s390 updates for the 5.5 merge window #2

- Make stack unwinder reliable and suitable for livepatching. Add unwinder
   testing module.
 
 - Fixes for CALL_ON_STACK helper used for stack switching.
 
 - Fix unwinding from bpf code.
 
 - Fix getcpu and remove compat support in vdso code.
 
 - Fix address space control registers initialization.
 
 - Save KASLR offset for early dumps.
 
 - Handle new FILTERED_BY_HYPERVISOR reply code in crypto code.
 
 - Minor perf code cleanup and potential memory leak fix.
 
 - Add couple of error messages for corner cases during PCI device
   creation.
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Merge tag 's390-5.5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull more s390 updates from Vasily Gorbik:

 - Make stack unwinder reliable and suitable for livepatching. Add
   unwinder testing module.

 - Fixes for CALL_ON_STACK helper used for stack switching.

 - Fix unwinding from bpf code.

 - Fix getcpu and remove compat support in vdso code.

 - Fix address space control registers initialization.

 - Save KASLR offset for early dumps.

 - Handle new FILTERED_BY_HYPERVISOR reply code in crypto code.

 - Minor perf code cleanup and potential memory leak fix.

 - Add couple of error messages for corner cases during PCI device
   creation.

* tag 's390-5.5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (33 commits)
  s390: remove compat vdso code
  s390/livepatch: Implement reliable stack tracing for the consistency model
  s390/unwind: add stack pointer alignment sanity checks
  s390/unwind: filter out unreliable bogus %r14
  s390/unwind: start unwinding from reliable state
  s390/test_unwind: add program check context tests
  s390/test_unwind: add irq context tests
  s390/test_unwind: print verbose unwinding results
  s390/test_unwind: add CALL_ON_STACK tests
  s390: fix register clobbering in CALL_ON_STACK
  s390/test_unwind: require that unwinding ended successfully
  s390/unwind: add a test for the internal API
  s390/unwind: always inline get_stack_pointer
  s390/pci: add error message on device number limit
  s390/pci: add error message for UID collision
  s390/cpum_sf: Check for SDBT and SDB consistency
  s390/cpum_sf: Use TEAR_REG macro consistantly
  s390/cpum_sf: Remove unnecessary check for pending SDBs
  s390/cpum_sf: Replace function name in debug statements
  s390/kaslr: store KASLR offset for early dumps
  ...

arch/s390/Kconfig

@@ -170,6 +170,7 @@ config S390
 	select HAVE_PERF_EVENTS
 	select HAVE_RCU_TABLE_FREE
 	select HAVE_REGS_AND_STACK_ACCESS_API
+	select HAVE_RELIABLE_STACKTRACE
 	select HAVE_RSEQ
 	select HAVE_SYSCALL_TRACEPOINTS
 	select HAVE_VIRT_CPU_ACCOUNTING
@@ -426,9 +427,6 @@ config COMPAT
 	  (and some other stuff like libraries and such) is needed for
 	  executing 31 bit applications.  It is safe to say "Y".
 
-config COMPAT_VDSO
-	def_bool COMPAT && !CC_IS_CLANG
-
 config SYSVIPC_COMPAT
 	def_bool y if COMPAT && SYSVIPC
 
@@ -1018,3 +1016,17 @@ config S390_GUEST
 	  the KVM hypervisor.
 
 endmenu
+
+menu "Selftests"
+
+config S390_UNWIND_SELFTEST
+	def_tristate n
+	prompt "Test unwind functions"
+	help
+	  This option enables s390 specific stack unwinder testing kernel
+	  module. This option is not useful for distributions or general
+	  kernels, but only for kernel developers working on architecture code.
+
+	  Say N if you are unsure.
+
+endmenu

arch/s390/Makefile

@@ -157,7 +157,6 @@ zfcpdump:
 
 vdso_install:
 	$(Q)$(MAKE) $(build)=arch/$(ARCH)/kernel/vdso64 $@
-	$(Q)$(MAKE) $(build)=arch/$(ARCH)/kernel/vdso32 $@
 
 archclean:
 	$(Q)$(MAKE) $(clean)=$(boot)

arch/s390/boot/startup.c

@@ -170,6 +170,11 @@ void startup_kernel(void)
 		handle_relocs(__kaslr_offset);
 
 	if (__kaslr_offset) {
+		/*
+		 * Save KASLR offset for early dumps, before vmcore_info is set.
+		 * Mark as uneven to distinguish from real vmcore_info pointer.
+		 */
+		S390_lowcore.vmcore_info = __kaslr_offset | 0x1UL;
 		/* Clear non-relocated kernel */
 		if (IS_ENABLED(CONFIG_KERNEL_UNCOMPRESSED))
 			memset(img, 0, vmlinux.image_size);

arch/s390/include/asm/cpu_mf.h

@@ -313,7 +313,7 @@ static inline unsigned long *trailer_entry_ptr(unsigned long v)
 	return (unsigned long *) ret;
 }
 
-/* Return if the entry in the sample data block table (sdbt)
+/* Return true if the entry in the sample data block table (sdbt)
  * is a link to the next sdbt */
 static inline int is_link_entry(unsigned long *s)
 {

arch/s390/include/asm/perf_event.h

@@ -12,6 +12,7 @@
 
 #include <linux/perf_event.h>
 #include <linux/device.h>
+#include <asm/stacktrace.h>
 
 /* Per-CPU flags for PMU states */
 #define PMU_F_RESERVED			0x1000
@@ -73,4 +74,10 @@ struct perf_sf_sde_regs {
 #define SDB_FULL_BLOCKS(hwc)	(SAMPL_FLAGS(hwc) & PERF_CPUM_SF_FULL_BLOCKS)
 #define SAMPLE_FREQ_MODE(hwc)	(SAMPL_FLAGS(hwc) & PERF_CPUM_SF_FREQ_MODE)
 
+#define perf_arch_fetch_caller_regs(regs, __ip) do {			\
+	(regs)->psw.addr = (__ip);					\
+	(regs)->gprs[15] = (unsigned long)__builtin_frame_address(0) -	\
+		offsetof(struct stack_frame, back_chain);		\
+} while (0)
+
 #endif /* _ASM_S390_PERF_EVENT_H */

arch/s390/include/asm/processor.h

@@ -310,7 +310,7 @@ void enabled_wait(void);
 /*
  * Function to drop a processor into disabled wait state
  */
-static inline void __noreturn disabled_wait(void)
+static __always_inline void __noreturn disabled_wait(void)
 {
 	psw_t psw;
 

arch/s390/include/asm/stacktrace.h

@@ -33,12 +33,12 @@ static inline bool on_stack(struct stack_info *info,
 	return addr >= info->begin && addr + len <= info->end;
 }
 
-static inline unsigned long get_stack_pointer(struct task_struct *task,
+static __always_inline unsigned long get_stack_pointer(struct task_struct *task,
-					      struct pt_regs *regs)
+						       struct pt_regs *regs)
 {
 	if (regs)
 		return (unsigned long) kernel_stack_pointer(regs);
-	if (!task || task == current)
+	if (task == current)
 		return current_stack_pointer();
 	return (unsigned long) task->thread.ksp;
 }
@@ -62,6 +62,17 @@ struct stack_frame {
 };
 #endif
 
+/*
+ * Unlike current_stack_pointer() which simply returns current value of %r15
+ * current_frame_address() returns function stack frame address, which matches
+ * %r15 upon function invocation. It may differ from %r15 later if function
+ * allocates stack for local variables or new stack frame to call other
+ * functions.
+ */
+#define current_frame_address()						\
+	((unsigned long)__builtin_frame_address(0) -			\
+	 offsetof(struct stack_frame, back_chain))
+
 #define CALL_ARGS_0()							\
 	register unsigned long r2 asm("2")
 #define CALL_ARGS_1(arg1)						\
@@ -95,20 +106,33 @@ struct stack_frame {
 
