From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
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@xxxxxxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Reviewed-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/cpu/bugs.c | 25 +++++++++++++++++--------
1 file changed, 17 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index e39a4f9ca69b..3ed67d5f1a04 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -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();
@@ -914,13 +921,15 @@ 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:
@@ -955,7 +964,7 @@ 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);
@@ -968,7 +977,7 @@ 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;
@@ -1285,7 +1294,7 @@ 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)
--
2.17.1
