Commit a7eb2880 authored by Heiko Carstens's avatar Heiko Carstens
Browse files

s390/mm: use __set_memory() variants where useful 



Use the __set_memory_yy() variants instead of set_memory_yy() where
useful. This allows to make the code a bit more readable.

This also fixes the debug pagealloc case, where set_memory_4k() might be
called for an area larger than 8TB which would lead to an overflow of
the num_pages parameter of set_memory_4k().

However RELOC_HIDE() has to be used for the __set_memory_4k() case for
the time being, to avoid compiler warnings because of performing pointer
arithmetic on a NULL pointer, which has undefined behavior. This happens
because __va(0) always translates to NULL. However this will change, and
as soon as this happens the RELOC_HIDE() hack can be removed again.

Reviewed-by: default avatarAlexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
parent 850612c8

arch/s390/mm/init.c

+1 −1
Original line number Diff line number Diff line
@@ -107,7 +107,7 @@ void mark_rodata_ro(void) 
{

	unsigned long size = __end_ro_after_init - __start_ro_after_init;



	set_memory_ro((unsigned long)__start_ro_after_init, size >> PAGE_SHIFT);

	__set_memory_ro(__start_ro_after_init, __end_ro_after_init);

	pr_info("Write protected read-only-after-init data: %luk\n", size >> 10);

	debug_checkwx();

}

arch/s390/mm/vmem.c

+10 −10
Original line number Diff line number Diff line
@@ -651,14 +651,10 @@ void vmem_unmap_4k_page(unsigned long addr) 


void __init vmem_map_init(void)

{

	set_memory_rox((unsigned long)_stext,

		       (unsigned long)(_etext - _stext) >> PAGE_SHIFT);

	set_memory_ro((unsigned long)_etext,

		      (unsigned long)(__end_rodata - _etext) >> PAGE_SHIFT);

	set_memory_rox((unsigned long)_sinittext,

		       (unsigned long)(_einittext - _sinittext) >> PAGE_SHIFT);

	set_memory_rox((unsigned long)__stext_amode31,

		       (unsigned long)(__etext_amode31 - __stext_amode31) >> PAGE_SHIFT);

	__set_memory_rox(_stext, _etext);

	__set_memory_ro(_etext, __end_rodata);

	__set_memory_rox(_sinittext, _einittext);

	__set_memory_rox(__stext_amode31, __etext_amode31);

	/*

	 * If the BEAR-enhancement facility is not installed the first

	 * prefix page is used to return to the previous context with
@@ -667,8 +663,12 @@ void __init vmem_map_init(void) 
	if (!static_key_enabled(&cpu_has_bear))

		set_memory_x(0, 1);

	if (debug_pagealloc_enabled()) {

		set_memory_4k((unsigned long)__va(0),

			      ident_map_size >> PAGE_SHIFT);

		/*

		 * Use RELOC_HIDE() as long as __va(0) translates to NULL,

		 * since performing pointer arithmetic on a NULL pointer

		 * has undefined behavior and generates compiler warnings.

		 */

		__set_memory_4k(__va(0), RELOC_HIDE(__va(0), ident_map_size));

	}

	if (MACHINE_HAS_NX)

		ctl_set_bit(0, 20);