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: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
Signed-off-by: Thomas 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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
index 8b09cbb..c202a64 100644 (file)
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -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,

diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 75bbeda..f6e73ec 100644 (file)
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -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);
@@ -415,14 +408,12 @@ 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);
        }