diff options
| author | Patrick Rudolph <siro@das-labor.org> | 2019-09-29 11:08:33 +0200 |
|---|---|---|
| committer | Patrick Georgi <pgeorgi@google.com> | 2020-07-08 07:28:32 +0000 |
| commit | 03a79520d6f62072ff3de75cc8bbbf0ff4876f62 (patch) | |
| tree | a5e64772b790c563e25dd872a48f2cbbcdf4192d /Documentation/arch | |
| parent | d5321bf2fb6ddbceea21e8b8e38ae89288fcfb1a (diff) | |
cpu/x86/smm: Add support for long mode
Enable long mode in SMM handler.
x86_32 isn't affected by this change.
As the rsm instruction used to leave SMM doesn't restore MSR registers,
drop back to protected mode after running the smi_handler and restore
IA32_EFER MSR (which enables long mode support) to previous value.
NOTE: This commit does NOT introduce a new security model. It uses the
same page tables as the remaining firmware does.
This can be a security risk if someone is able to manipulate the
page tables stored in ROM at runtime. USE FOR TESTING ONLY!
Tested on Qemu Q35.
Change-Id: I8bba4af4688c723fc079ae905dac95f57ea956f8
Signed-off-by: Patrick Rudolph <siro@das-labor.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/35681
Reviewed-by: Raul Rangel <rrangel@chromium.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Diffstat (limited to 'Documentation/arch')
| -rw-r--r-- | Documentation/arch/x86/index.md | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/Documentation/arch/x86/index.md b/Documentation/arch/x86/index.md index 30dcc10e91..f5546d18d5 100644 --- a/Documentation/arch/x86/index.md +++ b/Documentation/arch/x86/index.md @@ -45,6 +45,7 @@ At the moment *$n* is 4, which results in identity mapping the lower 4 GiB. * Add x86_64 exception handlers - *DONE* * Setup page tables for long mode - *DONE* * Add assembly code for long mode - *DONE* +* Add assembly code for SMM - *DONE* * Add assembly code for postcar stage - *TODO* * Add assembly code to return to protected mode - *TODO* * Implement reference code for mainboard `emulation/qemu-q35` - *TODO* |