Revert "x86, mm: Set NX across entire PMD at boot"

This reverts commit a5c187d92d2ce30315f333b9dff33af832e8b443 which
was commit 45e2a9d4701d8c624d4a4bcdd1084eae31e92f58 upstream.

The previous commit caused suspend/resume to stop working on at least
some systems - specifically, the system would reboot when woken.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: Steven Rostedt <rostedt@goodmis.org>

diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 266f717..a2340ee 100644 (file)
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -778,7 +778,7 @@ void mark_rodata_ro(void)
        unsigned long text_end = PAGE_ALIGN((unsigned long) &__stop___ex_table);
        unsigned long rodata_end = PAGE_ALIGN((unsigned long) &__end_rodata);
        unsigned long data_start = (unsigned long) &_sdata;
-       unsigned long all_end;
+       unsigned long all_end = PFN_ALIGN(&_end);
 
        printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
               (end - start) >> 10);
@@ -789,16 +789,7 @@ void mark_rodata_ro(void)
        /*
         * The rodata/data/bss/brk section (but not the kernel text!)
         * should also be not-executable.
-        *
-        * We align all_end to PMD_SIZE because the existing mapping
-        * is a full PMD. If we would align _brk_end to PAGE_SIZE we
-        * split the PMD and the reminder between _brk_end and the end
-        * of the PMD will remain mapped executable.
-        *
-        * Any PMD which was setup after the one which covers _brk_end
-        * has been zapped already via cleanup_highmem().
         */
-       all_end = roundup((unsigned long)_brk_end, PMD_SIZE);
        set_memory_nx(rodata_start, (all_end - rodata_start) >> PAGE_SHIFT);
 
        rodata_test();