From: ebiederm@xmission.com (Eric W. Biederman)
To: tip-bot for Dave Hansen <tipbot@zytor.com>
Cc: linux-tip-commits@vger.kernel.org, dave.hansen@linux.intel.com,
tglx@linutronix.de, linux-kernel@vger.kernel.org, hpa@zytor.com,
mingo@kernel.org, jannh@google.com,
sean.j.christopherson@intel.com, peterz@infradead.org,
luto@kernel.org
Subject: Re: [tip:x86/mm] x86/mm: Break out user address space handling
Date: Mon, 15 Oct 2018 00:43:57 -0500 [thread overview]
Message-ID: <87k1mjpxwi.fsf@xmission.com> (raw)
In-Reply-To: <tip-aa37c51b9421d66f7931c5fdcb9ce80c450974be@git.kernel.org> (tip-bot for Dave Hansen's message of "Tue, 9 Oct 2018 08:03:12 -0700")
tip-bot for Dave Hansen <tipbot@zytor.com> writes:
> Commit-ID: aa37c51b9421d66f7931c5fdcb9ce80c450974be
> Gitweb: https://git.kernel.org/tip/aa37c51b9421d66f7931c5fdcb9ce80c450974be
> Author: Dave Hansen <dave.hansen@linux.intel.com>
> AuthorDate: Fri, 28 Sep 2018 09:02:23 -0700
> Committer: Peter Zijlstra <peterz@infradead.org>
> CommitDate: Tue, 9 Oct 2018 16:51:15 +0200
>
> x86/mm: Break out user address space handling
>
> The last patch broke out kernel address space handing into its own
> helper. Now, do the same for user address space handling.
>
> Cc: x86@kernel.org
> Cc: Jann Horn <jannh@google.com>
> Cc: Sean Christopherson <sean.j.christopherson@intel.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Andy Lutomirski <luto@kernel.org>
> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> Link: http://lkml.kernel.org/r/20180928160223.9C4F6440@viggo.jf.intel.com
> ---
> arch/x86/mm/fault.c | 47 ++++++++++++++++++++++++++++-------------------
> 1 file changed, 28 insertions(+), 19 deletions(-)
>
> diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
> index c7e32f453852..0d1f5d39fc63 100644
> --- a/arch/x86/mm/fault.c
> +++ b/arch/x86/mm/fault.c
> @@ -966,6 +966,7 @@ bad_area_access_error(struct pt_regs *regs, unsigned long error_code,
> __bad_area(regs, error_code, address, vma, SEGV_ACCERR);
> }
>
> +/* Handle faults in the kernel portion of the address space */
^^^^^^
I believe you mean the __user__ portion of the address space.
Given that the call chain is:
do_user_addr_fault
handle_mm_fault
do_sigbus
> static void
> do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address,
> u32 *pkey, unsigned int fault)
> @@ -1254,14 +1255,11 @@ do_kern_addr_fault(struct pt_regs *regs, unsigned long hw_error_code,
> }
> NOKPROBE_SYMBOL(do_kern_addr_fault);
>
> -/*
> - * This routine handles page faults. It determines the address,
> - * and the problem, and then passes it off to one of the appropriate
> - * routines.
> - */
> -static noinline void
> -__do_page_fault(struct pt_regs *regs, unsigned long hw_error_code,
> - unsigned long address)
> +/* Handle faults in the user portion of the address space */
> +static inline
> +void do_user_addr_fault(struct pt_regs *regs,
> + unsigned long hw_error_code,
> + unsigned long address)
> {
> unsigned long sw_error_code;
> struct vm_area_struct *vma;
> @@ -1274,17 +1272,6 @@ __do_page_fault(struct pt_regs *regs, unsigned long hw_error_code,
> tsk = current;
> mm = tsk->mm;
>
> - prefetchw(&mm->mmap_sem);
> -
> - if (unlikely(kmmio_fault(regs, address)))
> - return;
> -
> - /* Was the fault on kernel-controlled part of the address space? */
> - if (unlikely(fault_in_kernel_space(address))) {
> - do_kern_addr_fault(regs, hw_error_code, address);
> - return;
> - }
> -
> /* kprobes don't want to hook the spurious faults: */
> if (unlikely(kprobes_fault(regs)))
> return;
> @@ -1488,6 +1475,28 @@ good_area:
>
> check_v8086_mode(regs, address, tsk);
> }
> +NOKPROBE_SYMBOL(do_user_addr_fault);
> +
> +/*
> + * This routine handles page faults. It determines the address,
> + * and the problem, and then passes it off to one of the appropriate
> + * routines.
> + */
> +static noinline void
> +__do_page_fault(struct pt_regs *regs, unsigned long hw_error_code,
> + unsigned long address)
> +{
> + prefetchw(¤t->mm->mmap_sem);
> +
> + if (unlikely(kmmio_fault(regs, address)))
> + return;
> +
> + /* Was the fault on kernel-controlled part of the address space? */
> + if (unlikely(fault_in_kernel_space(address)))
> + do_kern_addr_fault(regs, hw_error_code, address);
> + else
> + do_user_addr_fault(regs, hw_error_code, address);
> +}
> NOKPROBE_SYMBOL(__do_page_fault);
>
> static nokprobe_inline void
Eric
next prev parent reply other threads:[~2018-10-15 5:44 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-28 16:02 [PATCH 0/8] [v2] x86/mm: page fault handling cleanups Dave Hansen
2018-09-28 16:02 ` [PATCH 1/8] x86/mm: clarify hardware vs. software "error_code" Dave Hansen
2018-10-09 15:02 ` [tip:x86/mm] x86/mm: Clarify " tip-bot for Dave Hansen
2018-09-28 16:02 ` [PATCH 2/8] x86/mm: break out kernel address space handling Dave Hansen
2018-10-09 15:02 ` [tip:x86/mm] x86/mm: Break " tip-bot for Dave Hansen
2018-09-28 16:02 ` [PATCH 3/8] x86/mm: break out user " Dave Hansen
2018-10-09 15:03 ` [tip:x86/mm] x86/mm: Break " tip-bot for Dave Hansen
2018-10-15 5:43 ` Eric W. Biederman [this message]
2018-10-19 5:58 ` Ingo Molnar
2018-09-28 16:02 ` [PATCH 4/8] x86/mm: add clarifying comments for user addr space Dave Hansen
2018-10-09 15:03 ` [tip:x86/mm] x86/mm: Add " tip-bot for Dave Hansen
2018-09-28 16:02 ` [PATCH 5/8] x86/mm: fix exception table comments Dave Hansen
2018-10-09 15:04 ` [tip:x86/mm] x86/mm: Fix " tip-bot for Dave Hansen
2018-09-28 16:02 ` [PATCH 6/8] x86/mm: add vsyscall address helper Dave Hansen
2018-10-09 15:04 ` [tip:x86/mm] x86/mm: Add " tip-bot for Dave Hansen
2018-09-28 16:02 ` [PATCH 7/8] x86/mm/vsyscall: consider vsyscall page part of user address space Dave Hansen
2018-10-09 15:05 ` [tip:x86/mm] x86/mm/vsyscall: Consider " tip-bot for Dave Hansen
2018-09-28 16:02 ` [PATCH 8/8] x86/mm: remove spurious fault pkey check Dave Hansen
2018-10-09 15:05 ` [tip:x86/mm] x86/mm: Remove " tip-bot for Dave Hansen
2018-10-02 9:54 ` [PATCH 0/8] [v2] x86/mm: page fault handling cleanups Peter Zijlstra
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