From: Simon Marchi <simon.marchi@polymtl.ca>
To: John Baldwin <jhb@FreeBSD.org>, gdb-patches@sourceware.org
Subject: Re: [PATCH v6 08/15] gdb: Update x86 Linux architectures to support XSAVE layouts.
Date: Wed, 26 Jul 2023 16:45:17 -0400 [thread overview]
Message-ID: <45c8bfbf-42d2-c9d9-d246-0ffd6fc4668c@polymtl.ca> (raw)
In-Reply-To: <20230714155151.21723-9-jhb@FreeBSD.org>
> diff --git a/gdb/i386-linux-tdep.c b/gdb/i386-linux-tdep.c
> index 554c1455a5f..f27efbb1d59 100644
> --- a/gdb/i386-linux-tdep.c
> +++ b/gdb/i386-linux-tdep.c
> @@ -638,45 +638,51 @@ static int i386_linux_sc_reg_offset[] =
> 0 * 4 /* %gs */
> };
>
> -/* Get XSAVE extended state xcr0 from core dump. */
> +/* See i386-linux-tdep.h. */
>
> uint64_t
> -i386_linux_core_read_xcr0 (bfd *abfd)
> +i386_linux_core_read_xsave_info (bfd *abfd, x86_xsave_layout &layout)
> {
> asection *xstate = bfd_get_section_by_name (abfd, ".reg-xstate");
> - uint64_t xcr0;
> + if (xstate == nullptr)
> + return X86_XSTATE_SSE_MASK;
>
> - if (xstate)
> + /* Check extended state size. */
> + size_t size = bfd_section_size (xstate);
> + if (size < X86_XSTATE_AVX_SIZE)
> + return X86_XSTATE_SSE_MASK;
> +
> + char contents[8];
> + if (! bfd_get_section_contents (abfd, xstate, contents,
> + I386_LINUX_XSAVE_XCR0_OFFSET, 8))
> {
> - size_t size = bfd_section_size (xstate);
> -
> - /* Check extended state size. */
> - if (size < X86_XSTATE_AVX_SIZE)
> - xcr0 = X86_XSTATE_SSE_MASK;
> - else
> - {
> - char contents[8];
> -
> - if (! bfd_get_section_contents (abfd, xstate, contents,
> - I386_LINUX_XSAVE_XCR0_OFFSET,
> - 8))
> - {
> - warning (_("Couldn't read `xcr0' bytes from "
> - "`.reg-xstate' section in core file."));
> - return 0;
> - }
> -
> - xcr0 = bfd_get_64 (abfd, contents);
> - }
> + warning (_("Couldn't read `xcr0' bytes from "
> + "`.reg-xstate' section in core file."));
> + return X86_XSTATE_SSE_MASK;
> }
> - else
> - xcr0 = 0;
> +
> + uint64_t xcr0 = bfd_get_64 (abfd, contents);
> +
> + if (!i387_set_xsave_layout (xcr0, size, layout))
> + return X86_XSTATE_SSE_MASK;
>
> return xcr0;
> }
I think I spotted a change of behavior in
i386_linux_core_read_xsave_info, which has consequences down the line.
If there's no .reg-xstate section, we would previously return xcr0 == 0,
i386_linux_read_description would return nullptr, and we would choose
between X87 and SSE based on .reg-xfp.
After the patch, i386_linux_core_read_xsave_info returns SSE, meaning
we'll never reach the point that checks for .reg-xfp.
Maybe the first return (if there's not .reg-xstate section) should
return 0?
>
> /* See i386-linux-tdep.h. */
>
> +bool
> +i386_linux_core_read_x86_xsave_layout (struct gdbarch *gdbarch,
> + x86_xsave_layout &layout)
> +{
> + if (i386_linux_core_read_xsave_info (core_bfd, layout) == X86_XSTATE_SSE_MASK)
> + return false;
> +
> + return true;
> +}
Same as earlier, could be:
return i386_linux_core_read_xsave_info (core_bfd, layout) != X86_XSTATE_SSE_MASK;
... although if i386_linux_core_read_xsave_info can return 0, we'd need
to check for that too.
