From: Jason Yan <yanaijie@huawei.com>
To: Christophe Leroy <christophe.leroy@c-s.fr>,
Scott Wood <oss@buserror.net>
Cc: wangkefeng.wang@huawei.com, keescook@chromium.org,
kernel-hardening@lists.openwall.com, thunder.leizhen@huawei.com,
linux-kernel@vger.kernel.org, npiggin@gmail.com,
jingxiangfeng@huawei.com, diana.craciun@nxp.com,
paulus@samba.org, zhaohongjiang@huawei.com,
fanchengyang@huawei.com, linuxppc-dev@lists.ozlabs.org,
yebin10@huawei.com
Subject: Re: [PATCH v6 06/12] powerpc/fsl_booke/32: implement KASLR infrastructure
Date: Thu, 29 Aug 2019 14:26:47 +0800 [thread overview]
Message-ID: <11ef88f7-e418-c48e-f96c-1256c1179bca@huawei.com> (raw)
In-Reply-To: <2db76c55-df5f-5ca8-f0a6-bcee75b8edaa@c-s.fr>
On 2019/8/28 13:47, Christophe Leroy wrote:
>
>
> Le 28/08/2019 à 06:54, Scott Wood a écrit :
>> On Fri, Aug 09, 2019 at 06:07:54PM +0800, Jason Yan wrote:
>>> This patch add support to boot kernel from places other than KERNELBASE.
>>> Since CONFIG_RELOCATABLE has already supported, what we need to do is
>>> map or copy kernel to a proper place and relocate. Freescale Book-E
>>> parts expect lowmem to be mapped by fixed TLB entries(TLB1). The TLB1
>>> entries are not suitable to map the kernel directly in a randomized
>>> region, so we chose to copy the kernel to a proper place and restart to
>>> relocate.
>>>
>>> The offset of the kernel was not randomized yet(a fixed 64M is set). We
>>> will randomize it in the next patch.
>>>
>>> Signed-off-by: Jason Yan <yanaijie@huawei.com>
>>> Cc: Diana Craciun <diana.craciun@nxp.com>
>>> Cc: Michael Ellerman <mpe@ellerman.id.au>
>>> Cc: Christophe Leroy <christophe.leroy@c-s.fr>
>>> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
>>> Cc: Paul Mackerras <paulus@samba.org>
>>> Cc: Nicholas Piggin <npiggin@gmail.com>
>>> Cc: Kees Cook <keescook@chromium.org>
>>> Tested-by: Diana Craciun <diana.craciun@nxp.com>
>>> Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
>>> ---
>>> arch/powerpc/Kconfig | 11 ++++
>>> arch/powerpc/kernel/Makefile | 1 +
>>> arch/powerpc/kernel/early_32.c | 2 +-
>>> arch/powerpc/kernel/fsl_booke_entry_mapping.S | 17 +++--
>>> arch/powerpc/kernel/head_fsl_booke.S | 13 +++-
>>> arch/powerpc/kernel/kaslr_booke.c | 62 +++++++++++++++++++
>>> arch/powerpc/mm/mmu_decl.h | 7 +++
>>> arch/powerpc/mm/nohash/fsl_booke.c | 7 ++-
>>> 8 files changed, 105 insertions(+), 15 deletions(-)
>>> create mode 100644 arch/powerpc/kernel/kaslr_booke.c
>>>
>
> [...]
>
>>> diff --git a/arch/powerpc/kernel/kaslr_booke.c
>>> b/arch/powerpc/kernel/kaslr_booke.c
>>> new file mode 100644
>>> index 000000000000..f8dc60534ac1
>>> --- /dev/null
>>> +++ b/arch/powerpc/kernel/kaslr_booke.c
>>
>> Shouldn't this go under arch/powerpc/mm/nohash?
>>
>>> +/*
>>> + * To see if we need to relocate the kernel to a random offset
>>> + * void *dt_ptr - address of the device tree
>>> + * phys_addr_t size - size of the first memory block
>>> + */
>>> +notrace void __init kaslr_early_init(void *dt_ptr, phys_addr_t size)
>>> +{
>>> + unsigned long tlb_virt;
>>> + phys_addr_t tlb_phys;
>>> + unsigned long offset;
>>> + unsigned long kernel_sz;
>>> +
>>> + kernel_sz = (unsigned long)_end - KERNELBASE;
>>
>> Why KERNELBASE and not kernstart_addr?
