* Luck, Tony <tony.luck@xxxxxxxxx> wrote: > > could you send the .config you are using? > > Ok. Attached. thanks a ton - this produced a link error here too. after half an hour of head scratching, the updated patch below solves the build problem. The problem i believe is this code in arch/ia64/kernel/mca_asm.S: #define GET_IA64_MCA_DATA(reg) \ GET_THIS_PADDR(reg, ia64_mca_data) \ ;; \ ld8 reg=[reg] this i believe builds an implicit dependency between the mca_asm.o position within the image and the ia64_mca_data percpu variable it accesses - it relies on the immediate 22 addressing mode that has 4MB of scope. Per chance, the .config you sent creates a 14MB image, and the percpu variables moved too far away for the linker to be able to fulfill this constraint. The workaround is to define PER_CPU_ATTRIBUTES to link percpu variables back into the .percpu section on UP too - which ia64 links specially into its vmlinux.lds. But ultimately i think the better solution would be to remove this dependency between arch/ia64/kernel/mca_asm.S and the position of the percpu data. Is my analysis correct? Do you like my fix and does the patch build and boot on your system? Thanks, Ingo ---------------> Subject: ia64: on UP percpu variables are not small memory model From: Ingo Molnar <mingo@xxxxxxx> Tony says: | The CONFIG_SMP=n path in ia64 makes quite radical changes ... rather | than putting all the per-cpu stuff into the top 64K of address space | and providing a per-cpu TLB mapping for that range to a different | physical address ... it just makes all the per-cpu stuff link as ordinary | variables in .data. the new generic percpu code got confused about this as PER_CPU_ATTRIBUTES was defined even on UP, so it picked up that small memory model - which was not possible to get linked. The right fix is to only define that on SMP. This resolved the build failures in my cross-compiling environment. also link these variables into the .percpu section - some assembly code has offset dependencies. Signed-off-by: Ingo Molnar <mingo@xxxxxxx> --- include/asm-ia64/percpu.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) Index: linux-x86.q/include/asm-ia64/percpu.h =================================================================== --- linux-x86.q.orig/include/asm-ia64/percpu.h +++ linux-x86.q/include/asm-ia64/percpu.h @@ -15,18 +15,20 @@ #include <linux/threads.h> +#ifdef CONFIG_SMP + #ifdef HAVE_MODEL_SMALL_ATTRIBUTE # define PER_CPU_ATTRIBUTES __attribute__((__model__ (__small__))) #endif -#ifdef CONFIG_SMP - #define __my_cpu_offset __ia64_per_cpu_var(local_per_cpu_offset) extern void *per_cpu_init(void); #else /* ! SMP */ +#define PER_CPU_ATTRIBUTES __attribute__((__section__(".data.percpu"))) + #define per_cpu_init() (__phys_per_cpu_start) #endif /* SMP */ - To unsubscribe from this list: send the line "unsubscribe linux-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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