 #define CALL_ON_STACK(fn, stack, nr, args...)				\
 ({									\
+	unsigned long frame = current_frame_address();			\
 	CALL_ARGS_##nr(args);						\
 	unsigned long prev;						\
 									\
 	asm volatile(							\
 		"	la	%[_prev],0(15)\n"			\
-		"	la	15,0(%[_stack])\n"			\
+		"	lg	15,%[_stack]\n"				\
-		"	stg	%[_prev],%[_bc](15)\n"			\
+		"	stg	%[_frame],%[_bc](15)\n"			\
 		"	brasl	14,%[_fn]\n"				\
 		"	la	15,0(%[_prev])\n"			\
 		: [_prev] "=&a" (prev), CALL_FMT_##nr			\
-		  [_stack] "a" (stack),					\
+		  [_stack] "R" (stack),					\
 		  [_bc] "i" (offsetof(struct stack_frame, back_chain)),	\
+		  [_frame] "d" (frame),					\
 		  [_fn] "X" (fn) : CALL_CLOBBER_##nr);			\
 	r2;								\
 })
 
+#define CALL_ON_STACK_NORETURN(fn, stack)				\
+({									\
+	asm volatile(							\
+		"	la	15,0(%[_stack])\n"			\
+		"	xc	%[_bc](8,15),%[_bc](15)\n"		\
+		"	brasl	14,%[_fn]\n"				\
+		::[_bc] "i" (offsetof(struct stack_frame, back_chain)),	\
+		  [_stack] "a" (stack), [_fn] "X" (fn));		\
+	BUG();								\
+})
+
 #endif /* _ASM_S390_STACKTRACE_H */

arch/s390/include/asm/unwind.h

@@ -35,7 +35,6 @@ struct unwind_state {
 	struct task_struct *task;
 	struct pt_regs *regs;
 	unsigned long sp, ip;
-	bool reuse_sp;
 	int graph_idx;
 	bool reliable;
 	bool error;
@@ -59,10 +58,11 @@ static inline bool unwind_error(struct unwind_state *state)
 static inline void unwind_start(struct unwind_state *state,
 				struct task_struct *task,
 				struct pt_regs *regs,
-				unsigned long sp)
+				unsigned long first_frame)
 {
-	sp = sp ? : get_stack_pointer(task, regs);
+	task = task ?: current;
-	__unwind_start(state, task, regs, sp);
+	first_frame = first_frame ?: get_stack_pointer(task, regs);
+	__unwind_start(state, task, regs, first_frame);
 }
 
 static inline struct pt_regs *unwind_get_entry_regs(struct unwind_state *state)

arch/s390/include/asm/vdso.h

@@ -41,8 +41,17 @@ struct vdso_data {
 struct vdso_per_cpu_data {
 	__u64 ectg_timer_base;
 	__u64 ectg_user_time;
-	__u32 cpu_nr;
+	/*
-	__u32 node_id;
+	 * Note: node_id and cpu_nr must be at adjacent memory locations.
+	 * VDSO userspace must read both values with a single instruction.
+	 */
+	union {
+		__u64 getcpu_val;
+		struct {
+			__u32 node_id;
+			__u32 cpu_nr;
+		};
+	};
 };
 
 extern struct vdso_data *vdso_data;

arch/s390/kernel/Makefile

@@ -81,4 +81,3 @@ obj-$(CONFIG_TRACEPOINTS)	+= trace.o
 
 # vdso
 obj-y				+= vdso64/
-obj-$(CONFIG_COMPAT_VDSO)	+= vdso32/

arch/s390/kernel/asm-offsets.c

@@ -78,8 +78,7 @@ int main(void)
 	OFFSET(__VDSO_TS_END, vdso_data, ts_end);
 	OFFSET(__VDSO_ECTG_BASE, vdso_per_cpu_data, ectg_timer_base);
 	OFFSET(__VDSO_ECTG_USER, vdso_per_cpu_data, ectg_user_time);
-	OFFSET(__VDSO_CPU_NR, vdso_per_cpu_data, cpu_nr);
+	OFFSET(__VDSO_GETCPU_VAL, vdso_per_cpu_data, getcpu_val);
-	OFFSET(__VDSO_NODE_ID, vdso_per_cpu_data, node_id);
 	BLANK();
 	/* constants used by the vdso */
 	DEFINE(__CLOCK_REALTIME, CLOCK_REALTIME);

arch/s390/kernel/dumpstack.c

@@ -38,6 +38,7 @@ const char *stack_type_name(enum stack_type type)
 		return "unknown";
 	}
 }
+EXPORT_SYMBOL_GPL(stack_type_name);
 
 static inline bool in_stack(unsigned long sp, struct stack_info *info,
 			    enum stack_type type, unsigned long low,
@@ -93,7 +94,9 @@ int get_stack_info(unsigned long sp, struct task_struct *task,
 	if (!sp)
 		goto unknown;
 
-	task = task ? : current;
+	/* Sanity check: ABI requires SP to be aligned 8 bytes. */
+	if (sp & 0x7)
+		goto unknown;
 
 	/* Check per-task stack */
 	if (in_task_stack(sp, task, info))
@@ -128,8 +131,6 @@ void show_stack(struct task_struct *task, unsigned long *stack)
 	struct unwind_state state;
 
 	printk("Call Trace:\n");
-	if (!task)
-		task = current;
 	unwind_for_each_frame(&state, task, NULL, (unsigned long) stack)
 		printk(state.reliable ? " [<%016lx>] %pSR \n" :
 					"([<%016lx>] %pSR)\n",

arch/s390/kernel/head64.S

@@ -31,7 +31,7 @@ ENTRY(startup_continue)
 #
 	larl	%r14,init_task
 	stg	%r14,__LC_CURRENT
-	larl	%r15,init_thread_union+THREAD_SIZE-STACK_FRAME_OVERHEAD
+	larl	%r15,init_thread_union+THREAD_SIZE-STACK_FRAME_OVERHEAD-__PT_SIZE
 #ifdef CONFIG_KASAN
 	brasl	%r14,kasan_early_init
 #endif

arch/s390/kernel/machine_kexec.c

@@ -164,7 +164,9 @@ static bool kdump_csum_valid(struct kimage *image)
 #ifdef CONFIG_CRASH_DUMP
 	int rc;
 
+	preempt_disable();
 	rc = CALL_ON_STACK(do_start_kdump, S390_lowcore.nodat_stack, 1, image);
+	preempt_enable();
 	return rc == 0;
 #else
 	return false;
@@ -254,10 +256,10 @@ void arch_crash_save_vmcoreinfo(void)
 	VMCOREINFO_SYMBOL(lowcore_ptr);
 	VMCOREINFO_SYMBOL(high_memory);
 	VMCOREINFO_LENGTH(lowcore_ptr, NR_CPUS);
-	mem_assign_absolute(S390_lowcore.vmcore_info, paddr_vmcoreinfo_note());
 	vmcoreinfo_append_str("SDMA=%lx\n", __sdma);
 	vmcoreinfo_append_str("EDMA=%lx\n", __edma);
 	vmcoreinfo_append_str("KERNELOFFSET=%lx\n", kaslr_offset());
+	mem_assign_absolute(S390_lowcore.vmcore_info, paddr_vmcoreinfo_note());
 }
 
 void machine_shutdown(void)

arch/s390/kernel/perf_cpum_sf.c

@@ -156,8 +156,8 @@ static void free_sampling_buffer(struct sf_buffer *sfb)
 		}
 	}
 
-	debug_sprintf_event(sfdbg, 5, "%s freed sdbt %p\n", __func__,
+	debug_sprintf_event(sfdbg, 5, "%s: freed sdbt %#lx\n", __func__,
-			    sfb->sdbt);
+			    (unsigned long)sfb->sdbt);
 	memset(sfb, 0, sizeof(*sfb));
 }
 
@@ -193,7 +193,7 @@ static int realloc_sampling_buffer(struct sf_buffer *sfb,
 				   unsigned long num_sdb, gfp_t gfp_flags)
 {
 	int i, rc;
-	unsigned long *new, *tail;
+	unsigned long *new, *tail, *tail_prev = NULL;
 
 	if (!sfb->sdbt || !sfb->tail)
 		return -EINVAL;
@@ -213,9 +213,10 @@ static int realloc_sampling_buffer(struct sf_buffer *sfb,
 	 */
 	if (sfb->sdbt != get_next_sdbt(tail)) {
 		debug_sprintf_event(sfdbg, 3, "%s: "
-				    "sampling buffer is not linked: origin %p"
+				    "sampling buffer is not linked: origin %#lx"
-				    " tail %p\n", __func__,
+				    " tail %#lx\n", __func__,
-				    (void *)sfb->sdbt, (void *)tail);
+				    (unsigned long)sfb->sdbt,
+				    (unsigned long)tail);
 		return -EINVAL;
 	}
 
