From 516d980f85415d76ae3d0d2a871eb20243f46c95 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Wed, 23 Sep 2020 02:48:56 +0900 Subject: [PATCH 1/2] scripts/kallsyms: skip ppc compiler stub *.long_branch.* / *.plt_branch.* 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 --- scripts/kallsyms.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c index 0096cd96533275..7ecd2ccba531bb 100644 --- a/scripts/kallsyms.c +++ b/scripts/kallsyms.c @@ -82,6 +82,7 @@ static char *sym_name(const struct sym_entry *s) static bool is_ignored_symbol(const char *name, char type) { + /* Symbol names that exactly match to the following are ignored.*/ static const char * const ignored_symbols[] = { /* * Symbols which vary between passes. Passes 1 and 2 must have @@ -104,6 +105,7 @@ static bool is_ignored_symbol(const char *name, char type) NULL }; + /* Symbol names that begin with the following are ignored.*/ static const char * const ignored_prefixes[] = { "$", /* local symbols for ARM, MIPS, etc. */ ".LASANPC", /* s390 kasan local symbols */ @@ -113,6 +115,7 @@ static bool is_ignored_symbol(const char *name, char type) NULL }; + /* Symbol names that end with the following are ignored.*/ static const char * const ignored_suffixes[] = { "_from_arm", /* arm */ "_from_thumb", /* arm */ @@ -120,9 +123,15 @@ static bool is_ignored_symbol(const char *name, char type) NULL }; + /* Symbol names that contain the following are ignored.*/ + static const char * const ignored_matches[] = { + ".long_branch.", /* ppc stub */ + ".plt_branch.", /* ppc stub */ + NULL + }; + const char * const *p; - /* Exclude symbols which vary between passes. */ for (p = ignored_symbols; *p; p++) if (!strcmp(name, *p)) return true; @@ -138,6 +147,11 @@ static bool is_ignored_symbol(const char *name, char type) return true; } + for (p = ignored_matches; *p; p++) { + if (strstr(name, *p)) + return true; + } + if (type == 'U' || type == 'u') return true; /* exclude debugging symbols */ From e30d694c3381b565e043cf74b0bed059db1b4ac9 Mon Sep 17 00:00:00 2001 From: Florian Fainelli Date: Fri, 25 Sep 2020 08:21:14 -0700 Subject: [PATCH 2/2] Documentation/llvm: Fix clang target examples clang --target= is how we can specify a particular toolchain triple to be use, fix the two occurences in the documentation. Fixes: fcf1b6a35c16 ("Documentation/llvm: add documentation on building w/ Clang/LLVM") Signed-off-by: Florian Fainelli Reviewed-by: Nick Desaulniers Reviewed-by: Nathan Chancellor Signed-off-by: Masahiro Yamada --- Documentation/kbuild/llvm.rst | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/Documentation/kbuild/llvm.rst b/Documentation/kbuild/llvm.rst index 334df758dce360..dae90c21aed30d 100644 --- a/Documentation/kbuild/llvm.rst +++ b/Documentation/kbuild/llvm.rst @@ -39,10 +39,10 @@ which can help simplify cross compiling. :: ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- make CC=clang ``CROSS_COMPILE`` is not used to prefix the Clang compiler binary, instead -``CROSS_COMPILE`` is used to set a command line flag: ``--target ``. For +``CROSS_COMPILE`` is used to set a command line flag: ``--target=``. For example: :: - clang --target aarch64-linux-gnu foo.c + clang --target=aarch64-linux-gnu foo.c LLVM Utilities --------------