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Commit 376afe74 authored by Zhenzhong Duan's avatar Zhenzhong Duan Committed by Greg Kroah-Hartman
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x86/retpoline: Remove minimal retpoline support 



commit ef014aae8f1cd2793e4e014bbb102bed53f852b7 upstream.

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


Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 3dd518cb

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

+0 −2
Original line number Diff line number Diff line
@@ -223,8 +223,6 @@ 
/* 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
@@ -784,8 +784,6 @@ spectre_v2_user_select_mitigation(enum spectre_v2_mitigation_cmd v2_cmd) 


static const char * const 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",
@@ -810,11 +808,6 @@ static void __init spec_v2_print_cond(const char *reason, bool secure) 
		pr_info("%s selected on command line.\n", reason);

}



static inline bool retp_compiler(void)

{

	return __is_defined(CONFIG_RETPOLINE);

}



static enum spectre_v2_mitigation_cmd __init spectre_v2_parse_cmdline(void)

{

	enum spectre_v2_mitigation_cmd cmd = SPECTRE_V2_CMD_AUTO;
@@ -912,14 +905,12 @@ static void __init spectre_v2_select_mitigation(void) 
			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);

	}