@@ -232,6 +233,7 @@ static int realloc_sampling_buffer(struct sf_buffer *sfb,
 			sfb->num_sdbt++;
 			/* Link current page to tail of chain */
 			*tail = (unsigned long)(void *) new + 1;
+			tail_prev = tail;
 			tail = new;
 		}
 
@@ -241,18 +243,30 @@ static int realloc_sampling_buffer(struct sf_buffer *sfb,
 		 * issue, a new realloc call (if required) might succeed.
 		 */
 		rc = alloc_sample_data_block(tail, gfp_flags);
-		if (rc)
+		if (rc) {
+			/* Undo last SDBT. An SDBT with no SDB at its first
+			 * entry but with an SDBT entry instead can not be
+			 * handled by the interrupt handler code.
+			 * Avoid this situation.
+			 */
+			if (tail_prev) {
+				sfb->num_sdbt--;
+				free_page((unsigned long) new);
+				tail = tail_prev;
+			}
 			break;
+		}
 		sfb->num_sdb++;
 		tail++;
+		tail_prev = new = NULL;	/* Allocated at least one SBD */
 	}
 
 	/* Link sampling buffer to its origin */
 	*tail = (unsigned long) sfb->sdbt + 1;
 	sfb->tail = tail;
 
-	debug_sprintf_event(sfdbg, 4, "realloc_sampling_buffer: new buffer"
+	debug_sprintf_event(sfdbg, 4, "%s: new buffer"
-			    " settings: sdbt %lu sdb %lu\n",
+			    " settings: sdbt %lu sdb %lu\n", __func__,
 			    sfb->num_sdbt, sfb->num_sdb);
 	return rc;
 }
@@ -292,12 +306,13 @@ static int alloc_sampling_buffer(struct sf_buffer *sfb, unsigned long num_sdb)
 	rc = realloc_sampling_buffer(sfb, num_sdb, GFP_KERNEL);
 	if (rc) {
 		free_sampling_buffer(sfb);
-		debug_sprintf_event(sfdbg, 4, "alloc_sampling_buffer: "
+		debug_sprintf_event(sfdbg, 4, "%s: "
-			"realloc_sampling_buffer failed with rc %i\n", rc);
+			"realloc_sampling_buffer failed with rc %i\n",
+			__func__, rc);
 	} else
 		debug_sprintf_event(sfdbg, 4,
-			"alloc_sampling_buffer: tear %p dear %p\n",
+			"%s: tear %#lx dear %#lx\n", __func__,
-			sfb->sdbt, (void *)*sfb->sdbt);
+			(unsigned long)sfb->sdbt, (unsigned long)*sfb->sdbt);
 	return rc;
 }
 
@@ -465,8 +480,8 @@ static void sfb_account_overflows(struct cpu_hw_sf *cpuhw,
 	if (num)
 		sfb_account_allocs(num, hwc);
 
-	debug_sprintf_event(sfdbg, 5, "sfb: overflow: overflow %llu ratio %lu"
+	debug_sprintf_event(sfdbg, 5, "%s: overflow %llu ratio %lu num %lu\n",
-			    " num %lu\n", OVERFLOW_REG(hwc), ratio, num);
+			    __func__, OVERFLOW_REG(hwc), ratio, num);
 	OVERFLOW_REG(hwc) = 0;
 }
 
@@ -504,13 +519,13 @@ static void extend_sampling_buffer(struct sf_buffer *sfb,
 	 */
 	rc = realloc_sampling_buffer(sfb, num, GFP_ATOMIC);
 	if (rc)
-		debug_sprintf_event(sfdbg, 5, "sfb: extend: realloc "
+		debug_sprintf_event(sfdbg, 5, "%s: realloc failed with rc %i\n",
-				    "failed with rc %i\n", rc);
+				    __func__, rc);
 
 	if (sfb_has_pending_allocs(sfb, hwc))
-		debug_sprintf_event(sfdbg, 5, "sfb: extend: "
+		debug_sprintf_event(sfdbg, 5, "%s: "
 				    "req %lu alloc %lu remaining %lu\n",
-				    num, sfb->num_sdb - num_old,
+				    __func__, num, sfb->num_sdb - num_old,
 				    sfb_pending_allocs(sfb, hwc));
 }
 
@@ -600,13 +615,6 @@ static void hw_init_period(struct hw_perf_event *hwc, u64 period)
 	local64_set(&hwc->period_left, hwc->sample_period);
 }
 
-static void hw_reset_registers(struct hw_perf_event *hwc,
-			       unsigned long *sdbt_origin)
-{
-	/* (Re)set to first sample-data-block-table */
-	TEAR_REG(hwc) = (unsigned long) sdbt_origin;
-}
-
 static unsigned long hw_limit_rate(const struct hws_qsi_info_block *si,
 				   unsigned long rate)
 {
@@ -698,9 +706,9 @@ static unsigned long getrate(bool freq, unsigned long sample,
 		 */
 		if (sample_rate_to_freq(si, rate) >
 		    sysctl_perf_event_sample_rate) {
-			debug_sprintf_event(sfdbg, 1,
+			debug_sprintf_event(sfdbg, 1, "%s: "
 					    "Sampling rate exceeds maximum "
-					    "perf sample rate\n");
+					    "perf sample rate\n", __func__);
 			rate = 0;
 		}
 	}
@@ -745,10 +753,9 @@ static int __hw_perf_event_init_rate(struct perf_event *event,
 	attr->sample_period = rate;
 	SAMPL_RATE(hwc) = rate;
 	hw_init_period(hwc, SAMPL_RATE(hwc));
-	debug_sprintf_event(sfdbg, 4, "__hw_perf_event_init_rate:"
+	debug_sprintf_event(sfdbg, 4, "%s: cpu %d period %#llx freq %d,%#lx\n",
-			    "cpu:%d period:%#llx freq:%d,%#lx\n", event->cpu,
+			    __func__, event->cpu, event->attr.sample_period,
-			    event->attr.sample_period, event->attr.freq,
+			    event->attr.freq, SAMPLE_FREQ_MODE(hwc));
-			    SAMPLE_FREQ_MODE(hwc));
 	return 0;
 }
 
@@ -951,8 +958,7 @@ static void cpumsf_pmu_enable(struct pmu *pmu)
 			 * buffer extents
 			 */
 			sfb_account_overflows(cpuhw, hwc);
-			if (sfb_has_pending_allocs(&cpuhw->sfb, hwc))
+			extend_sampling_buffer(&cpuhw->sfb, hwc);
-				extend_sampling_buffer(&cpuhw->sfb, hwc);
 		}
 		/* Rate may be adjusted with ioctl() */
 		cpuhw->lsctl.interval = SAMPL_RATE(&cpuhw->event->hw);
@@ -973,12 +979,11 @@ static void cpumsf_pmu_enable(struct pmu *pmu)
 	/* Load current program parameter */
 	lpp(&S390_lowcore.lpp);
 
-	debug_sprintf_event(sfdbg, 6, "pmu_enable: es %i cs %i ed %i cd %i "
+	debug_sprintf_event(sfdbg, 6, "%s: es %i cs %i ed %i cd %i "
-			    "interval %#lx tear %p dear %p\n",
+			    "interval %#lx tear %#lx dear %#lx\n", __func__,
 			    cpuhw->lsctl.es, cpuhw->lsctl.cs, cpuhw->lsctl.ed,
 			    cpuhw->lsctl.cd, cpuhw->lsctl.interval,
-			    (void *) cpuhw->lsctl.tear,
+			    cpuhw->lsctl.tear, cpuhw->lsctl.dear);
-			    (void *) cpuhw->lsctl.dear);
 }
 
 static void cpumsf_pmu_disable(struct pmu *pmu)
@@ -1019,8 +1024,8 @@ static void cpumsf_pmu_disable(struct pmu *pmu)
 			cpuhw->lsctl.dear = si.dear;
 		}
 	} else
-		debug_sprintf_event(sfdbg, 3, "cpumsf_pmu_disable: "
+		debug_sprintf_event(sfdbg, 3, "%s: qsi() failed with err %i\n",
-				    "qsi() failed with err %i\n", err);
+				    __func__, err);
 
 	cpuhw->flags &= ~PMU_F_ENABLED;
 }
@@ -1265,9 +1270,9 @@ static void hw_perf_event_update(struct perf_event *event, int flush_all)
 			sampl_overflow += te->overflow;
 
