From: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
To: Luis Machado <luis.machado@arm.com>
Cc: gdb-patches@sourceware.org
Subject: Re: [PATCH v3 03/16] [gdb/gdbserver] refactor: Simplify SVE interface to read/write registers
Date: Mon, 24 Jul 2023 13:19:28 -0300 [thread overview]
Message-ID: <87bkg1jn8v.fsf@linaro.org> (raw)
In-Reply-To: <20230630134616.1238105-4-luis.machado@arm.com>
Luis Machado via Gdb-patches <gdb-patches@sourceware.org> writes:
> This is a patch in preparation to upcoming patches enabling SME support. It
> attempts to simplify the gdb/gdbserver shared interface used to read/write
> SVE registers.
>
> Where the current code makes use of unique_ptr, allocating a new buffer by
> hand and passing a buffer around, this patch makes that code use
> gdb::byte_vector and passes a reference to this byte vector to the functions,
> allowing the functions to have ready access to the size of the buffer.
Nice!
> It also shares a bit more code between gdb and gdbserver, in particular around
> handling of ptrace get/set requests for SVE.
Also nice!
> diff --git a/gdb/nat/aarch64-scalable-linux-ptrace.c b/gdb/nat/aarch64-scalable-linux-ptrace.c
> index cc43f510892..192eebcda19 100644
> --- a/gdb/nat/aarch64-scalable-linux-ptrace.c
> +++ b/gdb/nat/aarch64-scalable-linux-ptrace.c
> @@ -120,28 +120,44 @@ aarch64_sve_set_vq (int tid, struct reg_buffer_common *reg_buf)
>
> /* See nat/aarch64-scalable-linux-ptrace.h. */
>
> -std::unique_ptr<gdb_byte[]>
> -aarch64_sve_get_sveregs (int tid)
> +gdb::byte_vector
> +aarch64_fetch_sve_regset (int tid)
> {
> - struct iovec iovec;
> uint64_t vq = aarch64_sve_get_vq (tid);
>
> if (vq == 0)
> - perror_with_name (_("Unable to fetch SVE register header"));
> + perror_with_name (_("Unable to fetch SVE vector length"));
>
> /* A ptrace call with NT_ARM_SVE will return a header followed by either a
> dump of all the SVE and FP registers, or an fpsimd structure (identical to
> the one returned by NT_FPREGSET) if the kernel has not yet executed any
> SVE code. Make sure we allocate enough space for a full SVE dump. */
>
> - iovec.iov_len = SVE_PT_SIZE (vq, SVE_PT_REGS_SVE);
> - std::unique_ptr<gdb_byte[]> buf (new gdb_byte[iovec.iov_len]);
> - iovec.iov_base = buf.get ();
> + gdb::byte_vector sve_state (SVE_PT_SIZE (vq, SVE_PT_REGS_SVE), 0);
> +
> + struct iovec iovec;
> + iovec.iov_base = sve_state.data ();
> + iovec.iov_len = sve_state.size ();
>
> if (ptrace (PTRACE_GETREGSET, tid, NT_ARM_SVE, &iovec) < 0)
> perror_with_name (_("Unable to fetch SVE registers"));
>
> - return buf;
> + return sve_state;
> +}
> +
> +/* See nat/aarch64-scalable-linux-ptrace.h. */
> +
> +bool
This function always returns true, and its only caller doesn't use the
return value. Should it return void instead?
> +aarch64_store_sve_regset (int tid, const gdb::byte_vector &sve_state)
> +{
> + struct iovec iovec;
> + iovec.iov_base = (void *) sve_state.data ();
Minor nit: is the cast necessary? The code looks cleaner without it.
Also, it's not used in aarch64_fetch_sve_regset.
> + else
> + {
> + /* Otherwise, reformat the fpsimd structure into a full SVE set, by
> + expanding the V registers (working backwards so we don't splat
> + registers before they are copied) and using zero for everything
> + else.
> + Note that enough space for a full SVE dump was originally allocated
> + for base. */
> +
> + header->flags |= SVE_PT_REGS_SVE;
> + header->size = SVE_PT_SIZE (vq, SVE_PT_REGS_SVE);
> +
> + memcpy (base + SVE_PT_SVE_FPSR_OFFSET (vq), &fpsimd->fpsr,
> + sizeof (uint32_t));
> + memcpy (base + SVE_PT_SVE_FPCR_OFFSET (vq), &fpsimd->fpcr,
> + sizeof (uint32_t));
> +
> + for (int i = AARCH64_SVE_Z_REGS_NUM; i >= 0 ; i--)
Shouldn't i start from AARCH64_SVE_Z_REGS_NUM - 1? If this is correct, a
comment explaining why would be helpful.
