From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Andy Lutomirski <luto@kernel.org>
Cc: X86 ML <x86@kernel.org>, Borislav Petkov <bpetkov@suse.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Brian Gerst <brgerst@gmail.com>,
Dave Hansen <dave.hansen@intel.com>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH 02/16] x86/dumpstack: Add get_stack_info() support for the SYSENTER stack
Date: Mon, 20 Nov 2017 14:42:12 -0600 [thread overview]
Message-ID: <20171120204212.6rlbhh4btxqnjanm@treble> (raw)
In-Reply-To: <01c7223352405fe6d55d1ea7c0ff1d7282c30cc7.1511195781.git.luto@kernel.org>
On Mon, Nov 20, 2017 at 09:07:33AM -0800, Andy Lutomirski wrote:
> +bool in_SYSENTER_stack(unsigned long *stack, struct stack_info *info)
Can you make it lowercase for consistency with the other in_*_stack()
functions? For example, in_irq_stack() is all lowercase even though
"IRQ" is normally written in uppercase.
But also, I'm wondering whether this get_stack_info() support is even
really needed.
As currently written, the trampoline code doesn't have any ORC data
associated with it. So the unwinder would never have the need to
actually read the SYSENTER stack.
You _could_ add an UNWIND_HINT_IRET_REGS annotation after the simulated
iret frame is written, which would allow the unwinder to dump those regs
when unwinding from an NMI.
But there's only a tiny window where that would be possible: only a few
instructions. I'm not sure that would be worth the effort, unless we
got to the point where we expect to have 100% unwinder coverage. But
that's currently unrealistic anyway because of generated code and
runtime patching.
--
Josh
next prev parent reply other threads:[~2017-11-20 20:42 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-20 17:07 [PATCH 00/16] Entry stuff, in decent shape now Andy Lutomirski
2017-11-20 17:07 ` [PATCH 01/16] x86/asm/64: Allocate and enable the SYSENTER stack Andy Lutomirski
2017-11-20 21:55 ` Thomas Gleixner
2017-11-21 10:47 ` Borislav Petkov
2017-11-20 17:07 ` [PATCH 02/16] x86/dumpstack: Add get_stack_info() support for " Andy Lutomirski
2017-11-20 20:42 ` Josh Poimboeuf [this message]
2017-11-20 20:46 ` Andy Lutomirski
2017-11-20 21:00 ` Josh Poimboeuf
2017-11-20 21:07 ` Andy Lutomirski
2017-11-20 21:27 ` Josh Poimboeuf
2017-11-20 21:30 ` Andy Lutomirski
2017-11-20 21:55 ` Josh Poimboeuf
2017-11-21 1:39 ` Andy Lutomirski
2017-11-21 2:29 ` Josh Poimboeuf
2017-11-20 17:07 ` [PATCH 03/16] x86/gdt: Put per-cpu GDT remaps in ascending order Andy Lutomirski
2017-11-20 21:56 ` Thomas Gleixner
2017-11-21 17:16 ` Borislav Petkov
2017-11-20 17:07 ` [PATCH 04/16] x86/fixmap: Generalize the GDT fixmap mechanism Andy Lutomirski
2017-11-20 22:01 ` Thomas Gleixner
2017-11-21 1:21 ` Andy Lutomirski
2017-11-21 8:29 ` Thomas Gleixner
2017-11-20 17:07 ` [PATCH 05/16] x86/asm: Fix assumptions that the HW TSS is at the beginning of cpu_tss Andy Lutomirski
2017-11-20 22:22 ` Thomas Gleixner
2017-11-20 17:07 ` [PATCH 06/16] x86/dumpstack: Handle stack overflow on all stacks Andy Lutomirski
2017-11-20 17:07 ` [PATCH 07/16] x86/asm: Move SYSENTER_stack to the beginning of struct tss_struct Andy Lutomirski
2017-11-20 23:37 ` Thomas Gleixner
2017-11-21 1:25 ` Andy Lutomirski
2017-11-20 17:07 ` [PATCH 08/16] x86/asm: Remap the TSS into the cpu entry area Andy Lutomirski
2017-11-20 17:07 ` [PATCH 09/16] x86/asm/64: Separate cpu_current_top_of_stack from TSS.sp0 Andy Lutomirski
2017-11-20 17:07 ` [PATCH 10/16] x86/espfix/64: Stop assuming that pt_regs is on the entry stack Andy Lutomirski
2017-11-20 17:07 ` [PATCH 11/16] x86/asm/64: Use a percpu trampoline stack for IDT entries Andy Lutomirski
2017-11-21 7:20 ` Ingo Molnar
2017-11-21 15:36 ` Andy Lutomirski
2017-11-21 18:57 ` Dave Hansen
2017-11-22 3:45 ` Andy Lutomirski
2017-11-20 17:07 ` [PATCH 12/16] x86/asm/64: Return to userspace from the trampoline stack Andy Lutomirski
2017-11-20 17:07 ` [PATCH 13/16] x86/entry/64: Create a percpu SYSCALL entry trampoline Andy Lutomirski
2017-11-21 2:34 ` Josh Poimboeuf
2017-11-21 3:20 ` Andy Lutomirski
2017-11-20 17:07 ` [PATCH 14/16] x86/irq: Remove an old outdated comment about context tracking races Andy Lutomirski
2017-11-21 6:25 ` Ingo Molnar
2017-11-20 17:07 ` [PATCH 15/16] x86/irq/64: In the stack overflow warning, print the offending IP Andy Lutomirski
2017-11-21 6:26 ` Ingo Molnar
2017-11-20 17:07 ` [PATCH 16/16] x86/entry/64: Move the IST stacks into cpu_entry_area Andy Lutomirski
2017-11-21 7:38 ` Ingo Molnar
2017-11-21 14:45 ` Andrey Ryabinin
2017-11-23 15:25 ` Andy Lutomirski
2017-11-21 15:33 ` Andy Lutomirski
2017-11-20 18:48 ` [PATCH 00/16] Entry stuff, in decent shape now Andy Lutomirski
2017-11-21 7:33 ` Ingo Molnar
2017-11-21 15:59 ` Andy Lutomirski
2017-11-21 16:12 ` Andy Lutomirski
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