From: Anshuman Khandual <anshuman.khandual@arm.com>
To: Ard Biesheuvel <ardb@google.com>, linux-arm-kernel@lists.infradead.org
Cc: Ard Biesheuvel <ardb@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Ryan Roberts <ryan.roberts@arm.com>,
Kees Cook <keescook@chromium.org>
Subject: Re: [PATCH v6 01/41] arm64: kernel: Disable latent_entropy GCC plugin in early C runtime
Date: Thu, 30 Nov 2023 10:14:13 +0530 [thread overview]
Message-ID: <f9b42e4f-f443-4f75-8b07-b85379bbd35a@arm.com> (raw)
In-Reply-To: <20231129111555.3594833-44-ardb@google.com>
On 11/29/23 16:45, Ard Biesheuvel wrote:
> From: Ard Biesheuvel <ardb@kernel.org>
>
> In subsequent patches, mark portions of the early C code will be marked
Small nit - ^^^ redundant usage for mark ^^^^^^
> as __init. Unfortunarely, __init implies __latent_entropy, and this
Typo here - s/Unfortunarely/Unfortunately/
> would result in the early C code being instrumented in an unsafe manner.
>
> Disable the latent entropy plugin for the early C code.
I am just wondering if this '__latent_entropy' could be problematic for all
early __init code in each supported platform. Although this plugin does not
get disabled in that many places inside the kernel tree.
$git grep DISABLE_LATENT_ENTROPY_PLUGIN
arch/arm64/kernel/pi/Makefile: $(DISABLE_LATENT_ENTROPY_PLUGIN) \
arch/powerpc/kernel/Makefile:CFLAGS_early_32.o += $(DISABLE_LATENT_ENTROPY_PLUGIN)
arch/powerpc/kernel/Makefile:CFLAGS_cputable.o += $(DISABLE_LATENT_ENTROPY_PLUGIN)
arch/powerpc/kernel/Makefile:CFLAGS_prom_init.o += $(DISABLE_LATENT_ENTROPY_PLUGIN)
arch/powerpc/kernel/Makefile:CFLAGS_btext.o += $(DISABLE_LATENT_ENTROPY_PLUGIN)
arch/powerpc/kernel/Makefile:CFLAGS_prom.o += $(DISABLE_LATENT_ENTROPY_PLUGIN)
arch/powerpc/kernel/vdso/Makefile: CFLAGS_vgettimeofday-32.o += $(DISABLE_LATENT_ENTROPY_PLUGIN)
arch/powerpc/kernel/vdso/Makefile: CFLAGS_vgettimeofday-64.o += $(DISABLE_LATENT_ENTROPY_PLUGIN)
arch/powerpc/lib/Makefile:CFLAGS_code-patching.o += $(DISABLE_LATENT_ENTROPY_PLUGIN)
arch/powerpc/lib/Makefile:CFLAGS_feature-fixups.o += $(DISABLE_LATENT_ENTROPY_PLUGIN)
scripts/Makefile.gcc-plugins: DISABLE_LATENT_ENTROPY_PLUGIN += -fplugin-arg-latent_entropy_plugin-disable -ULATENT_ENTROPY_PLUGIN
scripts/Makefile.gcc-plugins:export DISABLE_LATENT_ENTROPY_PLUGIN
>
> Acked-by: Mark Rutland <mark.rutland@arm.com>
> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
> ---
> arch/arm64/kernel/pi/Makefile | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/arm64/kernel/pi/Makefile b/arch/arm64/kernel/pi/Makefile
> index 4c0ea3cd4ea4..c844a0546d7f 100644
> --- a/arch/arm64/kernel/pi/Makefile
> +++ b/arch/arm64/kernel/pi/Makefile
> @@ -3,6 +3,7 @@
>
> KBUILD_CFLAGS := $(subst $(CC_FLAGS_FTRACE),,$(KBUILD_CFLAGS)) -fpie \
> -Os -DDISABLE_BRANCH_PROFILING $(DISABLE_STACKLEAK_PLUGIN) \
> + $(DISABLE_LATENT_ENTROPY_PLUGIN) \
> $(call cc-option,-mbranch-protection=none) \
> -I$(srctree)/scripts/dtc/libfdt -fno-stack-protector \
> -include $(srctree)/include/linux/hidden.h \
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next prev parent reply other threads:[~2023-11-30 4:45 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-29 11:15 [PATCH v6 00/41] arm64: Reorganize kernel VA space for LPA2 Ard Biesheuvel
2023-11-29 11:15 ` [PATCH v6 01/41] arm64: kernel: Disable latent_entropy GCC plugin in early C runtime Ard Biesheuvel
2023-11-30 4:44 ` Anshuman Khandual [this message]
2023-11-29 11:15 ` [PATCH v6 02/41] arm64: mm: Take potential load offset into account when KASLR is off Ard Biesheuvel
2023-11-30 5:23 ` Anshuman Khandual
2023-12-04 14:12 ` Mark Rutland
2023-12-04 15:40 ` Ard Biesheuvel
2023-11-29 11:15 ` [PATCH v6 03/41] arm64: mm: get rid of kimage_vaddr global variable Ard Biesheuvel
2023-11-30 5:38 ` Anshuman Khandual
2023-12-04 14:37 ` Mark Rutland
2023-12-05 2:26 ` Anshuman Khandual
2023-11-29 11:16 ` [PATCH v6 04/41] arm64: mm: Move PCI I/O emulation region above the vmemmap region Ard Biesheuvel
2023-11-30 7:59 ` Anshuman Khandual
2023-11-30 8:02 ` Ard Biesheuvel
2023-11-30 8:52 ` Anshuman Khandual
2023-11-30 8:56 ` Ard Biesheuvel
2023-12-11 13:57 ` Mark Rutland
2023-12-11 14:10 ` Ard Biesheuvel
2023-12-11 14:21 ` Mark Rutland
2023-11-29 11:16 ` [PATCH v6 05/41] arm64: mm: Move fixmap region above " Ard Biesheuvel
2023-12-11 14:23 ` Mark Rutland
2023-11-29 11:16 ` [PATCH v6 06/41] arm64: ptdump: Allow all region boundaries to be defined at boot time Ard Biesheuvel
2023-12-11 14:15 ` Mark Rutland
2023-11-29 11:16 ` [PATCH v6 07/41] arm64: ptdump: Discover start of vmemmap region at runtime Ard Biesheuvel
2023-11-29 11:16 ` [PATCH v6 08/41] arm64: vmemmap: Avoid base2 order of struct page size to dimension region Ard Biesheuvel
2023-12-11 14:35 ` Mark Rutland
2023-12-12 21:34 ` Ard Biesheuvel
2023-11-29 11:16 ` [PATCH v6 09/41] arm64: mm: Reclaim unused vmemmap region for vmalloc use Ard Biesheuvel
2023-11-29 11:16 ` [PATCH v6 10/41] arm64: kaslr: Adjust randomization range dynamically Ard Biesheuvel
2023-11-29 11:16 ` [PATCH v6 11/41] arm64: kernel: Manage absolute relocations in code built under pi/ Ard Biesheuvel
2023-11-29 12:27 ` Marc Zyngier
2023-11-29 12:46 ` Ard Biesheuvel
2023-11-29 11:16 ` [PATCH v6 12/41] arm64: kernel: Don't rely on objcopy to make code under pi/ __init Ard Biesheuvel
2023-11-29 11:16 ` [PATCH v6 13/41] arm64: head: move relocation handling to C code Ard Biesheuvel
2023-11-29 11:16 ` [PATCH v6 14/41] arm64: idreg-override: Omit non-NULL checks for override pointer Ard Biesheuvel
2023-11-29 11:16 ` [PATCH v6 15/41] arm64: idreg-override: Prepare for place relative reloc patching Ard Biesheuvel
2023-11-29 11:16 ` [PATCH v6 16/41] arm64: idreg-override: Avoid parameq() and parameqn() Ard Biesheuvel
2023-11-29 11:16 ` [PATCH v6 17/41] arm64: idreg-override: avoid strlen() to check for empty strings Ard Biesheuvel
2023-11-29 11:16 ` [PATCH v6 18/41] arm64: idreg-override: Avoid sprintf() for simple string concatenation Ard Biesheuvel
2023-11-29 11:16 ` [PATCH v6 19/41] arm64: idreg-override: Avoid kstrtou64() to parse a single hex digit Ard Biesheuvel
2023-11-29 11:16 ` [PATCH v6 20/41] arm64/kernel: Move 'nokaslr' parsing out of early idreg code Ard Biesheuvel
2023-11-29 11:16 ` [PATCH v6 21/41] arm64: idreg-override: Move to early mini C runtime Ard Biesheuvel
2023-11-29 11:16 ` [PATCH v6 22/41] arm64: kernel: Remove early fdt remap code Ard Biesheuvel
2023-11-29 11:16 ` [PATCH v6 23/41] arm64: head: Clear BSS and the kernel page tables in one go Ard Biesheuvel
2023-11-29 11:16 ` [PATCH v6 24/41] arm64: Move feature overrides into the BSS section Ard Biesheuvel
2023-11-29 11:16 ` [PATCH v6 25/41] arm64: head: Run feature override detection before mapping the kernel Ard Biesheuvel
2023-11-29 11:16 ` [PATCH v6 26/41] arm64: head: move dynamic shadow call stack patching into early C runtime Ard Biesheuvel
2023-11-29 11:16 ` [PATCH v6 27/41] arm64: cpufeature: Add helper to test for CPU feature overrides Ard Biesheuvel
2023-11-29 11:16 ` [PATCH v6 28/41] arm64: kaslr: Use feature override instead of parsing the cmdline again Ard Biesheuvel
2023-11-29 11:16 ` [PATCH v6 29/41] arm64: idreg-override: Create a pseudo feature for rodata=off Ard Biesheuvel
2023-11-29 11:16 ` [PATCH v6 30/41] arm64: Add helpers to probe local CPU for PAC and BTI support Ard Biesheuvel
2023-11-29 11:16 ` [PATCH v6 31/41] arm64: head: allocate more pages for the kernel mapping Ard Biesheuvel
2023-11-29 11:16 ` [PATCH v6 32/41] arm64: head: move memstart_offset_seed handling to C code Ard Biesheuvel
2023-11-29 11:16 ` [PATCH v6 33/41] arm64: mm: Make kaslr_requires_kpti() a static inline Ard Biesheuvel
2023-11-29 11:16 ` [PATCH v6 34/41] arm64: mmu: Make __cpu_replace_ttbr1() out of line Ard Biesheuvel
2023-11-29 11:16 ` [PATCH v6 35/41] arm64: head: Move early kernel mapping routines into C code Ard Biesheuvel
2023-11-29 11:16 ` [PATCH v6 36/41] arm64: mm: Use 48-bit virtual addressing for the permanent ID map Ard Biesheuvel
2023-11-29 11:16 ` [PATCH v6 37/41] arm64: pgtable: Decouple PGDIR size macros from PGD/PUD/PMD levels Ard Biesheuvel
2023-11-29 11:16 ` [PATCH v6 38/41] arm64: kernel: Create initial ID map from C code Ard Biesheuvel
2023-11-29 11:16 ` [PATCH v6 39/41] arm64: mm: avoid fixmap for early swapper_pg_dir updates Ard Biesheuvel
2023-11-29 11:16 ` [PATCH v6 40/41] arm64: mm: omit redundant remap of kernel image Ard Biesheuvel
2023-11-29 11:16 ` [PATCH v6 41/41] arm64: Revert "mm: provide idmap pointer to cpu_replace_ttbr1()" Ard Biesheuvel
2023-12-12 17:20 ` [PATCH v6 00/41] arm64: Reorganize kernel VA space for LPA2 Will Deacon
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