Merge tag 's390-5.14-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull more s390 updates from Vasily Gorbik:

 - Fix preempt_count initialization.

 - Rework call_on_stack() macro to add proper type handling and avoid
   possible register corruption.

 - More error prone "register asm" removal and fixes.

 - Fix syscall restarting when multiple signals are coming in. This adds
   minimalistic trampolines to vdso so we can return from signal without
   using the stack which requires pgm check handler hacks when NX is
   enabled.

 - Remove HAVE_IRQ_EXIT_ON_IRQ_STACK since this is no longer true after
   switch to generic entry.

 - Fix protected virtualization secure storage access exception
   handling.

 - Make machine check C handler always enter with DAT enabled and move
   register validation to C code.

 - Fix tinyconfig boot problem by avoiding MONITOR CALL without
   CONFIG_BUG.

 - Increase asm symbols alignment to 16 to make it consistent with
   compilers.

 - Enable concurrent access to the CPU Measurement Counter Facility.

 - Add support for dynamic AP bus size limit and rework ap_dqap to deal
   with messages greater than recv buffer.

* tag 's390-5.14-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (41 commits)
  s390: preempt: Fix preempt_count initialization
  s390/linkage: increase asm symbols alignment to 16
  s390: rename CALL_ON_STACK_NORETURN() to call_on_stack_noreturn()
  s390: add type checking to CALL_ON_STACK_NORETURN() macro
  s390: remove old CALL_ON_STACK() macro
  s390/softirq: use call_on_stack() macro
  s390/lib: use call_on_stack() macro
  s390/smp: use call_on_stack() macro
  s390/kexec: use call_on_stack() macro
  s390/irq: use call_on_stack() macro
  s390/mm: use call_on_stack() macro
  s390: introduce proper type handling call_on_stack() macro
  s390/irq: simplify on_async_stack()
  s390/irq: inline do_softirq_own_stack()
  s390/irq: simplify do_softirq_own_stack()
  s390/ap: get rid of register asm in ap_dqap()
  s390: rename PIF_SYSCALL_RESTART to PIF_EXECVE_PGSTE_RESTART
  s390: move restart of execve() syscall
  s390/signal: remove sigreturn on stack
  s390/signal: switch to using vdso for sigreturn and syscall restart
  ...

1 files changed, 77 insertions, 52 deletions

diff --git a/arch/s390/kernel/nmi.c b/arch/s390/kernel/nmi.c
index 11f8c296f60d..20f8e1868853 100644
--- a/arch/s390/kernel/nmi.c
+++ b/arch/s390/kernel/nmi.c
@@ -189,12 +189,16 @@ void noinstr s390_handle_mcck(void)
  * returns 0 if all required registers are available
  * returns 1 otherwise
  */
-static int notrace s390_check_registers(union mci mci, int umode)
+static int notrace s390_validate_registers(union mci mci, int umode)
 {
+	struct mcesa *mcesa;
+	void *fpt_save_area;
 	union ctlreg2 cr2;
 	int kill_task;
+	u64 zero;
 
 	kill_task = 0;
+	zero = 0;
 
 	if (!mci.gr) {
 		/*
@@ -205,14 +209,6 @@ static int notrace s390_check_registers(union mci mci, int umode)
 			s390_handle_damage();
 		kill_task = 1;
 	}
-	/* Check control registers */
-	if (!mci.cr) {
-		/*
-		 * Control registers have unknown contents.
-		 * Can't recover and therefore stopping machine.
-		 */
-		s390_handle_damage();
-	}
 	if (!mci.fp) {
 		/*
 		 * Floating point registers can't be restored. If the
@@ -225,35 +221,89 @@ static int notrace s390_check_registers(union mci mci, int umode)
 		if (!test_cpu_flag(CIF_FPU))
 			kill_task = 1;
 	}
+	fpt_save_area = &S390_lowcore.floating_pt_save_area;
 	if (!mci.fc) {
 		/*
 		 * Floating point control register can't be restored.
 		 * If the kernel currently uses the floating pointer
 		 * registers and needs the FPC register the system is
 		 * stopped. If the process has its floating pointer
-		 * registers loaded it is terminated.
+		 * registers loaded it is terminated. Otherwise the
+		 * FPC is just validated.
 		 */
 		if (S390_lowcore.fpu_flags & KERNEL_FPC)
 			s390_handle_damage();
+		asm volatile(
+			"	lfpc	%0\n"
+			:
+			: "Q" (zero));
 		if (!test_cpu_flag(CIF_FPU))
 			kill_task = 1;
+	} else {
+		asm volatile(
+			"	lfpc	%0\n"
+			:
+			: "Q" (S390_lowcore.fpt_creg_save_area));
 	}
 
