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Remove some dead code from DDB's amd64 stack unwinder.

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The amd64 port copied some code from i386 to fetch function arguments and
display them in backtraces. However, it was commented out and can't easily
be implemented since the function arguments are passed in
registers rather than on the stack in amd64. Remove it in preparation for
some bug fixes in this area.

Reviewed by:	jhb
Sponsored by:	EMC / Isilon Storage Division
Differential Revision:	https://reviews.freebsd.org/D2857
This commit is contained in:
Mark Johnston 2015-07-21 23:03:21 +00:00
parent 300ca9a86e
commit 1a5bee0849
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=285773
1 changed files with 8 additions and 74 deletions
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82
sys/amd64/amd64/db_trace.c
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@ -188,9 +188,7 @@ db_ss(struct db_variable *vp, db_expr_t *valuep, int op)
#define TRAP_INTERRUPT 5
static void db_nextframe(struct amd64_frame **, db_addr_t *, struct thread *);
static int db_numargs(struct amd64_frame *);
static void db_print_stack_entry(const char *, int, char **, long *, db_addr_t,
void *);
static void db_print_stack_entry(const char *, db_addr_t, void *);
static void decode_syscall(int, struct thread *);
static const char * watchtype_str(int type);
@ -198,62 +196,11 @@ int amd64_set_watch(int watchnum, unsigned long watchaddr, int size,
int access, struct dbreg *d);
int amd64_clr_watch(int watchnum, struct dbreg *d);
/*
* Figure out how many arguments were passed into the frame at "fp".
*/
static int
db_numargs(fp)
struct amd64_frame *fp;
{
#if 1
return (0); /* regparm, needs dwarf2 info */
#else
long *argp;
int inst;
int args;
argp = (long *)db_get_value((long)&fp->f_retaddr, 8, FALSE);
/*
* XXX etext is wrong for LKMs. We should attempt to interpret
* the instruction at the return address in all cases. This
* may require better fault handling.
*/
if (argp < (long *)btext || argp >= (long *)etext) {
args = 5;
} else {
inst = db_get_value((long)argp, 4, FALSE);
if ((inst & 0xff) == 0x59) /* popl %ecx */
args = 1;
else if ((inst & 0xffff) == 0xc483) /* addl $Ibs, %esp */
args = ((inst >> 16) & 0xff) / 4;
else
args = 5;
}
return (args);
#endif
}
static void
db_print_stack_entry(name, narg, argnp, argp, callpc, frame)
const char *name;
int narg;
char **argnp;
long *argp;
db_addr_t callpc;
void *frame;
db_print_stack_entry(const char *name, db_addr_t callpc, void *frame)
{
db_printf("%s(", name);
#if 0
while (narg) {
if (argnp)
db_printf("%s=", *argnp++);
db_printf("%lr", (long)db_get_value((long)argp, 8, FALSE));
argp++;
if (--narg != 0)
db_printf(",");
}
#endif
db_printf(") at ");
db_printf("%s() at ", name);
db_printsym(callpc, DB_STGY_PROC);
if (frame != NULL)
db_printf("/frame 0x%lx", (register_t)frame);
@ -348,7 +295,7 @@ db_nextframe(struct amd64_frame **fp, db_addr_t *ip, struct thread *td)
return;
}
db_print_stack_entry(name, 0, 0, 0, rip, &(*fp)->f_frame);
db_print_stack_entry(name, rip, &(*fp)->f_frame);
/*
* Point to base of trapframe which is just above the
@ -388,13 +335,9 @@ db_backtrace(struct thread *td, struct trapframe *tf,
struct amd64_frame *frame, db_addr_t pc, int count)
{
struct amd64_frame *actframe;
#define MAXNARG 16
char *argnames[MAXNARG], **argnp = NULL;
const char *name;
long *argp;
db_expr_t offset;
c_db_sym_t sym;
int narg;
boolean_t first;
if (count == -1)
@ -444,22 +387,13 @@ db_backtrace(struct thread *td, struct trapframe *tf,
* Don't try to walk back on a stack for a
* process that hasn't actually been run yet.
*/
db_print_stack_entry(name, 0, 0, 0, pc,
actframe);
db_print_stack_entry(name, pc, actframe);
break;
}
first = FALSE;
}
argp = &actframe->f_arg0;
narg = MAXNARG;
if (sym != NULL && db_sym_numargs(sym, &narg, argnames)) {
argnp = argnames;
} else {
narg = db_numargs(frame);
}
db_print_stack_entry(name, narg, argnp, argp, pc, actframe);
db_print_stack_entry(name, pc, actframe);
if (actframe != frame) {
/* `frame' belongs to caller. */
@ -473,7 +407,7 @@ db_backtrace(struct thread *td, struct trapframe *tf,
if (INKERNEL((long)pc) && !INKERNEL((long)frame)) {
sym = db_search_symbol(pc, DB_STGY_ANY, &offset);
db_symbol_values(sym, &name, NULL);
db_print_stack_entry(name, 0, 0, 0, pc, frame);
db_print_stack_entry(name, pc, frame);
break;
}
if (!INKERNEL((long) frame)) {