kernel/arch/s390/boot/kaslr.c, branch linux-6.2.y

s390/boot: fix mem_detect extended area allocation

2023-03-10T08:28:16Z

[ Upstream commit 22476f47b6b7fb7d066c71f67ebc11892adb0849 ] Allocation of mem_detect extended area was not considered neither in commit 9641b8cc733f ("s390/ipl: read IPL report at early boot") nor in commit b2d24b97b2a9 ("s390/kernel: add support for kernel address space layout randomization (KASLR)"). As a result mem_detect extended theoretically may overlap with ipl report or randomized kernel image position. But as mem_detect code will allocate extended area only upon exceeding 255 online regions (which should alternate with offline memory regions) it is not seen in practice. To make sure mem_detect extended area does not overlap with ipl report or randomized kernel position extend usage of "safe_addr". Make initrd handling and mem_detect extended area allocation code move it further right and make KASLR takes in into consideration as well. Fixes: 9641b8cc733f ("s390/ipl: read IPL report at early boot") Fixes: b2d24b97b2a9 ("s390/kernel: add support for kernel address space layout randomization (KASLR)") Reviewed-by: Alexander Gordeev Signed-off-by: Vasily Gorbik Signed-off-by: Heiko Carstens Signed-off-by: Sasha Levin

s390/boot: get rid of startup archive

2022-05-06T18:45:14Z

The final kernel image is created by linking decompressor object files with a startup archive. The startup archive file however does not contain only optional code and data which can be discarded if not referenced. It also contains mandatory object data like head.o which must never be discarded, even if not referenced. Move the decompresser code and linker script to the boot directory and get rid of the startup archive so everything is kept during link time. Acked-by: Vasily Gorbik Signed-off-by: Heiko Carstens

s390/boot: introduce boot data 'initrd_data'

2021-07-27T07:39:15Z

The new boot data struct shall replace global variables INITRD_START and INITRD_SIZE. It is initialized in the decompressor and passed to the decompressed kernel. In comparison to the old solution, this one doesn't access data at fixed physical addresses which will become important when the decompressor becomes relocatable. Signed-off-by: Alexander Egorenkov Acked-by: Heiko Carstens Signed-off-by: Heiko Carstens

s390: unify identity mapping limits handling

2020-11-20T18:19:10Z

Currently we have to consider too many different values which in the end only affect identity mapping size. These are: 1. max_physmem_end - end of physical memory online or standby. Always <= end of the last online memory block (get_mem_detect_end()). 2. CONFIG_MAX_PHYSMEM_BITS - the maximum size of physical memory the kernel is able to support. 3. "mem=" kernel command line option which limits physical memory usage. 4. OLDMEM_BASE which is a kdump memory limit when the kernel is executed as crash kernel. 5. "hsa" size which is a memory limit when the kernel is executed during zfcp/nvme dump. Through out kernel startup and run we juggle all those values at once but that does not bring any amusement, only confusion and complexity. Unify all those values to a single one we should really care, that is our identity mapping size. Signed-off-by: Vasily Gorbik Reviewed-by: Alexander Gordeev Acked-by: Heiko Carstens Signed-off-by: Heiko Carstens

s390/kasan: move memory needs estimation into a function

2020-11-09T10:20:59Z

Also correct rounding downs in estimation calculations. Reviewed-by: Alexander Egorenkov Signed-off-by: Vasily Gorbik Signed-off-by: Heiko Carstens

s390/kaslr: correct and explain randomization base generation

2020-09-29T13:00:58Z

Currently there are several minor problems with randomization base generation code: 1. It might misbehave in low memory conditions. In particular there might be enough space for the kernel on [0, block_sum] but after if (base < safe_addr) base = safe_addr; it might not be enough anymore. 2. It does not correctly handle minimal address constraint. In condition if (base < safe_addr) base = safe_addr; a synthetic value is compared with an address. If we have a memory setup with memory holes due to offline memory regions, and safe_addr is close to the end of the first online memory block - we might position the kernel in invalid memory. 3. block_sum calculation logic contains off-by-one error. Let's say we have a memory block in which the kernel fits perfectly (end - start == kernel_size). In this case: if (end - start < kernel_size) continue; block_sum += end - start - kernel_size; block_sum is not increased, while it is a valid kernel position. So, address problems listed and explain algorithm used. Besides that restructuring the code makes it possible to extend kernel positioning algorithm further. Currently we pick position in between single [min, max] range (min = safe_addr, max = memory_limit). In future we can do that for multiple ranges as well (by calling count_valid_kernel_positions for each range). Reviewed-by: Philipp Rudo Reviewed-by: Alexander Egorenkov Signed-off-by: Vasily Gorbik

