linux/arch/s390
Vasily Gorbik c360c9a238 s390/kasan: support protvirt with 4-level paging
Currently the kernel crashes in Kasan instrumentation code if
CONFIG_KASAN_S390_4_LEVEL_PAGING is used on protected virtualization
capable machine where the ultravisor imposes addressing limitations on
the host and those limitations are lower then KASAN_SHADOW_OFFSET.

The problem is that Kasan has to know in advance where vmalloc/modules
areas would be. With protected virtualization enabled vmalloc/modules
areas are moved down to the ultravisor secure storage limit while kasan
still expects them at the very end of 4-level paging address space.

To fix that make Kasan recognize when protected virtualization is enabled
and predefine vmalloc/modules areas position which are compliant with
ultravisor secure storage limit.

Kasan shadow itself stays in place and might reside above that ultravisor
secure storage limit.

One slight difference compaired to a kernel without Kasan enabled is that
vmalloc/modules areas position is not reverted to default if ultravisor
initialization fails. It would still be below the ultravisor secure
storage limit.

Kernel layout with kasan, 4-level paging and protected virtualization
enabled (ultravisor secure storage limit is at 0x0000800000000000):
---[ vmemmap Area Start ]---
0x0000400000000000-0x0000400080000000
---[ vmemmap Area End ]---
---[ vmalloc Area Start ]---
0x00007fe000000000-0x00007fff80000000
---[ vmalloc Area End ]---
---[ Modules Area Start ]---
0x00007fff80000000-0x0000800000000000
---[ Modules Area End ]---
---[ Kasan Shadow Start ]---
0x0018000000000000-0x001c000000000000
---[ Kasan Shadow End ]---
0x001c000000000000-0x0020000000000000         1P PGD I

Kernel layout with kasan, 4-level paging and protected virtualization
disabled/unsupported:
---[ vmemmap Area Start ]---
0x0000400000000000-0x0000400060000000
---[ vmemmap Area End ]---
---[ Kasan Shadow Start ]---
0x0018000000000000-0x001c000000000000
---[ Kasan Shadow End ]---
---[ vmalloc Area Start ]---
0x001fffe000000000-0x001fffff80000000
---[ vmalloc Area End ]---
---[ Modules Area Start ]---
0x001fffff80000000-0x0020000000000000
---[ Modules Area End ]---

Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2020-09-16 14:08:48 +02:00
..
appldata s390/appldata: use struct_size() helper 2020-06-29 16:32:34 +02:00
boot s390/protvirt: parse prot_virt option in the decompressor 2020-09-16 14:08:47 +02:00
configs s390: add ARCH_HAS_DEBUG_WX support 2020-09-14 11:38:35 +02:00
crypto mm, treewide: rename kzfree() to kfree_sensitive() 2020-08-07 11:33:22 -07:00
hypfs fs_parse: fold fs_parameter_desc/fs_parameter_spec 2020-02-07 14:48:37 -05:00
include s390/kasan: support protvirt with 4-level paging 2020-09-16 14:08:48 +02:00
kernel s390/kasan: support protvirt with 4-level paging 2020-09-16 14:08:48 +02:00
kvm mm/gup: remove task_struct pointer for all gup code 2020-08-12 10:58:04 -07:00
lib s390/test_unwind: fix possible memleak in test_unwind() 2020-08-11 18:16:16 +02:00
mm s390/kasan: support protvirt with 4-level paging 2020-09-16 14:08:48 +02:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2020-08-05 20:13:21 -07:00
oprofile s390/unwind: introduce stack unwind API 2019-05-02 13:54:11 +02:00
pci s390/pci: add missing pci_iov.h include 2020-09-16 14:08:47 +02:00
purgatory .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
tools .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
Kbuild s390/numa: move code to arch/s390/kernel 2020-08-11 18:16:55 +02:00
Kconfig s390: add ARCH_HAS_DEBUG_WX support 2020-09-14 11:38:35 +02:00
Kconfig.debug s390/mm,ptdump: convert to generic page table dumper 2020-09-14 11:38:34 +02:00
Makefile kbuild: remove cc-option test of -ffreestanding 2020-07-07 11:13:10 +09:00