-	if (MACHINE_HAS_VX) {
+	mcesa = (struct mcesa *)(S390_lowcore.mcesad & MCESA_ORIGIN_MASK);
+	if (!MACHINE_HAS_VX) {
+		/* Validate floating point registers */
+		asm volatile(
+			"	ld	0,0(%0)\n"
+			"	ld	1,8(%0)\n"
+			"	ld	2,16(%0)\n"
+			"	ld	3,24(%0)\n"
+			"	ld	4,32(%0)\n"
+			"	ld	5,40(%0)\n"
+			"	ld	6,48(%0)\n"
+			"	ld	7,56(%0)\n"
+			"	ld	8,64(%0)\n"
+			"	ld	9,72(%0)\n"
+			"	ld	10,80(%0)\n"
+			"	ld	11,88(%0)\n"
+			"	ld	12,96(%0)\n"
+			"	ld	13,104(%0)\n"
+			"	ld	14,112(%0)\n"
+			"	ld	15,120(%0)\n"
+			:
+			: "a" (fpt_save_area)
+			: "memory");
+	} else {
+		/* Validate vector registers */
+		union ctlreg0 cr0;
+
 		if (!mci.vr) {
 			/*
 			 * Vector registers can't be restored. If the kernel
 			 * currently uses vector registers the system is
 			 * stopped. If the process has its vector registers
-			 * loaded it is terminated.
+			 * loaded it is terminated. Otherwise just validate
+			 * the registers.
 			 */
 			if (S390_lowcore.fpu_flags & KERNEL_VXR)
 				s390_handle_damage();
 			if (!test_cpu_flag(CIF_FPU))
 				kill_task = 1;
 		}
+		cr0.val = S390_lowcore.cregs_save_area[0];
+		cr0.afp = cr0.vx = 1;
+		__ctl_load(cr0.val, 0, 0);
+		asm volatile(
+			"	la	1,%0\n"
+			"	.word	0xe70f,0x1000,0x0036\n" /* vlm 0,15,0(1) */
+			"	.word	0xe70f,0x1100,0x0c36\n" /* vlm 16,31,256(1) */
+			:
+			: "Q" (*(struct vx_array *)mcesa->vector_save_area)
+			: "1");
+		__ctl_load(S390_lowcore.cregs_save_area[0], 0, 0);
 	}
-	/* Check if access registers are valid */
+	/* Validate access registers */
+	asm volatile(
+		"	lam	0,15,0(%0)\n"
+		:
+		: "a" (&S390_lowcore.access_regs_save_area)
+		: "memory");
 	if (!mci.ar) {
 		/*
 		 * Access registers have unknown contents.
@@ -261,7 +311,7 @@ static int notrace s390_check_registers(union mci mci, int umode)
 		 */
 		kill_task = 1;
 	}
-	/* Check guarded storage registers */
+	/* Validate guarded storage registers */
 	cr2.val = S390_lowcore.cregs_save_area[2];
 	if (cr2.gse) {
 		if (!mci.gs) {
@@ -271,31 +321,26 @@ static int notrace s390_check_registers(union mci mci, int umode)
 			 * It has to be terminated.
 			 */
 			kill_task = 1;
+		} else {
+			load_gs_cb((struct gs_cb *)mcesa->guarded_storage_save_area);
 		}
 	}
-	/* Check if old PSW is valid */
-	if (!mci.wp) {
-		/*
-		 * Can't tell if we come from user or kernel mode
-		 * -> stopping machine.
-		 */
-		s390_handle_damage();
-	}
-	/* Check for invalid kernel instruction address */
-	if (!mci.ia && !umode) {
-		/*
-		 * The instruction address got lost while running
-		 * in the kernel -> stopping machine.
-		 */
-		s390_handle_damage();
-	}
+	/*
+	 * The getcpu vdso syscall reads CPU number from the programmable
+	 * field of the TOD clock. Disregard the TOD programmable register
+	 * validity bit and load the CPU number into the TOD programmable
+	 * field unconditionally.
+	 */
+	set_tod_programmable_field(raw_smp_processor_id());
+	/* Validate clock comparator register */
+	set_clock_comparator(S390_lowcore.clock_comparator);
 
 	if (!mci.ms || !mci.pm || !mci.ia)
 		kill_task = 1;
 
 	return kill_task;
 }
-NOKPROBE_SYMBOL(s390_check_registers);
+NOKPROBE_SYMBOL(s390_validate_registers);
 
 /*
  * Backup the guest's machine check info to its description block
@@ -353,11 +398,6 @@ int notrace s390_do_machine_check(struct pt_regs *regs)
 	mci.val = S390_lowcore.mcck_interruption_code;
 	mcck = this_cpu_ptr(&cpu_mcck);
 
-	if (mci.sd) {
-		/* System damage -> stopping machine */
-		s390_handle_damage();
-	}
-
 	/*
 	 * Reinject the instruction processing damages' machine checks
 	 * including Delayed Access Exception into the guest
@@ -398,7 +438,7 @@ int notrace s390_do_machine_check(struct pt_regs *regs)
 			s390_handle_damage();
 		}
 	}
-	if (s390_check_registers(mci, user_mode(regs))) {
+	if (s390_validate_registers(mci, user_mode(regs))) {
 		/*
 		 * Couldn't restore all register contents for the
 		 * user space process -> mark task for termination.
@@ -428,21 +468,6 @@ int notrace s390_do_machine_check(struct pt_regs *regs)
 		mcck_pending = 1;
 	}
 
-	/*
-	 * Reinject storage related machine checks into the guest if they
-	 * happen when the guest is running.
-	 */
-	if (!test_cpu_flag(CIF_MCCK_GUEST)) {
-		if (mci.se)
-			/* Storage error uncorrected */
-			s390_handle_damage();
-		if (mci.ke)
-			/* Storage key-error uncorrected */
-			s390_handle_damage();
-		if (mci.ds && mci.fa)
-			/* Storage degradation */
-			s390_handle_damage();
-	}
 	if (mci.cp) {
 		/* Channel report word pending */
 		mcck->channel_report = 1;