Re: [PATCH 4/5] stack: Fix stack unwind failure on mips

["Ying Huang" <ying.huang@oss.cipunited.com>]

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Hi,

在 2023/5/12 00:07, Mark Wielaard 写道:
>>  libebl_backends_a_SOURCES = $(i386_SRCS) $(sh_SRCS) $(x86_64_SRCS) \
>>  			    $(ia64_SRCS) $(alpha_SRCS) $(arm_SRCS) \
>> diff --git a/backends/mips_cfi.c b/backends/mips_cfi.c
>> new file mode 100644
>> index 00000000..77132cc1
>> --- /dev/null
>> +++ b/backends/mips_cfi.c
>> @@ -0,0 +1,68 @@
>> +/* MIPS ABI-specified defaults for DWARF CFI.
>> +   Copyright (C) 2009 Red Hat, Inc.
>> +   Copyright (C) 2023 CIP United Inc.
>> +   This file is part of elfutils.
>> +
>> +   This file is free software; you can redistribute it and/or modify
>> +   it under the terms of either
>> +
>> +     * the GNU Lesser General Public License as published by the Free
>> +       Software Foundation; either version 3 of the License, or (at
>> +       your option) any later version
>> +
>> +   or
>> +
>> +     * the GNU General Public License as published by the Free
>> +       Software Foundation; either version 2 of the License, or (at
>> +       your option) any later version
>> +
>> +   or both in parallel, as here.
>> +
>> +   elfutils is distributed in the hope that it will be useful, but
>> +   WITHOUT ANY WARRANTY; without even the implied warranty of
>> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
>> +   General Public License for more details.
>> +
>> +   You should have received copies of the GNU General Public License and
>> +   the GNU Lesser General Public License along with this program.  If
>> +   not, see <http://www.gnu.org/licenses/>.  */
>> +
>> +#ifdef HAVE_CONFIG_H
>> +# include <config.h>
>> +#endif
>> +
>> +#include <dwarf.h>
>> +
>> +#define BACKEND mips_
>> +#include "libebl_CPU.h"
>> +
>> +int
>> +mips_abi_cfi (Ebl *ebl __attribute__ ((unused)), Dwarf_CIE *abi_info)
>> +{
>> +  static const uint8_t abi_cfi[] =
>> +    {
>> +      DW_CFA_def_cfa, ULEB128_7 (31), ULEB128_7 (0),
>> +      /* Callee-saved regs.  */
>> +      DW_CFA_same_value, ULEB128_7 (16), /* s0 */
>> +      DW_CFA_same_value, ULEB128_7 (17), /* s1 */
>> +      DW_CFA_same_value, ULEB128_7 (18), /* s2 */
>> +      DW_CFA_same_value, ULEB128_7 (19), /* s3 */
>> +      DW_CFA_same_value, ULEB128_7 (20), /* s4 */
>> +      DW_CFA_same_value, ULEB128_7 (21), /* s5 */
>> +      DW_CFA_same_value, ULEB128_7 (22), /* s6 */
>> +      DW_CFA_same_value, ULEB128_7 (23), /* s7 */
>> +      DW_CFA_same_value, ULEB128_7 (28), /* gp */
>> +      DW_CFA_same_value, ULEB128_7 (29), /* sp */
>> +      DW_CFA_same_value, ULEB128_7 (30), /* fp */
>> +
>> +      DW_CFA_val_offset, ULEB128_7 (29), ULEB128_7 (0),
>> +    };
>> +
>> +  abi_info->initial_instructions = abi_cfi;
>> +  abi_info->initial_instructions_end = &abi_cfi[sizeof abi_cfi];
>> +  abi_info->data_alignment_factor = -4;
>> +
>> +  abi_info->return_address_register = 31; /* %ra */
>> +
>> +  return 0;
>> +}
> Looks good, but do you have a reference to the ABI docs would be nice
> to add an URL as comment for people to double check.

    document:

    https://irix7.com/techpubs/007-2816-004.pdf

    Page17 Page18 Page14

>> diff --git a/backends/mips_initreg.c b/backends/mips_initreg.c
>> new file mode 100644
>> index 00000000..31b8de13
>> --- /dev/null
>> +++ b/backends/mips_initreg.c
>> @@ -0,0 +1,70 @@
>> +/* Fetch live process registers from TID.
>> +   Copyright (C) 2023 CIP United Inc.
>> +   This file is part of elfutils.
>> +
>> +   This file is free software; you can redistribute it and/or modify
>> +   it under the terms of either
>> +
>> +     * the GNU Lesser General Public License as published by the Free
>> +       Software Foundation; either version 3 of the License, or (at
>> +       your option) any later version
>> +
>> +   or
>> +
>> +     * the GNU General Public License as published by the Free
>> +       Software Foundation; either version 2 of the License, or (at
>> +       your option) any later version
>> +
>> +   or both in parallel, as here.
>> +
>> +   elfutils is distributed in the hope that it will be useful, but
>> +   WITHOUT ANY WARRANTY; without even the implied warranty of
>> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
>> +   General Public License for more details.
>> +
>> +   You should have received copies of the GNU General Public License and
>> +   the GNU Lesser General Public License along with this program.  If
>> +   not, see <http://www.gnu.org/licenses/>.  */
>> +
>> +#ifdef HAVE_CONFIG_H
>> +# include <config.h>
>> +#endif
>> +
>> +#include <stdlib.h>
>> +#if (defined(mips) || defined(__mips) || defined(__mips__) || defined(MIPS) || defined(__MIPS__)) && defined(__linux__)
>> +# include <sys/user.h>
>> +# include <sys/ptrace.h>
>> +#endif
>> +
>> +#define BACKEND mips_
>> +#include "libebl_CPU.h"
>> +#include <stdio.h>
>> +
>> +
>> +bool
>> +mips_set_initial_registers_tid (pid_t tid __attribute__ ((unused)),
>> +			  ebl_tid_registers_t *setfunc __attribute__ ((unused)),
>> +				  void *arg __attribute__ ((unused)))
>> +{
>> +#if (!defined(mips) && !defined(__mips) && !defined(__mips__) && !defined(MIPS) && !defined(__MIPS__)) || !defined(__linux__)
>> +  return false;
>> +#else /* __mips__ */
>> +/* For PTRACE_GETREGS */
>> +struct pt_regs {
>> +    uint64_t regs[32];
>> +    uint64_t lo;
>> +    uint64_t hi;
>> +    uint64_t pc;
>> +    uint64_t badvaddr;
>> +    uint64_t cause;
>> +    uint64_t status;
>> +};
> Isn't this defined in some standard (or glibc/linux specific) header?

    OK, I would add +#include <asm/ptrace.h>


    Thanks,

    Ying