From: Dave Hansen <dave.hansen@intel.com>
To: Andy Lutomirski <luto@kernel.org>, X86 ML <x86@kernel.org>
Cc: Borislav Petkov <bpetkov@suse.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Brian Gerst <brgerst@gmail.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Josh Poimboeuf <jpoimboe@redhat.com>
Subject: Re: [PATCH 11/16] x86/asm/64: Use a percpu trampoline stack for IDT entries
Date: Tue, 21 Nov 2017 10:57:31 -0800 [thread overview]
Message-ID: <3cd7d3eb-cf71-a015-b37f-4cb079ea3c00@intel.com> (raw)
In-Reply-To: <3ff604702987cf6af1e191705fd937517ceeeeb7.1511195781.git.luto@kernel.org>
On 11/20/2017 09:07 AM, Andy Lutomirski wrote:
> --- a/arch/x86/entry/entry_64.S
> +++ b/arch/x86/entry/entry_64.S
> @@ -560,6 +560,14 @@ END(irq_entries_start)
> .macro interrupt func
> cld
> ALLOC_PT_GPREGS_ON_STACK
> +
> + testb $3, CS(%rsp)
> + jz 1f
> + SWAPGS
> + call switch_to_thread_stack
> + SWAPGS
> +1:
This looks really weird to me. SWAPGS, switch stack, and SWAPGS again?
Is this so that we can use some per-cpu data in switch_to_thread_stack,
and then put GS back so that the normal, non-trampoline entry code can
do its normal SWAPGS voodoo?
next prev parent reply other threads:[~2017-11-21 18:57 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
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 [this message]
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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