kernel/linux.git/arch/x86/boot/string.c, branch v6.12.80

x86/boot: Remove redundant initialization of the 'delta' variable in strcmp()

2023-12-20T21:23:33+00:00

The 'delta' variable is zero-initialized, but never read before the real initialization happens. The assignment is redundant and can be removed. Signed-off-by: Colin Ian King Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20231219141304.367200-1-colin.i.king@gmail.com

x86/boot: Repair kernel-doc for boot_kstrtoul()

2022-11-02T09:20:02+00:00

Adjust the kernel-doc comment to have the proper function name: boot_kstrtoul(). [ bp: Massage commit message. ] Signed-off-by: Lukas Bulwahn Signed-off-by: Borislav Petkov Link: https://lore.kernel.org/r/20221031094835.15923-1-lukas.bulwahn@gmail.com

x86/boot: Add kstrtoul() from lib/

2020-05-04T13:19:07+00:00

Add kstrtoul() to ../boot/ to be used by facilities there too. [ bp: Massage, make _kstrtoul() static. Prepend function names with "boot_". This is a temporary workaround for build errors like: ld: arch/x86/boot/compressed/acpi.o: in function `count_immovable_mem_regions': acpi.c:(.text+0x463): undefined reference to `_kstrtoul' make[2]: *** [arch/x86/boot/compressed/Makefile:117: arch/x86/boot/compressed/vmlinux] Error 1 due to the namespace clash between x86/boot/ and kernel proper. Future reorg will get rid of the linux/linux/ namespace as much as possible so that x86/boot/ can be independent from kernel proper. ] Signed-off-by: Vamshi K Sthambamkadi Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/1587645588-7130-2-git-send-email-vamshi.k.sthambamkadi@gmail.com

x86/purgatory: Do not use __builtin_memcpy and __builtin_memset

2019-08-08T06:25:52+00:00

Implementing memcpy and memset in terms of __builtin_memcpy and __builtin_memset is problematic. GCC at -O2 will replace calls to the builtins with calls to memcpy and memset (but will generate an inline implementation at -Os). Clang will replace the builtins with these calls regardless of optimization level. $ llvm-objdump -dr arch/x86/purgatory/string.o | tail 0000000000000339 memcpy: 339: 48 b8 00 00 00 00 00 00 00 00 movabsq $0, %rax 000000000000033b: R_X86_64_64 memcpy 343: ff e0 jmpq *%rax 0000000000000345 memset: 345: 48 b8 00 00 00 00 00 00 00 00 movabsq $0, %rax 0000000000000347: R_X86_64_64 memset 34f: ff e0 Such code results in infinite recursion at runtime. This is observed when doing kexec. Instead, reuse an implementation from arch/x86/boot/compressed/string.c. This requires to implement a stub function for warn(). Also, Clang may lower memcmp's that compare against 0 to bcmp's, so add a small definition, too. See also: commit 5f074f3e192f ("lib/string.c: implement a basic bcmp") Fixes: 8fc5b4d4121c ("purgatory: core purgatory functionality") Reported-by: Vaibhav Rustagi Debugged-by: Vaibhav Rustagi Debugged-by: Manoj Gupta Suggested-by: Alistair Delva Signed-off-by: Nick Desaulniers Signed-off-by: Thomas Gleixner Tested-by: Vaibhav Rustagi Cc: stable@vger.kernel.org Link: https://bugs.chromium.org/p/chromium/issues/detail?id=984056 Link: https://lkml.kernel.org/r/20190807221539.94583-1-ndesaulniers@google.com

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 497

2019-06-19T15:09:53+00:00

Based on 1 normalized pattern(s): this file is part of the linux kernel and is made available under the terms of the gnu general public license version 2 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 28 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Enrico Weigelt Reviewed-by: Allison Randal Reviewed-by: Kate Stewart Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.534229504@linutronix.de Signed-off-by: Greg Kroah-Hartman

