x86/bugs: Replace CONFIG_SPECTRE_BHI_{ON,OFF} with CONFIG_MITIGATION_SPECTRE_BHI

For consistency with the other CONFIG_MITIGATION_* options, replace the
CONFIG_SPECTRE_BHI_{ON,OFF} options with a single
CONFIG_MITIGATION_SPECTRE_BHI option.

[ mingo: Fix ]
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nikolay Borisov <nik.borisov@suse.com>
Link: https://lore.kernel.org/r/3833812ea63e7fdbe36bf8b932e63f70d18e2a2a.1712813475.git.jpoimboe@kernel.org

arch/x86/Kconfig

@@ -2633,27 +2633,16 @@ config MITIGATION_RFDS
 	  stored in floating point, vector and integer registers.
 	  See also <file:Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst>
 
-choice
-	prompt "Clear branch history"
+config MITIGATION_SPECTRE_BHI
+	bool "Mitigate Spectre-BHB (Branch History Injection)"
 	depends on CPU_SUP_INTEL
-	default SPECTRE_BHI_ON
+	default y
 	help
 	  Enable BHI mitigations. BHI attacks are a form of Spectre V2 attacks
 	  where the branch history buffer is poisoned to speculatively steer
 	  indirect branches.
 	  See <file:Documentation/admin-guide/hw-vuln/spectre.rst>
 
-config SPECTRE_BHI_ON
-	bool "on"
-	help
-	  Equivalent to setting spectre_bhi=on command line parameter.
-config SPECTRE_BHI_OFF
-	bool "off"
-	help
-	  Equivalent to setting spectre_bhi=off command line parameter.
-
-endchoice
-
 endif
 
 config ARCH_HAS_ADD_PAGES

arch/x86/kernel/cpu/bugs.c

@@ -1628,7 +1628,7 @@ enum bhi_mitigations {
 };
 
 static enum bhi_mitigations bhi_mitigation __ro_after_init =
-	IS_ENABLED(CONFIG_SPECTRE_BHI_ON) ? BHI_MITIGATION_ON : BHI_MITIGATION_OFF;
+	IS_ENABLED(CONFIG_MITIGATION_SPECTRE_BHI) ? BHI_MITIGATION_ON : BHI_MITIGATION_OFF;
 
 static int __init spectre_bhi_parse_cmdline(char *str)
 {