-tip tree resume fail, bisect to 5bd5a45(x86: Add NX protection for kernel data)

[Lin Ming <ming.m.lin@intel.com>]

Hi, all

Current -tip tree(92c883a) fail to resume after suspend to mem.
Bisect to commit 5bd5a45(x86: Add NX protection for kernel data).

commit 5bd5a452662bc37c54fb6828db1a3faf87e6511c
Author: Matthieu Castet <castet.matthieu@free.fr>
Date:   Tue Nov 16 22:31:26 2010 +0100

    x86: Add NX protection for kernel data


I did some debug and found the regression is caused by below line.

-       set_memory_nx(rodata_start, (end - rodata_start) >> PAGE_SHIFT);
+       set_memory_nx(rodata_start, (kernel_end - rodata_start) >> PAGE_SHIFT);

In my machine,
rodata_start=0xffffffff81a00000, end=0xffffffff81e00000, kernel_end=0xffffffff82200000

Without this commit, kernel page table dumps

---[ High Kernel Mapping ]---
....
0xffffffff81a00000-0xffffffff81c00000           2M     ro         PSE GLB NX pmd
0xffffffff81c00000-0xffffffff81d91000        1604K     ro             GLB NX pte
0xffffffff81d91000-0xffffffff81e00000         444K     ro             GLB NX pte
0xffffffff81e00000-0xffffffff82000000           2M     RW         PSE GLB x  pmd
0xffffffff82000000-0xffffffff8200c000          48K     RW             GLB x  pte
0xffffffff8200c000-0xffffffff82100000         976K     RW             GLB x  pte
0xffffffff82100000-0xffffffff82200000           1M     RW             GLB x  pte
.....

With this commit, kernel page table dumps

---[ High Kernel Mapping ]---
....
0xffffffff81a00000-0xffffffff81c00000           2M     ro         PSE GLB NX pmd
0xffffffff81c00000-0xffffffff81d91000        1604K     ro             GLB NX pte
0xffffffff81d91000-0xffffffff81e00000         444K     ro             GLB NX pte
0xffffffff81e00000-0xffffffff82000000           2M     RW         PSE GLB NX pmd
0xffffffff82000000-0xffffffff8200c000          48K     RW             GLB NX pte
0xffffffff8200c000-0xffffffff82100000         976K     RW             GLB NX pte
0xffffffff82100000-0xffffffff82200000           1M     RW             GLB NX pte
.....

The only difference is 0xffffffff81e00000(end) to 0xffffffff82200000(kernel_end) is set to NX.

I guess this range code is used by resume wakeup code. So setting it to NX causes problem.

Any idea?

Thanks,
Lin Ming