user/sven/linux.git/scripts/kallsyms.c, branch v5.10.180

kallsyms: fix nonconverging kallsyms table with lld

2021-02-17T10:02:24Z

[ Upstream commit efe6e3068067212b85c2d0474b5ee3b2d0c7adab ] ARM randconfig builds with lld sometimes show a build failure from kallsyms: Inconsistent kallsyms data Try make KALLSYMS_EXTRA_PASS=1 as a workaround The problem is the veneers/thunks getting added by the linker extend the symbol table, which in turn leads to more veneers being needed, so it may take a few extra iterations to converge. This bug has been fixed multiple times before, but comes back every time a new symbol name is used. lld uses a different set of identifiers from ld.bfd, so the additional ones need to be added as well. I looked through the sources and found that arm64 and mips define similar prefixes, so I'm adding those as well, aside from the ones I observed. I'm not sure about powerpc64, which seems to already be handled through a section match, but if it comes back, the "__long_branch_" and "__plt_" prefixes would have to get added as well. Signed-off-by: Arnd Bergmann Signed-off-by: Masahiro Yamada Signed-off-by: Sasha Levin

scripts/kallsyms: skip ppc compiler stub .long_branch. / .plt_branch.

2020-09-24T15:41:54Z

PowerPC allmodconfig often fails to build as follows: LD .tmp_vmlinux.kallsyms1 KSYM .tmp_vmlinux.kallsyms1.o LD .tmp_vmlinux.kallsyms2 KSYM .tmp_vmlinux.kallsyms2.o LD .tmp_vmlinux.kallsyms3 KSYM .tmp_vmlinux.kallsyms3.o LD vmlinux SORTTAB vmlinux SYSMAP System.map Inconsistent kallsyms data Try make KALLSYMS_EXTRA_PASS=1 as a workaround make[2]: *** [../Makefile:1162: vmlinux] Error 1 Setting KALLSYMS_EXTRA_PASS=1 does not help. This is caused by the compiler inserting stubs such as *.long_branch.* and *.plt_branch.* $ powerpc-linux-nm -n .tmp_vmlinux.kallsyms2 [ snip ] c00000000210c010 t 00000075.plt_branch.da9:19 c00000000210c020 t 00000075.plt_branch.1677:5 c00000000210c030 t 00000075.long_branch.memmove c00000000210c034 t 00000075.plt_branch.9e0:5 c00000000210c044 t 00000075.plt_branch.free_initrd_mem ... Actually, the problem mentioned in scripts/link-vmlinux.sh comments; "In theory it's possible this results in even more stubs, but unlikely" is happening here, and ends up with another kallsyms step required. scripts/kallsyms.c already ignores various compiler stubs. Let's do similar to make kallsysms for PowerPC always succeed in 2 steps. Reported-by: Guenter Roeck Signed-off-by: Masahiro Yamada Tested-by: Guenter Roeck

KVM: arm64: Add build rules for separate VHE/nVHE object files

2020-07-05T17:37:55Z

Add new folders arch/arm64/kvm/hyp/{vhe,nvhe} and Makefiles for building code that runs in EL2 under VHE/nVHE KVM, repsectivelly. Add an include folder for hyp-specific header files which will include code common to VHE/nVHE. Build nVHE code with -D__KVM_NVHE_HYPERVISOR__, VHE code with -D__KVM_VHE_HYPERVISOR__. Under nVHE compile each source file into a `.hyp.tmp.o` object first, then prefix all its symbols with "__kvm_nvhe_" using `objcopy` and produce a `.hyp.o`. Suffixes were chosen so that it would be possible for VHE and nVHE to share some source files, but compiled with different CFLAGS. The nVHE ELF symbol prefix is added to kallsyms.c as ignored. EL2-only symbols will never appear in EL1 stack traces. Due to symbol prefixing, add a section in image-vars.h for aliases of symbols that are defined in nVHE EL2 and accessed by kernel in EL1 or vice versa. Signed-off-by: David Brazdil Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20200625131420.71444-4-dbrazdil@google.com

gcc-10 warnings: fix low-hanging fruit

2020-05-04T16:16:37Z

Due to a bug-report that was compiler-dependent, I updated one of my machines to gcc-10. That shows a lot of new warnings. Happily they seem to be mostly the valid kind, but it's going to cause a round of churn for getting rid of them.. This is the really low-hanging fruit of removing a couple of zero-sized arrays in some core code. We have had a round of these patches before, and we'll have many more coming, and there is nothing special about these except that they were particularly trivial, and triggered more warnings than most. Signed-off-by: Linus Torvalds

