We have finished the first prototype of kern/cpu_number.h http://dpaste.com/2QJB8VR
We have to improve many details, about initialization of structures and implementation of the function (may be better creates a cpu_number.c file, instead implement the function in the header), but now the compilation don't fails in this step. The compilation continues failing, anymore http://dpaste.com/26VWZ6G 2018-06-16 13:17 GMT+02:00 Almudena Garcia <liberamenso10...@gmail.com>: > Finally, we got to write a test function to get the apic_id, and It feels > to run correctly. > Now, we're trying to implement another function, to transform the apic_id > in the kernel cpuid. > > I attach the current test function to get apic_id with its test file > > 2018-06-15 19:36 GMT+02:00 Almudena Garcia <liberamenso10...@gmail.com>: > >> Yes, I saw this. >> >> When I test It in Linux, I used a dual core computer. But the snippet >> returns "8" number. >> >> Now I know the reason ;) >> >> 2018-06-15 19:25 GMT+02:00 Richard Braun <rbr...@sceen.net>: >> >>> On Fri, Jun 15, 2018 at 07:18:55PM +0200, Richard Braun wrote: >>> > On Fri, Jun 15, 2018 at 06:27:21PM +0200, Almudena Garcia wrote: >>> > > I'm trying to define the cpu_number() in multiprocessor. >>> > > >>> > > To do this, I tried to use CPUID assembly x86 instruction, to get >>> the CPU >>> > > SMP number. >>> > > The function, in C, is this: >>> > > >>> > > static inline char smp_processor_id(void) { >>> > > char apic_id = 0; >>> > > asm("mov $1, %%eax\n\t" >>> > > "cpuid\n\t" >>> > > "mov %%bh, %0\n\t" : "=g" (apic_id)); >>> > > return apic_id; >>> > > } >>> > > >>> > > In Linux, after executing this in a test source, It returns '8' >>> > > >>> > > But, when I try to execute It in Hurd, It shows a segmentation fault. >>> > > >>> > > I attach the test source file >>> > > >>> > > >>> > > Can you help me? >>> >>> Also note here that you're confusing the APIC ID, a device identifier at >>> the hardware level, with the CPU ID, a processor identifier at the kernel >>> level. On some machines, the APIC ID may be higher than or equal to the >>> maximum number of processor installed. >>> >>> -- >>> Richard Braun >>> >> >> >
