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Use kgdb_parse() instead of libkvm(3) to read the first instruction from

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"calltrap" to see which method is used to pass trap frames.  This seg
faulted on remote gdb connections (where libkvm isn't used).

MFC after:	3 days
This commit is contained in:
John Baldwin 2008-04-28 18:27:19 +00:00
parent 2bc24aa956
commit 34f36b232b
1 changed files with 9 additions and 16 deletions
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25
gnu/usr.bin/gdb/kgdb/trgt_i386.c
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@ -299,22 +299,15 @@ kgdb_trgt_trapframe_prev_register(struct frame_info *next_frame,
*realnump = -1;
if (!ofs_fixed) {
uintptr_t calltrap_addr;
char calltrap[1];
calltrap_addr = kgdb_lookup("calltrap");
if (calltrap_addr != 0) {
if (kvm_read(kvm, calltrap_addr, calltrap,
sizeof(calltrap)) != sizeof(calltrap)) {
warnx("kvm_read: %s", kvm_geterr(kvm));
} else if (calltrap[0] == 0x54) /* push %esp */ {
/*
* To accomodate for rev. 1.117 of
* i386/i386/exception.s
*/
ofs_fix = 4;
}
}
/*
* In revision 1.117 of i386/i386/exception.S trap handlers
* were changed to pass trapframes by reference rather than
* by value. Detect this by seeing if the first instruction
* at the 'calltrap' label is a "push %esp" which has the
* opcode 0x54.
*/
if (kgdb_parse("((char *)calltrap)[0]") == 0x54)
ofs_fix = 4;
ofs_fixed = 1;
}
ofs = (regnum >= I386_EAX_REGNUM && regnum <= I386_FS_REGNUM)