x86/boot: Restrict header scope to make Clang happy

2019-03-21T11:24:38+00:00

The inclusion of was causing issue as the definition of __arch_hweight64 from arch/x86/include/asm/arch_hweight.h eventually gets included. The definition is problematic when compiled with -m16 (all code in arch/x86/boot/ is) as the "D" inline assembly constraint is rejected by both compilers when passed an argument of type long long (regardless of signedness, anything smaller is fine). Because GCC performs inlining before semantic analysis, and __arch_hweight64 is dead in this translation unit, GCC does not report any issues at compile time. Clang does the semantic analysis in the front end, before inlining (run in the middle) can determine the code is dead. I consider this another case of PR33587, which I think we can do more work to solve. It turns out that arch/x86/boot/string.c doesn't actually need linux/kernel.h, simply linux/limits.h and linux/compiler.h. Suggested-by: Stephen Rothwell Signed-off-by: Nick Desaulniers Signed-off-by: Thomas Gleixner Tested-by: Nathan Chancellor Reviewed-by: Nathan Chancellor Cc: bp@alien8.de Cc: niravd@google.com Cc: "H. Peter Anvin" Cc: Chao Fan Cc: Uros Bizjak Link: https://bugs.llvm.org/show_bug.cgi?id=33587 Link: https://github.com/ClangBuiltLinux/linux/issues/347 Link: https://lkml.kernel.org/r/20190314221458.83047-1-ndesaulniers@google.com

x86/boot: Copy kstrtoull() to boot/string.c

2019-02-01T10:52:54+00:00

Copy kstrtoull() and the other necessary functions from lib/kstrtox.c to boot/string.c so that code in boot/ can use kstrtoull() and the old simple_strtoull() can gradually be phased out. Using div_u64() from math64.h directly will cause the dividend to be handled as a 64-bit value and cause the infamous __divdi3 linker error due to gcc trying to use its library function for the 64-bit division. Therefore, separate the dividend into an upper and lower part. [ bp: Rewrite commit message. ] Signed-off-by: Chao Fan Signed-off-by: Borislav Petkov Cc: bhe@redhat.com Cc: caoj.fnst@cn.fujitsu.com Cc: "H. Peter Anvin" Cc: indou.takao@jp.fujitsu.com Cc: Ingo Molnar Cc: kasong@redhat.com Cc: Kees Cook Cc: msys.mizuma@gmail.com Cc: Thomas Gleixner Cc: x86-ml Link: https://lkml.kernel.org/r/20190123110850.12433-2-fanc.fnst@cn.fujitsu.com

x86/boot: Use CC_SET()/CC_OUT() instead of open coding it

2018-08-02T12:30:42+00:00

Remove open-coded uses of set instructions with CC_SET()/CC_OUT(). Signed-off-by: Uros Bizjak Signed-off-by: Thomas Gleixner Link: https://lkml.kernel.org/r/20180629142844.15200-1-ubizjak@gmail.com

x86/boot: #undef memcpy() et al in string.c

2017-07-25T09:13:55+00:00

undef memcpy() and friends in boot/string.c so that the functions defined here will have the correct names, otherwise we end up up trying to redefine __builtin_memcpy() etc. Surprisingly, GCC allows this (and, helpfully, discards the __builtin_ prefix from the function name when compiling it), but clang does not. Adding these #undef's appears to preserve what I assume was the original intent of the code. Signed-off-by: Michael Davidson Signed-off-by: Matthias Kaehlcke Acked-by: H. Peter Anvin Cc: Arnd Bergmann Cc: Bernhard.Rosenkranzer@linaro.org Cc: Greg Hackmann Cc: Kees Cook Cc: Linus Torvalds Cc: Nick Desaulniers Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20170724235155.79255-1-mka@chromium.org Signed-off-by: Ingo Molnar

x86/KASLR: Parse all 'memmap=' boot option entries

2017-05-24T07:50:27+00:00

In commit: f28442497b5c ("x86/boot: Fix KASLR and memmap= collision") ... the memmap= option is parsed so that KASLR can avoid those reserved regions. It uses cmdline_find_option() to get the value if memmap= is specified, however the problem is that cmdline_find_option() can only find the last entry if multiple memmap entries are provided. This is not correct. Address this by checking each command line token for a "memmap=" match and parse each instance instead of using cmdline_find_option(). Signed-off-by: Baoquan He Acked-by: Kees Cook Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: dan.j.williams@intel.com Cc: douly.fnst@cn.fujitsu.com Cc: dyoung@redhat.com Cc: m.mizuma@jp.fujitsu.com Link: http://lkml.kernel.org/r/1494654390-23861-2-git-send-email-bhe@redhat.com Signed-off-by: Ingo Molnar