From: Andy Lutomirski <luto@kernel.org>
To: Changbin Du <changbin.du@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>, X86 ML <x86@kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] x86/mm: determine whether the fault address is canonical
Date: Fri, 4 Oct 2019 07:59:00 -0700 [thread overview]
Message-ID: <CALCETrWEhNCWDz7OVpbYJceJ5eShsWWhuyuAQQSzAdKncUo7zA@mail.gmail.com> (raw)
In-Reply-To: <20191004134501.30651-1-changbin.du@gmail.com>
On Fri, Oct 4, 2019 at 6:45 AM Changbin Du <changbin.du@gmail.com> wrote:
>
> We know the answer, so don't ask the user.
>
> Signed-off-by: Changbin Du <changbin.du@gmail.com>
> ---
> arch/x86/mm/extable.c | 5 ++++-
> arch/x86/mm/mm_internal.h | 11 +++++++++++
> 2 files changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c
> index 4d75bc656f97..5196e586756f 100644
> --- a/arch/x86/mm/extable.c
> +++ b/arch/x86/mm/extable.c
> @@ -8,6 +8,8 @@
> #include <asm/traps.h>
> #include <asm/kdebug.h>
>
> +#include "mm_internal.h"
> +
> typedef bool (*ex_handler_t)(const struct exception_table_entry *,
> struct pt_regs *, int, unsigned long,
> unsigned long);
> @@ -123,7 +125,8 @@ __visible bool ex_handler_uaccess(const struct exception_table_entry *fixup,
> unsigned long error_code,
> unsigned long fault_addr)
> {
> - WARN_ONCE(trapnr == X86_TRAP_GP, "General protection fault in user access. Non-canonical address?");
> + WARN_ONCE(trapnr == X86_TRAP_GP, "General protection fault at %s address in user access.",
> + is_canonical_addr(fault_addr) ? "canonical" : "non-canonical");
Unless the hardware behaves rather differently from the way I think it
does, fault_addr is garbage for anything other than #PF and sometimes
for #DF. (And maybe the virtualization faults?) I don't believe that
#GP fills in CR2.
next prev parent reply other threads:[~2019-10-04 14:59 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-04 13:45 [PATCH] x86/mm: determine whether the fault address is canonical Changbin Du
2019-10-04 14:39 ` Dave Hansen
2019-10-04 15:31 ` Sean Christopherson
2019-10-07 14:32 ` Ingo Molnar
2019-10-07 14:44 ` Ingo Molnar
2019-10-07 15:13 ` Sean Christopherson
2019-10-04 14:59 ` Andy Lutomirski [this message]
2019-10-04 15:14 ` Dave Hansen
2019-10-06 2:29 ` Changbin Du
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