linux/arch/arc/mm
Eugeniy Paltsev a8c715b4dd ARC: mm: SIGSEGV userspace trying to access kernel virtual memory
As of today if userspace process tries to access a kernel virtual addres
(0x7000_0000 to 0x7ffff_ffff) such that a legit kernel mapping already
exists, that process hangs instead of being killed with SIGSEGV

Fix that by ensuring that do_page_fault() handles kenrel vaddr only if
in kernel mode.

And given this, we can also simplify the code a bit. Now a vmalloc fault
implies kernel mode so its failure (for some reason) can reuse the
@no_context label and we can remove @bad_area_nosemaphore.

Reproduce user test for original problem:

------------------------>8-----------------
 #include <stdlib.h>
 #include <stdint.h>

 int main(int argc, char *argv[])
 {
 	volatile uint32_t temp;

 	temp = *(uint32_t *)(0x70000000);
 }
------------------------>8-----------------

Cc: <stable@vger.kernel.org>
Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2019-05-20 10:09:10 -07:00
..
cache.c ARC: PAE40: don't panic and instead turn off hw ioc 2019-04-02 12:03:07 -07:00
dma.c dma-mapping: zero memory returned from dma_alloc_* 2018-12-20 08:13:52 +01:00
extable.c ARC: uaccess: enable INLINE_COPY_{TO,FROM}_USER ... 2017-03-30 00:07:48 -04:00
fault.c ARC: mm: SIGSEGV userspace trying to access kernel virtual memory 2019-05-20 10:09:10 -07:00
highmem.c treewide: add checks for the return value of memblock_alloc*() 2019-03-12 10:04:02 -07:00
init.c init: provide a generic free_initmem implementation 2019-05-14 09:47:47 -07:00
ioremap.c ARCv2: Support dynamic peripheral address space in HS38 rel 3.0 cores 2016-09-30 14:48:17 -07:00
Makefile ARC: mm: HIGHMEM: kmap API implementation 2015-10-28 19:49:04 +05:30
mmap.c mm: larger stack guard gap, between vmas 2017-06-19 21:50:20 +08:00
tlb.c ARC: fix build warnings 2019-05-20 10:09:10 -07:00
tlbex.S ARC: [plat-eznps] Fix TLB Errata 2017-08-28 15:17:36 -07:00