[tip: x86/fred] x86/fred: Add Kconfig option for FRED (CONFIG_X86_FRED)

[tip-bot2 for H. Peter Anvin (Intel)]

The following commit has been merged into the x86/fred branch of tip:

Commit-ID:     2cce95918d635126098d784c040b59333c464b20
Gitweb:        https://git.kernel.org/tip/2cce95918d635126098d784c040b59333c464b20
Author:        H. Peter Anvin (Intel) <hpa@xxxxxxxxx>
AuthorDate:    Tue, 05 Dec 2023 02:49:54 -08:00
Committer:     Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Thu, 25 Jan 2024 19:10:30 +01:00

x86/fred: Add Kconfig option for FRED (CONFIG_X86_FRED)

Add the configuration option CONFIG_X86_FRED to enable FRED.

Signed-off-by: H. Peter Anvin (Intel) <hpa@xxxxxxxxx>
Signed-off-by: Xin Li <xin3.li@xxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Tested-by: Shan Kang <shan.kang@xxxxxxxxx>
Link: https://lore.kernel.org/r/20231205105030.8698-6-xin3.li@xxxxxxxxx

---
 arch/x86/Kconfig |  9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 5edec17..854ab38 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -496,6 +496,15 @@ config X86_CPU_RESCTRL
 
 	  Say N if unsure.
 
+config X86_FRED
+	bool "Flexible Return and Event Delivery"
+	depends on X86_64
+	help
+	  When enabled, try to use Flexible Return and Event Delivery
+	  instead of the legacy SYSCALL/SYSENTER/IDT architecture for
+	  ring transitions and exception/interrupt handling if the
+	  system supports.
+
 if X86_32
 config X86_BIGSMP
 	bool "Support for big SMP systems with more than 8 CPUs"