[PATCH 4.4 186/193] x86/spectre: Simplify spectre_v2 command line parsing

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

--

From: KarimAllah Ahmed 

(cherry picked from commit 9005c6834c0ffdfe46afa76656bd9276cca864f6)

[dwmw2: Use ARRAY_SIZE]

Signed-off-by: KarimAllah Ahmed 
Signed-off-by: David Woodhouse 
Signed-off-by: Thomas Gleixner 
Cc: pet...@infradead.org
Cc: b...@alien8.de
Link: 
https://lkml.kernel.org/r/1517484441-1420-3-git-send-email-d...@amazon.co.uk
Signed-off-by: David Woodhouse 
[jwang: cherry pick to 4.4]
Signed-off-by: Jack Wang 
Signed-off-by: Greg Kroah-Hartman 
---
 arch/x86/kernel/cpu/bugs.c |   84 +
 1 file changed, 55 insertions(+), 29 deletions(-)

--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -119,13 +119,13 @@ static inline const char *spectre_v2_mod
 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)
@@ -140,42 +140,68 @@ static inline bool match_option(const ch
return len == arglen && !strncmp(arg, opt, len);
 }
 
+static const struct {
+   const 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 },
+   { "auto",  SPECTRE_V2_CMD_AUTO,  false },
+};
+
 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;
+   else {
+   ret = cmdline_find_option(boot_command_line, "spectre_v2", arg,
+ sizeof(arg));
+   if (ret < 0)
+   return SPECTRE_V2_CMD_AUTO;
 
-   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")) {
-   spec2_print_if_insecure("retpoline selected on command 
line.");
-   return SPECTRE_V2_CMD_RETPOLINE;
-   } else if (match_option(arg, ret, "retpoline,amd")) {
-   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")) {
-   spec2_print_if_insecure("generic retpoline selected on 
command line.");
-   return SPECTRE_V2_CMD_RETPOLINE_GENERIC;
-   } else if (match_option(arg, ret, "auto")) {
+   for (i = 0; i < ARRAY_SIZE(mitigation_options); i++) {
+   if (!match_option(arg, ret, 
mitigation_options[i].option))
+   continue;
+   cmd = mitigation_options[i].cmd;
+   break;
+   }
+
+   if (i >= ARRAY_SIZE(mitigation_options)) {
+   pr_err("unknown option (%s). Switching to AUTO 
select\n",
+  mitigation_options[i].option);
return SPECTRE_V2_CMD_AUTO;
}
}
 
-   if (!cmdline_find_option_bool(boot_command_line, "nospectre_v2"))
+   if ((cmd == SPECTRE_V2_CMD_RETPOLINE ||
+cmd == SPECTRE_V2_CMD_RETPOLINE_AMD ||
+cmd == 

[PATCH 4.4 186/193] x86/spectre: Simplify spectre_v2 command line parsing

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

--

From: KarimAllah Ahmed 

(cherry picked from commit 9005c6834c0ffdfe46afa76656bd9276cca864f6)

[dwmw2: Use ARRAY_SIZE]

Signed-off-by: KarimAllah Ahmed 
Signed-off-by: David Woodhouse 
Signed-off-by: Thomas Gleixner 
Cc: pet...@infradead.org
Cc: b...@alien8.de
Link: 
https://lkml.kernel.org/r/1517484441-1420-3-git-send-email-d...@amazon.co.uk
Signed-off-by: David Woodhouse 
[jwang: cherry pick to 4.4]
Signed-off-by: Jack Wang 
Signed-off-by: Greg Kroah-Hartman 
---
 arch/x86/kernel/cpu/bugs.c |   84 +
 1 file changed, 55 insertions(+), 29 deletions(-)

--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -119,13 +119,13 @@ static inline const char *spectre_v2_mod
 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)
@@ -140,42 +140,68 @@ static inline bool match_option(const ch
return len == arglen && !strncmp(arg, opt, len);
 }
 
+static const struct {
+   const 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 },
+   { "auto",  SPECTRE_V2_CMD_AUTO,  false },
+};
+
 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;
+   else {
+   ret = cmdline_find_option(boot_command_line, "spectre_v2", arg,
+ sizeof(arg));
+   if (ret < 0)
+   return SPECTRE_V2_CMD_AUTO;
 
-   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")) {
-   spec2_print_if_insecure("retpoline selected on command 
line.");
-   return SPECTRE_V2_CMD_RETPOLINE;
-   } else if (match_option(arg, ret, "retpoline,amd")) {
-   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")) {
-   spec2_print_if_insecure("generic retpoline selected on 
command line.");
-   return SPECTRE_V2_CMD_RETPOLINE_GENERIC;
-   } else if (match_option(arg, ret, "auto")) {
+   for (i = 0; i < ARRAY_SIZE(mitigation_options); i++) {
+   if (!match_option(arg, ret, 
mitigation_options[i].option))
+   continue;
+   cmd = mitigation_options[i].cmd;
+   break;
+   }
+
+   if (i >= ARRAY_SIZE(mitigation_options)) {
+   pr_err("unknown option (%s). Switching to AUTO 
select\n",
+  mitigation_options[i].option);
return SPECTRE_V2_CMD_AUTO;
}
}
 
-   if (!cmdline_find_option_bool(boot_command_line, "nospectre_v2"))
+   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",
+