kernel/linux.git/scripts, branch v5.10.138

modules: Ensure natural alignment for .altinstructions and __bug_table sections

2022-08-25T09:38:19+00:00

[ Upstream commit 87c482bdfa79f378297d92af49cdf265be199df5 ] In the kernel image vmlinux.lds.S linker scripts the .altinstructions and __bug_table sections are 4- or 8-byte aligned because they hold 32- and/or 64-bit values. Most architectures use altinstructions and BUG() or WARN() in modules as well, but in the module linker script (module.lds.S) those sections are currently missing. As consequence the linker will store their content byte-aligned by default, which then can lead to unnecessary unaligned memory accesses by the CPU when those tables are processed at runtime. Usually unaligned memory accesses are unnoticed, because either the hardware (as on x86 CPUs) or in-kernel exception handlers (e.g. on parisc or sparc) emulate and fix them up at runtime. Nevertheless, such unaligned accesses introduce a performance penalty and can even crash the kernel if there is a bug in the unalignment exception handlers (which happened once to me on the parisc architecture and which is why I noticed that issue at all). This patch fixes a non-critical issue and might be backported at any time. It's trivial and shouldn't introduce any regression because it simply tells the linker to use a different (8-byte alignment) for those sections by default. Signed-off-by: Helge Deller Link: https://lore.kernel.org/all/Yr8%2Fgr8e8I7tVX4d@p100/ Signed-off-by: Luis Chamberlain Signed-off-by: Sasha Levin

gcc-plugins: Undefine LATENT_ENTROPY_PLUGIN when plugin disabled for a file

2022-08-25T09:38:10+00:00

commit 012e8d2034f1bda8863435cd589636e618d6a659 upstream. Commit 36d4b36b6959 ("lib/nodemask: inline next_node_in() and node_random()") refactored some code by moving node_random() from lib/nodemask.c to include/linux/nodemask.h, thus requiring nodemask.h to include random.h, which conditionally defines add_latent_entropy() depending on whether the macro LATENT_ENTROPY_PLUGIN is defined. This broke the build on powerpc, where nodemask.h is indirectly included in arch/powerpc/kernel/prom_init.c, part of the early boot machinery that is excluded from the latent entropy plugin using DISABLE_LATENT_ENTROPY_PLUGIN. It turns out that while we add a gcc flag to disable the actual plugin, we don't undefine LATENT_ENTROPY_PLUGIN. This leads to the following: CC arch/powerpc/kernel/prom_init.o In file included from ./include/linux/nodemask.h:97, from ./include/linux/mmzone.h:17, from ./include/linux/gfp.h:7, from ./include/linux/xarray.h:15, from ./include/linux/radix-tree.h:21, from ./include/linux/idr.h:15, from ./include/linux/kernfs.h:12, from ./include/linux/sysfs.h:16, from ./include/linux/kobject.h:20, from ./include/linux/pci.h:35, from arch/powerpc/kernel/prom_init.c:24: ./include/linux/random.h: In function 'add_latent_entropy': ./include/linux/random.h:25:46: error: 'latent_entropy' undeclared (first use in this function); did you mean 'add_latent_entropy'? 25 | add_device_randomness((const void *)&latent_entropy, sizeof(latent_entropy)); | ^~~~~~~~~~~~~~ | add_latent_entropy ./include/linux/random.h:25:46: note: each undeclared identifier is reported only once for each function it appears in make[2]: *** [scripts/Makefile.build:249: arch/powerpc/kernel/prom_init.o] Fehler 1 make[1]: *** [scripts/Makefile.build:465: arch/powerpc/kernel] Fehler 2 make: *** [Makefile:1855: arch/powerpc] Error 2 Change the DISABLE_LATENT_ENTROPY_PLUGIN flags to undefine LATENT_ENTROPY_PLUGIN for files where the plugin is disabled. Cc: Yury Norov Fixes: 38addce8b600 ("gcc-plugins: Add latent_entropy plugin") Link: https://bugzilla.kernel.org/show_bug.cgi?id=216367 Link: https://lore.kernel.org/linuxppc-dev/alpine.DEB.2.22.394.2208152006320.289321@ramsan.of.borg/ Reported-by: Erhard Furtner Signed-off-by: Andrew Donnellan Reviewed-by: Yury Norov Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20220816051720.44108-1-ajd@linux.ibm.com Signed-off-by: Greg Kroah-Hartman

