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From: Dave Hansen <dave.hansen@linux.intel.com>
To: Ingo Molnar <mingo@kernel.org>, linux-kernel@vger.kernel.org
Cc: Andy Lutomirski <luto@amacapital.net>,
	Thomas Gleixner <tglx@linutronix.de>,
	"H . Peter Anvin" <hpa@zytor.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Borislav Petkov <bp@alien8.de>,
	Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH 16/21] x86/entry/64: Use a per-CPU trampoline stack for IDT entries
Date: Fri, 1 Dec 2017 09:06:32 -0800	[thread overview]
Message-ID: <305ed448-6f8e-eecd-d120-546efc185443@linux.intel.com> (raw)
In-Reply-To: <20171127104529.12435-17-mingo@kernel.org>

On 11/27/2017 02:45 AM, Ingo Molnar wrote:
> --- a/arch/x86/kernel/cpu/common.c
> +++ b/arch/x86/kernel/cpu/common.c
> @@ -1645,11 +1645,13 @@ void cpu_init(void)
>  	setup_cpu_entry_area(cpu);
>  
>  	/*
> -	 * Initialize the TSS.  Don't bother initializing sp0, as the initial
> -	 * task never enters user mode.
> +	 * Initialize the TSS.  sp0 points to the entry trampoline stack
> +	 * regardless of what task is running.
>  	 */
>  	set_tss_desc(cpu, &get_cpu_entry_area(cpu)->tss.x86_tss);
>  	load_TR_desc();
> +	load_sp0((unsigned long)&get_cpu_entry_area(cpu)->tss +
> +		 offsetofend(struct tss_struct, SYSENTER_stack));
>  
>  	load_mm_ldt(&init_mm);

Does this also mean that our stack dumps will say "<SYSENTER>" in oopses?

> [   30.811750] CR2: fffffffffdeb2f98 CR3: 0000000423fae001 CR4: 00000000001607e0                                                                                                           
> [   30.819712] Call Trace:                                                                                                                                                                 
> [   30.822442]  <SYSENTER>                                                                                                                                                                 
> [   30.825170]  trace_hardirqs_on_thunk+0x1c/0x1c                                                                                                                                          
...
> [   31.000571] R13: 0000000000000050 R14: 0000000000000076 R15: 00007f59f76f2d60                                                                                                           
> [   31.008533]  </SYSENTER>                                                                                                    

Should we change that string to something more descriptive?

  reply	other threads:[~2017-12-01 17:06 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-11-27 10:45 [PATCH 00/21] Preparatory patches for x86 KAISER support Ingo Molnar
2017-11-27 10:45 ` [PATCH 01/21] x86/unwinder/orc: Don't bail on stack overflow Ingo Molnar
2017-11-27 14:47   ` Borislav Petkov
2017-11-27 10:45 ` [PATCH 02/21] x86/unwinder: Handle stack overflows more gracefully Ingo Molnar
2017-11-27 17:36   ` Borislav Petkov
2017-11-28  4:55     ` Josh Poimboeuf
2017-11-27 10:45 ` [PATCH 03/21] x86/irq: Remove an old outdated comment about context tracking races Ingo Molnar
2017-11-27 10:45 ` [PATCH 04/21] x86/irq/64: Print the offending IP in the stack overflow warning Ingo Molnar
2017-11-27 10:45 ` [PATCH 05/21] x86/entry/64: Allocate and enable the SYSENTER stack Ingo Molnar
2017-11-27 10:45 ` [PATCH 06/21] x86/dumpstack: Add get_stack_info() support for " Ingo Molnar
2017-11-27 10:45 ` [PATCH 07/21] x86/entry/gdt: Put per-CPU GDT remaps in ascending order Ingo Molnar
2017-11-27 10:45 ` [PATCH 08/21] x86/mm/fixmap: Generalize the GDT fixmap mechanism, introduce 'struct cpu_entry_area' Ingo Molnar
2017-11-27 10:45 ` [PATCH 09/21] x86/kasan/64: Teach KASAN about the cpu_entry_area Ingo Molnar
2017-11-27 10:45 ` [PATCH 10/21] x86/entry: Fix assumptions that the HW TSS is at the beginning of cpu_tss Ingo Molnar
2017-11-27 10:45 ` [PATCH 11/21] x86/dumpstack: Handle stack overflow on all stacks Ingo Molnar
2017-11-27 19:26   ` Linus Torvalds
2017-11-28  4:29     ` Josh Poimboeuf
2017-11-28  5:29       ` Andy Lutomirski
2017-11-28 18:15         ` Josh Poimboeuf
2017-11-27 10:45 ` [PATCH 12/21] x86/entry: Move SYSENTER_stack to the beginning of struct tss_struct Ingo Molnar
2017-11-27 10:45 ` [PATCH 13/21] x86/entry: Remap the TSS into the CPU entry area Ingo Molnar
2017-11-27 10:45 ` [PATCH 14/21] x86/entry/64: Separate cpu_current_top_of_stack from TSS.sp0 Ingo Molnar
2017-11-27 10:45 ` [PATCH 15/21] x86/espfix/64: Stop assuming that pt_regs is on the entry stack Ingo Molnar
2017-11-27 10:45 ` [PATCH 16/21] x86/entry/64: Use a per-CPU trampoline stack for IDT entries Ingo Molnar
2017-12-01 17:06   ` Dave Hansen [this message]
2017-12-01 17:44     ` Andy Lutomirski
2017-12-01 21:21       ` Dave Hansen
2017-12-01 21:59         ` Andy Lutomirski
2017-12-02  6:41         ` Kevin Easton
2017-11-27 10:45 ` [PATCH 17/21] x86/entry/64: Return to userspace from the trampoline stack Ingo Molnar
2017-11-27 10:45 ` [PATCH 18/21] x86/entry/64: Create a per-CPU SYSCALL entry trampoline Ingo Molnar
2017-11-27 10:45 ` [PATCH 19/21] x86/entry/64: Move the IST stacks into 'struct cpu_entry_area' Ingo Molnar
2017-11-27 10:45 ` [PATCH 20/21] x86/entry/64: Remove the SYSENTER stack canary Ingo Molnar
2017-11-27 10:45 ` [PATCH 21/21] x86/entry: Clean up the SYSENTER_stack code Ingo Molnar
2017-12-01 17:59   ` Borislav Petkov

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