On Mon 2018-03-05 14:37:42, Sergey Senozhatsky wrote: > We want to move dump_stack related functions out of printk C > code and consolidate them in lib/dump_stack file. The reason why > dump_stack_print_info()/etc ended up in printk.c was a "generic" > (dummy) lib dump_stack() function, which archs can override. > For example, blackfin and nds32, define their own EXPORT_SYMBOL > dump_stack() functions. > > In case of blackfin that arch-specific dump_stack() symbol invokes > a global dump_stack_print_info() function. So we can't easily move > dump_stack_print_info() to lib/dump_stack, because this way we will > link with lib/dump_stack.o file, which will bring in a generic > dump_stack() symbol with it, causing a multiple definitions error: > - one dump_stack() from arch/blackfin/dumpstack > - the other one from lib/dump_stack > > Convert generic dump_stack() into a weak symbol. So we will be > able link with lib/dump_stack and at the same time archs will > be able to override dump_stack(). It also opens up a way for us > to move dump_stack_set_arch_desc(), dump_stack_print_info() and > show_regs_print_info() to lib/dump_stack. > > Signed-off-by: Sergey Senozhatsky <sergey.senozhat...@gmail.com> > --- > arch/blackfin/kernel/dumpstack.c | 1 - > arch/nds32/kernel/traps.c | 2 -- > lib/dump_stack.c | 4 ++-- > 3 files changed, 2 insertions(+), 5 deletions(-) > > diff --git a/arch/blackfin/kernel/dumpstack.c > b/arch/blackfin/kernel/dumpstack.c > index 3c992c1f8ef2..61af017130cd 100644 > --- a/arch/blackfin/kernel/dumpstack.c > +++ b/arch/blackfin/kernel/dumpstack.c > @@ -174,4 +174,3 @@ void dump_stack(void) > show_stack(current, &stack); > trace_buffer_restore(tflags); > } > -EXPORT_SYMBOL(dump_stack);
I was afraid that blackfin modules would not longer be able to use arch-specific dump_stack symbol. But it seems that only the symbol name is important. Alos the list of symbols look promissing: before: $> objdump -x vmlinux | less | grep dump_stack 00248530 l O __ksymtab 00000008 ___ksymtab_dump_stack 002500d4 l O __ksymtab_strings 0000000c ___kstrtab_dump_stack 00272bb6 l O .bss 00000080 _dump_stack_arch_desc_str 000051a8 g F .text 00000042 _dump_stack 002ab05c g F .init.text 0000002a _dump_stack_set_arch_desc 0003051c g F .text 000000a4 _dump_stack_print_info after: $> objdump -x vmlinux.patched | less | grep dump_stack 00000000 l df *ABS* 00000000 lib/dump_stack.c 0027c3e8 l O .bss 00000080 _dump_stack_arch_desc_str 00248580 l O __ksymtab 00000008 ___ksymtab_dump_stack 002653d4 l O __ksymtab_strings 0000000c ___kstrtab_dump_stack 000051a8 g F .text 00000042 _dump_stack 002b69dc g F .init.text 0000002a _dump_stack_set_arch_desc 001c2a90 g F .text 000000a4 _dump_stack_print_info I hope that I did not miss anything. I could not try this at runtime. I could just cross-compile. Anyway, from my side: Reviewed-by: Petr Mladek <pmla...@suse.com> I'll wait a bit and push it into printk.git for-4.17. Greentime Hu, you tested this on nds32. Could I use your Tested-by, please? Best Regards, Petr