--
Thiago
next prev parent reply other threads:[~2023-07-24 16:19 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-30 13:46 [PATCH v3 00/16] SME support for AArch64 gdb/gdbserver on Linux Luis Machado
2023-06-30 13:46 ` [PATCH v3 01/16] [gdb/aarch64] Fix register fetch/store order for native AArch64 Linux Luis Machado
2023-07-24 15:53 ` Thiago Jung Bauermann
2023-07-24 16:26 ` Luis Machado
2023-06-30 13:46 ` [PATCH v3 02/16] [gdb/aarch64] refactor: Rename SVE-specific files Luis Machado
2023-06-30 13:46 ` [PATCH v3 03/16] [gdb/gdbserver] refactor: Simplify SVE interface to read/write registers Luis Machado
2023-07-24 16:19 ` Thiago Jung Bauermann [this message]
2023-07-25 9:28 ` Luis Machado
2023-06-30 13:46 ` [PATCH v3 04/16] [gdb/aarch64] sve: Fix return command when using V registers in a SVE-enabled target Luis Machado
2023-06-30 13:46 ` [PATCH v3 05/16] [gdb/aarch64] sme: Enable SME registers and pseudo-registers Luis Machado
2023-07-26 20:01 ` Thiago Jung Bauermann
2023-07-27 9:01 ` Luis Machado
2023-07-28 1:19 ` Thiago Jung Bauermann
2023-06-30 13:46 ` [PATCH v3 06/16] [gdbserver/aarch64] refactor: Adjust expedited registers dynamically Luis Machado
2023-06-30 13:46 ` [PATCH v3 07/16] [gdbserver/aarch64] sme: Add support for SME Luis Machado
2023-07-27 19:41 ` Thiago Jung Bauermann
2023-06-30 13:46 ` [PATCH v3 08/16] [gdb/aarch64] sve: Fix signal frame z/v register restore Luis Machado
2023-07-27 21:52 ` Thiago Jung Bauermann
2023-07-31 12:22 ` Luis Machado
2023-06-30 13:46 ` [PATCH v3 09/16] [gdb/aarch64] sme: Signal frame support Luis Machado
2023-07-27 22:25 ` Thiago Jung Bauermann
2023-07-31 12:23 ` Luis Machado
2023-06-30 13:46 ` [PATCH v3 10/16] [gdb/aarch64] sme: Fixup sigframe gdbarch when vg/svg changes Luis Machado
2023-07-28 1:01 ` Thiago Jung Bauermann
2023-07-31 12:27 ` Luis Machado
2023-06-30 13:46 ` [PATCH v3 11/16] [gdb/aarch64] sme: Support TPIDR2 signal frame context Luis Machado
2023-06-30 13:46 ` [PATCH v3 12/16] [gdb/generic] corefile/bug: Use thread-specific gdbarch when dumping register state to core files Luis Machado
2023-06-30 13:46 ` [PATCH v3 13/16] [gdb/generic] corefile/bug: Fixup (gcore) core file target description reading order Luis Machado
2023-07-28 3:12 ` Thiago Jung Bauermann
2023-07-31 11:38 ` Luis Machado
2023-09-05 8:28 ` Luis Machado
2023-06-30 13:46 ` [PATCH v3 14/16] [gdb/aarch64] sme: Core file support for Linux Luis Machado
2023-08-03 0:18 ` Thiago Jung Bauermann
2023-08-03 11:37 ` Luis Machado
2023-08-04 20:45 ` Thiago Jung Bauermann
2023-06-30 13:46 ` [PATCH v3 15/16] [gdb/testsuite] sme: Add SVE/SME testcases Luis Machado
2023-08-04 0:59 ` Thiago Jung Bauermann
2023-08-11 15:42 ` Luis Machado
2023-08-12 0:42 ` Thiago Jung Bauermann
2023-06-30 13:46 ` [PATCH v3 16/16] [gdb/docs] sme: Document SME registers and features Luis Machado
2023-07-01 8:58 ` Eli Zaretskii
2023-07-03 9:52 ` Luis Machado
2023-07-03 12:03 ` Eli Zaretskii
2023-07-03 12:06 ` Luis Machado
2023-07-17 11:40 ` [PING][PATCH v3 00/16] SME support for AArch64 gdb/gdbserver on Linux Luis Machado
2023-07-24 8:15 ` Luis Machado
2023-08-04 21:24 ` [PATCH " Thiago Jung Bauermann
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