/*
* Kernel Debugger Architecture Dependent Stack Traceback
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (c) 1999-2004 Silicon Graphics, Inc. All Rights Reserved.
*/
#include <linux/config.h>
#include <linux/ctype.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/kallsyms.h>
#include <linux/kdb.h>
#include <linux/kdbprivate.h>
#include <asm/system.h>
/*
* bt_print_one
*
* Print one back trace entry.
*
* Inputs:
* ip Current program counter.
* symtab Information about symbol that ip falls within.
* ar Activation record for this frame.
* argcount Maximum number of arguments to print.
* Outputs:
* None.
* Returns:
* None.
* Locking:
* None.
* Remarks:
* None.
*/
static void
bt_print_one(kdb_machreg_t ip, const kdb_ar_t *ar,
const kdb_symtab_t *symtab, int argcount,
struct unw_frame_info *info /* FIXME: should be part of ar for ia64 */)
{
int btsymarg = 0; /* Convert arguments to symbols */
int btsp = 0; /* Print stack and backing store pointers */
int nosect = 0; /* Suppress section data */
kdb_machreg_t sp, bsp, cfm; /* FIXME: should be part of ar for ia64 */
kdbgetintenv("BTSYMARG", &btsymarg);
kdbgetintenv("BTSP", &btsp);
kdbgetintenv("NOSECT", &nosect);
unw_get_sp(info, &sp); /* FIXME: should be part of ar for ia64 */
unw_get_bsp(info, &bsp); /* FIXME: should be part of ar for ia64 */
unw_get_cfm(info, &cfm); /* FIXME: info/cfm should be part of ar for ia64 */
kdb_symbol_print(ip, symtab, KDB_SP_VALUE|KDB_SP_NEWLINE);
/* FIXME: number of args should be set in prologue code */
((kdb_ar_t *)ar)->args = (cfm >> 7) & 0x7f; /* sol */
if (!ar->args)
((kdb_ar_t *)ar)->args = cfm & 0x7f; /* no in/local, use sof instead */
if (argcount && ar->args) {
int i, argc = ar->args;
kdb_printf(" args (");
if (argc > argcount)
argc = argcount;
for(i = 0; i < argc; i++){
/* FIXME: prologue code should extract arguments */
kdb_machreg_t arg;
char nat;
if (unw_access_gr(info, i+32, &arg, &nat, 0))
arg = 0;
if (i)
kdb_printf(", ");
kdb_printf("0x%lx", arg);
}
kdb_printf(")\n");
if (btsymarg) {
kdb_symtab_t arg_symtab;
kdb_machreg_t arg;
for(i = 0; i < argc; i++){
/* FIXME: prologue code should extract arguments */
char nat;
if (unw_access_gr(info, i+32, &arg, &nat, 0))
arg = 0;
if (kdbnearsym(arg, &arg_symtab)) {
kdb_printf(" arg %d ", i);
kdb_symbol_print(arg, &arg_symtab, KDB_SP_DEFAULT|KDB_SP_NEWLINE);
}
}
}
}
if (symtab->sym_name) {
if (!nosect) {
kdb_printf(" %s", symtab->mod_name);
if (symtab->sec_name)
kdb_printf(" %s 0x%lx", symtab->sec_name, symtab->sec_start);
kdb_printf(" 0x%lx", symtab->sym_start);
if (symtab->sym_end)
kdb_printf(" 0x%lx", symtab->sym_end);
kdb_printf("\n");
}
if (strncmp(symtab->sym_name, "ia64_spinlock_contention", 24) == 0) {
kdb_machreg_t r31;
char nat;
kdb_printf(" r31 (spinlock address) ");
if (unw_access_gr(info, 31, &r31, &nat, 0))
r31 = 0;
kdb_symbol_print(r31, NULL, KDB_SP_VALUE|KDB_SP_NEWLINE);
}
}
if (btsp)
kdb_printf(" sp 0x%016lx bsp 0x%016lx cfm 0x%016lx info->pfs_loc 0x%016lx 0x%016lx\n",
sp, bsp, cfm, (u64) info->pfs_loc, info->pfs_loc ? *(info->pfs_loc) : 0);
}
/*
* kdba_bt_stack
*
* Unwind the ia64 backtrace for a specified process.
*
* Inputs:
* argcount
* p Pointer to task structure to unwind.
* Outputs:
* None.
* Returns:
* zero for success, a kdb diagnostic if error
* Locking:
* none.
* Remarks:
* none.
