| From 547da673173de51f73887377eb275304775064ad Mon Sep 17 00:00:00 2001 |
| From: "Maciej W. Rozycki" <macro@mips.com> |
| Date: Tue, 7 Nov 2017 19:09:20 +0000 |
| Subject: MIPS: Fix an n32 core file generation regset support regression |
| |
| From: Maciej W. Rozycki <macro@mips.com> |
| |
| commit 547da673173de51f73887377eb275304775064ad upstream. |
| |
| Fix a commit 7aeb753b5353 ("MIPS: Implement task_user_regset_view.") |
| regression, then activated by commit 6a9c001b7ec3 ("MIPS: Switch ELF |
| core dumper to use regsets.)", that caused n32 processes to dump o32 |
| core files by failing to set the EF_MIPS_ABI2 flag in the ELF core file |
| header's `e_flags' member: |
| |
| $ file tls-core |
| tls-core: ELF 32-bit MSB executable, MIPS, N32 MIPS64 rel2 version 1 (SYSV), [...] |
| $ ./tls-core |
| Aborted (core dumped) |
| $ file core |
| core: ELF 32-bit MSB core file MIPS, MIPS-I version 1 (SYSV), SVR4-style |
| $ |
| |
| Previously the flag was set as the result of a: |
| |
| statement placed in arch/mips/kernel/binfmt_elfn32.c, however in the |
| regset case, i.e. when CORE_DUMP_USE_REGSET is set, ELF_CORE_EFLAGS is |
| no longer used by `fill_note_info' in fs/binfmt_elf.c, and instead the |
| `->e_flags' member of the regset view chosen is. We have the views |
| defined in arch/mips/kernel/ptrace.c, however only an o32 and an n64 |
| one, and the latter is used for n32 as well. Consequently an o32 core |
| file is incorrectly dumped from n32 processes (the ELF32 vs ELF64 class |
| is chosen elsewhere, and the 32-bit one is correctly selected for n32). |
| |
| Correct the issue then by defining an n32 regset view and using it as |
| appropriate. Issue discovered in GDB testing. |
| |
| Fixes: 7aeb753b5353 ("MIPS: Implement task_user_regset_view.") |
| Signed-off-by: Maciej W. Rozycki <macro@mips.com> |
| Cc: Ralf Baechle <ralf@linux-mips.org> |
| Cc: Djordje Todorovic <djordje.todorovic@rt-rk.com> |
| Cc: linux-mips@linux-mips.org |
| Patchwork: https://patchwork.linux-mips.org/patch/17617/ |
| Signed-off-by: James Hogan <jhogan@kernel.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| arch/mips/kernel/ptrace.c | 17 +++++++++++++++++ |
| 1 file changed, 17 insertions(+) |
| |
| --- a/arch/mips/kernel/ptrace.c |
| +++ b/arch/mips/kernel/ptrace.c |
| @@ -522,6 +522,19 @@ static const struct user_regset_view use |
| .n = ARRAY_SIZE(mips64_regsets), |
| }; |
| |
| +#ifdef CONFIG_MIPS32_N32 |
| + |
| +static const struct user_regset_view user_mipsn32_view = { |
| + .name = "mipsn32", |
| + .e_flags = EF_MIPS_ABI2, |
| + .e_machine = ELF_ARCH, |
| + .ei_osabi = ELF_OSABI, |
| + .regsets = mips64_regsets, |
| + .n = ARRAY_SIZE(mips64_regsets), |
| +}; |
| + |
| +#endif /* CONFIG_MIPS32_N32 */ |
| + |
| #endif /* CONFIG_64BIT */ |
| |
| const struct user_regset_view *task_user_regset_view(struct task_struct *task) |
| @@ -533,6 +546,10 @@ const struct user_regset_view *task_user |
| if (test_tsk_thread_flag(task, TIF_32BIT_REGS)) |
| return &user_mips_view; |
| #endif |
| +#ifdef CONFIG_MIPS32_N32 |
| + if (test_tsk_thread_flag(task, TIF_32BIT_ADDR)) |
| + return &user_mipsn32_view; |
| +#endif |
| return &user_mips64_view; |
| #endif |
| } |