scripts/kallsyms: fix wrong kallsyms_relative_base

2020-03-19T14:40:20Z

There is the code in the read_symbol function in 'scripts/kallsyms.c': if (is_ignored_symbol(name, type)) return NULL; /* Ignore most absolute/undefined (?) symbols. */ if (strcmp(name, "_text") == 0) _text = addr; But the is_ignored_symbol function returns true for name="_text" and type='A'. So the next condition is not executed and the _text variable is always zero. It makes the wrong kallsyms_relative_base symbol as a result of the code (CONFIG_KALLSYMS_BASE_RELATIVE is defined): if (base_relative) { output_label("kallsyms_relative_base"); output_address(relative_base); printf("\n"); } Because the output_address function uses the _text variable. So the kallsyms_lookup function and all related functions in the kernel do not work properly. For example, the stack trace in oops: Call Trace: [aa095e58] [809feab8] kobj_ns_ops_tbl+0x7ff09ac8/0x7ff1c1c4 (unreliable) [aa095e98] [80002b64] kobj_ns_ops_tbl+0x7f50db74/0x80000010 [aa095ef8] [809c3d24] kobj_ns_ops_tbl+0x7feced34/0x7ff1c1c4 [aa095f28] [80002ed0] kobj_ns_ops_tbl+0x7f50dee0/0x80000010 [aa095f38] [8000f238] kobj_ns_ops_tbl+0x7f51a248/0x80000010 The right stack trace: Call Trace: [aa095e58] [809feab8] module_vdu_video_init+0x2fc/0x3bc (unreliable) [aa095e98] [80002b64] do_one_initcall+0x40/0x1f0 [aa095ef8] [809c3d24] kernel_init_freeable+0x164/0x1d8 [aa095f28] [80002ed0] kernel_init+0x14/0x124 [aa095f38] [8000f238] ret_from_kernel_thread+0x14/0x1c [masahiroy@kernel.org: This issue happens on binutils <= 2.22 The following commit fixed it: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=d2667025dd30611514810c28bee9709e4623012a The symbol type of _text is 'T' on binutils >= 2.23 The minimal supported binutils version for the kernel build is 2.21 ] Signed-off-by: Mikhail Petrov Signed-off-by: Masahiro Yamada

scripts/kallsyms: fix memory corruption caused by write over-run

2020-02-10T20:18:09Z

memcpy() writes one more byte than allocated. Fixes: 8d60526999aa ("scripts/kallsyms: change table to store (strcut sym_entry *)") Reported-by: youling257 Reported-by: Pavel Machek Signed-off-by: Masahiro Yamada Tested-by: Pavel Machek

scripts/kallsyms: change table to store (strcut sym_entry *)

2020-02-03T16:54:30Z

The symbol table is extended every 10000 addition by using realloc(), where data copy might occur to the new buffer. To decrease the amount of possible data copy, let's change the table to store the pointer. The symbol type + symbol name part is appended at the end of (struct sym_entry), and allocated together with the struct body. Signed-off-by: Masahiro Yamada

scripts/kallsyms: rename local variables in read_symbol()

2020-02-03T16:54:15Z

I will use 'sym' for the point to struce sym_entry in the next commit. Rename 'sym', 'stype' to 'name', 'type', which are more intuitive. Signed-off-by: Masahiro Yamada

scripts/kallsyms: fix offset overflow of kallsyms_relative_base

2019-12-14T06:53:04Z

Since commit 5e5c4fa78745 ("scripts/kallsyms: shrink table before sorting it"), kallsyms_relative_base can be larger than _text, which causes overflow when building the 32-bit kernel. https://lkml.org/lkml/2019/12/7/156 This is because _text is, unless --all-symbols is specified, now trimmed from the symbol table before record_relative_base() is called. Handle the offset signedness also for kallsyms_relative_base. Introduce a new helper, output_address(), to reduce the code duplication. Fixes: 5e5c4fa78745 ("scripts/kallsyms: shrink table before sorting it") Reported-by: Olof Johansson Signed-off-by: Masahiro Yamada

scripts/kallsyms: remove redundant initializers

2019-11-25T12:07:05Z

These are set to zero without the explicit initializers. Signed-off-by: Masahiro Yamada