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x86: use ELF section to list CPU vendor specific code

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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>
This commit is contained in:
Thomas Petazzoni
2008-02-15 12:00:23 +01:00
committed by Ingo Molnar
parent bc7c314d70
commit 03ae5768b6
10 changed files with 46 additions and 69 deletions
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33
arch/x86/kernel/cpu/common.c
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@@ -328,14 +328,9 @@ static void __init early_cpu_detect(void)
get_cpu_vendor(c, 1);
switch (c->x86_vendor) {
case X86_VENDOR_AMD:
early_init_amd(c);
break;
case X86_VENDOR_INTEL:
early_init_intel(c);
break;
}
if (c->x86_vendor != X86_VENDOR_UNKNOWN &&
cpu_devs[c->x86_vendor]->c_early_init)
cpu_devs[c->x86_vendor]->c_early_init(c);
early_get_cap(c);
}
@@ -616,23 +611,15 @@ __setup("clearcpuid=", setup_disablecpuid);
cpumask_t cpu_initialized __cpuinitdata = CPU_MASK_NONE;
/* This is hacky. :)
* We're emulating future behavior.
* In the future, the cpu-specific init functions will be called implicitly
* via the magic of initcalls.
* They will insert themselves into the cpu_devs structure.
* Then, when cpu_init() is called, we can just iterate over that array.
*/
void __init early_cpu_init(void)
{
intel_cpu_init();
cyrix_init_cpu();
nsc_init_cpu();
amd_init_cpu();
centaur_init_cpu();
transmeta_init_cpu();
nexgen_init_cpu();
umc_init_cpu();
struct cpu_vendor_dev *cvdev;
for (cvdev = __x86cpuvendor_start ;
cvdev < __x86cpuvendor_end ;
cvdev++)
cpu_devs[cvdev->vendor] = cvdev->cpu_dev;
early_cpu_detect();
}