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Message-Id: <1516476182-5153-8-git-send-email-karahmed@amazon.de>
Date: Sat, 20 Jan 2018 20:22:58 +0100
From: KarimAllah Ahmed <karahmed@...zon.de>
To: linux-kernel@...r.kernel.org
Cc: KarimAllah Ahmed <karahmed@...zon.de>,
Andi Kleen <ak@...ux.intel.com>,
Andrea Arcangeli <aarcange@...hat.com>,
Andy Lutomirski <luto@...nel.org>,
Arjan van de Ven <arjan@...ux.intel.com>,
Ashok Raj <ashok.raj@...el.com>,
Asit Mallick <asit.k.mallick@...el.com>,
Borislav Petkov <bp@...e.de>,
Dan Williams <dan.j.williams@...el.com>,
Dave Hansen <dave.hansen@...el.com>,
David Woodhouse <dwmw@...zon.co.uk>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
"H . Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...hat.com>,
Janakarajan Natarajan <Janakarajan.Natarajan@....com>,
Joerg Roedel <joro@...tes.org>,
Jun Nakajima <jun.nakajima@...el.com>,
Laura Abbott <labbott@...hat.com>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Masami Hiramatsu <mhiramat@...nel.org>,
Paolo Bonzini <pbonzini@...hat.com>,
Peter Zijlstra <peterz@...radead.org>,
Radim Krčmář <rkrcmar@...hat.com>,
Thomas Gleixner <tglx@...utronix.de>,
Tim Chen <tim.c.chen@...ux.intel.com>,
Tom Lendacky <thomas.lendacky@....com>, kvm@...r.kernel.org,
x86@...nel.org
Subject: [RFC 07/10] x86: Simplify spectre_v2 command line parsing
Signed-off-by: KarimAllah Ahmed <karahmed@...zon.de>
---
arch/x86/kernel/cpu/bugs.c | 106 +++++++++++++++++++++++++--------------------
1 file changed, 58 insertions(+), 48 deletions(-)
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 1d5e12f..349c7f4 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -99,13 +99,13 @@ static enum spectre_v2_mitigation spectre_v2_enabled = SPECTRE_V2_NONE;
static void __init spec2_print_if_insecure(const char *reason)
{
if (boot_cpu_has_bug(X86_BUG_SPECTRE_V2))
- pr_info("%s\n", reason);
+ pr_info("%s selected on command line.\n", reason);
}
static void __init spec2_print_if_secure(const char *reason)
{
if (!boot_cpu_has_bug(X86_BUG_SPECTRE_V2))
- pr_info("%s\n", reason);
+ pr_info("%s selected on command line.\n", reason);
}
static inline bool retp_compiler(void)
@@ -120,61 +120,71 @@ static inline bool match_option(const char *arg, int arglen, const char *opt)
return len == arglen && !strncmp(arg, opt, len);
}
+static struct {
+ char *option;
+ enum spectre_v2_mitigation_cmd cmd;
+ bool secure;
+} mitigation_options[] = {
+ { "off", SPECTRE_V2_CMD_NONE, false },
+ { "on", SPECTRE_V2_CMD_FORCE, true },
+ { "retpoline", SPECTRE_V2_CMD_RETPOLINE, false },
+ { "retpoline,amd", SPECTRE_V2_CMD_RETPOLINE_AMD, false },
+ { "retpoline,generic", SPECTRE_V2_CMD_RETPOLINE_GENERIC, false },
+ { "ibrs", SPECTRE_V2_CMD_IBRS, false },
+ { "auto", SPECTRE_V2_CMD_AUTO, false },
+};
+
+static const int mitigation_options_count = sizeof(mitigation_options) /
+ sizeof(mitigation_options[0]);
+
static enum spectre_v2_mitigation_cmd __init spectre_v2_parse_cmdline(void)
{
char arg[20];
- int ret;
+ int ret, i;
+ enum spectre_v2_mitigation_cmd cmd = SPECTRE_V2_CMD_AUTO;
+
+ if (cmdline_find_option_bool(boot_command_line, "nospectre_v2"))
+ return SPECTRE_V2_CMD_NONE;
