
ksym_end = bootinfo.bi_esymtab;
db_fetch_ksymtab(bootinfo.bi_symtab, bootinfo.bi_esymtab);
#endif
kdb_init();
@ -3013,8 +3008,7 @@ init386(first)
#endif
#ifdef DDB
ksym_start = bootinfo.bi_symtab;
ksym_end = bootinfo.bi_esymtab;
db_fetch_ksymtab(bootinfo.bi_symtab, bootinfo.bi_esymtab);
#endif
kdb_init();

6
sys/mips/mips/machdep.c
View File

@ -167,9 +167,6 @@ extern char MipsCache[], MipsCacheEnd[];
extern char MipsWaitStart[], MipsWaitEnd[];
extern char edata[], end[];
#ifdef DDB
extern vm_offset_t ksym_start, ksym_end;
#endif
u_int32_t bootdev;
struct bootinfo bootinfo;
@ -434,6 +431,8 @@ mips_postboot_fixup(void)
#ifdef DDB
Elf_Size *trampoline_data = (Elf_Size*)kernel_kseg0_end;
Elf_Size symtabsize = 0;
vm_offset_t ksym_start;
vm_offset_t ksym_end;
if (trampoline_data[0] == SYMTAB_MAGIC) {
symtabsize = trampoline_data[1];
@ -443,6 +442,7 @@ mips_postboot_fixup(void)
kernel_kseg0_end += symtabsize;
/* end of .strtab */
ksym_end = kernel_kseg0_end;
db_fetch_ksymtab(ksym_start, ksym_end);
}
#endif
}

7
sys/pc98/pc98/machdep.c
View File

@ -169,10 +169,6 @@ SYSINIT(cpu, SI_SUB_CPU, SI_ORDER_FIRST, cpu_startup, NULL);
int need_pre_dma_flush; /* If 1, use wbinvd befor DMA transfer. */
int need_post_dma_flush; /* If 1, use invd after DMA transfer. */
#ifdef DDB
extern vm_offset_t ksym_start, ksym_end;
#endif
int _udatasel, _ucodesel;
u_int basemem;
@ -2298,8 +2294,7 @@ init386(first)
#endif
#ifdef DDB
ksym_start = bootinfo.bi_symtab;
ksym_end = bootinfo.bi_esymtab;
db_fetch_ksymtab(bootinfo.bi_symtab,bootinfo.bi_esymtab);
#endif
kdb_init();

9
sys/powerpc/aim/machdep.c
View File

@ -129,10 +129,6 @@ __FBSDID("$FreeBSD$");
#include <dev/ofw/openfirm.h>
#ifdef DDB
extern vm_offset_t ksym_start, ksym_end;
#endif
int cold = 1;
#ifdef __powerpc64__
extern int n_slbs;
@ -268,6 +264,10 @@ powerpc_init(vm_offset_t startkernel, vm_offset_t endkernel,
#ifndef __powerpc64__
int ppc64;
#endif
#ifdef DDB
vm_offset_t ksym_start;
vm_offset_t ksym_end;
#endif
kmdp = NULL;
trap_offset = 0;
@ -302,6 +302,7 @@ powerpc_init(vm_offset_t startkernel, vm_offset_t endkernel,
#ifdef DDB
ksym_start = MD_FETCH(kmdp, MODINFOMD_SSYM, uintptr_t);
ksym_end = MD_FETCH(kmdp, MODINFOMD_ESYM, uintptr_t);
db_fetch_ksymtab(ksym_start, ksym_end);
#endif
}
}

7
sys/powerpc/booke/machdep.c
View File

@ -142,7 +142,7 @@ __FBSDID("$FreeBSD$");
#include <dev/ofw/openfirm.h>
#ifdef DDB
extern vm_offset_t ksym_start, ksym_end;
#include <ddb/ddb.h>
#endif
#ifdef DEBUG
@ -300,6 +300,10 @@ booke_init(uint32_t arg1, uint32_t arg2)
struct pcpu *pc;
void *kmdp, *mdp;
vm_offset_t dtbp, end;
#ifdef DDB
vm_offset_t ksym_start;
vm_offset_t ksym_end;
#endif
kmdp = NULL;
@ -360,6 +364,7 @@ booke_init(uint32_t arg1, uint32_t arg2)
#ifdef DDB
ksym_start = MD_FETCH(kmdp, MODINFOMD_SSYM, uintptr_t);
ksym_end = MD_FETCH(kmdp, MODINFOMD_ESYM, uintptr_t);
db_fetch_ksymtab(ksym_start, ksym_end);
#endif
}
} else {

4
sys/sparc64/sparc64/machdep.c
View File

@ -114,10 +114,6 @@ __FBSDID("$FreeBSD$");
typedef int ofw_vec_t(void *);
#ifdef DDB
extern vm_offset_t ksym_start, ksym_end;
#endif
int dtlb_slots;
int itlb_slots;
struct tlb_entry *kernel_tlbs;

79
sys/x86/xen/pv.c
View File

@ -29,12 +29,15 @@
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_ddb.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>
@ -66,6 +69,10 @@ __FBSDID("$FreeBSD$");
#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 */
@ -93,6 +100,12 @@ extern int bootAP;
extern char *bootSTK;
#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 = {
@ -297,6 +310,68 @@ xen_pv_set_boothowto(void)
}
}
#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)
{
@ -304,6 +379,10 @@ xen_pv_parse_preload_data(u_int64_t modulep)
xen_pv_set_env();
xen_pv_set_boothowto();
#ifdef DDB
xen_pv_parse_symtab();
#endif
return (NULL);
}