x86: use ELF section to list CPU vendor specific code

Replace the hardcoded list of initialization functions for each CPU
vendor by a list in an ELF section, which is read at initialization in
arch/x86/kernel/cpu/cpu.c to fill the cpu_devs[] array. The ELF
section, named .x86cpuvendor.init, is reclaimed after boot, and
contains entries of type "struct cpu_vendor_dev" which associates a
vendor number with a pointer to a "struct cpu_dev" structure.

This first modification allows to remove all the VENDOR_init_cpu()
functions.

This patch also removes the hardcoded calls to early_init_amd() and
early_init_intel(). Instead, we add a "c_early_init" member to the
cpu_dev structure, which is then called if not NULL by the generic CPU
initialization code. Unfortunately, in early_cpu_detect(), this_cpu is
not yet set, so we have to use the cpu_devs[] array directly.

This patch is part of the Linux Tiny project, and is needed for
further patch that will allow to disable compilation of unused CPU
support code.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 3 insertions, 6 deletions

diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index fae31ce747bd..34468b2e2507 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -30,7 +30,7 @@
 struct movsl_mask movsl_mask __read_mostly;
 #endif
 
-void __cpuinit early_init_intel(struct cpuinfo_x86 *c)
+static void __cpuinit early_init_intel(struct cpuinfo_x86 *c)
 {
         /* Netburst reports 64 bytes clflush size, but does IO in 128 bytes */
         if (c->x86 == 15 && c->x86_cache_alignment == 64)
@@ -290,15 +290,12 @@ static struct cpu_dev intel_cpu_dev __cpuinitdata = {
                   }
                 },
         },
+        .c_early_init   = early_init_intel,
         .c_init         = init_intel,
         .c_size_cache   = intel_size_cache,
 };
 
-__init int intel_cpu_init(void)
-{
-        cpu_devs[X86_VENDOR_INTEL] = &intel_cpu_dev;
-        return 0;
-}
+cpu_vendor_dev_register(X86_VENDOR_INTEL, &intel_cpu_dev);
 
 #ifndef CONFIG_X86_CMPXCHG
 unsigned long cmpxchg_386_u8(volatile void *ptr, u8 old, u8 new)