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Commit 10c24dc6 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Greg Kroah-Hartman
Browse files

x86/speculation: Reorder the spec_v2 code 



commit 15d6b7aab0793b2de8a05d8a828777dd24db424e upstream

Reorder the code so it is better grouped. No functional change.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarIngo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Woodhouse <dwmw@amazon.co.uk>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Casey Schaufler <casey.schaufler@intel.com>
Cc: Asit Mallick <asit.k.mallick@intel.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Jon Masters <jcm@redhat.com>
Cc: Waiman Long <longman9394@gmail.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Dave Stewart <david.c.stewart@intel.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20181125185004.707122879@linutronix.de


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 1572793b

arch/x86/kernel/cpu/bugs.c

+84 −84
Original line number Diff line number Diff line
@@ -124,29 +124,6 @@ void __init check_bugs(void) 
#endif

}



/* The kernel command line selection */

enum spectre_v2_mitigation_cmd {

	SPECTRE_V2_CMD_NONE,

	SPECTRE_V2_CMD_AUTO,

	SPECTRE_V2_CMD_FORCE,

	SPECTRE_V2_CMD_RETPOLINE,

	SPECTRE_V2_CMD_RETPOLINE_GENERIC,

	SPECTRE_V2_CMD_RETPOLINE_AMD,

};



static const char *spectre_v2_strings[] = {

	[SPECTRE_V2_NONE]			= "Vulnerable",

	[SPECTRE_V2_RETPOLINE_GENERIC]		= "Mitigation: Full generic retpoline",

	[SPECTRE_V2_RETPOLINE_AMD]		= "Mitigation: Full AMD retpoline",

	[SPECTRE_V2_IBRS_ENHANCED]		= "Mitigation: Enhanced IBRS",

};



#undef pr_fmt

#define pr_fmt(fmt)     "Spectre V2 : " fmt



static enum spectre_v2_mitigation spectre_v2_enabled __ro_after_init =

	SPECTRE_V2_NONE;



void

x86_virt_spec_ctrl(u64 guest_spec_ctrl, u64 guest_virt_spec_ctrl, bool setguest)

{
@@ -216,6 +193,12 @@ static void x86_amd_ssb_disable(void) 
		wrmsrl(MSR_AMD64_LS_CFG, msrval);

}



#undef pr_fmt

#define pr_fmt(fmt)     "Spectre V2 : " fmt



static enum spectre_v2_mitigation spectre_v2_enabled __ro_after_init =

	SPECTRE_V2_NONE;



#ifdef RETPOLINE

static bool spectre_v2_bad_module;
@@ -237,18 +220,6 @@ static inline const char *spectre_v2_module_string(void) 
static inline const char *spectre_v2_module_string(void) { return ""; }

#endif



static void __init spec2_print_if_insecure(const char *reason)

{

	if (boot_cpu_has_bug(X86_BUG_SPECTRE_V2))

		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 selected on command line.\n", reason);

}



static inline bool match_option(const char *arg, int arglen, const char *opt)

{

	int len = strlen(opt);
@@ -256,6 +227,23 @@ static inline bool match_option(const char *arg, int arglen, const char *opt) 
	return len == arglen && !strncmp(arg, opt, len);

}



/* The kernel command line selection for spectre v2 */

enum spectre_v2_mitigation_cmd {

	SPECTRE_V2_CMD_NONE,

	SPECTRE_V2_CMD_AUTO,

	SPECTRE_V2_CMD_FORCE,

	SPECTRE_V2_CMD_RETPOLINE,

	SPECTRE_V2_CMD_RETPOLINE_GENERIC,

	SPECTRE_V2_CMD_RETPOLINE_AMD,

};



static const char *spectre_v2_strings[] = {

	[SPECTRE_V2_NONE]			= "Vulnerable",

	[SPECTRE_V2_RETPOLINE_GENERIC]		= "Mitigation: Full generic retpoline",

	[SPECTRE_V2_RETPOLINE_AMD]		= "Mitigation: Full AMD retpoline",

	[SPECTRE_V2_IBRS_ENHANCED]		= "Mitigation: Enhanced IBRS",

};



static const struct {

	const char *option;

	enum spectre_v2_mitigation_cmd cmd;
@@ -269,11 +257,23 @@ static const struct { 
	{ "auto",		SPECTRE_V2_CMD_AUTO,		  false },

