From: Ingo Molnar <mingo@kernel.org>
To: Arvind Sankar <nivedita@alum.mit.edu>
Cc: Kees Cook <keescook@chromium.org>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 7/8] x86/kaslr: Clean up slot handling
Date: Tue, 28 Jul 2020 12:59:26 +0200 [thread overview]
Message-ID: <20200728105926.GD222284@gmail.com> (raw)
In-Reply-To: <20200727215047.3341098-8-nivedita@alum.mit.edu>
* Arvind Sankar <nivedita@alum.mit.edu> wrote:
> The number of slots and slot areas can be unsigned int, since on 64-bit,
> the maximum amount of memory is 2^52, the minimum alignment is 2^21, so
> the slot number cannot be greater than 2^31. The slot areas are limited
> by MAX_SLOT_AREA, currently 100. Replace the type used for slot number,
> which is currently a mix of int and unsigned long, with unsigned int
> consistently.
>
> Drop unnecessary check that number of slots is not zero in
> store_slot_info, it's guaranteed to be at least 1 by the calculation.
>
> Drop unnecessary alignment of image_size to CONFIG_PHYSICAL_ALIGN in
> find_random_virt_addr, it cannot change the result: the largest valid
> slot is the largest n that satisfies
>
> minimum + n * CONFIG_PHYSICAL_ALIGN + image_size <= KERNEL_IMAGE_SIZE
>
> (since minimum is already aligned) and so n is equal to
>
> (KERNEL_IMAGE_SIZE - minimum - image_size) / CONFIG_PHYSICAL_ALIGN
>
> even if image_size is not aligned to CONFIG_PHYSICAL_ALIGN.
Please split this up into a couple of easily bisectable patches as
well:
- first one harmonizes the integer types used
- patch that drops the unnecessary check
- patch that drops the unnecessary alignment operation
Thanks,
Ingo
next prev parent reply other threads:[~2020-07-28 10:59 UTC|newest]
Thread overview: 91+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-27 21:50 [PATCH 0/8] x86/kaslr: Cleanup and small bugfixes Arvind Sankar
2020-07-27 21:50 ` [PATCH 1/8] x86/kaslr: Make command line handling safer Arvind Sankar
2020-07-27 21:50 ` [PATCH 2/8] x86/kaslr: Remove bogus warning and unnecessary goto Arvind Sankar
2020-07-27 21:50 ` [PATCH 3/8] x86/kaslr: Fix process_efi_entries comment Arvind Sankar
2020-07-27 21:50 ` [PATCH 4/8] x86/kaslr: Initialize mem_limit to the real maximum address Arvind Sankar
2020-07-27 21:50 ` [PATCH 5/8] x86/kaslr: Simplify __process_mem_region Arvind Sankar
2020-07-28 10:57 ` Ingo Molnar
2020-07-27 21:50 ` [PATCH 6/8] x86/kaslr: Simplify process_gb_huge_pages Arvind Sankar
2020-07-28 10:58 ` Ingo Molnar
2020-07-27 21:50 ` [PATCH 7/8] x86/kaslr: Clean up slot handling Arvind Sankar
2020-07-28 10:59 ` Ingo Molnar [this message]
2020-07-27 21:50 ` [PATCH 8/8] x86/kaslr: Don't use 64-bit mem_vector for 32-bit kernel Arvind Sankar
2020-07-28 11:05 ` Ingo Molnar
2020-07-27 23:07 ` [PATCH v2 0/8] x86/kaslr: Cleanup and small bugfixes Arvind Sankar
2020-07-28 11:06 ` Ingo Molnar
2020-07-28 14:24 ` Arvind Sankar
2020-07-28 22:57 ` [PATCH v3 00/21] " Arvind Sankar
2020-07-30 18:02 ` Arvind Sankar
2020-07-31 9:21 ` Ingo Molnar
2020-07-31 23:33 ` Kees Cook