 		/* Timestamps are valid for full sample-data-blocks only */
-		debug_sprintf_event(sfdbg, 6, "%s: sdbt %p "
+		debug_sprintf_event(sfdbg, 6, "%s: sdbt %#lx "
 				    "overflow %llu timestamp %#llx\n",
-				    __func__, sdbt, te->overflow,
+				    __func__, (unsigned long)sdbt, te->overflow,
 				    (te->f) ? trailer_timestamp(te) : 0ULL);
 
 		/* Collect all samples from a single sample-data-block and
@@ -1312,8 +1317,10 @@ static void hw_perf_event_update(struct perf_event *event, int flush_all)
 						 sampl_overflow, 1 + num_sdb);
 	if (sampl_overflow || event_overflow)
 		debug_sprintf_event(sfdbg, 4, "%s: "
-				    "overflow stats: sample %llu event %llu\n",
+				    "overflows: sample %llu event %llu"
-				    __func__, sampl_overflow, event_overflow);
+				    " total %llu num_sdb %llu\n",
+				    __func__, sampl_overflow, event_overflow,
+				    OVERFLOW_REG(hwc), num_sdb);
 }
 
 #define AUX_SDB_INDEX(aux, i) ((i) % aux->sfb.num_sdb)
@@ -1424,10 +1431,10 @@ static int aux_output_begin(struct perf_output_handle *handle,
 	cpuhw->lsctl.tear = base + offset * sizeof(unsigned long);
 	cpuhw->lsctl.dear = aux->sdb_index[head];
 
-	debug_sprintf_event(sfdbg, 6, "aux_output_begin: "
+	debug_sprintf_event(sfdbg, 6, "%s: "
 			    "head->alert_mark->empty_mark (num_alert, range)"
 			    "[%#lx -> %#lx -> %#lx] (%#lx, %#lx) "
-			    "tear index %#lx, tear %#lx dear %#lx\n",
+			    "tear index %#lx, tear %#lx dear %#lx\n", __func__,
 			    aux->head, aux->alert_mark, aux->empty_mark,
 			    AUX_SDB_NUM_ALERT(aux), range,
 			    head / CPUM_SF_SDB_PER_TABLE,
@@ -1571,7 +1578,9 @@ static void hw_collect_aux(struct cpu_hw_sf *cpuhw)
 			pr_err("The AUX buffer with %lu pages for the "
 			       "diagnostic-sampling mode is full\n",
 				num_sdb);
-			debug_sprintf_event(sfdbg, 1, "AUX buffer used up\n");
+			debug_sprintf_event(sfdbg, 1,
+					    "%s: AUX buffer used up\n",
+					    __func__);
 			break;
 		}
 		if (WARN_ON_ONCE(!aux))
@@ -1594,23 +1603,25 @@ static void hw_collect_aux(struct cpu_hw_sf *cpuhw)
 			perf_aux_output_end(&cpuhw->handle, size);
 			pr_err("Sample data caused the AUX buffer with %lu "
 			       "pages to overflow\n", num_sdb);
-			debug_sprintf_event(sfdbg, 1, "head %#lx range %#lx "
+			debug_sprintf_event(sfdbg, 1, "%s: head %#lx range %#lx "
-					    "overflow %#llx\n",
+					    "overflow %#llx\n", __func__,
 					    aux->head, range, overflow);
 		} else {
 			size = AUX_SDB_NUM_ALERT(aux) << PAGE_SHIFT;
 			perf_aux_output_end(&cpuhw->handle, size);
-			debug_sprintf_event(sfdbg, 6, "head %#lx alert %#lx "
+			debug_sprintf_event(sfdbg, 6, "%s: head %#lx alert %#lx "
 					    "already full, try another\n",
+					    __func__,
 					    aux->head, aux->alert_mark);
 		}
 	}
 
 	if (done)
-		debug_sprintf_event(sfdbg, 6, "aux_reset_buffer: "
+		debug_sprintf_event(sfdbg, 6, "%s: aux_reset_buffer "
 				    "[%#lx -> %#lx -> %#lx] (%#lx, %#lx)\n",
-				    aux->head, aux->alert_mark, aux->empty_mark,
+				    __func__, aux->head, aux->alert_mark,
-				    AUX_SDB_NUM_ALERT(aux), range);
+				    aux->empty_mark, AUX_SDB_NUM_ALERT(aux),
+				    range);
 }
 
 /*
@@ -1633,8 +1644,8 @@ static void aux_buffer_free(void *data)
 	kfree(aux->sdb_index);
 	kfree(aux);
 
-	debug_sprintf_event(sfdbg, 4, "aux_buffer_free: free "
+	debug_sprintf_event(sfdbg, 4, "%s: free "
-			    "%lu SDBTs\n", num_sdbt);
+			    "%lu SDBTs\n", __func__, num_sdbt);
 }
 
 static void aux_sdb_init(unsigned long sdb)
@@ -1742,9 +1753,8 @@ static void *aux_buffer_setup(struct perf_event *event, void **pages,
 	 */
 	aux->empty_mark = sfb->num_sdb - 1;
 
-	debug_sprintf_event(sfdbg, 4, "aux_buffer_setup: setup %lu SDBTs"
+	debug_sprintf_event(sfdbg, 4, "%s: setup %lu SDBTs and %lu SDBs\n",
-			    " and %lu SDBs\n",
+			    __func__, sfb->num_sdbt, sfb->num_sdb);
-			    sfb->num_sdbt, sfb->num_sdb);
 
 	return aux;
 
@@ -1797,9 +1807,9 @@ static int cpumsf_pmu_check_period(struct perf_event *event, u64 value)
 	event->attr.sample_period = rate;
 	SAMPL_RATE(&event->hw) = rate;
 	hw_init_period(&event->hw, SAMPL_RATE(&event->hw));
-	debug_sprintf_event(sfdbg, 4, "cpumsf_pmu_check_period:"
+	debug_sprintf_event(sfdbg, 4, "%s:"
-			    "cpu:%d value:%#llx period:%#llx freq:%d\n",
+			    " cpu %d value %#llx period %#llx freq %d\n",
-			    event->cpu, value,
+			    __func__, event->cpu, value,
 			    event->attr.sample_period, do_freq);
 	return 0;
 }
@@ -1875,7 +1885,7 @@ static int cpumsf_pmu_add(struct perf_event *event, int flags)
 	if (!SAMPL_DIAG_MODE(&event->hw)) {
 		cpuhw->lsctl.tear = (unsigned long) cpuhw->sfb.sdbt;
 		cpuhw->lsctl.dear = *(unsigned long *) cpuhw->sfb.sdbt;
-		hw_reset_registers(&event->hw, cpuhw->sfb.sdbt);
+		TEAR_REG(&event->hw) = (unsigned long) cpuhw->sfb.sdbt;
 	}
 
 	/* Ensure sampling functions are in the disabled state.  If disabled,
@@ -2030,7 +2040,7 @@ static void cpumf_measurement_alert(struct ext_code ext_code,
 
 	/* Report measurement alerts only for non-PRA codes */
 	if (alert != CPU_MF_INT_SF_PRA)
-		debug_sprintf_event(sfdbg, 6, "measurement alert: %#x\n",
+		debug_sprintf_event(sfdbg, 6, "%s: alert %#x\n", __func__,
 				    alert);
 
