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Date: Thu, 8 Aug 2019 12:29:08 +0800
From: Jason Yan <yanaijie@...wei.com>
To: Michael Ellerman <mpe@...erman.id.au>,
<linuxppc-dev@...ts.ozlabs.org>, <diana.craciun@....com>,
<christophe.leroy@....fr>, <benh@...nel.crashing.org>,
<paulus@...ba.org>, <npiggin@...il.com>, <keescook@...omium.org>,
<kernel-hardening@...ts.openwall.com>
CC: <linux-kernel@...r.kernel.org>, <wangkefeng.wang@...wei.com>,
<yebin10@...wei.com>, <thunder.leizhen@...wei.com>,
<jingxiangfeng@...wei.com>, <fanchengyang@...wei.com>,
<zhaohongjiang@...wei.com>
Subject: Re: [PATCH v5 03/10] powerpc: introduce kimage_vaddr to store the
kernel base
On 2019/8/7 21:03, Michael Ellerman wrote:
> Jason Yan <yanaijie@...wei.com> writes:
>> Now the kernel base is a fixed value - KERNELBASE. To support KASLR, we
>> need a variable to store the kernel base.
>>
>> Signed-off-by: Jason Yan <yanaijie@...wei.com>
>> Cc: Diana Craciun <diana.craciun@....com>
>> Cc: Michael Ellerman <mpe@...erman.id.au>
>> Cc: Christophe Leroy <christophe.leroy@....fr>
>> Cc: Benjamin Herrenschmidt <benh@...nel.crashing.org>
>> Cc: Paul Mackerras <paulus@...ba.org>
>> Cc: Nicholas Piggin <npiggin@...il.com>
>> Cc: Kees Cook <keescook@...omium.org>
>> Reviewed-by: Christophe Leroy <christophe.leroy@....fr>
>> Reviewed-by: Diana Craciun <diana.craciun@....com>
>> Tested-by: Diana Craciun <diana.craciun@....com>
>> ---
>> arch/powerpc/include/asm/page.h | 2 ++
>> arch/powerpc/mm/init-common.c | 2 ++
>> 2 files changed, 4 insertions(+)
>>
>> diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h
>> index 0d52f57fca04..60a68d3a54b1 100644
>> --- a/arch/powerpc/include/asm/page.h
>> +++ b/arch/powerpc/include/asm/page.h
>> @@ -315,6 +315,8 @@ void arch_free_page(struct page *page, int order);
>>
>> struct vm_area_struct;
>>
>> +extern unsigned long kimage_vaddr;
>> +
>> #include <asm-generic/memory_model.h>
>> #endif /* __ASSEMBLY__ */
>> #include <asm/slice.h>
>> diff --git a/arch/powerpc/mm/init-common.c b/arch/powerpc/mm/init-common.c
>> index 152ae0d21435..d4801ce48dc5 100644
>> --- a/arch/powerpc/mm/init-common.c
>> +++ b/arch/powerpc/mm/init-common.c
>> @@ -25,6 +25,8 @@ phys_addr_t memstart_addr = (phys_addr_t)~0ull;
>> EXPORT_SYMBOL_GPL(memstart_addr);
>> phys_addr_t kernstart_addr;
>> EXPORT_SYMBOL_GPL(kernstart_addr);
>> +unsigned long kimage_vaddr = KERNELBASE;
>> +EXPORT_SYMBOL_GPL(kimage_vaddr);
>
> The names of the #defines and variables we use for these values are not
> very consistent already, but using kimage_vaddr makes it worse I think.
>
> Isn't this going to have the same value as kernstart_addr, but the
> virtual rather than physical address?
>
Yes, that's true.
> If so kernstart_virt_addr would seem better.
>
OK, I will take kernstart_virt_addr if no better name appears.
> cheers
>
> .
>
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