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, 4 insertions, 1 deletions

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 693e353999cd..cab4e562b5cb 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -63,7 +63,7 @@ static __cpuinit int amd_apic_timer_broken(void)
 
 int force_mwait __cpuinitdata;
 
-void __cpuinit early_init_amd(struct cpuinfo_x86 *c)
+static void __cpuinit early_init_amd(struct cpuinfo_x86 *c)
 {
         if (cpuid_eax(0x80000000) >= 0x80000007) {
                 c->x86_power = cpuid_edx(0x80000007);
@@ -336,6 +336,7 @@ static struct cpu_dev amd_cpu_dev __cpuinitdata = {
                   }
                 },
         },
+        .c_early_init   = early_init_amd,
         .c_init         = init_amd,
         .c_size_cache   = amd_size_cache,
 };
@@ -345,3 +346,5 @@ int __init amd_init_cpu(void)
         cpu_devs[X86_VENDOR_AMD] = &amd_cpu_dev;
         return 0;
 }
+
+cpu_vendor_dev_register(X86_VENDOR_AMD, &amd_cpu_dev);