s390/kaslr: avoid mixing valid random value and an error code

2020-09-29T13:00:58Z

0 is a valid random value. To avoid mixing it with error code 0 as an return code make get_random() take extra argument to output random value and return an error code. Reviewed-by: Philipp Rudo Reviewed-by: Alexander Egorenkov Signed-off-by: Vasily Gorbik

mm: reorder includes after introduction of linux/pgtable.h

2020-06-09T16:39:13Z

The replacement of with made the include of the latter in the middle of asm includes. Fix this up with the aid of the below script and manual adjustments here and there. import sys import re if len(sys.argv) is not 3: print "USAGE: %s

" % (sys.argv[0]) sys.exit(1) hdr_to_move="#include " % sys.argv[2] moved = False in_hdrs = False with open(sys.argv[1], "r") as f: lines = f.readlines() for _line in lines: line = _line.rstrip(' ') if line == hdr_to_move: continue if line.startswith("#include Signed-off-by: Andrew Morton Cc: Arnd Bergmann Cc: Borislav Petkov Cc: Brian Cain Cc: Catalin Marinas Cc: Chris Zankel Cc: "David S. Miller" Cc: Geert Uytterhoeven Cc: Greentime Hu Cc: Greg Ungerer Cc: Guan Xuetao Cc: Guo Ren Cc: Heiko Carstens Cc: Helge Deller Cc: Ingo Molnar Cc: Ley Foon Tan Cc: Mark Salter Cc: Matthew Wilcox Cc: Matt Turner Cc: Max Filippov Cc: Michael Ellerman Cc: Michal Simek Cc: Nick Hu Cc: Paul Walmsley Cc: Richard Weinberger Cc: Rich Felker Cc: Russell King Cc: Stafford Horne Cc: Thomas Bogendoerfer Cc: Thomas Gleixner Cc: Tony Luck Cc: Vincent Chen Cc: Vineet Gupta Cc: Will Deacon Cc: Yoshinori Sato Link: http://lkml.kernel.org/r/20200514170327.31389-4-rppt@kernel.org Signed-off-by: Linus Torvalds

mm: introduce include/linux/pgtable.h

2020-06-09T16:39:13Z

The include/linux/pgtable.h is going to be the home of generic page table manipulation functions. Start with moving asm-generic/pgtable.h to include/linux/pgtable.h and make the latter include asm/pgtable.h. Signed-off-by: Mike Rapoport Signed-off-by: Andrew Morton Cc: Arnd Bergmann Cc: Borislav Petkov Cc: Brian Cain Cc: Catalin Marinas Cc: Chris Zankel Cc: "David S. Miller" Cc: Geert Uytterhoeven Cc: Greentime Hu Cc: Greg Ungerer Cc: Guan Xuetao Cc: Guo Ren Cc: Heiko Carstens Cc: Helge Deller Cc: Ingo Molnar Cc: Ley Foon Tan Cc: Mark Salter Cc: Matthew Wilcox Cc: Matt Turner Cc: Max Filippov Cc: Michael Ellerman Cc: Michal Simek Cc: Nick Hu Cc: Paul Walmsley Cc: Richard Weinberger Cc: Rich Felker Cc: Russell King Cc: Stafford Horne Cc: Thomas Bogendoerfer Cc: Thomas Gleixner Cc: Tony Luck Cc: Vincent Chen Cc: Vineet Gupta Cc: Will Deacon Cc: Yoshinori Sato Link: http://lkml.kernel.org/r/20200514170327.31389-3-rppt@kernel.org Signed-off-by: Linus Torvalds

s390/kaslr: Fix casts in get_random

2020-02-17T17:01:58Z

Clang warns: ../arch/s390/boot/kaslr.c:78:25: warning: passing 'char *' to parameter of type 'const u8 *' (aka 'const unsigned char *') converts between pointers to integer types with different sign [-Wpointer-sign] (char *) entropy, (char *) entropy, ^~~~~~~~~~~~~~~~ ../arch/s390/include/asm/cpacf.h:280:28: note: passing argument to parameter 'src' here u8 *dest, const u8 *src, long src_len) ^ 2 warnings generated. Fix the cast to match what else is done in this function. Fixes: b2d24b97b2a9 ("s390/kernel: add support for kernel address space layout randomization (KASLR)") Link: https://github.com/ClangBuiltLinux/linux/issues/862 Link: https://lkml.kernel.org/r/20200208141052.48476-1-natechancellor@gmail.com Signed-off-by: Nathan Chancellor Signed-off-by: Vasily Gorbik