[PATCH 4.20 143/145] parisc: Remap hugepage-aligned pages in set_kernel_text_rw()

From: Greg Kroah-Hartman
Date: Mon Jan 07 2019 - 07:44:50 EST

4.20-stable review patch. If anyone has any objections, please let me know.


From: Helge Deller <deller@xxxxxx>

commit dfbaecb2b707cfdc5276b548d52b437384bd6483 upstream.

The alternative coding patch for parisc in kernel 4.20 broke booting
machines with PA8500-PA8700 CPUs. The problem is, that for such machines
the parisc kernel automatically utilizes huge pages to access kernel
text code, but the set_kernel_text_rw() function, which is used shortly
before applying any alternative patches, didn't used the correctly
hugepage-aligned addresses to remap the kernel text read-writeable.

Fixes: 3847dab77421 ("parisc: Add alternative coding infrastructure")
Cc: <stable@xxxxxxxxxxxxxxx> [4.20]
Signed-off-by: Helge Deller <deller@xxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

arch/parisc/mm/init.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/arch/parisc/mm/init.c
+++ b/arch/parisc/mm/init.c
@@ -512,8 +512,8 @@ static void __init map_pages(unsigned lo

void __init set_kernel_text_rw(int enable_read_write)
- unsigned long start = (unsigned long)__init_begin;
- unsigned long end = (unsigned long)_etext;
+ unsigned long start = (unsigned long) _text;
+ unsigned long end = (unsigned long) &data_start;

map_pages(start, __pa(start), end-start,
PAGE_KERNEL_RWX, enable_read_write ? 1:0);