 	/* Sampling authorization change request */

arch/s390/kernel/setup.c

@@ -355,7 +355,6 @@ early_initcall(async_stack_realloc);
 
 void __init arch_call_rest_init(void)
 {
-	struct stack_frame *frame;
 	unsigned long stack;
 
 	stack = stack_alloc();
@@ -368,13 +367,7 @@ void __init arch_call_rest_init(void)
 	set_task_stack_end_magic(current);
 	stack += STACK_INIT_OFFSET;
 	S390_lowcore.kernel_stack = stack;
-	frame = (struct stack_frame *) stack;
+	CALL_ON_STACK_NORETURN(rest_init, stack);
-	memset(frame, 0, sizeof(*frame));
-	/* Branch to rest_init on the new stack, never returns */
-	asm volatile(
-		"	la	15,0(%[_frame])\n"
-		"	jg	rest_init\n"
-		: : [_frame] "a" (frame));
 }
 
 static void __init setup_lowcore_dat_off(void)

arch/s390/kernel/smp.c

@@ -262,10 +262,13 @@ static void pcpu_prepare_secondary(struct pcpu *pcpu, int cpu)
 	lc->spinlock_index = 0;
 	lc->percpu_offset = __per_cpu_offset[cpu];
 	lc->kernel_asce = S390_lowcore.kernel_asce;
+	lc->user_asce = S390_lowcore.kernel_asce;
 	lc->machine_flags = S390_lowcore.machine_flags;
 	lc->user_timer = lc->system_timer =
 		lc->steal_timer = lc->avg_steal_timer = 0;
 	__ctl_store(lc->cregs_save_area, 0, 15);
+	lc->cregs_save_area[1] = lc->kernel_asce;
+	lc->cregs_save_area[7] = lc->vdso_asce;
 	save_access_regs((unsigned int *) lc->access_regs_save_area);
 	memcpy(lc->stfle_fac_list, S390_lowcore.stfle_fac_list,
 	       sizeof(lc->stfle_fac_list));
@@ -844,6 +847,8 @@ static void smp_init_secondary(void)
 
 	S390_lowcore.last_update_clock = get_tod_clock();
 	restore_access_regs(S390_lowcore.access_regs_save_area);
+	set_cpu_flag(CIF_ASCE_PRIMARY);
+	set_cpu_flag(CIF_ASCE_SECONDARY);
 	cpu_init();
 	preempt_disable();
 	init_cpu_timer();
@@ -871,7 +876,7 @@ static void __no_sanitize_address smp_start_secondary(void *cpuvoid)
 	S390_lowcore.restart_source = -1UL;
 	__ctl_load(S390_lowcore.cregs_save_area, 0, 15);
 	__load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
-	CALL_ON_STACK(smp_init_secondary, S390_lowcore.kernel_stack, 0);
+	CALL_ON_STACK_NORETURN(smp_init_secondary, S390_lowcore.kernel_stack);
 }
 
 /* Upping and downing of CPUs */

arch/s390/kernel/stacktrace.c

@@ -9,6 +9,7 @@
 #include <linux/stacktrace.h>
 #include <asm/stacktrace.h>
 #include <asm/unwind.h>
+#include <asm/kprobes.h>
 
 void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
 		     struct task_struct *task, struct pt_regs *regs)
@@ -22,3 +23,45 @@ void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
 			break;
 	}
 }
+
+/*
+ * This function returns an error if it detects any unreliable features of the
+ * stack.  Otherwise it guarantees that the stack trace is reliable.
+ *
+ * If the task is not 'current', the caller *must* ensure the task is inactive.
+ */
+int arch_stack_walk_reliable(stack_trace_consume_fn consume_entry,
+			     void *cookie, struct task_struct *task)
+{
+	struct unwind_state state;
+	unsigned long addr;
+
+	unwind_for_each_frame(&state, task, NULL, 0) {
+		if (state.stack_info.type != STACK_TYPE_TASK)
+			return -EINVAL;
+
+		if (state.regs)
+			return -EINVAL;
+
+		addr = unwind_get_return_address(&state);
+		if (!addr)
+			return -EINVAL;
+
+#ifdef CONFIG_KPROBES
+		/*
+		 * Mark stacktraces with kretprobed functions on them
+		 * as unreliable.
+		 */
+		if (state.ip == (unsigned long)kretprobe_trampoline)
+			return -EINVAL;
+#endif
+
+		if (!consume_entry(cookie, addr, false))
+			return -EINVAL;
+	}
+
+	/* Check for stack corruption */
+	if (unwind_error(&state))
+		return -EINVAL;
+	return 0;
+}

arch/s390/kernel/unwind_bc.c

@@ -36,6 +36,12 @@ static bool update_stack_info(struct unwind_state *state, unsigned long sp)
 	return true;
 }
 
+static inline bool is_task_pt_regs(struct unwind_state *state,
+				   struct pt_regs *regs)
+{
+	return task_pt_regs(state->task) == regs;
+}
+
 bool unwind_next_frame(struct unwind_state *state)
 {
 	struct stack_info *info = &state->stack_info;
@@ -46,20 +52,16 @@ bool unwind_next_frame(struct unwind_state *state)
 
 	regs = state->regs;
 	if (unlikely(regs)) {
-		if (state->reuse_sp) {
+		sp = state->sp;
-			sp = state->sp;
-			state->reuse_sp = false;
-		} else {
-			sp = READ_ONCE_NOCHECK(regs->gprs[15]);
-			if (unlikely(outside_of_stack(state, sp))) {
-				if (!update_stack_info(state, sp))
-					goto out_err;
-			}
-		}
 		sf = (struct stack_frame *) sp;
 		ip = READ_ONCE_NOCHECK(sf->gprs[8]);
 		reliable = false;
 		regs = NULL;
+		if (!__kernel_text_address(ip)) {
+			/* skip bogus %r14 */
+			state->regs = NULL;
+			return unwind_next_frame(state);
+		}
 	} else {
 		sf = (struct stack_frame *) state->sp;
 		sp = READ_ONCE_NOCHECK(sf->back_chain);
@@ -76,15 +78,24 @@ bool unwind_next_frame(struct unwind_state *state)
 			/* No back-chain, look for a pt_regs structure */
 			sp = state->sp + STACK_FRAME_OVERHEAD;
 			if (!on_stack(info, sp, sizeof(struct pt_regs)))
-				goto out_stop;
+				goto out_err;
 			regs = (struct pt_regs *) sp;
-			if (READ_ONCE_NOCHECK(regs->psw.mask) & PSW_MASK_PSTATE)
+			if (is_task_pt_regs(state, regs))
 				goto out_stop;
 			ip = READ_ONCE_NOCHECK(regs->psw.addr);
+			sp = READ_ONCE_NOCHECK(regs->gprs[15]);
+			if (unlikely(outside_of_stack(state, sp))) {
+				if (!update_stack_info(state, sp))
+					goto out_err;
+			}
 			reliable = true;
 		}
 	}
 
+	/* Sanity check: ABI requires SP to be aligned 8 bytes. */
+	if (sp & 0x7)
+		goto out_err;
+
 	ip = ftrace_graph_ret_addr(state->task, &state->graph_idx, ip, (void *) sp);
 
 	/* Update unwind state */
@@ -103,13 +114,11 @@ out_stop:
 EXPORT_SYMBOL_GPL(unwind_next_frame);
 
 void __unwind_start(struct unwind_state *state, struct task_struct *task,
-		    struct pt_regs *regs, unsigned long sp)
+		    struct pt_regs *regs, unsigned long first_frame)
 {
 	struct stack_info *info = &state->stack_info;
-	unsigned long *mask = &state->stack_mask;
-	bool reliable, reuse_sp;
 	struct stack_frame *sf;
-	unsigned long ip;
+	unsigned long ip, sp;
 
 	memset(state, 0, sizeof(*state));
 	state->task = task;
@@ -121,25 +130,28 @@ void __unwind_start(struct unwind_state *state, struct task_struct *task,
 		return;
 	}
 
+	/* Get the instruction pointer from pt_regs or the stack frame */
+	if (regs) {
+		ip = regs->psw.addr;
+		sp = regs->gprs[15];
+	} else if (task == current) {
+		sp = current_frame_address();
+	} else {
+		sp = task->thread.ksp;
+	}
+
 	/* Get current stack pointer and initialize stack info */
-	if (get_stack_info(sp, task, info, mask) != 0 ||
+	if (!update_stack_info(state, sp)) {
-	    !on_stack(info, sp, sizeof(struct stack_frame))) {
 		/* Something is wrong with the stack pointer */
 		info->type = STACK_TYPE_UNKNOWN;
 		state->error = true;
 		return;
 	}
 
