Unverified Commit e77c0a41 authored by openeuler-ci-bot's avatar openeuler-ci-bot Committed by Gitee
Browse files

!585 x86/speculation: Allow enabling STIBP with legacy IBRS 

Merge Pull Request from: @ci-robot 
 
PR sync from:  Wei Li <liwei391@huawei.com>
 https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/thread/UNWNKYXBCMVT2QIU4QPROMO5UMGXKQS7/ 
 
 
Link:https://gitee.com/openeuler/kernel/pulls/585

 

Reviewed-by: default avatarXiongfeng Wang <wangxiongfeng2@huawei.com>
Signed-off-by: default avatarJialin Zhang <zhangjialin11@huawei.com>
parents 693a53a5 811a507c

arch/x86/kernel/cpu/bugs.c

+18 −7
Original line number Diff line number Diff line
@@ -1051,14 +1051,18 @@ spectre_v2_parse_user_cmdline(void) 
	return SPECTRE_V2_USER_CMD_AUTO;

}



static inline bool spectre_v2_in_ibrs_mode(enum spectre_v2_mitigation mode)

static inline bool spectre_v2_in_eibrs_mode(enum spectre_v2_mitigation mode)

{

	return mode == SPECTRE_V2_IBRS ||

	       mode == SPECTRE_V2_EIBRS ||

	return mode == SPECTRE_V2_EIBRS ||

	       mode == SPECTRE_V2_EIBRS_RETPOLINE ||

	       mode == SPECTRE_V2_EIBRS_LFENCE;

}



static inline bool spectre_v2_in_ibrs_mode(enum spectre_v2_mitigation mode)

{

	return spectre_v2_in_eibrs_mode(mode) || mode == SPECTRE_V2_IBRS;

}



static void __init

spectre_v2_user_select_mitigation(void)

{
@@ -1121,12 +1125,19 @@ spectre_v2_user_select_mitigation(void) 
	}



	/*

	 * If no STIBP, IBRS or enhanced IBRS is enabled, or SMT impossible,

	 * STIBP is not required.

	 * If no STIBP, enhanced IBRS is enabled, or SMT impossible, STIBP

	 * is not required.

	 *

	 * Enhanced IBRS also protects against cross-thread branch target

	 * injection in user-mode as the IBRS bit remains always set which

	 * implicitly enables cross-thread protections.  However, in legacy IBRS

	 * mode, the IBRS bit is set only on kernel entry and cleared on return

	 * to userspace. This disables the implicit cross-thread protection,

	 * so allow for STIBP to be selected in that case.

	 */

	if (!boot_cpu_has(X86_FEATURE_STIBP) ||

	    !smt_possible ||

	    spectre_v2_in_ibrs_mode(spectre_v2_enabled))

	    spectre_v2_in_eibrs_mode(spectre_v2_enabled))

		return;



	/*
@@ -2220,7 +2231,7 @@ static ssize_t mmio_stale_data_show_state(char *buf) 


static char *stibp_state(void)

{

	if (spectre_v2_in_ibrs_mode(spectre_v2_enabled))

	if (spectre_v2_in_eibrs_mode(spectre_v2_enabled))

		return "";



	switch (spectre_v2_user_stibp) {