From: Catalin Marinas <catalin.marinas@arm.com>
To: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
Will Deacon <will.deacon@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
James Morse <james.morse@arm.com>,
Andrey Konovalov <andreyknvl@google.com>
Subject: Re: [PATCH V2 3/4] arm64/mm: Consolidate page fault information capture
Date: Tue, 4 Jun 2019 15:42:09 +0100 [thread overview]
Message-ID: <20190604144209.GJ6610@arrakis.emea.arm.com> (raw)
In-Reply-To: <1559544085-7502-4-git-send-email-anshuman.khandual@arm.com>
On Mon, Jun 03, 2019 at 12:11:24PM +0530, Anshuman Khandual wrote:
> diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
> index da02678..4bb65f3 100644
> --- a/arch/arm64/mm/fault.c
> +++ b/arch/arm64/mm/fault.c
> @@ -435,6 +435,14 @@ static bool is_el0_instruction_abort(unsigned int esr)
> return ESR_ELx_EC(esr) == ESR_ELx_EC_IABT_LOW;
> }
>
> +/*
> + * This is applicable only for EL0 write aborts.
> + */
> +static bool is_el0_write_abort(unsigned int esr)
> +{
> + return (esr & ESR_ELx_WNR) && !(esr & ESR_ELx_CM);
> +}
What makes this EL0 only?
> +
> static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
> struct pt_regs *regs)
> {
> @@ -443,6 +451,9 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
> vm_fault_t fault, major = 0;
> unsigned long vm_flags = VM_READ | VM_WRITE;
> unsigned int mm_flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
> + bool is_user = user_mode(regs);
> + bool is_el0_exec = is_el0_instruction_abort(esr);
> + bool is_el0_write = is_el0_write_abort(esr);
>
> if (notify_page_fault(regs, esr))
> return 0;
> @@ -454,12 +465,12 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
> if (faulthandler_disabled() || !mm)
> goto no_context;
>
> - if (user_mode(regs))
> + if (is_user)
> mm_flags |= FAULT_FLAG_USER;
>
> - if (is_el0_instruction_abort(esr)) {
> + if (is_el0_exec) {
> vm_flags = VM_EXEC;
> - } else if ((esr & ESR_ELx_WNR) && !(esr & ESR_ELx_CM)) {
> + } else if (is_el0_write) {
> vm_flags = VM_WRITE;
> mm_flags |= FAULT_FLAG_WRITE;
> }
This can be triggered by an EL1 write to a user mapping, so is_el0_write
is misleading.
--
Catalin
next prev parent reply other threads:[~2019-06-04 14:42 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-03 6:41 [PATCH V2 0/4] arm64/mm: Clean ups for do_page_fault() Anshuman Khandual
2019-06-03 6:41 ` [PATCH V2 1/4] arm64/mm: Drop mmap_sem before calling __do_kernel_fault() Anshuman Khandual
2019-06-04 14:44 ` Catalin Marinas
2019-06-03 6:41 ` [PATCH V2 2/4] arm64/mm: Drop task_struct argument from __do_page_fault() Anshuman Khandual
2019-06-04 14:45 ` Catalin Marinas
2019-06-03 6:41 ` [PATCH V2 3/4] arm64/mm: Consolidate page fault information capture Anshuman Khandual
2019-06-04 14:42 ` Catalin Marinas [this message]
2019-06-06 9:38 ` Mark Rutland
2019-06-06 11:23 ` Catalin Marinas
2019-06-03 6:41 ` [PATCH V2 4/4] arm64/mm: Drop local variable vm_fault_t from __do_page_fault() Anshuman Khandual
2019-06-04 14:56 ` Catalin Marinas
2019-06-06 4:54 ` Anshuman Khandual
2019-06-06 11:27 ` Catalin Marinas
2019-06-06 11:31 ` Mark Rutland
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