kbuild: dummy-tools: avoid tmpdir leak in dummy gcc

2022-08-25T09:38:01+00:00

commit aac289653fa5adf9e9985e4912c1d24a3e8cbab2 upstream. When passed -print-file-name=plugin, the dummy gcc script creates a temporary directory that is never cleaned up. To avoid cluttering $TMPDIR, instead use a static directory included in the source tree. Fixes: 76426e238834 ("kbuild: add dummy toolchains to enable all cc-option etc. in Kconfig") Signed-off-by: Ondrej Mosnacek Signed-off-by: Masahiro Yamada Signed-off-by: Greg Kroah-Hartman

scripts/faddr2line: Fix vmlinux detection on arm64

2022-08-21T13:16:12+00:00

[ Upstream commit b6a5068854cfe372da7dee3224dcf023ed5b00cb ] Since commit dcea997beed6 ("faddr2line: Fix overlapping text section failures, the sequel"), faddr2line is completely broken on arm64. For some reason, on arm64, the vmlinux ELF object file type is ET_DYN rather than ET_EXEC. Check for both when determining whether the object is vmlinux. Modules and vmlinux.o have type ET_REL on all arches. Fixes: dcea997beed6 ("faddr2line: Fix overlapping text section failures, the sequel") Reported-by: John Garry Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Tested-by: John Garry Link: https://lore.kernel.org/r/dad1999737471b06d6188ce4cdb11329aa41682c.1658426357.git.jpoimboe@kernel.org Signed-off-by: Sasha Levin

x86/retbleed: Add fine grained Kconfig knobs

2022-07-25T09:26:50+00:00

commit f43b9876e857c739d407bc56df288b0ebe1a9164 upstream. Do fine-grained Kconfig for all the various retbleed parts. NOTE: if your compiler doesn't support return thunks this will silently 'upgrade' your mitigation to IBPB, you might not like this. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Borislav Petkov [cascardo: there is no CONFIG_OBJTOOL] [cascardo: objtool calling and option parsing has changed] Signed-off-by: Thadeu Lima de Souza Cascardo [bwh: Backported to 5.10: - In scripts/Makefile.build, add the objtool option with an ifdef block, same as for other options - Adjust filename, context] Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman

objtool: Add entry UNRET validation

2022-07-25T09:26:45+00:00

commit a09a6e2399ba0595c3042b3164f3ca68a3cff33e upstream. Since entry asm is tricky, add a validation pass that ensures the retbleed mitigation has been done before the first actual RET instruction. Entry points are those that either have UNWIND_HINT_ENTRY, which acts as UNWIND_HINT_EMPTY but marks the instruction as an entry point, or those that have UWIND_HINT_IRET_REGS at +0. This is basically a variant of validate_branch() that is intra-function and it will simply follow all branches from marked entry points and ensures that all paths lead to ANNOTATE_UNRET_END. If a path hits RET or an indirection the path is a fail and will be reported. There are 3 ANNOTATE_UNRET_END instances: - UNTRAIN_RET itself - exception from-kernel; this path doesn't need UNTRAIN_RET - all early exceptions; these also don't need UNTRAIN_RET Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Borislav Petkov Reviewed-by: Josh Poimboeuf Signed-off-by: Borislav Petkov [cascardo: arch/x86/entry/entry_64.S no pt_regs return at .Lerror_entry_done_lfence] [cascardo: tools/objtool/builtin-check.c no link option validation] [cascardo: tools/objtool/check.c opts.ibt is ibt] [cascardo: tools/objtool/include/objtool/builtin.h leave unret option as bool, no struct opts] [cascardo: objtool is still called from scripts/link-vmlinux.sh] [cascardo: no IBT support] Signed-off-by: Thadeu Lima de Souza Cascardo [bwh: Backported to 5.10: - In scripts/link-vmlinux.sh, use "test -n" instead of is_enabled - Adjust context] Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman

