Re: [PATCH v5 0/6] implement KASLR for powerpc/fsl_booke/64

From: Jason Yan
Date: Wed Apr 22 2020 - 21:11:48 EST


Hi Michael,

What's the status of this series?

Thanks,
Jason

在 2020/3/30 10:20, Jason Yan 写道:
This is a try to implement KASLR for Freescale BookE64 which is based on
my earlier implementation for Freescale BookE32:
https://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=131718&state=*

The implementation for Freescale BookE64 is similar as BookE32. One
difference is that Freescale BookE64 set up a TLB mapping of 1G during
booting. Another difference is that ppc64 needs the kernel to be
64K-aligned. So we can randomize the kernel in this 1G mapping and make
it 64K-aligned. This can save some code to creat another TLB map at
early boot. The disadvantage is that we only have about 1G/64K = 16384
slots to put the kernel in.

KERNELBASE

64K |--> kernel <--|
| | |
+--+--+--+ +--+--+--+--+--+--+--+--+--+ +--+--+
| | | |....| | | | | | | | | |....| | |
+--+--+--+ +--+--+--+--+--+--+--+--+--+ +--+--+
| | 1G
|-----> offset <-----|

kernstart_virt_addr

I'm not sure if the slot numbers is enough or the design has any
defects. If you have some better ideas, I would be happy to hear that.

Thank you all.

v4->v5:
Fix "-Werror=maybe-uninitialized" compile error.
Fix typo "similar as" -> "similar to".
v3->v4:
Do not define __kaslr_offset as a fixed symbol. Reference __run_at_load and
__kaslr_offset by symbol instead of magic offsets.
Use IS_ENABLED(CONFIG_PPC32) instead of #ifdef CONFIG_PPC32.
Change kaslr-booke32 to kaslr-booke in index.rst
Switch some instructions to 64-bit.
v2->v3:
Fix build error when KASLR is disabled.
v1->v2:
Add __kaslr_offset for the secondary cpu boot up.

Jason Yan (6):
powerpc/fsl_booke/kaslr: refactor kaslr_legal_offset() and
kaslr_early_init()
powerpc/fsl_booke/64: introduce reloc_kernel_entry() helper
powerpc/fsl_booke/64: implement KASLR for fsl_booke64
powerpc/fsl_booke/64: do not clear the BSS for the second pass
powerpc/fsl_booke/64: clear the original kernel if randomized
powerpc/fsl_booke/kaslr: rename kaslr-booke32.rst to kaslr-booke.rst
and add 64bit part

Documentation/powerpc/index.rst | 2 +-
.../{kaslr-booke32.rst => kaslr-booke.rst} | 35 ++++++-
arch/powerpc/Kconfig | 2 +-
arch/powerpc/kernel/exceptions-64e.S | 23 +++++
arch/powerpc/kernel/head_64.S | 13 +++
arch/powerpc/kernel/setup_64.c | 3 +
arch/powerpc/mm/mmu_decl.h | 23 +++--
arch/powerpc/mm/nohash/kaslr_booke.c | 91 +++++++++++++------
8 files changed, 147 insertions(+), 45 deletions(-)
rename Documentation/powerpc/{kaslr-booke32.rst => kaslr-booke.rst} (59%)