This series of patches allows the ARM kernel page tables to gain better
permission separation. With a fixed[1] CONFIG_ARM_PTDUMP enabled, you
can see the before and after in /sys/kernel/debug/kernel_page_tables.
Before:
---[ Kernel Mapping ]---
0xc0000000-0xc0800000 8M RW x SHD
0xc0800000-0xc1e00000 22M RW NX SHD
0xc2000000-0xc3000000 16M RW x SHD
0xc3800000-0xd1000000 216M RW x SHD
0xd1800000-0xef800000 480M RW x SHD
After:
---[ Kernel Mapping ]---
0xc0000000-0xc0100000 1M RW NX SHD
0xc0100000-0xc0700000 6M ro x SHD
0xc0700000-0xc0a00000 3M ro NX SHD
0xc0a00000-0xc1e00000 20M RW NX SHD
0xc2000000-0xc3000000 16M RW NX SHD
0xc3800000-0xd1000000 216M RW NX SHD
0xd1800000-0xef800000 480M RW NX SHD
This is available via CONFIG_ARM_KERNMEM_PERMS and CONFIG_DEBUG_RODATA.
The latter exists to match the x86 option of the same name, and is
left as a configurable since each additional region adds more potential
memory padding.
The series is based on earlier work from Brad Spengler, Larry Bassel,
and Laura Abbott.
Thanks,
-Kees
[1] these patches are needed to get the correct output:
https://lkml.org/lkml/2014/2/12/662
https://lkml.org/lkml/2014/2/12/663
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