2020-08-03 1:15 ` [PATCH 0/1] x86/kaslr: Replace strlen with strnlen Arvind Sankar
2020-08-03 1:15 ` [PATCH 1/1] " Arvind Sankar
2020-08-06 23:38 ` [tip: x86/kaslr] x86/kaslr: Replace strlen() with strnlen() tip-bot2 for Arvind Sankar
2020-08-14 22:47 ` [PATCH v3 00/21] x86/kaslr: Cleanup and small bugfixes Arvind Sankar
2020-07-28 22:57 ` [PATCH v3 01/21] x86/kaslr: Make command line handling safer Arvind Sankar
2020-07-28 22:57 ` [PATCH v3 02/21] x86/kaslr: Remove bogus warning and unnecessary goto Arvind Sankar
2020-07-28 22:57 ` [PATCH v3 03/21] x86/kaslr: Fix process_efi_entries comment Arvind Sankar
2020-07-28 22:57 ` [PATCH v3 04/21] x86/kaslr: Initialize mem_limit to the real maximum address Arvind Sankar
2020-07-28 22:57 ` [PATCH v3 05/21] x86/kaslr: Fix off-by-one error in __process_mem_region Arvind Sankar
2020-08-06 23:39 ` [tip: x86/kaslr] x86/kaslr: Fix off-by-one error in __process_mem_region() tip-bot2 for Arvind Sankar
2020-07-28 22:57 ` [PATCH v3 06/21] x86/kaslr: Drop redundant cur_entry from __process_mem_region Arvind Sankar
2020-08-06 23:39 ` [tip: x86/kaslr] x86/kaslr: Drop redundant cur_entry from __process_mem_region() tip-bot2 for Arvind Sankar
2020-07-28 22:57 ` [PATCH v3 07/21] x86/kaslr: Eliminate start_orig from __process_mem_region Arvind Sankar
2020-08-06 23:38 ` [tip: x86/kaslr] x86/kaslr: Eliminate 'start_orig' local variable from __process_mem_region() tip-bot2 for Arvind Sankar
2020-07-28 22:57 ` [PATCH v3 08/21] x86/kaslr: Drop redundant variable in __process_mem_region Arvind Sankar
2020-08-06 23:38 ` [tip: x86/kaslr] x86/kaslr: Drop redundant variable in __process_mem_region() tip-bot2 for Arvind Sankar
2020-07-28 22:57 ` [PATCH v3 09/21] x86/kaslr: Drop some redundant checks from __process_mem_region Arvind Sankar
2020-08-06 23:38 ` [tip: x86/kaslr] x86/kaslr: Drop some redundant checks from __process_mem_region() tip-bot2 for Arvind Sankar
2020-07-28 22:57 ` [PATCH v3 10/21] x86/kaslr: Fix off-by-one error in process_gb_huge_pages Arvind Sankar
2020-08-06 23:38 ` [tip: x86/kaslr] x86/kaslr: Fix off-by-one error in process_gb_huge_pages() tip-bot2 for Arvind Sankar
2020-07-28 22:57 ` [PATCH v3 11/21] x86/kaslr: Short-circuit gb_huge_pages on x86-32 Arvind Sankar
2020-08-06 23:38 ` [tip: x86/kaslr] " tip-bot2 for Arvind Sankar
2020-07-28 22:57 ` [PATCH v3 12/21] x86/kaslr: Simplify process_gb_huge_pages Arvind Sankar
2020-08-06 23:38 ` [tip: x86/kaslr] x86/kaslr: Simplify process_gb_huge_pages() tip-bot2 for Arvind Sankar
2020-07-28 22:57 ` [PATCH v3 13/21] x86/kaslr: Drop test for command-line parameters before parsing Arvind Sankar
2020-08-06 23:38 ` [tip: x86/kaslr] " tip-bot2 for Arvind Sankar
2020-07-28 22:57 ` [PATCH v3 14/21] x86/kaslr: Make the type of number of slots/slot areas consistent Arvind Sankar
2020-08-06 23:38 ` [tip: x86/kaslr] " tip-bot2 for Arvind Sankar
2020-07-28 22:57 ` [PATCH v3 15/21] x86/kaslr: Drop redundant check in store_slot_info Arvind Sankar
2020-08-06 23:38 ` [tip: x86/kaslr] x86/kaslr: Drop redundant check in store_slot_info() tip-bot2 for Arvind Sankar