-	/* Get the instruction pointer from pt_regs or the stack frame */
+	if (!regs) {
-	if (regs) {
+		/* Stack frame is within valid stack */
-		ip = READ_ONCE_NOCHECK(regs->psw.addr);
+		sf = (struct stack_frame *)sp;
-		reliable = true;
-		reuse_sp = true;
-	} else {
-		sf = (struct stack_frame *) sp;
 		ip = READ_ONCE_NOCHECK(sf->gprs[8]);
-		reliable = false;
-		reuse_sp = false;
 	}
 
 	ip = ftrace_graph_ret_addr(state->task, &state->graph_idx, ip, NULL);
@@ -147,7 +159,17 @@ void __unwind_start(struct unwind_state *state, struct task_struct *task,
 	/* Update unwind state */
 	state->sp = sp;
 	state->ip = ip;
-	state->reliable = reliable;
+	state->reliable = true;
-	state->reuse_sp = reuse_sp;
+
+	if (!first_frame)
+		return;
+	/* Skip through the call chain to the specified starting frame */
+	while (!unwind_done(state)) {
+		if (on_stack(&state->stack_info, first_frame, sizeof(struct stack_frame))) {
+			if (state->sp >= first_frame)
+				break;
+		}
+		unwind_next_frame(state);
+	}
 }
 EXPORT_SYMBOL_GPL(__unwind_start);

arch/s390/kernel/vdso.c

@@ -29,13 +29,6 @@
 #include <asm/vdso.h>
 #include <asm/facility.h>
 
-#ifdef CONFIG_COMPAT_VDSO
-extern char vdso32_start, vdso32_end;
-static void *vdso32_kbase = &vdso32_start;
-static unsigned int vdso32_pages;
-static struct page **vdso32_pagelist;
-#endif
-
 extern char vdso64_start, vdso64_end;
 static void *vdso64_kbase = &vdso64_start;
 static unsigned int vdso64_pages;
@@ -55,12 +48,6 @@ static vm_fault_t vdso_fault(const struct vm_special_mapping *sm,
 
 	vdso_pagelist = vdso64_pagelist;
 	vdso_pages = vdso64_pages;
-#ifdef CONFIG_COMPAT_VDSO
-	if (vma->vm_mm->context.compat_mm) {
-		vdso_pagelist = vdso32_pagelist;
-		vdso_pages = vdso32_pages;
-	}
-#endif
 
 	if (vmf->pgoff >= vdso_pages)
 		return VM_FAULT_SIGBUS;
@@ -76,10 +63,6 @@ static int vdso_mremap(const struct vm_special_mapping *sm,
 	unsigned long vdso_pages;
 
 	vdso_pages = vdso64_pages;
-#ifdef CONFIG_COMPAT_VDSO
-	if (vma->vm_mm->context.compat_mm)
-		vdso_pages = vdso32_pages;
-#endif
 
 	if ((vdso_pages << PAGE_SHIFT) != vma->vm_end - vma->vm_start)
 		return -EINVAL;
@@ -209,12 +192,10 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 	if (!vdso_enabled)
 		return 0;
 
+	if (is_compat_task())
+		return 0;
+
 	vdso_pages = vdso64_pages;
-#ifdef CONFIG_COMPAT_VDSO
-	mm->context.compat_mm = is_compat_task();
-	if (mm->context.compat_mm)
-		vdso_pages = vdso32_pages;
-#endif
 	/*
 	 * vDSO has a problem and was disabled, just don't "enable" it for
 	 * the process
@@ -267,23 +248,6 @@ static int __init vdso_init(void)
 	int i;
 
 	vdso_init_data(vdso_data);
-#ifdef CONFIG_COMPAT_VDSO
-	/* Calculate the size of the 32 bit vDSO */
-	vdso32_pages = ((&vdso32_end - &vdso32_start
-			 + PAGE_SIZE - 1) >> PAGE_SHIFT) + 1;
-
-	/* Make sure pages are in the correct state */
-	vdso32_pagelist = kcalloc(vdso32_pages + 1, sizeof(struct page *),
-				  GFP_KERNEL);
-	BUG_ON(vdso32_pagelist == NULL);
-	for (i = 0; i < vdso32_pages - 1; i++) {
-		struct page *pg = virt_to_page(vdso32_kbase + i*PAGE_SIZE);
-		get_page(pg);
-		vdso32_pagelist[i] = pg;
-	}
-	vdso32_pagelist[vdso32_pages - 1] = virt_to_page(vdso_data);
-	vdso32_pagelist[vdso32_pages] = NULL;
-#endif
 
 	/* Calculate the size of the 64 bit vDSO */
 	vdso64_pages = ((&vdso64_end - &vdso64_start

arch/s390/kernel/vdso32/.gitignore

@@ -1 +0,0 @@
-vdso32.lds

arch/s390/kernel/vdso32/Makefile

@@ -1,66 +0,0 @@
-# SPDX-License-Identifier: GPL-2.0
-# List of files in the vdso, has to be asm only for now
-
-KCOV_INSTRUMENT := n
-
-obj-vdso32 = gettimeofday.o clock_getres.o clock_gettime.o note.o getcpu.o
-
-# Build rules
-
-targets := $(obj-vdso32) vdso32.so vdso32.so.dbg
-obj-vdso32 := $(addprefix $(obj)/, $(obj-vdso32))
-
-KBUILD_AFLAGS += -DBUILD_VDSO
-KBUILD_CFLAGS += -DBUILD_VDSO
-
-KBUILD_AFLAGS_31 := $(filter-out -m64,$(KBUILD_AFLAGS))
-KBUILD_AFLAGS_31 += -m31 -s
-
-KBUILD_CFLAGS_31 := $(filter-out -m64,$(KBUILD_CFLAGS))
-KBUILD_CFLAGS_31 += -m31 -fPIC -shared -fno-common -fno-builtin
-KBUILD_CFLAGS_31 += -nostdlib -Wl,-soname=linux-vdso32.so.1 \
-		    -Wl,--hash-style=both
-
-$(targets:%=$(obj)/%.dbg): KBUILD_CFLAGS = $(KBUILD_CFLAGS_31)
-$(targets:%=$(obj)/%.dbg): KBUILD_AFLAGS = $(KBUILD_AFLAGS_31)
-
-obj-y += vdso32_wrapper.o
-extra-y += vdso32.lds
-CPPFLAGS_vdso32.lds += -P -C -U$(ARCH)
-
-# Disable gcov profiling, ubsan and kasan for VDSO code
-GCOV_PROFILE := n
-UBSAN_SANITIZE := n
-KASAN_SANITIZE := n
-
-# Force dependency (incbin is bad)
-$(obj)/vdso32_wrapper.o : $(obj)/vdso32.so
-
-# link rule for the .so file, .lds has to be first
-$(obj)/vdso32.so.dbg: $(src)/vdso32.lds $(obj-vdso32) FORCE
-	$(call if_changed,vdso32ld)
-
-# strip rule for the .so file
-$(obj)/%.so: OBJCOPYFLAGS := -S
-$(obj)/%.so: $(obj)/%.so.dbg FORCE
-	$(call if_changed,objcopy)
-
-# assembly rules for the .S files
-$(obj-vdso32): %.o: %.S FORCE
-	$(call if_changed_dep,vdso32as)
-
-# actual build commands
-quiet_cmd_vdso32ld = VDSO32L $@
-      cmd_vdso32ld = $(CC) $(c_flags) -Wl,-T $(filter %.lds %.o,$^) -o $@
-quiet_cmd_vdso32as = VDSO32A $@
-      cmd_vdso32as = $(CC) $(a_flags) -c -o $@ $<
-
-# install commands for the unstripped file
-quiet_cmd_vdso_install = INSTALL $@
-      cmd_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/vdso/$@
-
-vdso32.so: $(obj)/vdso32.so.dbg
-	@mkdir -p $(MODLIB)/vdso
-	$(call cmd,vdso_install)
-
-vdso_install: vdso32.so

