Commit ef014aae authored by Zhenzhong Duan's avatar Zhenzhong Duan Committed by Thomas Gleixner
Browse files

x86/retpoline: Remove minimal retpoline support 



Now that CONFIG_RETPOLINE hard depends on compiler support, there is no
reason to keep the minimal retpoline support around which only provided
basic protection in the assembly files.

Suggested-by: default avatarPeter Zijlstra <peterz@infradead.org>
Signed-off-by: default avatarZhenzhong Duan <zhenzhong.duan@oracle.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: David Woodhouse <dwmw@amazon.co.uk>
Cc: Borislav Petkov <bp@suse.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: <srinivas.eeda@oracle.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/f06f0a89-5587-45db-8ed2-0a9d6638d5c0@default
parent 4cd24de3

arch/x86/include/asm/nospec-branch.h

+0 −2
Original line number Diff line number Diff line
@@ -221,8 +221,6 @@ 
/* The Spectre V2 mitigation variants */

enum spectre_v2_mitigation {

	SPECTRE_V2_NONE,

	SPECTRE_V2_RETPOLINE_MINIMAL,

	SPECTRE_V2_RETPOLINE_MINIMAL_AMD,

	SPECTRE_V2_RETPOLINE_GENERIC,

	SPECTRE_V2_RETPOLINE_AMD,

	SPECTRE_V2_IBRS_ENHANCED,

arch/x86/kernel/cpu/bugs.c

+2 −11
Original line number Diff line number Diff line
@@ -135,8 +135,6 @@ enum spectre_v2_mitigation_cmd { 


static const char *spectre_v2_strings[] = {

	[SPECTRE_V2_NONE]			= "Vulnerable",

	[SPECTRE_V2_RETPOLINE_MINIMAL]		= "Vulnerable: Minimal generic ASM retpoline",

	[SPECTRE_V2_RETPOLINE_MINIMAL_AMD]	= "Vulnerable: Minimal AMD ASM retpoline",

	[SPECTRE_V2_RETPOLINE_GENERIC]		= "Mitigation: Full generic retpoline",

	[SPECTRE_V2_RETPOLINE_AMD]		= "Mitigation: Full AMD retpoline",

	[SPECTRE_V2_IBRS_ENHANCED]		= "Mitigation: Enhanced IBRS",
@@ -250,11 +248,6 @@ static void __init spec2_print_if_secure(const char *reason) 
		pr_info("%s selected on command line.\n", reason);

}



static inline bool retp_compiler(void)

{

	return __is_defined(CONFIG_RETPOLINE);

}



static inline bool match_option(const char *arg, int arglen, const char *opt)

{

	int len = strlen(opt);
@@ -417,14 +410,12 @@ retpoline_auto: 
			pr_err("Spectre mitigation: LFENCE not serializing, switching to generic retpoline\n");

			goto retpoline_generic;

		}

		mode = retp_compiler() ? SPECTRE_V2_RETPOLINE_AMD :

					 SPECTRE_V2_RETPOLINE_MINIMAL_AMD;

		mode = SPECTRE_V2_RETPOLINE_AMD;

		setup_force_cpu_cap(X86_FEATURE_RETPOLINE_AMD);

		setup_force_cpu_cap(X86_FEATURE_RETPOLINE);

	} else {

	retpoline_generic:

		mode = retp_compiler() ? SPECTRE_V2_RETPOLINE_GENERIC :

					 SPECTRE_V2_RETPOLINE_MINIMAL;

		mode = SPECTRE_V2_RETPOLINE_GENERIC;

		setup_force_cpu_cap(X86_FEATURE_RETPOLINE);

	}

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