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

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commit 166115c08a9b0b846b783088808a27d739be6e8d upstream.

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

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Peter Zijlstra 2022-11-17 18:19:34 +09:00 committed by Greg Kroah-Hartman
parent c1493b60fd
commit 6cc8bd7dd3
1 changed files with 17 additions and 8 deletions
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25
arch/x86/kernel/cpu/bugs.c
View File

@ -36,8 +36,9 @@
#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);
@ -136,13 +137,19 @@ 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();
@ -918,13 +925,15 @@ 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:
@ -959,7 +968,7 @@ 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);
@ -972,7 +981,7 @@ 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;
@ -1289,7 +1298,7 @@ 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)