From: Michael Ellerman <mpe@ellerman.id.au>
To: Jason Yan <yanaijie@huawei.com>,
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, Jason Yan <yanaijie@huawei.com>
Subject: Re: [PATCH v5 10/10] powerpc/fsl_booke/kaslr: dump out kernel offset information on panic
Date: Wed, 07 Aug 2019 23:03:35 +1000 [thread overview]
Message-ID: <87zhklt9eg.fsf@concordia.ellerman.id.au> (raw)
In-Reply-To: <20190807065706.11411-11-yanaijie@huawei.com>
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.
> 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.
> 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?
> }
cheers
next prev parent reply other threads:[~2019-08-07 13:04 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 [this message]
2019-08-08 8:39 ` Jason Yan
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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