Commit 8edb9e77 authored by David Kaplan's avatar David Kaplan Committed by Borislav Petkov (AMD)
Browse files

x86/bugs: Use early_param() for spectre_v2_user 



Most of the mitigations in bugs.c use early_param() to parse their command
line options.  Modify spectre_v2_user to use early_param() for consistency.

Remove spec_v2_user_print_cond() because informing a user about their
cmdline choice isn't very interesting and the chosen mitigation is already
printed in spectre_v2_user_update_mitigation().

Signed-off-by: default avatarDavid Kaplan <david.kaplan@amd.com>
Signed-off-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: default avatarPawan Gupta <pawan.kumar.gupta@linux.intel.com>
Link: https://lore.kernel.org/r/20250819192200.2003074-2-david.kaplan@amd.com
parent 5799d5d8

arch/x86/kernel/cpu/bugs.c

+26 −42
Original line number Diff line number Diff line
@@ -1847,7 +1847,7 @@ enum spectre_v2_mitigation_cmd { 


static enum spectre_v2_mitigation_cmd spectre_v2_cmd __ro_after_init = SPECTRE_V2_CMD_AUTO;



enum spectre_v2_user_cmd {

enum spectre_v2_user_mitigation_cmd {

	SPECTRE_V2_USER_CMD_NONE,

	SPECTRE_V2_USER_CMD_AUTO,

	SPECTRE_V2_USER_CMD_FORCE,
@@ -1857,6 +1857,9 @@ enum spectre_v2_user_cmd { 
	SPECTRE_V2_USER_CMD_SECCOMP_IBPB,

};



static enum spectre_v2_user_mitigation_cmd spectre_v2_user_cmd __ro_after_init =

	IS_ENABLED(CONFIG_MITIGATION_SPECTRE_V2) ? SPECTRE_V2_USER_CMD_AUTO : SPECTRE_V2_USER_CMD_NONE;



static const char * const spectre_v2_user_strings[] = {

	[SPECTRE_V2_USER_NONE]			= "User space: Vulnerable",

	[SPECTRE_V2_USER_STRICT]		= "User space: Mitigation: STIBP protection",
@@ -1865,50 +1868,31 @@ static const char * const spectre_v2_user_strings[] = { 
	[SPECTRE_V2_USER_SECCOMP]		= "User space: Mitigation: STIBP via seccomp and prctl",

};



static const struct {

	const char			*option;

	enum spectre_v2_user_cmd	cmd;

	bool				secure;

} v2_user_options[] __initconst = {

	{ "auto",		SPECTRE_V2_USER_CMD_AUTO,		false },

	{ "off",		SPECTRE_V2_USER_CMD_NONE,		false },

	{ "on",			SPECTRE_V2_USER_CMD_FORCE,		true  },

	{ "prctl",		SPECTRE_V2_USER_CMD_PRCTL,		false },

	{ "prctl,ibpb",		SPECTRE_V2_USER_CMD_PRCTL_IBPB,		false },

	{ "seccomp",		SPECTRE_V2_USER_CMD_SECCOMP,		false },

	{ "seccomp,ibpb",	SPECTRE_V2_USER_CMD_SECCOMP_IBPB,	false },

};



static void __init spec_v2_user_print_cond(const char *reason, bool secure)

static int __init spectre_v2_user_parse_cmdline(char *str)

{

	if (boot_cpu_has_bug(X86_BUG_SPECTRE_V2) != secure)

		pr_info("spectre_v2_user=%s forced on command line.\n", reason);

}



static enum spectre_v2_user_cmd __init spectre_v2_parse_user_cmdline(void)

{

	char arg[20];

	int ret, i;



	if (!IS_ENABLED(CONFIG_MITIGATION_SPECTRE_V2))

		return SPECTRE_V2_USER_CMD_NONE;



	ret = cmdline_find_option(boot_command_line, "spectre_v2_user",

				  arg, sizeof(arg));

	if (ret < 0)

		return SPECTRE_V2_USER_CMD_AUTO;

	if (!str)

		return -EINVAL;



	for (i = 0; i < ARRAY_SIZE(v2_user_options); i++) {

		if (match_option(arg, ret, v2_user_options[i].option)) {

			spec_v2_user_print_cond(v2_user_options[i].option,

						v2_user_options[i].secure);

			return v2_user_options[i].cmd;

		}

	}

	if (!strcmp(str, "auto"))

		spectre_v2_user_cmd = SPECTRE_V2_USER_CMD_AUTO;

	else if (!strcmp(str, "off"))

		spectre_v2_user_cmd = SPECTRE_V2_USER_CMD_NONE;

	else if (!strcmp(str, "on"))

		spectre_v2_user_cmd = SPECTRE_V2_USER_CMD_FORCE;

	else if (!strcmp(str, "prctl"))

		spectre_v2_user_cmd = SPECTRE_V2_USER_CMD_PRCTL;

	else if (!strcmp(str, "prctl,ibpb"))

		spectre_v2_user_cmd = SPECTRE_V2_USER_CMD_PRCTL_IBPB;

	else if (!strcmp(str, "seccomp"))

		spectre_v2_user_cmd = SPECTRE_V2_USER_CMD_SECCOMP;

	else if (!strcmp(str, "seccomp,ibpb"))

		spectre_v2_user_cmd = SPECTRE_V2_USER_CMD_SECCOMP_IBPB;

	else

		pr_err("Ignoring unknown spectre_v2_user option (%s).", str);



	pr_err("Unknown user space protection option (%s). Switching to default\n", arg);

	return SPECTRE_V2_USER_CMD_AUTO;

	return 0;

}

early_param("spectre_v2_user", spectre_v2_user_parse_cmdline);



static inline bool spectre_v2_in_ibrs_mode(enum spectre_v2_mitigation mode)

{
@@ -1920,7 +1904,7 @@ static void __init spectre_v2_user_select_mitigation(void) 
	if (!boot_cpu_has(X86_FEATURE_IBPB) && !boot_cpu_has(X86_FEATURE_STIBP))

		return;



	switch (spectre_v2_parse_user_cmdline()) {

	switch (spectre_v2_user_cmd) {

	case SPECTRE_V2_USER_CMD_NONE:

		return;

	case SPECTRE_V2_USER_CMD_FORCE: