* [PATCH] gdbserver: Clear X86_XSTATE_MPX bits in xcr0 on x32
[not found] <20240319152558.45742-1-hjl.tools@gmail.com>
@ 2024-03-19 18:36 ` H.J. Lu
2024-03-20 8:40 ` Willgerodt, Felix
0 siblings, 1 reply; 3+ messages in thread
From: H.J. Lu @ 2024-03-19 18:36 UTC (permalink / raw)
To: GDB, John Baldwin, Felix Willgerodt
Since MPX isn't available for x32, we should clear X86_XSTATE_MPX bits
on x32.
PR server/31511
* linux-x86-low.cc (x86_linux_read_description): Clear
X86_XSTATE_MPX bits in xcr0 on x32.
---
gdbserver/linux-x86-low.cc | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/gdbserver/linux-x86-low.cc b/gdbserver/linux-x86-low.cc
index 3af0a009052..28b5d523b8e 100644
--- a/gdbserver/linux-x86-low.cc
+++ b/gdbserver/linux-x86-low.cc
@@ -938,6 +938,10 @@ x86_linux_read_description (void)
xcr0 = xstateregs[(I386_LINUX_XSAVE_XCR0_OFFSET
/ sizeof (uint64_t))];
+ /* No MPX on x32. */
+ if (!is_elf64)
+ xcr0 &= ~X86_XSTATE_MPX;
+
xsave_len = x86_xsave_length ();
/* Use PTRACE_GETREGSET if it is available. */
--
2.44.0
--
H.J.
^ permalink raw reply [flat|nested] 3+ messages in thread
* RE: [PATCH] gdbserver: Clear X86_XSTATE_MPX bits in xcr0 on x32
2024-03-19 18:36 ` [PATCH] gdbserver: Clear X86_XSTATE_MPX bits in xcr0 on x32 H.J. Lu
@ 2024-03-20 8:40 ` Willgerodt, Felix
2024-03-20 10:48 ` H.J. Lu
0 siblings, 1 reply; 3+ messages in thread
From: Willgerodt, Felix @ 2024-03-20 8:40 UTC (permalink / raw)
To: H.J. Lu, GDB, John Baldwin
> -----Original Message-----
> From: H.J. Lu <hjl.tools@gmail.com>
> Sent: Dienstag, 19. März 2024 19:36
> To: GDB <gdb-patches@sourceware.org>; John Baldwin <jhb@freebsd.org>;
> Willgerodt, Felix <felix.willgerodt@intel.com>
> Subject: [PATCH] gdbserver: Clear X86_XSTATE_MPX bits in xcr0 on x32
>
> Since MPX isn't available for x32, we should clear X86_XSTATE_MPX bits
> on x32.
>
> PR server/31511
> * linux-x86-low.cc (x86_linux_read_description): Clear
> X86_XSTATE_MPX bits in xcr0 on x32.
> ---
> gdbserver/linux-x86-low.cc | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/gdbserver/linux-x86-low.cc b/gdbserver/linux-x86-low.cc
> index 3af0a009052..28b5d523b8e 100644
> --- a/gdbserver/linux-x86-low.cc
> +++ b/gdbserver/linux-x86-low.cc
> @@ -938,6 +938,10 @@ x86_linux_read_description (void)
> xcr0 = xstateregs[(I386_LINUX_XSAVE_XCR0_OFFSET
> / sizeof (uint64_t))];
>
> + /* No MPX on x32. */
> + if (!is_elf64)
> + xcr0 &= ~X86_XSTATE_MPX;
> +
Doesn't that also disable it for 32-bit?
x86_target::low_siginfo_fixup() uses this to check x32:
/* No fixup for native x32 GDB. */
else if (!is_elf64 && sizeof (void *) == 8)
Felix
Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] gdbserver: Clear X86_XSTATE_MPX bits in xcr0 on x32
2024-03-20 8:40 ` Willgerodt, Felix
@ 2024-03-20 10:48 ` H.J. Lu
0 siblings, 0 replies; 3+ messages in thread
From: H.J. Lu @ 2024-03-20 10:48 UTC (permalink / raw)
To: Willgerodt, Felix; +Cc: GDB, John Baldwin
On Wed, Mar 20, 2024 at 1:40 AM Willgerodt, Felix
<felix.willgerodt@intel.com> wrote:
>
> > -----Original Message-----
> > From: H.J. Lu <hjl.tools@gmail.com>
> > Sent: Dienstag, 19. März 2024 19:36
> > To: GDB <gdb-patches@sourceware.org>; John Baldwin <jhb@freebsd.org>;
> > Willgerodt, Felix <felix.willgerodt@intel.com>
> > Subject: [PATCH] gdbserver: Clear X86_XSTATE_MPX bits in xcr0 on x32
> >
> > Since MPX isn't available for x32, we should clear X86_XSTATE_MPX bits
> > on x32.
> >
> > PR server/31511
> > * linux-x86-low.cc (x86_linux_read_description): Clear
> > X86_XSTATE_MPX bits in xcr0 on x32.
> > ---
> > gdbserver/linux-x86-low.cc | 4 ++++
> > 1 file changed, 4 insertions(+)
> >
> > diff --git a/gdbserver/linux-x86-low.cc b/gdbserver/linux-x86-low.cc
> > index 3af0a009052..28b5d523b8e 100644
> > --- a/gdbserver/linux-x86-low.cc
> > +++ b/gdbserver/linux-x86-low.cc
> > @@ -938,6 +938,10 @@ x86_linux_read_description (void)
> > xcr0 = xstateregs[(I386_LINUX_XSAVE_XCR0_OFFSET
> > / sizeof (uint64_t))];
> >
> > + /* No MPX on x32. */
> > + if (!is_elf64)
> > + xcr0 &= ~X86_XSTATE_MPX;
> > +
>
> Doesn't that also disable it for 32-bit?
Fixed in the v2 patch with
+ /* No MPX on x32. */
+ if (machine == EM_X86_64 && !is_elf64)
+ xcr0 &= ~X86_XSTATE_MPX;
+
> x86_target::low_siginfo_fixup() uses this to check x32:
>
> /* No fixup for native x32 GDB. */
> else if (!is_elf64 && sizeof (void *) == 8)
>
>
Thanks.
--
H.J.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2024-03-19 18:36 ` [PATCH] gdbserver: Clear X86_XSTATE_MPX bits in xcr0 on x32 H.J. Lu
2024-03-20 8:40 ` Willgerodt, Felix
2024-03-20 10:48 ` H.J. Lu
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