From: Jason Yan <yanaijie@huawei.com>
To: Michael Ellerman <mpe@ellerman.id.au>,
<linuxppc-dev@lists.ozlabs.org>, <diana.craciun@nxp.com>,
<christophe.leroy@c-s.fr>, <benh@kernel.crashing.org>,
<paulus@samba.org>, <npiggin@gmail.com>, <keescook@chromium.org>,
<kernel-hardening@lists.openwall.com>
Cc: <linux-kernel@vger.kernel.org>, <wangkefeng.wang@huawei.com>,
<yebin10@huawei.com>, <thunder.leizhen@huawei.com>,
<jingxiangfeng@huawei.com>, <fanchengyang@huawei.com>,
<zhaohongjiang@huawei.com>
Subject: Re: [PATCH v5 10/10] powerpc/fsl_booke/kaslr: dump out kernel offset information on panic
Date: Thu, 8 Aug 2019 16:39:26 +0800 [thread overview]
Message-ID: <9113cc5b-0e89-f423-712a-79220af82b92@huawei.com> (raw)
In-Reply-To: <87zhklt9eg.fsf@concordia.ellerman.id.au>
On 2019/8/7 21:03, Michael Ellerman wrote:
> Jason Yan <yanaijie@huawei.com> writes:
>> When kaslr is enabled, the kernel offset is different for every boot.
>> This brings some difficult to debug the kernel. Dump out the kernel
>> offset when panic so that we can easily debug the kernel.
>
> Some of this is taken from the arm64 version right? Please say so when
> you copy other people's code.
>
No problem. Architectures like x86 or arm64 or s390 both have this
similar code. I guess x86 is the first one.
>> diff --git a/arch/powerpc/kernel/machine_kexec.c b/arch/powerpc/kernel/machine_kexec.c
>> index c4ed328a7b96..078fe3d76feb 100644
>> --- a/arch/powerpc/kernel/machine_kexec.c
>> +++ b/arch/powerpc/kernel/machine_kexec.c
>> @@ -86,6 +86,7 @@ void arch_crash_save_vmcoreinfo(void)
>> VMCOREINFO_STRUCT_SIZE(mmu_psize_def);
>> VMCOREINFO_OFFSET(mmu_psize_def, shift);
>> #endif
>> + vmcoreinfo_append_str("KERNELOFFSET=%lx\n", kaslr_offset());
>> }
>
> There's no mention of that in the commit log.
>
> Please split it into a separate patch and describe what you're doing and
> why.
OK
>
>> diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
>> index 1f8db666468d..064075f02837 100644
>> --- a/arch/powerpc/kernel/setup-common.c
>> +++ b/arch/powerpc/kernel/setup-common.c
>> @@ -715,12 +715,31 @@ static struct notifier_block ppc_panic_block = {
>> .priority = INT_MIN /* may not return; must be done last */
>> };
>>
>> +/*
>> + * Dump out kernel offset information on panic.
>> + */
>> +static int dump_kernel_offset(struct notifier_block *self, unsigned long v,
>> + void *p)
>> +{
>> + pr_emerg("Kernel Offset: 0x%lx from 0x%lx\n",
>> + kaslr_offset(), KERNELBASE);
>> +
>> + return 0;
>> +}
>> +
>> +static struct notifier_block kernel_offset_notifier = {
>> + .notifier_call = dump_kernel_offset
>> +};
>> +
>> void __init setup_panic(void)
>> {
>> /* PPC64 always does a hard irq disable in its panic handler */
>> if (!IS_ENABLED(CONFIG_PPC64) && !ppc_md.panic)
>> return;
>> atomic_notifier_chain_register(&panic_notifier_list, &ppc_panic_block);
>
>> + if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && kaslr_offset() > 0)
>> + atomic_notifier_chain_register(&panic_notifier_list,
>> + &kernel_offset_notifier);
>
> Don't you want to do that before the return above?
>
Eagle eye. This should not affected by the conditions above.
>> }
>
> cheers
>
> .
>
next prev parent reply other threads:[~2019-08-08 8:40 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-07 6:56 [PATCH v5 00/10] implement KASLR for powerpc/fsl_booke/32 Jason Yan
2019-08-07 6:56 ` [PATCH v5 01/10] powerpc: unify definition of M_IF_NEEDED Jason Yan
2019-08-07 13:13 ` Michael Ellerman
2019-08-08 3:25 ` Jason Yan
2019-08-07 6:56 ` [PATCH v5 02/10] powerpc: move memstart_addr and kernstart_addr to init-common.c Jason Yan
2019-08-07 13:02 ` Michael Ellerman
2019-08-08 3:32 ` Jason Yan
2019-08-07 6:56 ` [PATCH v5 03/10] powerpc: introduce kimage_vaddr to store the kernel base Jason Yan
2019-08-07 13:03 ` Michael Ellerman
2019-08-08 4:29 ` Jason Yan
2019-08-07 6:57 ` [PATCH v5 04/10] powerpc/fsl_booke/32: introduce create_tlb_entry() helper Jason Yan
2019-08-07 6:57 ` [PATCH v5 05/10] powerpc/fsl_booke/32: introduce reloc_kernel_entry() helper Jason Yan
2019-08-07 6:57 ` [PATCH v5 06/10] powerpc/fsl_booke/32: implement KASLR infrastructure Jason Yan
2019-08-07 13:04 ` Michael Ellerman
2019-08-08 6:19 ` Jason Yan
2019-08-07 6:57 ` [PATCH v5 07/10] powerpc/fsl_booke/32: randomize the kernel image offset Jason Yan
2019-08-07 13:03 ` Michael Ellerman
2019-08-08 7:08 ` Jason Yan
2019-08-07 6:57 ` [PATCH v5 08/10] powerpc/fsl_booke/kaslr: clear the original kernel if randomized Jason Yan
2019-08-07 6:57 ` [PATCH v5 09/10] powerpc/fsl_booke/kaslr: support nokaslr cmdline parameter Jason Yan
2019-08-07 13:03 ` Michael Ellerman
2019-08-08 8:19 ` Jason Yan
2019-08-07 6:57 ` [PATCH v5 10/10] powerpc/fsl_booke/kaslr: dump out kernel offset information on panic Jason Yan
2019-08-07 13:03 ` Michael Ellerman
2019-08-08 8:39 ` Jason Yan [this message]
2019-08-07 13:12 ` [PATCH v5 00/10] implement KASLR for powerpc/fsl_booke/32 Michael Ellerman
2019-08-08 3:19 ` Jason Yan
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