arch/s390/kernel/vdso32/clock_getres.S

@@ -1,44 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * Userland implementation of clock_getres() for 32 bits processes in a
- * s390 kernel for use in the vDSO
- *
- *  Copyright IBM Corp. 2008
- *  Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
- */
-#include <asm/vdso.h>
-#include <asm/asm-offsets.h>
-#include <asm/unistd.h>
-#include <asm/dwarf.h>
-
-	.text
-	.align 4
-	.globl __kernel_clock_getres
-	.type  __kernel_clock_getres,@function
-__kernel_clock_getres:
-	CFI_STARTPROC
-	basr	%r1,0
-	la	%r1,4f-.(%r1)
-	chi	%r2,__CLOCK_REALTIME
-	je	0f
-	chi	%r2,__CLOCK_MONOTONIC
-	je	0f
-	la	%r1,5f-4f(%r1)
-	chi	%r2,__CLOCK_REALTIME_COARSE
-	je	0f
-	chi	%r2,__CLOCK_MONOTONIC_COARSE
-	jne	3f
-0:	ltr	%r3,%r3
-	jz	2f				/* res == NULL */
-1:	l	%r0,0(%r1)
-	xc	0(4,%r3),0(%r3)			/* set tp->tv_sec to zero */
-	st	%r0,4(%r3)			/* store tp->tv_usec */
-2:	lhi	%r2,0
-	br	%r14
-3:	lhi	%r1,__NR_clock_getres		/* fallback to svc */
-	svc	0
-	br	%r14
-	CFI_ENDPROC
-4:	.long	__CLOCK_REALTIME_RES
-5:	.long	__CLOCK_COARSE_RES
-	.size	__kernel_clock_getres,.-__kernel_clock_getres

arch/s390/kernel/vdso32/clock_gettime.S

@@ -1,179 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * Userland implementation of clock_gettime() for 32 bits processes in a
- * s390 kernel for use in the vDSO
- *
- *  Copyright IBM Corp. 2008
- *  Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
- */
-#include <asm/vdso.h>
-#include <asm/asm-offsets.h>
-#include <asm/unistd.h>
-#include <asm/dwarf.h>
-#include <asm/ptrace.h>
-
-	.text
-	.align 4
-	.globl __kernel_clock_gettime
-	.type  __kernel_clock_gettime,@function
-__kernel_clock_gettime:
-	CFI_STARTPROC
-	ahi	%r15,-16
-	CFI_DEF_CFA_OFFSET STACK_FRAME_OVERHEAD+16
-	CFI_VAL_OFFSET 15, -STACK_FRAME_OVERHEAD
-	basr	%r5,0
-0:	al	%r5,21f-0b(%r5)			/* get &_vdso_data */
-	chi	%r2,__CLOCK_REALTIME_COARSE
-	je	10f
-	chi	%r2,__CLOCK_REALTIME
-	je	11f
-	chi	%r2,__CLOCK_MONOTONIC_COARSE
-	je	9f
-	chi	%r2,__CLOCK_MONOTONIC
-	jne	19f
-
-	/* CLOCK_MONOTONIC */
-1:	l	%r4,__VDSO_UPD_COUNT+4(%r5)	/* load update counter */
-	tml	%r4,0x0001			/* pending update ? loop */
-	jnz	1b
-	stcke	0(%r15)				/* Store TOD clock */
-	lm	%r0,%r1,1(%r15)
-	s	%r0,__VDSO_XTIME_STAMP(%r5)	/* TOD - cycle_last */
-	sl	%r1,__VDSO_XTIME_STAMP+4(%r5)
-	brc	3,2f
-	ahi	%r0,-1
-2:	ms	%r0,__VDSO_TK_MULT(%r5)		/*  * tk->mult */
-	lr	%r2,%r0
-	l	%r0,__VDSO_TK_MULT(%r5)
-	ltr	%r1,%r1
-	mr	%r0,%r0
-	jnm	3f
-	a	%r0,__VDSO_TK_MULT(%r5)
-3:	alr	%r0,%r2
-	al	%r0,__VDSO_WTOM_NSEC(%r5)
-	al	%r1,__VDSO_WTOM_NSEC+4(%r5)
-	brc	12,5f
-	ahi	%r0,1
-5:	l	%r2,__VDSO_TK_SHIFT(%r5)	/* Timekeeper shift */
-	srdl	%r0,0(%r2)			/*  >> tk->shift */
-	l	%r2,__VDSO_WTOM_SEC+4(%r5)
-	cl	%r4,__VDSO_UPD_COUNT+4(%r5)	/* check update counter */
-	jne	1b
-	basr	%r5,0
-6:	ltr	%r0,%r0
-	jnz	7f
-	cl	%r1,20f-6b(%r5)
-	jl	8f
-7:	ahi	%r2,1
-	sl	%r1,20f-6b(%r5)
-	brc	3,6b
-	ahi	%r0,-1
-	j	6b
-8:	st	%r2,0(%r3)			/* store tp->tv_sec */
-	st	%r1,4(%r3)			/* store tp->tv_nsec */
-	lhi	%r2,0
-	ahi	%r15,16
-	CFI_DEF_CFA_OFFSET STACK_FRAME_OVERHEAD
-	CFI_RESTORE 15
-	br	%r14
-
-	/* CLOCK_MONOTONIC_COARSE */
-	CFI_DEF_CFA_OFFSET STACK_FRAME_OVERHEAD+16
-	CFI_VAL_OFFSET 15, -STACK_FRAME_OVERHEAD
-9:	l	%r4,__VDSO_UPD_COUNT+4(%r5)	/* load update counter */
-	tml	%r4,0x0001			/* pending update ? loop */
-	jnz	9b
-	l	%r2,__VDSO_WTOM_CRS_SEC+4(%r5)
-	l	%r1,__VDSO_WTOM_CRS_NSEC+4(%r5)
-	cl	%r4,__VDSO_UPD_COUNT+4(%r5)	/* check update counter */
-	jne	9b
-	j	8b
-
-	/* CLOCK_REALTIME_COARSE */
-10:	l	%r4,__VDSO_UPD_COUNT+4(%r5)	/* load update counter */
-	tml	%r4,0x0001			/* pending update ? loop */
-	jnz	10b
-	l	%r2,__VDSO_XTIME_CRS_SEC+4(%r5)
-	l	%r1,__VDSO_XTIME_CRS_NSEC+4(%r5)
-	cl	%r4,__VDSO_UPD_COUNT+4(%r5)	/* check update counter */
-	jne	10b
-	j	17f
-
-	/* CLOCK_REALTIME */
-11:	l	%r4,__VDSO_UPD_COUNT+4(%r5)	/* load update counter */
-	tml	%r4,0x0001			/* pending update ? loop */
-	jnz	11b
-	stcke	0(%r15)				/* Store TOD clock */
-	lm	%r0,%r1,__VDSO_TS_END(%r5)	/* TOD steering end time */
-	s	%r0,1(%r15)			/* no - ts_steering_end */
-	sl	%r1,5(%r15)
-	brc	3,22f
-	ahi	%r0,-1
-22:	ltr	%r0,%r0				/* past end of steering? */
-	jm	24f
-	srdl	%r0,15				/* 1 per 2^16 */
-	tm	__VDSO_TS_DIR+3(%r5),0x01	/* steering direction? */
-	jz	23f
-	lcr	%r0,%r0				/* negative TOD offset */
-	lcr	%r1,%r1
-	je	23f
-	ahi	%r0,-1
-23:	a	%r0,1(%r15)			/* add TOD timestamp */
-	al	%r1,5(%r15)
-	brc	12,25f
-	ahi	%r0,1
-	j	25f
-24:	lm	%r0,%r1,1(%r15)			/* load TOD timestamp */
-25:	s	%r0,__VDSO_XTIME_STAMP(%r5)	/* TOD - cycle_last */
-	sl	%r1,__VDSO_XTIME_STAMP+4(%r5)
-	brc	3,12f
-	ahi	%r0,-1
-12:	ms	%r0,__VDSO_TK_MULT(%r5)		/*  * tk->mult */
-	lr	%r2,%r0
-	l	%r0,__VDSO_TK_MULT(%r5)
-	ltr	%r1,%r1
-	mr	%r0,%r0
-	jnm	13f
-	a	%r0,__VDSO_TK_MULT(%r5)
-13:	alr	%r0,%r2
-	al	%r0,__VDSO_XTIME_NSEC(%r5)	/*  + tk->xtime_nsec */
-	al	%r1,__VDSO_XTIME_NSEC+4(%r5)
-	brc	12,14f
-	ahi	%r0,1
-14:	l	%r2,__VDSO_TK_SHIFT(%r5)	/* Timekeeper shift */
-	srdl	%r0,0(%r2)			/*  >> tk->shift */
-	l	%r2,__VDSO_XTIME_SEC+4(%r5)
-	cl	%r4,__VDSO_UPD_COUNT+4(%r5)	/* check update counter */
-	jne	11b
-	basr	%r5,0
-15:	ltr	%r0,%r0
-	jnz	16f
-	cl	%r1,20f-15b(%r5)
-	jl	17f
-16:	ahi	%r2,1
-	sl	%r1,20f-15b(%r5)
-	brc	3,15b
-	ahi	%r0,-1
-	j	15b
-17:	st	%r2,0(%r3)			/* store tp->tv_sec */
-	st	%r1,4(%r3)			/* store tp->tv_nsec */
-	lhi	%r2,0
-	ahi	%r15,16
-	CFI_DEF_CFA_OFFSET STACK_FRAME_OVERHEAD
-	CFI_RESTORE 15
-	br	%r14
-
-	/* Fallback to system call */
-	CFI_DEF_CFA_OFFSET STACK_FRAME_OVERHEAD+16
-	CFI_VAL_OFFSET 15, -STACK_FRAME_OVERHEAD
-19:	lhi	%r1,__NR_clock_gettime
-	svc	0
-	ahi	%r15,16
-	CFI_DEF_CFA_OFFSET STACK_FRAME_OVERHEAD
-	CFI_RESTORE 15
-	br	%r14
-	CFI_ENDPROC
-
-20:	.long	1000000000
-21:	.long	_vdso_data - 0b
-	.size	__kernel_clock_gettime,.-__kernel_clock_gettime

