Commit 166115c0 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Borislav Petkov
Browse files

x86/bugs: Split spectre_v2_select_mitigation() and spectre_v2_user_select_mitigation() 



retbleed will depend on spectre_v2, while spectre_v2_user depends on
retbleed. Break this cycle.

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Reviewed-by: default avatarJosh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
parent 7c693f54

arch/x86/kernel/cpu/bugs.c

+17 −8
Original line number Diff line number Diff line
@@ -37,8 +37,9 @@ 
#include "cpu.h"



static void __init spectre_v1_select_mitigation(void);

static void __init retbleed_select_mitigation(void);

static void __init spectre_v2_select_mitigation(void);

static void __init retbleed_select_mitigation(void);

static void __init spectre_v2_user_select_mitigation(void);

static void __init ssb_select_mitigation(void);

static void __init l1tf_select_mitigation(void);

static void __init mds_select_mitigation(void);
@@ -145,13 +146,19 @@ void __init check_bugs(void) 


	/* Select the proper CPU mitigations before patching alternatives: */

	spectre_v1_select_mitigation();

	spectre_v2_select_mitigation();

	/*

	 * retbleed_select_mitigation() relies on the state set by

	 * spectre_v2_select_mitigation(); specifically it wants to know about

	 * spectre_v2=ibrs.

	 */

	retbleed_select_mitigation();

	/*

	 * spectre_v2_select_mitigation() relies on the state set by

	 * spectre_v2_user_select_mitigation() relies on the state set by

	 * retbleed_select_mitigation(); specifically the STIBP selection is

	 * forced for UNRET.

	 */

	spectre_v2_select_mitigation();

	spectre_v2_user_select_mitigation();

	ssb_select_mitigation();

	l1tf_select_mitigation();

	md_clear_select_mitigation();
@@ -1013,13 +1020,15 @@ static void __init spec_v2_user_print_cond(const char *reason, bool secure) 
		pr_info("spectre_v2_user=%s forced on command line.\n", reason);

}



static __ro_after_init enum spectre_v2_mitigation_cmd spectre_v2_cmd;



static enum spectre_v2_user_cmd __init

spectre_v2_parse_user_cmdline(enum spectre_v2_mitigation_cmd v2_cmd)

spectre_v2_parse_user_cmdline(void)

{

	char arg[20];

	int ret, i;



	switch (v2_cmd) {

	switch (spectre_v2_cmd) {

	case SPECTRE_V2_CMD_NONE:

		return SPECTRE_V2_USER_CMD_NONE;

	case SPECTRE_V2_CMD_FORCE:
@@ -1054,7 +1063,7 @@ static inline bool spectre_v2_in_ibrs_mode(enum spectre_v2_mitigation mode) 
}



static void __init

spectre_v2_user_select_mitigation(enum spectre_v2_mitigation_cmd v2_cmd)

spectre_v2_user_select_mitigation(void)

{

	enum spectre_v2_user_mitigation mode = SPECTRE_V2_USER_NONE;

	bool smt_possible = IS_ENABLED(CONFIG_SMP);
@@ -1067,7 +1076,7 @@ spectre_v2_user_select_mitigation(enum spectre_v2_mitigation_cmd v2_cmd) 
	    cpu_smt_control == CPU_SMT_NOT_SUPPORTED)

		smt_possible = false;



	cmd = spectre_v2_parse_user_cmdline(v2_cmd);

	cmd = spectre_v2_parse_user_cmdline();

	switch (cmd) {

	case SPECTRE_V2_USER_CMD_NONE:

		goto set_mode;
@@ -1391,7 +1400,7 @@ static void __init spectre_v2_select_mitigation(void) 
	}



	/* Set up IBPB and STIBP depending on the general spectre V2 command */

	spectre_v2_user_select_mitigation(cmd);

	spectre_v2_cmd = cmd;

}



static void update_stibp_msr(void * __unused)