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db_nextframe/i386: reduce the number of special frame types

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This change removes TRAP_INTERRUPT and TRAP_TIMERINT frame types.

Their names are a bit confusing: trap + interrupt, what is that?
The TRAP_TIMERINT name is too specific -- can it only be used for timer
"trap-interrupts"?  What is so special about them?

My understanding of the code is that INTERRUPT, TRAP_INTERRUPT and
TRAP_TIMERINT differ only in how an offset from callee's frame pointer to a
trap frame on the stack is calculated.  And that depends on a number of
arguments that a special handler passes to a callee (a function with a
normal C calling convention).

So, this change makes that logic explicit and collapses all interrupt frame
types into the INTERRUPT type.

Reviewed by:	markj
Discussed with:	kib, jhb
MFC after:	3 weeks
Differential Revision: https://reviews.freebsd.org/D22303
This commit is contained in:
Andriy Gapon 2019-11-11 19:06:04 +00:00
parent a600a25e3e
commit 7aff07d914
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=354627
1 changed files with 25 additions and 20 deletions
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45
sys/i386/i386/db_trace.c
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@ -191,8 +191,6 @@ db_ss(struct db_variable *vp, db_expr_t *valuep, int op)
#define INTERRUPT 2
#define SYSCALL 3
#define DOUBLE_FAULT 4
#define TRAP_INTERRUPT 5
#define TRAP_TIMERINT 6
static void db_nextframe(struct i386_frame **, db_addr_t *, struct thread *);
static int db_numargs(struct i386_frame *);
@ -299,6 +297,7 @@ db_nextframe(struct i386_frame **fp, db_addr_t *ip, struct thread *td)
{
struct trapframe *tf;
int frame_type;
int narg;
int eip, esp, ebp;
db_expr_t offset;
c_db_sym_t sym;
@ -317,6 +316,15 @@ db_nextframe(struct i386_frame **fp, db_addr_t *ip, struct thread *td)
* actually made the call.
*/
frame_type = NORMAL;
/*
* This is the number of arguments that a syscall / trap / interrupt
* service routine passes to its callee. This number is used only for
* special frame types. In most cases there is one argument: the trap
* frame address.
*/
narg = 1;
if (eip >= PMAP_TRM_MIN_ADDRESS) {
sym = db_search_symbol(eip - 1 - setidt_disp, DB_STGY_ANY,
&offset);
@ -329,20 +337,24 @@ db_nextframe(struct i386_frame **fp, db_addr_t *ip, struct thread *td)
strcmp(name, "fork_trampoline") == 0)
frame_type = TRAP;
else if (strncmp(name, "Xatpic_intr", 11) == 0 ||
strncmp(name, "Xapic_isr", 9) == 0)
strncmp(name, "Xapic_isr", 9) == 0) {
/* Additional argument: vector number. */
narg = 2;
frame_type = INTERRUPT;
else if (strcmp(name, "Xlcall_syscall") == 0 ||
} else if (strcmp(name, "Xlcall_syscall") == 0 ||
strcmp(name, "Xint0x80_syscall") == 0)
frame_type = SYSCALL;
else if (strcmp(name, "dblfault_handler") == 0)
frame_type = DOUBLE_FAULT;
/* XXX: These are interrupts with trap frames. */
else if (strcmp(name, "Xtimerint") == 0)
frame_type = TRAP_TIMERINT;
frame_type = INTERRUPT;
else if (strcmp(name, "Xcpustop") == 0 ||
strcmp(name, "Xrendezvous") == 0 ||
strcmp(name, "Xipi_intr_bitmap_handler") == 0)
frame_type = TRAP_INTERRUPT;
strcmp(name, "Xipi_intr_bitmap_handler") == 0) {
/* No arguments. */
narg = 0;
frame_type = INTERRUPT;
}
}
/*
@ -375,14 +387,11 @@ db_nextframe(struct i386_frame **fp, db_addr_t *ip, struct thread *td)
/*
* Point to base of trapframe which is just above the
* current frame.
* current frame. Note that struct i386_frame already accounts for one
* argument.
*/
if (frame_type == INTERRUPT)
tf = (struct trapframe *)((int)*fp + 16);
else if (frame_type == TRAP_INTERRUPT)
tf = (struct trapframe *)((int)*fp + 8);
else
tf = (struct trapframe *)((int)*fp + 12);
tf = (struct trapframe *)((char *)*fp + sizeof(struct i386_frame) +
4 * (narg - 1));
esp = get_esp(tf);
eip = tf->tf_eip;
@ -395,8 +404,6 @@ db_nextframe(struct i386_frame **fp, db_addr_t *ip, struct thread *td)
db_printf("--- syscall");
decode_syscall(tf->tf_eax, td);
break;
case TRAP_TIMERINT:
case TRAP_INTERRUPT:
case INTERRUPT:
db_printf("--- interrupt");
break;
@ -407,8 +414,6 @@ db_nextframe(struct i386_frame **fp, db_addr_t *ip, struct thread *td)
switch (frame_type) {
case TRAP:
case TRAP_TIMERINT:
case TRAP_INTERRUPT:
case INTERRUPT:
if ((tf->tf_eflags & PSL_VM) != 0 ||
(tf->tf_cs & SEL_RPL_MASK) != 0)
@ -418,7 +423,7 @@ db_nextframe(struct i386_frame **fp, db_addr_t *ip, struct thread *td)
ebp = 0;
break;
}
*ip = (db_addr_t) eip;
*fp = (struct i386_frame *) ebp;
}