[coreboot-gerrit] Change in coreboot[master]: cpu/x86/64bit: Add code to call function in protected mode

[Patrick Rudolph (Code Review)]

Hello build bot (Jenkins), Patrick Georgi, Martin Roth, Arthur Heymans, Andrey Petrov, Patrick Rudolph,

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

https://review.coreboot.org/c/coreboot/+/48175

to look at the new patch set (#6).

Change subject: cpu/x86/64bit: Add code to call function in protected mode
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cpu/x86/64bit: Add code to call function in protected mode

This adds a helper function for long mode to call some code in protected
mode and return back to long mode.

The primary use case is to run binaries that have been compiled for
protected mode, like the FSP or MRC binaries.

Tested on Intel Skylake. The FSP-M runs and returns without error while
coreboot runs in long mode.

Change-Id: I22af2d224b546c0be9e7295330b4b6602df106d6
Signed-off-by: Patrick Rudolph 
---
A src/arch/x86/include/mode_switch.h
A src/cpu/x86/64bit/mode_switch.S
M src/cpu/x86/Makefile.inc
3 files changed, 143 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/75/48175/6