ret = cmdline_find_option(boot_command_line, "spectre_v2", arg,
sizeof(arg));
- if (ret > 0) {
- if (match_option(arg, ret, "off")) {
- goto disable;
- } else if (match_option(arg, ret, "on")) {
- spec2_print_if_secure("force enabled on command line.");
- return SPECTRE_V2_CMD_FORCE;
- } else if (match_option(arg, ret, "retpoline")) {
- if (!IS_ENABLED(CONFIG_RETPOLINE)) {
- pr_err("retpoline selected but not compiled in. Switching to AUTO select\n");
- return SPECTRE_V2_CMD_AUTO;
- }
- spec2_print_if_insecure("retpoline selected on command line.");
- return SPECTRE_V2_CMD_RETPOLINE;
- } else if (match_option(arg, ret, "retpoline,amd")) {
- if (!IS_ENABLED(CONFIG_RETPOLINE)) {
- pr_err("retpoline,amd selected but not compiled in. Switching to AUTO select\n");
- return SPECTRE_V2_CMD_AUTO;
- }
- if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD) {
- pr_err("retpoline,amd selected but CPU is not AMD. Switching to AUTO select\n");
- return SPECTRE_V2_CMD_AUTO;
- }
- spec2_print_if_insecure("AMD retpoline selected on command line.");
- return SPECTRE_V2_CMD_RETPOLINE_AMD;
- } else if (match_option(arg, ret, "retpoline,generic")) {
- if (!IS_ENABLED(CONFIG_RETPOLINE)) {
- pr_err("retpoline,generic selected but not compiled in. Switching to AUTO select\n");
- return SPECTRE_V2_CMD_AUTO;
- }
- spec2_print_if_insecure("generic retpoline selected on command line.");
- return SPECTRE_V2_CMD_RETPOLINE_GENERIC;
- } else if (match_option(arg, ret, "ibrs")) {
- if (!boot_cpu_has(X86_FEATURE_SPEC_CTRL)) {
- pr_err("IBRS selected but no CPU support. Switching to AUTO select\n");
- return SPECTRE_V2_CMD_AUTO;
- }
- spec2_print_if_insecure("IBRS seleted on command line.");
- return SPECTRE_V2_CMD_IBRS;
- } else if (match_option(arg, ret, "auto")) {
- return SPECTRE_V2_CMD_AUTO;
- }
+ if (ret < 0)
+ return SPECTRE_V2_CMD_AUTO;
+
+ for (i = 0; i < mitigation_options_count; i++) {
+ if (!match_option(arg, ret, mitigation_options[i].option))
+ continue;
+ cmd = mitigation_options[i].cmd;
+ break;
}
- if (!cmdline_find_option_bool(boot_command_line, "nospectre_v2"))
+ if (i >= mitigation_options_count) {
+ pr_err("unknown option (%s). Switching to AUTO select\n",
+ mitigation_options[i].option);
return SPECTRE_V2_CMD_AUTO;
-disable:
- spec2_print_if_insecure("disabled on command line.");
- return SPECTRE_V2_CMD_NONE;
+ }
+
+ if ((cmd == SPECTRE_V2_CMD_RETPOLINE ||
+ cmd == SPECTRE_V2_CMD_RETPOLINE_AMD ||
+ cmd == SPECTRE_V2_CMD_RETPOLINE_GENERIC) &&
+ !IS_ENABLED(CONFIG_RETPOLINE)) {
+ pr_err("%s selected but not compiled in. Switching to AUTO select\n",
+ mitigation_options[i].option);
+ return SPECTRE_V2_CMD_AUTO;
+ }
+
+ if (cmd == SPECTRE_V2_CMD_RETPOLINE_AMD &&
+ boot_cpu_data.x86_vendor != X86_VENDOR_AMD) {
+ pr_err("retpoline,amd selected but CPU is not AMD. Switching to AUTO select\n");
+ return SPECTRE_V2_CMD_AUTO;
+ }
+
+ if (mitigation_options[i].secure)
+ spec2_print_if_secure(mitigation_options[i].option);
+ else
+ spec2_print_if_insecure(mitigation_options[i].option);
+
+ return cmd;
}
/* Check for Skylake-like CPUs (for RSB and IBRS handling) */
--
2.7.4
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