2020-07-28 22:57 ` [PATCH v3 16/21] x86/kaslr: Drop unnecessary alignment in find_random_virt_addr Arvind Sankar
2020-08-06 23:38 ` [tip: x86/kaslr] x86/kaslr: Drop unnecessary alignment in find_random_virt_addr() tip-bot2 for Arvind Sankar
2020-07-28 22:57 ` [PATCH v3 17/21] x86/kaslr: Small cleanup of find_random_phys_addr Arvind Sankar
2020-08-06 23:38 ` [tip: x86/kaslr] x86/kaslr: Small cleanup of find_random_phys_addr() tip-bot2 for Arvind Sankar
2020-07-28 22:57 ` [PATCH v3 18/21] x86/kaslr: Make minimum/image_size unsigned long Arvind Sankar
2020-08-06 23:38 ` [tip: x86/kaslr] x86/kaslr: Make minimum/image_size 'unsigned long' tip-bot2 for Arvind Sankar
2020-07-28 22:57 ` [PATCH v3 19/21] x86/kaslr: Replace unsigned long long with u64 Arvind Sankar
2020-08-06 23:38 ` [tip: x86/kaslr] x86/kaslr: Replace 'unsigned long long' with 'u64' tip-bot2 for Arvind Sankar
2020-07-28 22:57 ` [PATCH v3 20/21] x86/kaslr: Make local variables 64-bit Arvind Sankar
2020-08-06 23:38 ` [tip: x86/kaslr] " tip-bot2 for Arvind Sankar
2020-07-28 22:57 ` [PATCH v3 21/21] x86/kaslr: Add a check that the random address is in range Arvind Sankar
2020-08-06 23:38 ` [tip: x86/kaslr] " tip-bot2 for Arvind Sankar
2020-07-27 23:07 ` [PATCH v2 1/8] x86/kaslr: Make command line handling safer Arvind Sankar
2020-07-28 12:29 ` [tip: x86/kaslr] " tip-bot2 for Arvind Sankar
2020-07-28 18:26 ` [PATCH v2 1/8] " Kees Cook
2020-08-06 23:39 ` [tip: x86/kaslr] " tip-bot2 for Arvind Sankar
2020-07-27 23:07 ` [PATCH v2 2/8] x86/kaslr: Remove bogus warning and unnecessary goto Arvind Sankar
2020-07-28 12:29 ` [tip: x86/kaslr] " tip-bot2 for Arvind Sankar
2020-07-28 18:26 ` [PATCH v2 2/8] " Kees Cook
2020-08-06 23:39 ` [tip: x86/kaslr] " tip-bot2 for Arvind Sankar
2020-07-27 23:07 ` [PATCH v2 3/8] x86/kaslr: Fix process_efi_entries comment Arvind Sankar
2020-07-28 12:29 ` [tip: x86/kaslr] " tip-bot2 for Arvind Sankar
2020-07-28 18:27 ` [PATCH v2 3/8] " Kees Cook
2020-08-06 23:39 ` [tip: x86/kaslr] " tip-bot2 for Arvind Sankar
2020-07-27 23:07 ` [PATCH v2 4/8] x86/kaslr: Initialize mem_limit to the real maximum address Arvind Sankar
2020-07-28 12:29 ` [tip: x86/kaslr] " tip-bot2 for Arvind Sankar
2020-07-28 18:49 ` [PATCH v2 4/8] " Kees Cook
2020-08-06 23:39 ` [tip: x86/kaslr] " tip-bot2 for Arvind Sankar
2020-07-27 23:07 ` [PATCH v2 5/8] x86/kaslr: Simplify __process_mem_region Arvind Sankar
2020-07-28 19:25 ` Kees Cook
2020-07-28 19:42 ` Arvind Sankar
2020-07-27 23:07 ` [PATCH v2 6/8] x86/kaslr: Simplify process_gb_huge_pages Arvind Sankar
2020-07-28 19:27 ` Kees Cook
2020-07-28 19:45 ` Arvind Sankar
2020-07-28 20:13 ` Kees Cook
2020-07-27 23:08 ` [PATCH v2 7/8] x86/kaslr: Clean up slot handling Arvind Sankar
2020-07-28 19:34 ` Kees Cook
2020-07-28 20:04 ` Arvind Sankar
2020-07-27 23:08 ` [PATCH v2 8/8] x86/kaslr: Don't use 64-bit mem_vector for 32-bit kernel Arvind Sankar
2020-07-28 19:37 ` Kees Cook
2020-07-28 20:08 ` Arvind Sankar
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