kernel/linux.git/arch/s390/include/asm/setup.h, branch linux-5.9.y

s390: prevent leaking kernel address in BEAR

2020-03-10T14:16:25+00:00

When userspace executes a syscall or gets interrupted, BEAR contains a kernel address when returning to userspace. This make it pretty easy to figure out where the kernel is mapped even with KASLR enabled. To fix this, add lpswe to lowcore and always execute it there, so userspace sees only the lowcore address of lpswe. For this we have to extend both critical_cleanup and the SWITCH_ASYNC macro to also check for lpswe addresses in lowcore. Fixes: b2d24b97b2a9 ("s390/kernel: add support for kernel address space layout randomization (KASLR)") Cc: # v5.2+ Reviewed-by: Gerald Schaefer Signed-off-by: Sven Schnelle Signed-off-by: Vasily Gorbik

s390/boot: add dfltcc= kernel command line parameter

2020-01-31T18:30:40+00:00

Add the new kernel command line parameter 'dfltcc=' to configure s390 zlib hardware support. Format: { on | off | def_only | inf_only | always } on: s390 zlib hardware support for compression on level 1 and decompression (default) off: No s390 zlib hardware support def_only: s390 zlib hardware support for deflate only (compression on level 1) inf_only: s390 zlib hardware support for inflate only (decompression) always: Same as 'on' but ignores the selected compression level always using hardware support (used for debugging) Link: http://lkml.kernel.org/r/20200103223334.20669-5-zaslonko@linux.ibm.com Signed-off-by: Mikhail Zaslonko Cc: Chris Mason Cc: Christian Borntraeger Cc: David Sterba Cc: Eduard Shishkin Cc: Heiko Carstens Cc: Ilya Leoshkevich Cc: Josef Bacik Cc: Richard Purdie Cc: Vasily Gorbik Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

s390: remove last diag 0x44 caller

2019-12-11T18:53:24+00:00

diag 0x44 is a voluntary undirected yield of a virtual CPU. This has caused a lot of performance issues in the past. There is only one caller left, and that one is only executed if diag 0x9c (directed yield) is not present. Given that all hypervisors implement diag 0x9c anyway, remove the last diag 0x44 to avoid that more callers will be added. Worst case that could happen now, if diag 0x9c is not present, is that a virtual CPU would loop a bit instead of giving its time slice up. diag 0x44 statistics in debugfs are kept and will always be zero, so that user space can tell that there are no calls. Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

Merge tag 's390-5.4-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

2019-09-17T21:04:43+00:00

Pull s390 updates from Vasily Gorbik: - Add support for IBM z15 machines. - Add SHA3 and CCA AES cipher key support in zcrypt and pkey refactoring. - Move to arch_stack_walk infrastructure for the stack unwinder. - Various kasan fixes and improvements. - Various command line parsing fixes. - Improve decompressor phase debuggability. - Lift no bss usage restriction for the early code. - Use refcount_t for reference counters for couple of places in mm code. - Logging improvements and return code fix in vfio-ccw code. - Couple of zpci fixes and minor refactoring. - Remove some outdated documentation. - Fix secure boot detection. - Other various minor code clean ups. * tag 's390-5.4-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (48 commits) s390: remove pointless drivers-y in drivers/s390/Makefile s390/cpum_sf: Fix line length and format string s390/pci: fix MSI message data s390: add support for IBM z15 machines s390/crypto: Support for SHA3 via CPACF (MSA6) s390/startup: add pgm check info printing s390/crypto: xts-aes-s390 fix extra run-time crypto self tests finding vfio-ccw: fix error return code in vfio_ccw_sch_init() s390: vfio-ap: fix warning reset not completed s390/base: remove unused s390_base_mcck_handler s390/sclp: Fix bit checked for has_sipl s390/zcrypt: fix wrong handling of cca cipher keygenflags s390/kasan: add kdump support s390/setup: avoid using strncmp with hardcoded length s390/sclp: avoid using strncmp with hardcoded length s390/module: avoid using strncmp with hardcoded length s390/pci: avoid using strncmp with hardcoded length s390/kaslr: reserve memory for kasan usage s390/mem_detect: provide single get_mem_detect_end s390/cmma: reuse kstrtobool for option value parsing ...

