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From: Ard Biesheuvel <ardb@kernel.org>
To: Christoph Hellwig <hch@lst.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	linux-hyperv@vger.kernel.org,
	Peter Zijlstra <peterz@infradead.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	X86 ML <x86@kernel.org>, Dexuan Cui <decui@microsoft.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-mm@kvack.org, Jessica Yu <jeyu@kernel.org>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Will Deacon <will@kernel.org>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 2/3] arm64: use PAGE_KERNEL_ROX directly in alloc_insn_page
Date: Sat, 27 Jun 2020 09:34:42 +0200	[thread overview]
Message-ID: <CAMj1kXH985Aqma47yf96N45CYkTGePVpvihrc_TmOAp2f0vN-g@mail.gmail.com> (raw)
In-Reply-To: <20200618064307.32739-3-hch@lst.de>

On Thu, 18 Jun 2020 at 08:44, Christoph Hellwig <hch@lst.de> wrote:
>
> Use PAGE_KERNEL_ROX directly instead of allocating RWX and setting the
> page read-only just after the allocation.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  arch/arm64/kernel/probes/kprobes.c | 12 +++---------
>  1 file changed, 3 insertions(+), 9 deletions(-)
>
> diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c
> index d1c95dcf1d7833..cbe49cd117cfec 100644
> --- a/arch/arm64/kernel/probes/kprobes.c
> +++ b/arch/arm64/kernel/probes/kprobes.c
> @@ -120,15 +120,9 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
>
>  void *alloc_insn_page(void)
>  {
> -       void *page;
> -
> -       page = vmalloc_exec(PAGE_SIZE);
> -       if (page) {
> -               set_memory_ro((unsigned long)page, 1);
> -               set_vm_flush_reset_perms(page);
> -       }
> -
> -       return page;
> +       return __vmalloc_node_range(PAGE_SIZE, 1, VMALLOC_START, VMALLOC_END,
> +                       GFP_KERNEL, PAGE_KERNEL_ROX, VM_FLUSH_RESET_PERMS,
> +                       NUMA_NO_NODE, __func__);

Why is this passing a string for the 'caller' argument, and not the
address of the caller?


>  }
>
>  /* arm kprobe: install breakpoint in text */
> --
> 2.26.2
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

WARNING: multiple messages have this Message-ID (diff)
From: Ard Biesheuvel <ardb@kernel.org>
To: Christoph Hellwig <hch@lst.de>
Cc: linux-hyperv@vger.kernel.org,
	Peter Zijlstra <peterz@infradead.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	X86 ML <x86@kernel.org>, Dexuan Cui <decui@microsoft.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-mm@kvack.org, Jessica Yu <jeyu@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Will Deacon <will@kernel.org>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 2/3] arm64: use PAGE_KERNEL_ROX directly in alloc_insn_page
Date: Sat, 27 Jun 2020 09:34:42 +0200	[thread overview]
Message-ID: <CAMj1kXH985Aqma47yf96N45CYkTGePVpvihrc_TmOAp2f0vN-g@mail.gmail.com> (raw)
In-Reply-To: <20200618064307.32739-3-hch@lst.de>

On Thu, 18 Jun 2020 at 08:44, Christoph Hellwig <hch@lst.de> wrote:
>
> Use PAGE_KERNEL_ROX directly instead of allocating RWX and setting the
> page read-only just after the allocation.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  arch/arm64/kernel/probes/kprobes.c | 12 +++---------
>  1 file changed, 3 insertions(+), 9 deletions(-)
>
> diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c
> index d1c95dcf1d7833..cbe49cd117cfec 100644
> --- a/arch/arm64/kernel/probes/kprobes.c
> +++ b/arch/arm64/kernel/probes/kprobes.c
> @@ -120,15 +120,9 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
>
>  void *alloc_insn_page(void)
>  {
> -       void *page;
> -
> -       page = vmalloc_exec(PAGE_SIZE);
> -       if (page) {
> -               set_memory_ro((unsigned long)page, 1);
> -               set_vm_flush_reset_perms(page);
> -       }
> -
> -       return page;
> +       return __vmalloc_node_range(PAGE_SIZE, 1, VMALLOC_START, VMALLOC_END,
> +                       GFP_KERNEL, PAGE_KERNEL_ROX, VM_FLUSH_RESET_PERMS,
> +                       NUMA_NO_NODE, __func__);

Why is this passing a string for the 'caller' argument, and not the
address of the caller?


>  }
>
>  /* arm kprobe: install breakpoint in text */
> --
> 2.26.2
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  parent reply	other threads:[~2020-06-27  7:34 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-18  6:43 fix a hyperv W^X violation and remove vmalloc_exec Christoph Hellwig
2020-06-18  6:43 ` Christoph Hellwig
2020-06-18  6:43 ` [PATCH 1/3] x86/hyperv: allocate the hypercall page with only read and execute bits Christoph Hellwig
2020-06-18  6:43   ` Christoph Hellwig
2020-06-18 11:47   ` Wei Liu
2020-06-18 11:47     ` Wei Liu
2020-06-18  6:43 ` [PATCH 2/3] arm64: use PAGE_KERNEL_ROX directly in alloc_insn_page Christoph Hellwig
2020-06-18  6:43   ` Christoph Hellwig
2020-06-18  8:55   ` David Hildenbrand
2020-06-18  8:55     ` David Hildenbrand
2020-06-18 10:35     ` Peter Zijlstra
2020-06-18 10:35       ` Peter Zijlstra
2020-06-18 13:50       ` Christoph Hellwig
2020-06-18 13:50         ` Christoph Hellwig
2020-06-18  9:27   ` Peter Zijlstra
2020-06-18  9:27     ` Peter Zijlstra
2020-06-21  2:16   ` Andrew Morton
2020-06-23  9:05     ` Christoph Hellwig
2020-06-23  9:07       ` Will Deacon
2020-06-23  9:37         ` Peter Zijlstra
2020-06-23  9:57           ` Will Deacon
2020-06-27  7:34   ` Ard Biesheuvel [this message]
2020-06-27  7:34     ` Ard Biesheuvel
2020-06-27  7:34     ` Ard Biesheuvel
2020-06-27  7:56     ` Christoph Hellwig
2020-06-27  7:56       ` Christoph Hellwig
2020-06-27  7:57       ` Ard Biesheuvel
2020-06-27  7:57         ` Ard Biesheuvel
2020-06-27  7:57         ` Ard Biesheuvel
2020-06-18  6:43 ` [PATCH 3/3] mm: remove vmalloc_exec Christoph Hellwig
2020-06-18  6:43   ` Christoph Hellwig
2020-06-18  8:53   ` David Hildenbrand
2020-06-18  8:53     ` David Hildenbrand
2020-06-18  9:28 ` fix a hyperv W^X violation and " Peter Zijlstra
2020-06-18  9:28   ` Peter Zijlstra

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