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Re: [PATCH v3] Fix PTRACE_GETREGSET failure for compat inferiors on arm64
- From: Kees Cook <keescook at chromium dot org>
- To: gdb-patches at sourceware dot org
- Cc: Yao Qi <qiyaoltc at gmail dot com>, Doug Evans <dje at google dot com>, Brian Murray <brian dot murray at canonical dot com>, Matthias Klose <matthias dot klose at canonical dot com>
- Date: Thu, 26 Jan 2017 11:43:16 -0800
- Subject: Re: [PATCH v3] Fix PTRACE_GETREGSET failure for compat inferiors on arm64
- Authentication-results: sourceware.org; auth=none
- References: <20170119210015.GA87383@beast>
On Thu, Jan 19, 2017 at 1:00 PM, Kees Cook <keescook@chromium.org> wrote:
> When running a 32-bit ARM inferior with a 32-bit ARM GDB on a 64-bit
> AArch64 host, only VFP registers (NT_ARM_VFP) are available. The FPA
> registers (NT_PRFPREG) are not available so GDB must not request them, as
> this will fail with -EINVAL. This is most noticeably exposed when running
> "generate-core-file":
>
> (gdb) generate-core-file myprog.core
> Unable to fetch the floating point registers.: Invalid argument.
>
> ptrace(PTRACE_GETREGSET, 27642, NT_FPREGSET, 0xffcc67f0) = -1 EINVAL (Invalid argument)
>
> gdb/ChangeLog:
>
> 2016-12-19 Kees Cook <keescook@google.com>
>
> * gdb/arm-linux-nat.c: Skip soft-float registers when using hard-float.
Hi! Friendly ping on this patch. Are there any corrections to be made,
or can someone commit it?
Thanks!
-Kees
> ---
> v3:
> - argh, actually drop needless other change.
> v2:
> - check have_fpa_registers instead, dropped needless other change: qiyaoltc
> ---
> gdb/arm-linux-nat.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/gdb/arm-linux-nat.c b/gdb/arm-linux-nat.c
> index d11bdc6..4fa5204 100644
> --- a/gdb/arm-linux-nat.c
> +++ b/gdb/arm-linux-nat.c
> @@ -384,13 +384,14 @@ arm_linux_fetch_inferior_registers (struct target_ops *ops,
> if (-1 == regno)
> {
> fetch_regs (regcache);
> - fetch_fpregs (regcache);
> if (tdep->have_wmmx_registers)
> fetch_wmmx_regs (regcache);
> if (tdep->vfp_register_count > 0)
> fetch_vfp_regs (regcache);
> + if (tdep->have_fpa_registers)
> + fetch_fpregs (regcache);
> }
> - else
> + else
> {
> if (regno < ARM_F0_REGNUM || regno == ARM_PS_REGNUM)
> fetch_regs (regcache);
> @@ -420,11 +421,12 @@ arm_linux_store_inferior_registers (struct target_ops *ops,
> if (-1 == regno)
> {
> store_regs (regcache);
> - store_fpregs (regcache);
> if (tdep->have_wmmx_registers)
> store_wmmx_regs (regcache);
> if (tdep->vfp_register_count > 0)
> store_vfp_regs (regcache);
> + if (tdep->have_fpa_registers)
> + store_fpregs (regcache);
> }
> else
> {
> --
> 2.7.4
>
>
> --
> Kees Cook
> Nexus Security
--
Kees Cook
Nexus Security