NetBSD Problem Report #54185
From mgorny@pomiocikbsd.local Thu May 9 16:47:47 2019
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Date: Thu, 9 May 2019 07:10:37 +0200 (CEST)
From: mgorny@NetBSD.org
Reply-To: mgorny@NetBSD.org
To: gnats-bugs@NetBSD.org
Subject: PT_{G,S}ETXMMREGS not implemented in compat32
X-Send-Pr-Version: 3.95
>Number: 54185
>Category: port-amd64
>Synopsis: PT_{G,S}ETXMMREGS ptrace() requests are not implemented in compat32 on amd64
>Confidential: no
>Severity: non-critical
>Priority: low
>Responsible: port-amd64-maintainer
>State: open
>Class: sw-bug
>Submitter-Id: net
>Arrival-Date: Thu May 09 16:50:00 +0000 2019
>Originator: Michał Górny
>Release: NetBSD 8.99.37
>Organization:
NetBSD
>Environment:
System: NetBSD pomiocikbsd.local 8.99.37 NetBSD 8.99.37 (GENERIC) #0: Fri May 3 22:06:59 CEST 2019 root@pomiocikbsd.local:/usr/obj/sys/arch/amd64/compile/GENERIC amd64
Architecture: x86_64
Machine: amd64
>Description:
It seems that the PT_GETXMMREGS and PT_SETXMMREGS ptrace() requests
are not implemented in compat32 of amd64 kernel. When trying to run
a test I've written for i386, I get the following failure:
failed: /usr/src/tests/lib/libc/sys/t_ptrace_x86_wait.h:2438:
ptrace(PT_GETXMMREGS, child, &fpr, 0) != -1: Not supported
With PT_GETFPREGS correctly emulating i386 API, this makes it
impossible to query XMM registers of a 32-bit program via ptrace
(unless I'm mistaken).
>How-To-Repeat:
cat > test.c <<EOF
#include <sys/types.h>
#include <sys/ptrace.h>
#include <sys/wait.h>
#undef _NDEBUG
#include <assert.h>
#include <signal.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
int main()
{
char out[512];
int ret;
int pid;
int st;
pid = fork();
assert(pid != -1);
if (pid == 0)
{
assert(ptrace(PT_TRACE_ME, 0, NULL, 0) != -1);
raise(SIGSTOP);
_exit(0);
}
assert(wait(&st) == pid);
ret = ptrace(PT_GETXMMREGS, pid, out, 0);
if (ret == -1)
perror("ptrace(PT_GETXMMREGS) failed");
return 0;
}
EOF
cc -m32 test.c
./a.out
>Fix:
FTR, I don't consider this very important since I'll be working
on adding full xsave support via a new ptrace() request. When done,
it will probably render using i386-specific PT_GETXMMREGS unnecessary.
(Contact us)
$NetBSD: query-full-pr,v 1.43 2018/01/16 07:36:43 maya Exp $
$NetBSD: gnats_config.sh,v 1.9 2014/08/02 14:16:04 spz Exp $
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