5 files changed, 24 insertions, 14 deletions

diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index cf81848b72f4..f9d060e71c3e 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -1133,14 +1133,18 @@ 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)
 {
@@ -1203,12 +1207,19 @@ 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;
 
 	/*
@@ -2340,7 +2351,7 @@ 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) {
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index e2c1599d1b37..884b6e9a7e31 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -314,7 +314,7 @@ static void update_cpu_closid_rmid(void *info)
 	 * executing task might have its own closid selected. Just reuse
 	 * the context switch code.
 	 */
-	resctrl_sched_in();
+	resctrl_sched_in(current);
 }
 
 /*
@@ -530,7 +530,7 @@ static void _update_task_closid_rmid(void *task)
 	 * Otherwise, the MSR is updated when the task is scheduled in.
 	 */
 	if (task == current)
-		resctrl_sched_in();
+		resctrl_sched_in(task);
 }
 
 static void update_task_closid_rmid(struct task_struct *t)
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 470c128759ea..708c87b88cc1 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -212,7 +212,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
 	switch_fpu_finish();
 
 	/* Load the Intel cache allocation PQR MSR. */
-	resctrl_sched_in();
+	resctrl_sched_in(next_p);
 
 	return prev_p;
 }
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 4e34b3b68ebd..bb65a68b4b49 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -656,7 +656,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
 	}
 
 	/* Load the Intel cache allocation PQR MSR. */
-	resctrl_sched_in();
+	resctrl_sched_in(next_p);
 
 	return prev_p;
 }
diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c
index cdf6c6060170..37307b40f8da 100644
--- a/arch/x86/kernel/unwind_orc.c
+++ b/arch/x86/kernel/unwind_orc.c
@@ -484,6 +484,8 @@ bool unwind_next_frame(struct unwind_state *state)
 		goto the_end;
 	}
 
+	state->signal = orc->signal;
+
 	/* Find the previous frame's stack: */
 	switch (orc->sp_reg) {
 	case ORC_REG_SP:
@@ -563,7 +565,6 @@ bool unwind_next_frame(struct unwind_state *state)
 		state->sp = sp;
 		state->regs = NULL;
 		state->prev_regs = NULL;
-		state->signal = false;
 		break;
 
 	case UNWIND_HINT_TYPE_REGS:
@@ -587,7 +588,6 @@ bool unwind_next_frame(struct unwind_state *state)
 		state->regs = (struct pt_regs *)sp;
 		state->prev_regs = NULL;
 		state->full_regs = true;
-		state->signal = true;
 		break;
 
 	case UNWIND_HINT_TYPE_REGS_PARTIAL:
@@ -604,7 +604,6 @@ bool unwind_next_frame(struct unwind_state *state)
 			state->prev_regs = state->regs;
 		state->regs = (void *)sp - IRET_FRAME_OFFSET;
 		state->full_regs = false;
-		state->signal = true;
 		break;
 
 	default: