From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ard Biesheuvel Subject: Re: [PATCH v2 5/7] arm: efi: split zImage code and data into separate PE/COFF sections Date: Fri, 8 Sep 2017 16:11:53 +0100 Message-ID: References: <20170629081849.15081-1-ard.biesheuvel@linaro.org> <20170629081849.15081-6-ard.biesheuvel@linaro.org> <87r2vhs3il.fsf@free-electrons.com> <87mv65s1iu.fsf@free-electrons.com> <87efrhs0gj.fsf@free-electrons.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Return-path: In-Reply-To: Sender: linux-efi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Gregory CLEMENT Cc: Thomas Petazzoni , Andrew Lunn , "linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Jason Cooper , Matt Fleming , =?UTF-8?Q?Antoine_T=C3=A9nart?= , Russell King , Leif Lindholm , Miquel RAYNAL , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , Sebastian Hesselbarth List-Id: linux-efi@vger.kernel.org On 8 September 2017 at 15:57, Ard Biesheuvel wrote: > On 8 September 2017 at 15:56, Gregory CLEMENT > wrote: >> Hi Ard, >> >> On ven., sept. 08 2017, Ard Biesheuvel wrote: >> >>> On 8 September 2017 at 15:33, Gregory CLEMENT >>> wrote: >>>> Hi Ard, >>>> >>>> On ven., sept. 08 2017, Ard Biesheuvel wrote: >>>> >>>>> On 8 September 2017 at 14:54, Ard Biesheuvel wrote: >>>>>> On 8 September 2017 at 14:50, Gregory CLEMENT >>>>>> wrote: >>>>>>> Hi Ard, >>>>>>> >>>>>>> On jeu., juin 29 2017, Ard Biesheuvel wrote: >>>>>>> >>>>>>>> To prevent unintended modifications to the kernel text (malicious or >>>>>>>> otherwise) while running the EFI stub, describe the kernel image as >>>>>>>> two separate sections: a .text section with read-execute permissions, >>>>>>>> covering .text, .rodata, .piggytext and the GOT sections (which the >>>>>>>> stub does not care about anyway), and a .data section with read-write >>>>>>>> permissions, covering .data and .bss. >>>>>>>> >>>>>>>> This relies on the firmware to actually take the section permission >>>>>>>> flags into account, but this is something that is currently being >>>>>>>> implemented in EDK2, which means we will likely start seeing it in >>>>>>>> the wild between one and two years from now. >>>>>>> >>>>>>> This patch had been merged in mainline yesterday and now prevent the >>>>>>> Marvell Armada 370 and the Armada XP based SoC to boot. I also suspect >>>>>>> that more Socs are impacted because the number of boot fail exploded >>>>>>> according to kci: >>>>>>> https://kernelci.org/boot/all/job/mainline/branch/master/kernel/v4.13-8899-g8dc5b3a6cb2f/ >>>>>>> >>>>>> >>>>>> Ouch. >>>>>> >>>>>>> I found this patch after bisecting (I can provide the bisect log if >>>>>>> needed). >>>>>>> >>>>>>> The kernel failed to boot only if CONFIG_EFI is enabled so it occurs in >>>>>>> multi_v7_defconfig but not with mvebu_v7_defconfig. >>>>>>> >>>>>>> Currently the solution is to revert this patch. >>>>>>> >>>>>>> Have you a better option? >>>>>>> >>>>>> >>>>>> I will investigate. >>>>> >>>>> I cannot reproduce this on QEMU or my Beaglebone white. I have tried a >>>>> locally built zImage as well as the one built by kernelci. >>>>> >>>>> Could you please try whether this fixes things? It does not explain >>>>> anything but it will help me figure out what is going on (hopefully) >>>> >>>> I've just tested this change and it didn't fix anything. >>>> >>>> Gregory >>>> >>>>> >>>>> >>>>> diff --git a/arch/arm/boot/compressed/efi-header.S >>>>> b/arch/arm/boot/compressed/efi-header.S >>>>> index c94a88ae834d..671a6e5b7b99 100644 >>>>> --- a/arch/arm/boot/compressed/efi-header.S >>>>> +++ b/arch/arm/boot/compressed/efi-header.S >>>>> @@ -127,7 +127,7 @@ section_table: >>>>> >>>>> .set section_count, (. - section_table) / 40 >>>>> >>>>> - .align 12 >>>>> + .align 9 >>>>> __efi_start: >>>>> #endif >>>>> .endm >>>> >>> >>> >>> How about this? >> >> It fixed the bug! (I tested with and without your previous patch and it >> worked in both case) >> >> When you will send your patch, you can add my: >> Tested-by: Gregory CLEMENT >> Would you mind checking whether this fixes the issue as well? diff --git a/arch/arm/boot/compressed/piggy.S b/arch/arm/boot/compressed/piggy.S index f72088495f43..5d52c556dd32 100644 --- a/arch/arm/boot/compressed/piggy.S +++ b/arch/arm/boot/compressed/piggy.S @@ -1,5 +1,6 @@ .section .piggydata,#alloc .globl input_data + .align 2 input_data: .incbin "arch/arm/boot/compressed/piggy_data" .globl input_data_end There may be other reasons than ksymtab entries that could result in piggydata ending up unaligned in the decompressor (which is what caused the issue before) This is a better fix, because it addresses the root cause. From mboxrd@z Thu Jan 1 00:00:00 1970 From: ard.biesheuvel@linaro.org (Ard Biesheuvel) Date: Fri, 8 Sep 2017 16:11:53 +0100 Subject: [PATCH v2 5/7] arm: efi: split zImage code and data into separate PE/COFF sections In-Reply-To: References: <20170629081849.15081-1-ard.biesheuvel@linaro.org> <20170629081849.15081-6-ard.biesheuvel@linaro.org> <87r2vhs3il.fsf@free-electrons.com> <87mv65s1iu.fsf@free-electrons.com> <87efrhs0gj.fsf@free-electrons.com> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 8 September 2017 at 15:57, Ard Biesheuvel wrote: > On 8 September 2017 at 15:56, Gregory CLEMENT > wrote: >> Hi Ard, >> >> On ven., sept. 08 2017, Ard Biesheuvel wrote: >> >>> On 8 September 2017 at 15:33, Gregory CLEMENT >>> wrote: >>>> Hi Ard, >>>> >>>> On ven., sept. 08 2017, Ard Biesheuvel wrote: >>>> >>>>> On 8 September 2017 at 14:54, Ard Biesheuvel wrote: >>>>>> On 8 September 2017 at 14:50, Gregory CLEMENT >>>>>> wrote: >>>>>>> Hi Ard, >>>>>>> >>>>>>> On jeu., juin 29 2017, Ard Biesheuvel wrote: >>>>>>> >>>>>>>> To prevent unintended modifications to the kernel text (malicious or >>>>>>>> otherwise) while running the EFI stub, describe the kernel image as >>>>>>>> two separate sections: a .text section with read-execute permissions, >>>>>>>> covering .text, .rodata, .piggytext and the GOT sections (which the >>>>>>>> stub does not care about anyway), and a .data section with read-write >>>>>>>> permissions, covering .data and .bss. >>>>>>>> >>>>>>>> This relies on the firmware to actually take the section permission >>>>>>>> flags into account, but this is something that is currently being >>>>>>>> implemented in EDK2, which means we will likely start seeing it in >>>>>>>> the wild between one and two years from now. >>>>>>> >>>>>>> This patch had been merged in mainline yesterday and now prevent the >>>>>>> Marvell Armada 370 and the Armada XP based SoC to boot. I also suspect >>>>>>> that more Socs are impacted because the number of boot fail exploded >>>>>>> according to kci: >>>>>>> https://kernelci.org/boot/all/job/mainline/branch/master/kernel/v4.13-8899-g8dc5b3a6cb2f/ >>>>>>> >>>>>> >>>>>> Ouch. >>>>>> >>>>>>> I found this patch after bisecting (I can provide the bisect log if >>>>>>> needed). >>>>>>> >>>>>>> The kernel failed to boot only if CONFIG_EFI is enabled so it occurs in >>>>>>> multi_v7_defconfig but not with mvebu_v7_defconfig. >>>>>>> >>>>>>> Currently the solution is to revert this patch. >>>>>>> >>>>>>> Have you a better option? >>>>>>> >>>>>> >>>>>> I will investigate. >>>>> >>>>> I cannot reproduce this on QEMU or my Beaglebone white. I have tried a >>>>> locally built zImage as well as the one built by kernelci. >>>>> >>>>> Could you please try whether this fixes things? It does not explain >>>>> anything but it will help me figure out what is going on (hopefully) >>>> >>>> I've just tested this change and it didn't fix anything. >>>> >>>> Gregory >>>> >>>>> >>>>> >>>>> diff --git a/arch/arm/boot/compressed/efi-header.S >>>>> b/arch/arm/boot/compressed/efi-header.S >>>>> index c94a88ae834d..671a6e5b7b99 100644 >>>>> --- a/arch/arm/boot/compressed/efi-header.S >>>>> +++ b/arch/arm/boot/compressed/efi-header.S >>>>> @@ -127,7 +127,7 @@ section_table: >>>>> >>>>> .set section_count, (. - section_table) / 40 >>>>> >>>>> - .align 12 >>>>> + .align 9 >>>>> __efi_start: >>>>> #endif >>>>> .endm >>>> >>> >>> >>> How about this? >> >> It fixed the bug! (I tested with and without your previous patch and it >> worked in both case) >> >> When you will send your patch, you can add my: >> Tested-by: Gregory CLEMENT >> Would you mind checking whether this fixes the issue as well? diff --git a/arch/arm/boot/compressed/piggy.S b/arch/arm/boot/compressed/piggy.S index f72088495f43..5d52c556dd32 100644 --- a/arch/arm/boot/compressed/piggy.S +++ b/arch/arm/boot/compressed/piggy.S @@ -1,5 +1,6 @@ .section .piggydata,#alloc .globl input_data + .align 2 input_data: .incbin "arch/arm/boot/compressed/piggy_data" .globl input_data_end There may be other reasons than ksymtab entries that could result in piggydata ending up unaligned in the decompressor (which is what caused the issue before) This is a better fix, because it addresses the root cause.