Messages in this thread | | | Date | Thu, 15 Jul 2010 17:05:14 +0200 | From | Sam Ravnborg <> | Subject | Re: [PATCH] tracing: properly align linker defined symbols |
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On Sat, Jul 10, 2010 at 08:34:59AM +0200, Sam Ravnborg wrote: > Zeev - please try this replacement patch. > The alignmnet is increased to 32 bytes compared to my previous version and > we introduce alignmnet for ftrace_events too. > > Sam
Steven - Zeev reported that this fixed the boot problem. What is next step? Do you forward this patch or do you prefer another fix?
Sam
> > From 40bedb8fda25d2cf9ecdd41ab48a24104607c37e Mon Sep 17 00:00:00 2001 > From: Sam Ravnborg <sam@ravnborg.org> > Date: Sat, 10 Jul 2010 08:24:12 +0200 > Subject: [PATCH] tracing: properly align linker defined symbols > > We define a number of symbols in the linker scipt like this: > > __start_syscalls_metadata = .; > *(__syscalls_metadata) > > But we do not know the alignment of "." when we assign > the __start_syscalls_metadata symbol. > gcc started to uses bigger alignment for structs (32 bytes), > so we saw situations where the linker due to alignment > constraints increased the value of "." after the symbol assignment. > > This resulted in boot fails. > > Fix this by forcing a 32 byte alignment of "." before the > assignment. > > This patch introduces the forced alignment for > ftrace_events and syscalls_metadata. > It may be required in more places. > > Reported-by: Zeev Tarantov <zeev.tarantov@gmail.com> > Signed-off-by: Sam Ravnborg <sam@ravnborg.org> > Cc: Steven Rostedt <rostedt@goodmis.org> > Cc: Frederic Weisbecker <fweisbec@gmail.com> > --- > include/asm-generic/vmlinux.lds.h | 10 ++++++++++ > 1 files changed, 10 insertions(+), 0 deletions(-) > > diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h > index 48c5299..4b5902a 100644 > --- a/include/asm-generic/vmlinux.lds.h > +++ b/include/asm-generic/vmlinux.lds.h > @@ -63,6 +63,12 @@ > /* Align . to a 8 byte boundary equals to maximum function alignment. */ > #define ALIGN_FUNCTION() . = ALIGN(8) > > +/* > + * Align to a 32 byte boundary equal to the > + * alignment gcc 4.5 uses for a struct > + */ > +#define STRUCT_ALIGN() . = ALIGN(32) > + > /* The actual configuration determine if the init/exit sections > * are handled as text/data or they can be discarded (which > * often happens at runtime) > @@ -166,7 +172,11 @@ > LIKELY_PROFILE() \ > BRANCH_PROFILE() \ > TRACE_PRINTKS() \ > + \ > + STRUCT_ALIGN(); \ > FTRACE_EVENTS() \ > + \ > + STRUCT_ALIGN(); \ > TRACE_SYSCALLS() > > /* > -- > 1.6.0.6 >
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