diff mbox series

[v13,08/35] x86/fred: Disable FRED by default in its early stage

Message ID 20231205105030.8698-9-xin3.li@intel.com
State New
Headers
Series x86: enable FRED for x86-64 |

Commit Message

Li, Xin3 Dec. 5, 2023, 10:49 a.m. UTC 
  To enable FRED, a new kernel command line option "fred" needs to be added.

Tested-by: Shan Kang <shan.kang@intel.com>
Signed-off-by: Xin Li <xin3.li@intel.com>
---
 Documentation/admin-guide/kernel-parameters.txt | 3 +++
 arch/x86/kernel/cpu/common.c                    | 3 +++
 2 files changed, 6 insertions(+)

Comments

Borislav Petkov Jan. 22, 2024, 1:19 p.m. UTC | #1 
On Tue, Dec 05, 2023 at 02:49:57AM -0800, Xin Li wrote:
>  			Warning: use of this parameter will taint the kernel
>  			and may cause unknown problems.
>  
> +	fred		[X86-64]
> +			Enable flexible return and event delivery

Let's make it accept multiple options from the get-go:

fred=on,disable-when,foo,bar,bla...

in case we need to tweak its behavior.

If it is only "fred" it will propagate this way downstream and it'll
lead to confusion later when people have to update their scripts and
config files when "fred" alone doesn't do what they're expecting
anymore.

Thx.
diff mbox series

Patch

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 65731b060e3f..6992b392e8d3 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1526,6 +1526,9 @@ 
 			Warning: use of this parameter will taint the kernel
 			and may cause unknown problems.
 
+	fred		[X86-64]
+			Enable flexible return and event delivery
+
 	ftrace=[tracer]
 			[FTRACE] will set and start the specified tracer
 			as early as possible in order to facilitate early
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 4d4b87c6885d..68102acd63b0 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1491,6 +1491,9 @@  static void __init cpu_parse_early_param(void)
 	char *argptr = arg, *opt;
 	int arglen, taint = 0;
 
+	if (!cmdline_find_option_bool(boot_command_line, "fred"))
+		setup_clear_cpu_cap(X86_FEATURE_FRED);
+
 #ifdef CONFIG_X86_32
 	if (cmdline_find_option_bool(boot_command_line, "no387"))
 #ifdef CONFIG_MATH_EMULATION