*/
static int
kdba_bt_stack(int argcount, struct task_struct *p)
{
kdb_symtab_t symtab;
kdb_ar_t ar;
struct unw_frame_info info; /* FIXME: should be part of ar */
struct switch_stack *sw; /* FIXME: should be part of ar */
struct pt_regs *regs = NULL; /* FIXME: should be part of ar */
int count = 0;
int btsp = 0; /* Backtrace the kdb code as well */
u64 *prev_pfs_loc = NULL;
extern char __attribute__ ((weak)) ia64_spinlock_contention_pre3_4[];
extern char __attribute__ ((weak)) ia64_spinlock_contention_pre3_4_end[];
extern char ia64_ivt[];
/* FIXME: All the arch specific code should be in activation records, not here */
memset(&ar, 0, sizeof(ar));
/*
* Upon entering kdb_main_loop, the stack frame looks like this:
*
* +---------------------+
* | struct pt_regs |
* +---------------------+
* | |
* | kernel stack |
* | |
* +=====================+ <--- top of stack upon entering kdb
* | struct pt_regs |
* +---------------------+
* | |
* | kdb stack |
* | |
* +---------------------+
* | struct switch_stack |
* +=====================+ <--- kdb_running_process[cpu].arch.sw from do_kdba_main_loop
*
* When looking at another process, we do not have the address of the
* current pt_regs, it is NULL. If the process has saved its state, use
* that pt_regs instead.
*/
kdbgetintenv("BTSP", &btsp);
if (kdb_task_has_cpu(p)) {
struct kdb_running_process *krp = kdb_running_process + kdb_process_cpu(p);
if (krp->seqno) {
sw = krp->arch.sw;
regs = krp->regs;
}
else
sw = NULL;
}
else {
/* Not running, assume blocked */
sw = (struct switch_stack *) (p->thread.ksp + 16);
}
if (!sw) {
kdb_printf("Process does not have a switch_stack, cannot backtrace\n");
kdb_ps1(p);
return 0;
}
unw_init_frame_info(&info, p, sw); /* FIXME: should be using activation records */
/* If we have the address of pt_regs, suppress backtrace on the frames below
* pt_regs. No point in displaying kdb itself, unless the user is debugging
* the unwinder using set BTSP=1.
*/
if (regs && !btsp) {
kdb_machreg_t sp; /* FIXME: should be part of ar for ia64 */
if (user_mode(regs)) {
kdb_printf("Process was interrupted in user mode, no backtrace available\n");
return 0;
}
do {
unw_get_sp(&info, &sp);
if (sp >= (kdb_machreg_t)regs)
break;
} while (unw_unwind(&info) >= 0 && count++ < 200); /* FIXME: should be using activation records */
}
do {
kdb_machreg_t ip;
/* Avoid unsightly console message from unw_unwind() when attempting
* to unwind through the Interrupt Vector Table which has no unwind
* information.
*/
if (info.ip >= (u64)ia64_ivt && info.ip < (u64)ia64_ivt+32768)
return 0;
/* WAR for spinlock contention from leaf functions. ia64_spinlock_contention_pre3_4
* has ar.pfs == r0. Leaf functions do not modify ar.pfs so ar.pfs remains
* as 0, stopping the backtrace. Record the previous ar.pfs when the current
* IP is in ia64_spinlock_contention_pre3_4 then unwind, if pfs_loc has not changed
* after unwind then use pt_regs.ar_pfs which is where the real ar.pfs is for
* leaf functions.
*/
if (prev_pfs_loc && regs && info.pfs_loc == prev_pfs_loc)
info.pfs_loc = ®s->ar_pfs;
prev_pfs_loc = (info.ip >= (u64)ia64_spinlock_contention_pre3_4 &&
info.ip < (u64)ia64_spinlock_contention_pre3_4_end) ?
info.pfs_loc : NULL;
unw_get_ip(&info, &ip); /* FIXME: should be using activation records */
if (ip == 0)
break;
kdbnearsym(ip, &symtab);
if (!symtab.sym_name) {
kdb_printf("0x%0*lx - No name. May be an area that has no unwind data\n",
(int)(2*sizeof(ip)), ip);
return 0;
}
bt_print_one(ip, &ar, &symtab, argcount, &info);
} while (unw_unwind(&info) >= 0 && count++ < 200); /* FIXME: should be using activation records */
if (count >= 200)
kdb_printf("bt truncated, count limit reached\n");
return 0;
}
int
kdba_bt_address(kdb_machreg_t addr, int argcount)
{
kdb_printf("Backtrace from a stack address is not supported on ia64\n");
return KDB_NOTIMP;
}
/*
* kdba_bt_process
*
* Do a backtrace for a specified process.
*
* Inputs:
* p Struct task pointer extracted by 'bt' command.
* argcount
* Outputs:
* None.
* Returns:
* zero for success, a kdb diagnostic if error
* Locking:
* none.
*/
int
kdba_bt_process(struct task_struct *p, int argcount)
{
return kdba_bt_stack(argcount, p);
}
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