Simon
next prev parent reply other threads:[~2023-07-26 20:45 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-14 15:51 [PATCH v6 00/15] Handle variable " John Baldwin
2023-07-14 15:51 ` [PATCH v6 01/15] x86: Add an x86_xsave_layout structure to handle " John Baldwin
2023-07-26 19:22 ` Simon Marchi
2023-07-26 21:27 ` John Baldwin
2023-07-26 22:51 ` Simon Marchi
2023-07-14 15:51 ` [PATCH v6 02/15] gdb: Store an x86_xsave_layout in i386_gdbarch_tdep John Baldwin
2023-07-14 15:51 ` [PATCH v6 03/15] core: Support fetching x86 XSAVE layout from architectures John Baldwin
2023-07-26 19:37 ` Simon Marchi
2023-07-26 21:28 ` John Baldwin
2023-07-14 15:51 ` [PATCH v6 04/15] nat/x86-cpuid.h: Add x86_cpuid_count wrapper around __get_cpuid_count John Baldwin
2023-07-26 19:41 ` Simon Marchi
2023-07-14 15:51 ` [PATCH v6 05/15] x86 nat: Add helper functions to save the XSAVE layout for the host John Baldwin
2023-07-26 19:48 ` Simon Marchi
2023-07-26 21:37 ` John Baldwin
2023-07-14 15:51 ` [PATCH v6 06/15] gdb: Update x86 FreeBSD architectures to support XSAVE layouts John Baldwin
2023-07-26 20:04 ` Simon Marchi
2023-07-26 21:43 ` John Baldwin
2023-07-28 21:23 ` [PATCH v6a " John Baldwin
2023-08-28 16:01 ` Simon Marchi
2023-07-14 15:51 ` [PATCH v6 07/15] gdb: Support XSAVE layouts for the current host in the FreeBSD x86 targets John Baldwin
2023-07-26 20:26 ` Simon Marchi
2023-07-14 15:51 ` [PATCH v6 08/15] gdb: Update x86 Linux architectures to support XSAVE layouts John Baldwin
2023-07-26 20:45 ` Simon Marchi [this message]
2023-07-26 21:16 ` John Baldwin
2023-07-27 21:48 ` Simon Marchi
2023-07-28 16:30 ` John Baldwin
2023-07-28 17:58 ` Simon Marchi
2023-07-28 21:30 ` John Baldwin
2023-07-28 21:29 ` [PATCH v6a " John Baldwin
2023-08-14 17:52 ` John Baldwin
2023-08-28 16:21 ` Simon Marchi
2023-07-14 15:51 ` [PATCH v6 09/15] gdb: Support XSAVE layouts for the current host in the Linux x86 targets John Baldwin
2023-07-26 20:51 ` Simon Marchi
2023-07-14 15:51 ` [PATCH v6 10/15] gdb: Use x86_xstate_layout to parse the XSAVE extended state area John Baldwin
2023-08-28 16:34 ` Simon Marchi
2023-07-14 15:51 ` [PATCH v6 11/15] gdbserver: Add a function to set the XSAVE mask and size John Baldwin
2023-08-28 16:46 ` Simon Marchi
2023-07-14 15:51 ` [PATCH v6 12/15] gdbserver: Refactor the legacy region within the xsave struct John Baldwin
2023-08-28 16:50 ` Simon Marchi
2023-08-28 17:32 ` John Baldwin
2023-07-14 15:51 ` [PATCH v6 13/15] gdbserver: Use x86_xstate_layout to parse the XSAVE extended state area John Baldwin
2023-08-28 18:15 ` Simon Marchi
2023-08-28 18:37 ` John Baldwin
2023-07-14 15:51 ` [PATCH v6 14/15] x86: Remove X86_XSTATE_SIZE and related constants John Baldwin
2023-08-28 20:38 ` Simon Marchi
2023-07-14 15:51 ` [PATCH v6 15/15] gdbserver: Simplify handling of ZMM registers John Baldwin
2023-08-28 20:57 ` Simon Marchi
2023-07-14 15:58 ` [PATCH v6 00/15] Handle variable XSAVE layouts John Baldwin
2023-07-26 8:31 ` Willgerodt, Felix
2023-07-25 17:17 ` Keith Seitz
2023-07-25 18:15 ` John Baldwin
2023-07-25 18:43 ` Keith Seitz
2023-07-25 18:59 ` John Baldwin
2023-07-25 20:42 ` Keith Seitz
2023-07-25 22:05 ` John Baldwin
2023-07-26 22:31 ` John Baldwin
2023-07-27 21:36 ` Keith Seitz
2023-07-28 16:35 ` John Baldwin
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