Messages in this thread | | | Date | Wed, 7 Sep 2011 15:46:32 -0700 | From | "Paul E. McKenney" <> | Subject | Re: CRC calculation in Module.symvers |
| |
On Wed, Sep 07, 2011 at 11:28:46AM +0530, Shakthi Kannan wrote: > Greetings! > > I would like to know as to: > > 1. How the CRC is computed for an exported symbol present in > Module.symvers file, and > 2. Given a kernel .c file, how can I obtain the CRC checksums for a symbol. > > For linux-3.0.2 (example), I compiled with CONFIG_MODVERSIONS=y, and > running 'make' built vmlinux, and generated the Module.symvers file. I > believe genksyms is used to create the Module.symvers file? > > I had referred the "Kernel Symbols and CONFIG_MODVERSIONS" > documentation [1] written by Mark McLoughlin. I tried the following in > the top-level kernel sources: > > $ gcc -E -D__GENKSYMS__ -DCONFIG_MODVERSIONS -DEXPORT_SYMTAB > crypto/api.c -I/tmp/linux-3.0.2/include > -I/tmp/linux-3.0.2/arch/x86/include | ./scripts/genksyms/genksyms > > and I get the following error output: > > === Output === > > /tmp/linux-3.0.2/include/linux/jiffies.h:43:42: error: division by zero in #if > In file included from /tmp/linux-3.0.2/include/linux/tracepoint.h:19:0, > from /tmp/linux-3.0.2/include/linux/module.h:18, > from crypto/api.c:22: > /tmp/linux-3.0.2/include/linux/rcupdate.h:160:2: error: #error > "Unknown RCU implementation specified to kernel configuration"
The above error message is emitted if none of CONFIG_TINY_RCU, CONFIG_TINY_PREEMPT_RCU, CONFIG_TREE_RCU, and CONFIG_TREE_PREEMPT_RCU is defined. Given that these four are in a "choice", I suspect that you have broken the kernel build pretty impressively.
Thanx, Paul
> In file included from /tmp/linux-3.0.2/include/linux/module.h:21:0, > from crypto/api.c:22: > /tmp/linux-3.0.2/arch/x86/include/asm/module.h:59:2: error: #error > unknown processor family > > === End === > > The documentation for genksyms is old, and now there is no -k option? > > Appreciate any inputs in this regard, > > Thanks! > > SK > > [1] Kernel Symbols and CONFIG_MODVERSIONS. > http://www.skynet.ie/~mark/pub/symbols.txt > > -- > Shakthi Kannan > http://www.shakthimaan.com > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
| |