s390: move vmalloc option parsing to startup code

2019-08-21T10:41:43+00:00

Few other crucial memory setup options are already handled in the startup code. Those values are needed by kaslr and kasan implementations. "vmalloc" is the last piece required for future improvements such as early decision on kernel page levels depth required for actual memory setup, as well as vmalloc memory area access monitoring in kasan. Reviewed-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/boot: add missing declarations and includes

2019-07-29T16:05:02+00:00

Add __swsusp_reset_dma declaration to avoid the following sparse warnings: arch/s390/kernel/setup.c:107:15: warning: symbol '__swsusp_reset_dma' was not declared. Should it be static? arch/s390/boot/startup.c:52:15: warning: symbol '__swsusp_reset_dma' was not declared. Should it be static? Add verify_facilities declaration to avoid the following sparse warning: arch/s390/boot/als.c:105:6: warning: symbol 'verify_facilities' was not declared. Should it be static? Include "boot.h" into arch/s390/boot/kaslr.c to expose get_random_base function declaration and avoid the following sparse warning: arch/s390/boot/kaslr.c:90:15: warning: symbol 'get_random_base' was not declared. Should it be static? Signed-off-by: Vasily Gorbik

s390: enable detection of kernel version from bzImage

2019-07-23T08:43:50+00:00

Extend "parmarea" to include an offset of the version string, which is stored as 8-byte big endian value. To retrieve version string from bzImage reliably, one should check the presence of "S390EP" ascii string at 0x10008 (available since v3.2), then read the version string offset from 0x10428 (which has been 0 since v3.2 up to now). The string is null terminated. Could be retrieved with the following "file" command magic (requires file v5.34): 8 string \x02\x00\x00\x18\x60\x00\x00\x50\x02\x00\x00\x68\x60\x00\x00\x50\x40\x40\x40\x40\x40\x40\x40\x40 Linux S390 >0x10008 string S390EP >>0x10428 bequad >0 >>>(0x10428.Q) string >\0 \b, version %s Reported-by: Petr Tesarik Suggested-by: Petr Tesarik Reviewed-by: Heiko Carstens Signed-off-by: Vasily Gorbik Signed-off-by: Heiko Carstens

arch: replace _BITUL() in kernel-space headers with BIT()

2019-07-17T02:23:22+00:00

Now that BIT() can be used from assembly code, we can safely replace _BITUL() with equivalent BIT(). UAPI headers are still required to use _BITUL(), but there is no more reason to use it in kernel headers. BIT() is shorter. Link: http://lkml.kernel.org/r/20190609153941.17249-2-yamada.masahiro@socionext.com Signed-off-by: Masahiro Yamada Cc: Heiko Carstens Cc: Vasily Gorbik Cc: Christian Borntraeger Cc: Vineet Gupta Cc: Catalin Marinas Cc: Will Deacon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

s390/kernel: add support for kernel address space layout randomization (KASLR)

2019-04-29T08:47:10+00:00

This patch adds support for relocating the kernel to a random address. The random kernel offset is obtained from cpacf, using either TRNG, PRNO, or KMC_PRNG, depending on supported MSA level. KERNELOFFSET is added to vmcoreinfo, for crash --kaslr support. Signed-off-by: Gerald Schaefer Reviewed-by: Philipp Rudo Signed-off-by: Martin Schwidefsky

s390/sclp: do not use static sccbs

2019-04-29T08:47:10+00:00

The sccbs for init/read/sdias/early have to be located below 2 GB, and they are currently defined as a static buffer. With a relocatable kernel that could reside at any place in memory, this will no longer guarantee the location below 2 GB, so use a dynamic GFP_DMA allocation instead. The sclp_early_sccb buffer needs special handling, as it can be used very early, and by both the decompressor and also the decompressed kernel. Therefore, a fixed 4 KB buffer is introduced at 0x11000, the former PARMAREA_END. The new PARMAREA_END is now 0x12000, and it is renamed to HEAD_END, as it is rather the end of head.S and not the end of the parmarea. Signed-off-by: Gerald Schaefer Reviewed-by: Philipp Rudo Signed-off-by: Martin Schwidefsky