From: Alexander Gordeev agordeev@linux.ibm.com
[ Upstream commit 2ed8b509753a0454b52b2d72e982265472c8d861 ]
Since commit 3b5c3f000c2e ("s390/kasan: move shadow mapping to decompressor") the decompressor establishes mappings for the shadow memory and sets initial protection attributes to RWX. The decompressed kernel resets protection to RW+NX later on.
In case a shadow memory range is not aligned on page boundary (e.g. as result of mem= kernel command line parameter use), the "Checked W+X mappings: FAILED, 1 W+X pages found" warning hits.
Reported-by: Vasily Gorbik gor@linux.ibm.com Fixes: 557b19709da9 ("s390/kasan: move shadow mapping to decompressor") Reviewed-by: Vasily Gorbik gor@linux.ibm.com Signed-off-by: Alexander Gordeev agordeev@linux.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/s390/mm/vmem.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-)
diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c index 5b22c6e24528a..b9dcb4ae6c59a 100644 --- a/arch/s390/mm/vmem.c +++ b/arch/s390/mm/vmem.c @@ -667,7 +667,15 @@ static void __init memblock_region_swap(void *a, void *b, int size)
#ifdef CONFIG_KASAN #define __sha(x) ((unsigned long)kasan_mem_to_shadow((void *)x)) + +static inline int set_memory_kasan(unsigned long start, unsigned long end) +{ + start = PAGE_ALIGN_DOWN(__sha(start)); + end = PAGE_ALIGN(__sha(end)); + return set_memory_rwnx(start, (end - start) >> PAGE_SHIFT); +} #endif + /* * map whole physical memory to virtual memory (identity mapping) * we reserve enough space in the vmalloc area for vmemmap to hotplug @@ -737,10 +745,8 @@ void __init vmem_map_init(void) }
#ifdef CONFIG_KASAN - for_each_mem_range(i, &base, &end) { - set_memory_rwnx(__sha(base), - (__sha(end) - __sha(base)) >> PAGE_SHIFT); - } + for_each_mem_range(i, &base, &end) + set_memory_kasan(base, end); #endif set_memory_rox((unsigned long)_stext, (unsigned long)(_etext - _stext) >> PAGE_SHIFT);