>>
>>> +
>>> + offset = kaslr_choose_location(dt_ptr, size, kernel_sz);
>>> +
>>> + if (offset == 0)
>>> + return;
>>> +
>>> + kernstart_virt_addr += offset;
>>> + kernstart_addr += offset;
>>> +
>>> + is_second_reloc = 1;
>>> +
>>> + if (offset >= SZ_64M) {
>>> + tlb_virt = round_down(kernstart_virt_addr, SZ_64M);
>>> + tlb_phys = round_down(kernstart_addr, SZ_64M);
>>
>> If kernstart_addr wasn't 64M-aligned before adding offset, then "offset
>>> = SZ_64M" is not necessarily going to detect when you've crossed a
>> mapping boundary.
>>
>>> +
>>> + /* Create kernel map to relocate in */
>>> + create_tlb_entry(tlb_phys, tlb_virt, 1);
>>> + }
>>> +
>>> + /* Copy the kernel to it's new location and run */
>>> + memcpy((void *)kernstart_virt_addr, (void *)KERNELBASE, kernel_sz);
>>> +
>>> + reloc_kernel_entry(dt_ptr, kernstart_virt_addr);
>>> +}
>>
>> After copying, call flush_icache_range() on the destination.
>
> Function copy_and_flush() does the copy and the flush. I think it should
> be used instead of memcpy() + flush_icache_range()
>
Hi Christophe,
Thanks for the suggestion. But I think copy_and_flush() is not included
in fsl booke code, maybe move this function to misc.S?
> Christophe
>
> .
>
next prev parent reply other threads:[~2019-08-29 6:29 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-09 10:07 [PATCH v6 00/12] implement KASLR for powerpc/fsl_booke/32 Jason Yan
2019-08-09 10:07 ` [PATCH v6 01/12] powerpc: unify definition of M_IF_NEEDED Jason Yan
2019-08-09 10:07 ` [PATCH v6 02/12] powerpc: move memstart_addr and kernstart_addr to init-common.c Jason Yan
2019-08-09 10:07 ` [PATCH v6 03/12] powerpc: introduce kernstart_virt_addr to store the kernel base Jason Yan
2019-08-09 10:07 ` [PATCH v6 04/12] powerpc/fsl_booke/32: introduce create_tlb_entry() helper Jason Yan
2019-08-27 22:07 ` Scott Wood
2019-08-28 5:33 ` Jason Yan
2019-08-09 10:07 ` [PATCH v6 05/12] powerpc/fsl_booke/32: introduce reloc_kernel_entry() helper Jason Yan
2019-08-09 10:07 ` [PATCH v6 06/12] powerpc/fsl_booke/32: implement KASLR infrastructure Jason Yan
2019-08-28 4:54 ` Scott Wood
2019-08-28 5:47 ` Christophe Leroy
2019-08-29 6:26 ` Jason Yan [this message]
2019-08-28 11:03 ` Jason Yan
2019-08-28 16:44 ` Scott Wood
2019-08-09 10:07 ` [PATCH v6 07/12] powerpc/fsl_booke/32: randomize the kernel image offset Jason Yan
2019-08-09 10:07 ` [PATCH v6 08/12] powerpc/fsl_booke/kaslr: clear the original kernel if randomized Jason Yan
2019-08-09 10:07 ` [PATCH v6 09/12] powerpc/fsl_booke/kaslr: support nokaslr cmdline parameter Jason Yan
2019-08-09 10:07 ` [PATCH v6 10/12] powerpc/fsl_booke/kaslr: dump out kernel offset information on panic Jason Yan
2019-08-09 10:07 ` [PATCH v6 11/12] powerpc/fsl_booke/kaslr: export offset in VMCOREINFO ELF notes Jason Yan
2019-08-09 10:08 ` [PATCH v6 12/12] powerpc/fsl_booke/32: Document KASLR implementation Jason Yan
2019-08-19 6:12 ` [PATCH v6 00/12] implement KASLR for powerpc/fsl_booke/32 Jason Yan
2019-08-27 0:39 ` Jason Yan
2019-08-27 1:33 ` Michael Ellerman
2019-08-28 5:08 ` Scott Wood
2019-08-28 13:01 ` Michael Ellerman
2019-08-28 4:05 ` Scott Wood
2019-08-28 4:59 ` Scott Wood
2019-08-29 2:41 ` Jason Yan
2019-08-29 1:57 ` Jason Yan
2019-09-10 5:34 ` Jason Yan
2019-09-14 14:28 ` Scott Wood
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