Change in ...coreboot[master]: src/arch/x86: Use core apic id to get cpu_index()

[Subrata Banik (Code Review)]

Hello Aaron Durbin, Patrick Rudolph, ron minnich, Paul Menzel, build bot (Jenkins), Nico Huber,

I'd like you to reexamine a change. Please visit

https://review.coreboot.org/c/coreboot/+/26346

to look at the new patch set (#16).

Change subject: src/arch/x86: Use core apic id to get cpu_index()
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src/arch/x86: Use core apic id to get cpu_index()

This cpu_index() implementation assumes that cpu_index() function
might always getting called from coreboot context (ESP stack
pointer will always refer to coreboot).

This might not be true in case of proposed PI spec MP_SERVICES_PPI
implementation, where FSP context (stack pointer refers to fsp)
will request to get cpu_index(), natural alignment logic will
use ESP and retrieve struct cpu_info *ci from (stack_top - 8 byte).
This is not the place where cpu_index is actually stored by
ramstage c_start.S

Hence this patch tries to remove those dependencies while retrieving
cpu_index(), rather it uses cpuid to fetch lapic id and matches with
cpu_mp structure to get correct cpu_index().

BRANCH=none
BUG=b:79562868
TEST=Ensures functions can be run on APs without any failure and
cpu_index() also provides correct index number.

Change-Id: I55023a3e0cf42f0496d45bc6af8ead447f402350
Signed-off-by: Subrata Banik 
---
M src/arch/x86/cpu.c
M src/arch/x86/include/arch/cpu.h
2 files changed, 22 insertions(+), 7 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/46/26346/16