x86: Add straight-line-speculation mitigation

2022-07-25T09:26:30+00:00

commit e463a09af2f0677b9485a7e8e4e70b396b2ffb6f upstream. Make use of an upcoming GCC feature to mitigate straight-line-speculation for x86: https://gcc.gnu.org/g:53a643f8568067d7700a9f2facc8ba39974973d3 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102952 https://bugs.llvm.org/show_bug.cgi?id=52323 It's built tested on x86_64-allyesconfig using GCC-12 and GCC-11. Maintenance overhead of this should be fairly low due to objtool validation. Size overhead of all these additional int3 instructions comes to: text data bss dec hex filename 22267751 6933356 2011368 31212475 1dc43bb defconfig-build/vmlinux 22804126 6933356 1470696 31208178 1dc32f2 defconfig-build/vmlinux.sls Or roughly 2.4% additional text. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Borislav Petkov Link: https://lore.kernel.org/r/20211204134908.140103474@infradead.org Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman [bwh: Backported to 5.10: - In scripts/Makefile.build, add the objtool option with an ifdef block, same as for other options - Adjust context] Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman

modpost: fix section mismatch check for exported init/exit sections

2022-06-29T06:59:54+00:00

commit 28438794aba47a27e922857d27b31b74e8559143 upstream. Since commit f02e8a6596b7 ("module: Sort exported symbols"), EXPORT_SYMBOL* is placed in the individual section ___ksymtab(_gpl)+ (3 leading underscores instead of 2). Since then, modpost cannot detect the bad combination of EXPORT_SYMBOL and __init/__exit. Fix the .fromsec field. Fixes: f02e8a6596b7 ("module: Sort exported symbols") Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers Signed-off-by: Greg Kroah-Hartman

faddr2line: Fix overlapping text section failures, the sequel

2022-06-22T12:13:17+00:00

[ Upstream commit dcea997beed694cbd8705100ca1a6eb0d886de69 ] If a function lives in a section other than .text, but .text also exists in the object, faddr2line may wrongly assume .text. This can result in comically wrong output. For example: $ scripts/faddr2line vmlinux.o enter_from_user_mode+0x1c enter_from_user_mode+0x1c/0x30: find_next_bit at /home/jpoimboe/git/linux/./include/linux/find.h:40 (inlined by) perf_clear_dirty_counters at /home/jpoimboe/git/linux/arch/x86/events/core.c:2504 Fix it by passing the section name to addr2line, unless the object file is vmlinux, in which case the symbol table uses absolute addresses. Fixes: 1d1a0e7c5100 ("scripts/faddr2line: Fix overlapping text section failures") Reported-by: Peter Zijlstra Signed-off-by: Josh Poimboeuf Link: https://lore.kernel.org/r/7d25bc1408bd3a750ac26e60d2f2815a5f4a8363.1654130536.git.jpoimboe@kernel.org Signed-off-by: Sasha Levin

scripts/gdb: change kernel config dumping method

2022-06-14T16:32:45+00:00

[ Upstream commit 1f7a6cf6b07c74a17343c2559cd5f5018a245961 ] MAGIC_START("IKCFG_ST") and MAGIC_END("IKCFG_ED") are moved out from the kernel_config_data variable. Thus, we parse kernel_config_data directly instead of considering offset of MAGIC_START and MAGIC_END. Fixes: 13610aa908dc ("kernel/configs: use .incbin directive to embed config_data.gz") Signed-off-by: Kuan-Ying Lee Signed-off-by: Masahiro Yamada Signed-off-by: Sasha Levin