EliasFleckenstein03
/
plan9front
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

snap: use Mach->szaddr as the width of the stack pointer (fixes snap on amd64) 

to read the value of the stack pointer register, snap
used Machdata->szreg to determine the width of the
SP register in the Ureg structure. however, the value
does not match the Ureg.sp type for a number of architectures
(mips2, amd64) and it is unclear if this was an oversight
as it is rarely used (snap is indeed the only user) or
if it was intended for a different purpose.

so we use szaddr instead which matches the stack pointer
width in the Ureg and fixes the truncated stack issue on
amd64.
front
cinap_lenrek 2018-11-22 20:27:27 +01:00
parent 6bd0764167
commit 434de8db8d
1 changed files with 3 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
sys/src/cmd/snap/take.c
View File

@ -166,18 +166,17 @@ stackptr(Proc *proc, int fd)
if((dreg = proc->d[Pregs]) == nil)
return 0;
if(r->roffs+mach->szreg > dreg->len) {
if(r->roffs+mach->szaddr > dreg->len) {
fprint(2, "SP register too far into registers?\n");
return 0;
}
q = dreg->data+r->roffs;
switch(mach->szreg) {
case 2: return machdata->swab(*(ushort*)q);
switch(mach->szaddr) {
case 4: return machdata->swal(*(ulong*)q);
case 8: return machdata->swav(*(uvlong*)q);
default:
fprint(2, "register size is %d bytes?\n", mach->szreg);
fprint(2, "address size is %d bytes?\n", mach->szaddr);
return 0;
}
}