};



static void __init spec2_print_if_insecure(const char *reason)

{

	if (boot_cpu_has_bug(X86_BUG_SPECTRE_V2))

		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 selected on command line.\n", reason);

}



static enum spectre_v2_mitigation_cmd __init spectre_v2_parse_cmdline(void)

{

	enum spectre_v2_mitigation_cmd cmd = SPECTRE_V2_CMD_AUTO;

	char arg[20];

	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;
@@ -316,48 +316,6 @@ static enum spectre_v2_mitigation_cmd __init spectre_v2_parse_cmdline(void) 
	return cmd;

}



static bool stibp_needed(void)

{

	if (spectre_v2_enabled == SPECTRE_V2_NONE)

		return false;



	/* Enhanced IBRS makes using STIBP unnecessary. */

	if (spectre_v2_enabled == SPECTRE_V2_IBRS_ENHANCED)

		return false;



	if (!boot_cpu_has(X86_FEATURE_STIBP))

		return false;



	return true;

}



static void update_stibp_msr(void *info)

{

	wrmsrl(MSR_IA32_SPEC_CTRL, x86_spec_ctrl_base);

}



void arch_smt_update(void)

{

	u64 mask;



	if (!stibp_needed())

		return;



	mutex_lock(&spec_ctrl_mutex);



	mask = x86_spec_ctrl_base & ~SPEC_CTRL_STIBP;

	if (sched_smt_active())

		mask |= SPEC_CTRL_STIBP;



	if (mask != x86_spec_ctrl_base) {

		pr_info("Spectre v2 cross-process SMT mitigation: %s STIBP\n",

			mask & SPEC_CTRL_STIBP ? "Enabling" : "Disabling");

		x86_spec_ctrl_base = mask;

		on_each_cpu(update_stibp_msr, NULL, 1);

	}

	mutex_unlock(&spec_ctrl_mutex);

}



static void __init spectre_v2_select_mitigation(void)

{

	enum spectre_v2_mitigation_cmd cmd = spectre_v2_parse_cmdline();
@@ -460,6 +418,48 @@ static void __init spectre_v2_select_mitigation(void) 
	arch_smt_update();

}



static bool stibp_needed(void)

{

	if (spectre_v2_enabled == SPECTRE_V2_NONE)

		return false;



	/* Enhanced IBRS makes using STIBP unnecessary. */

	if (spectre_v2_enabled == SPECTRE_V2_IBRS_ENHANCED)

		return false;



	if (!boot_cpu_has(X86_FEATURE_STIBP))

		return false;



	return true;

}



static void update_stibp_msr(void *info)

{

	wrmsrl(MSR_IA32_SPEC_CTRL, x86_spec_ctrl_base);

}



void arch_smt_update(void)

{

	u64 mask;



	if (!stibp_needed())

		return;



	mutex_lock(&spec_ctrl_mutex);



	mask = x86_spec_ctrl_base & ~SPEC_CTRL_STIBP;

	if (sched_smt_active())

		mask |= SPEC_CTRL_STIBP;



	if (mask != x86_spec_ctrl_base) {

		pr_info("Spectre v2 cross-process SMT mitigation: %s STIBP\n",

			mask & SPEC_CTRL_STIBP ? "Enabling" : "Disabling");

		x86_spec_ctrl_base = mask;

		on_each_cpu(update_stibp_msr, NULL, 1);

	}

	mutex_unlock(&spec_ctrl_mutex);

}



#undef pr_fmt

#define pr_fmt(fmt)	"Speculative Store Bypass: " fmt