From: "Ard Biesheuvel" <ardb@kernel.org>
To: "Kevin Brodsky" <kevin.brodsky@arm.com>,
"Ard Biesheuvel" <ardb+git@google.com>,
linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org, "Will Deacon" <will@kernel.org>,
"Catalin Marinas" <catalin.marinas@arm.com>,
"Mark Rutland" <mark.rutland@arm.com>,
"Ryan Roberts" <ryan.roberts@arm.com>,
"Anshuman Khandual" <anshuman.khandual@arm.com>,
"Liz Prucka" <lizprucka@google.com>,
"Seth Jenkins" <sethjenkins@google.com>,
"Kees Cook" <kees@kernel.org>, "Mike Rapoport" <rppt@kernel.org>,
"David Hildenbrand" <david@kernel.org>,
"Andrew Morton" <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-hardening@vger.kernel.org
Subject: Re: [PATCH v4 15/15] arm64: mm: Remap linear aliases of the fixmap page tables read-only
Date: Wed, 29 Apr 2026 16:08:48 +0200 [thread overview]
Message-ID: <5e0a87ad-50d5-420b-ad5a-c2882a619b35@app.fastmail.com> (raw)
In-Reply-To: <21a547ae-7121-4cd1-b203-4d8182eb7cc9@arm.com>
Hi Ard,
On Wed, 29 Apr 2026, at 15:57, Kevin Brodsky wrote:
> On 27/04/2026 17:34, Ard Biesheuvel wrote:
>> [...]
>>
>> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
>> index 84d81bae07a7..e76fe5b0c5fe 100644
>> --- a/arch/arm64/mm/mmu.c
>> +++ b/arch/arm64/mm/mmu.c
>> @@ -1076,6 +1076,11 @@ void __init mark_linear_text_alias_ro(void)
>> (unsigned long)__init_begin - (unsigned long)_text,
>> pgprot_tagged(PAGE_KERNEL_RO));
>>
>> + /* Map the fixmap PTE table at __fixmap_pgdir_start R/O in linear map too */
>> + update_mapping_prot(__pa_symbol(__fixmap_pgdir_start),
>> + (unsigned long)lm_alias(__fixmap_pgdir_start),
>> + PAGE_SIZE, pgprot_tagged(PAGE_KERNEL_RO));
>
> Is that definitely just one page?
>
No it most definitely is not - thanks for spotting that :-)
prev parent reply other threads:[~2026-04-29 14:09 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-27 15:34 [PATCH v4 00/15] arm64: Unmap linear alias of kernel data/bss Ard Biesheuvel
2026-04-27 15:34 ` [PATCH v4 01/15] arm64: mm: Map the linear alias of text/rodata as tagged Ard Biesheuvel
2026-04-28 14:16 ` Kevin Brodsky
2026-04-28 16:23 ` Ard Biesheuvel
2026-04-29 7:57 ` Kevin Brodsky
2026-04-29 7:58 ` Ard Biesheuvel
2026-04-27 15:34 ` [PATCH v4 02/15] mm: Make empty_zero_page __ro_after_init Ard Biesheuvel
2026-04-28 12:27 ` Mike Rapoport
2026-04-28 14:16 ` Kevin Brodsky
2026-04-28 19:51 ` David Hildenbrand (Arm)
2026-04-27 15:34 ` [PATCH v4 03/15] arm64: mm: Preserve existing table mappings when mapping DRAM Ard Biesheuvel
2026-04-27 15:34 ` [PATCH v4 04/15] arm64: mm: Preserve non-contiguous descriptors " Ard Biesheuvel
2026-04-27 15:34 ` [PATCH v4 05/15] arm64: mm: Remove bogus stop condition from map_mem() loop Ard Biesheuvel
2026-04-28 14:33 ` Kevin Brodsky
2026-04-27 15:34 ` [PATCH v4 06/15] arm64: mm: Drop redundant pgd_t* argument from map_mem() Ard Biesheuvel
2026-04-28 14:33 ` Kevin Brodsky
2026-04-27 15:34 ` [PATCH v4 07/15] arm64: mm: Permit contiguous descriptors to be rewritten Ard Biesheuvel
2026-04-27 15:34 ` [PATCH v4 08/15] arm64: kfence: Avoid NOMAP tricks when mapping the early pool Ard Biesheuvel
2026-04-27 15:34 ` [PATCH v4 09/15] arm64: mm: Permit contiguous attribute for preliminary mappings Ard Biesheuvel
2026-04-27 15:34 ` [PATCH v4 10/15] arm64: Move fixmap page tables to end of kernel image Ard Biesheuvel
2026-04-29 13:52 ` Kevin Brodsky
2026-04-27 15:34 ` [PATCH v4 11/15] arm64: mm: Don't abuse memblock NOMAP to check for overlaps Ard Biesheuvel
2026-04-29 10:54 ` Kevin Brodsky
2026-04-29 14:23 ` Ard Biesheuvel
2026-04-29 14:30 ` Kevin Brodsky
2026-04-27 15:34 ` [PATCH v4 12/15] arm64: mm: Map the kernel data/bss read-only in the linear map Ard Biesheuvel
2026-04-29 13:54 ` Kevin Brodsky
2026-04-29 14:46 ` Ard Biesheuvel
2026-05-04 8:50 ` Kevin Brodsky
2026-04-27 15:34 ` [PATCH v4 13/15] arm64: mm: Unmap kernel data/bss entirely from " Ard Biesheuvel
2026-04-29 13:55 ` Kevin Brodsky
2026-04-29 17:37 ` Ard Biesheuvel
2026-05-04 8:52 ` Kevin Brodsky
2026-04-27 15:34 ` [PATCH v4 14/15] arm64: mm: Generalize manipulation code of read-only descriptors Ard Biesheuvel
2026-04-29 13:57 ` Kevin Brodsky
2026-04-27 15:34 ` [PATCH v4 15/15] arm64: mm: Remap linear aliases of the fixmap page tables read-only Ard Biesheuvel
2026-04-29 13:57 ` Kevin Brodsky
2026-04-29 14:08 ` Ard Biesheuvel [this message]
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