From dd649bd0b3aa012740059b1ba31ecad28a408f7f Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Thu, 28 May 2020 16:13:48 -0400 Subject: x86/cpu: Add 'unsafe_fsgsbase' to enable CR4.FSGSBASE This is temporary. It will allow the next few patches to be tested incrementally. Setting unsafe_fsgsbase is a root hole. Don't do it. Signed-off-by: Andy Lutomirski Signed-off-by: Chang S. Bae Signed-off-by: Thomas Gleixner Signed-off-by: Sasha Levin Signed-off-by: Thomas Gleixner Reviewed-by: Andi Kleen Reviewed-by: Andy Lutomirski Link: https://lkml.kernel.org/r/1557309753-24073-4-git-send-email-chang.seok.bae@intel.com Link: https://lkml.kernel.org/r/20200528201402.1708239-3-sashal@kernel.org --- Documentation/admin-guide/kernel-parameters.txt | 3 +++ 1 file changed, 3 insertions(+) (limited to 'Documentation/admin-guide') diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index fb95fad81c79..7308db7308ba 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -3079,6 +3079,9 @@ no5lvl [X86-64] Disable 5-level paging mode. Forces kernel to use 4-level paging instead. + unsafe_fsgsbase [X86] Allow FSGSBASE instructions. This will be + replaced with a nofsgsbase flag. + no_console_suspend [HW] Never suspend the console Disable suspending of consoles during suspend and -- cgit v1.2.3 From b745cfba44c152c34363eea9e052367b6b1d652b Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Thu, 28 May 2020 16:13:58 -0400 Subject: x86/cpu: Enable FSGSBASE on 64bit by default and add a chicken bit Now that FSGSBASE is fully supported, remove unsafe_fsgsbase, enable FSGSBASE by default, and add nofsgsbase to disable it. Signed-off-by: Andy Lutomirski Signed-off-by: Chang S. Bae Signed-off-by: Thomas Gleixner Signed-off-by: Sasha Levin Signed-off-by: Thomas Gleixner Reviewed-by: Andi Kleen Link: https://lkml.kernel.org/r/1557309753-24073-17-git-send-email-chang.seok.bae@intel.com Link: https://lkml.kernel.org/r/20200528201402.1708239-13-sashal@kernel.org --- Documentation/admin-guide/kernel-parameters.txt | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'Documentation/admin-guide') diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 7308db7308ba..8c0d045f1dc7 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -3079,8 +3079,7 @@ no5lvl [X86-64] Disable 5-level paging mode. Forces kernel to use 4-level paging instead. - unsafe_fsgsbase [X86] Allow FSGSBASE instructions. This will be - replaced with a nofsgsbase flag. + nofsgsbase [X86] Disables FSGSBASE instructions. no_console_suspend [HW] Never suspend the console -- cgit v1.2.3