arch/s390/kernel/vdso32/getcpu.S

@@ -1,33 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * Userland implementation of getcpu() for 32 bits processes in a
- * s390 kernel for use in the vDSO
- *
- *  Copyright IBM Corp. 2016
- *  Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
- */
-#include <asm/vdso.h>
-#include <asm/asm-offsets.h>
-#include <asm/dwarf.h>
-
-	.text
-	.align 4
-	.globl __kernel_getcpu
-	.type  __kernel_getcpu,@function
-__kernel_getcpu:
-	CFI_STARTPROC
-	la	%r4,0
-	sacf	256
-	l	%r5,__VDSO_CPU_NR(%r4)
-	l	%r4,__VDSO_NODE_ID(%r4)
-	sacf	0
-	ltr	%r2,%r2
-	jz	2f
-	st	%r5,0(%r2)
-2:	ltr	%r3,%r3
-	jz	3f
-	st	%r4,0(%r3)
-3:	lhi	%r2,0
-	br	%r14
-	CFI_ENDPROC
-	.size	__kernel_getcpu,.-__kernel_getcpu

arch/s390/kernel/vdso32/gettimeofday.S

@@ -1,103 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * Userland implementation of gettimeofday() for 32 bits processes in a
- * s390 kernel for use in the vDSO
- *
- *  Copyright IBM Corp. 2008
- *  Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
- */
-#include <asm/vdso.h>
-#include <asm/asm-offsets.h>
-#include <asm/unistd.h>
-#include <asm/dwarf.h>
-#include <asm/ptrace.h>
-
-	.text
-	.align 4
-	.globl __kernel_gettimeofday
-	.type  __kernel_gettimeofday,@function
-__kernel_gettimeofday:
-	CFI_STARTPROC
-	ahi	%r15,-16
-	CFI_ADJUST_CFA_OFFSET 16
-	CFI_VAL_OFFSET 15, -STACK_FRAME_OVERHEAD
-	basr	%r5,0
-0:	al	%r5,13f-0b(%r5)			/* get &_vdso_data */
-1:	ltr	%r3,%r3				/* check if tz is NULL */
-	je	2f
-	mvc	0(8,%r3),__VDSO_TIMEZONE(%r5)
-2:	ltr	%r2,%r2				/* check if tv is NULL */
-	je	10f
-	l	%r4,__VDSO_UPD_COUNT+4(%r5)	/* load update counter */
-	tml	%r4,0x0001			/* pending update ? loop */
-	jnz	1b
-	stcke	0(%r15)				/* Store TOD clock */
-	lm	%r0,%r1,__VDSO_TS_END(%r5)	/* TOD steering end time */
-	s	%r0,1(%r15)
-	sl	%r1,5(%r15)
-	brc	3,14f
-	ahi	%r0,-1
-14:	ltr	%r0,%r0				/* past end of steering? */
-	jm	16f
-	srdl	%r0,15				/* 1 per 2^16 */
-	tm	__VDSO_TS_DIR+3(%r5),0x01	/* steering direction? */
-	jz	15f
-	lcr	%r0,%r0				/* negative TOD offset */
-	lcr	%r1,%r1
-	je	15f
-	ahi	%r0,-1
-15:	a	%r0,1(%r15)			/* add TOD timestamp */
-	al	%r1,5(%r15)
-	brc	12,17f
-	ahi	%r0,1
-	j	17f
-16:	lm	%r0,%r1,1(%r15)			/* load TOD timestamp */
-17:	s	%r0,__VDSO_XTIME_STAMP(%r5)	/* TOD - cycle_last */
-	sl	%r1,__VDSO_XTIME_STAMP+4(%r5)
-	brc	3,3f
-	ahi	%r0,-1
-3:	ms	%r0,__VDSO_TK_MULT(%r5)		/*  * tk->mult */
-	st	%r0,0(%r15)
-	l	%r0,__VDSO_TK_MULT(%r5)
-	ltr	%r1,%r1
-	mr	%r0,%r0
-	jnm	4f
-	a	%r0,__VDSO_TK_MULT(%r5)
-4:	al	%r0,0(%r15)
-	al	%r0,__VDSO_XTIME_NSEC(%r5)	/*  + xtime */
-	al	%r1,__VDSO_XTIME_NSEC+4(%r5)
-	brc	12,5f
-	ahi	%r0,1
-5:	mvc	0(4,%r15),__VDSO_XTIME_SEC+4(%r5)
-	cl	%r4,__VDSO_UPD_COUNT+4(%r5)	/* check update counter */
-	jne	1b
-	l	%r4,__VDSO_TK_SHIFT(%r5)	/* Timekeeper shift */
-	srdl	%r0,0(%r4)			/*  >> tk->shift */
-	l	%r4,0(%r15)			/* get tv_sec from stack */
-	basr	%r5,0
-6:	ltr	%r0,%r0
-	jnz	7f
-	cl	%r1,11f-6b(%r5)
-	jl	8f
-7:	ahi	%r4,1
-	sl	%r1,11f-6b(%r5)
-	brc	3,6b
-	ahi	%r0,-1
-	j	6b
-8:	st	%r4,0(%r2)			/* store tv->tv_sec */
-	ltr	%r1,%r1
-	m	%r0,12f-6b(%r5)
-	jnm	9f
-	al	%r0,12f-6b(%r5)
-9:	srl	%r0,6
-	st	%r0,4(%r2)			/* store tv->tv_usec */
-10:	slr	%r2,%r2
-	ahi	%r15,16
-	CFI_ADJUST_CFA_OFFSET -16
-	CFI_RESTORE 15
-	br	%r14
-	CFI_ENDPROC
-11:	.long	1000000000
-12:	.long	274877907
-13:	.long	_vdso_data - 0b
-	.size	__kernel_gettimeofday,.-__kernel_gettimeofday

arch/s390/kernel/vdso32/note.S

@@ -1,13 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * This supplies .note.* sections to go into the PT_NOTE inside the vDSO text.
- * Here we can supply some information useful to userland.
- */
-
-#include <linux/uts.h>
-#include <linux/version.h>
-#include <linux/elfnote.h>
-
-ELFNOTE_START(Linux, 0, "a")
-	.long LINUX_VERSION_CODE
-ELFNOTE_END

arch/s390/kernel/vdso32/vdso32.lds.S

@@ -1,142 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * This is the infamous ld script for the 32 bits vdso
- * library
- */
-
-#include <asm/page.h>
-#include <asm/vdso.h>
-
-OUTPUT_FORMAT("elf32-s390", "elf32-s390", "elf32-s390")
-OUTPUT_ARCH(s390:31-bit)
-ENTRY(_start)
-
-SECTIONS
-{
-	. = VDSO32_LBASE + SIZEOF_HEADERS;
-
-	.hash		: { *(.hash) }			:text
-	.gnu.hash	: { *(.gnu.hash) }
-	.dynsym		: { *(.dynsym) }
-	.dynstr		: { *(.dynstr) }
-	.gnu.version	: { *(.gnu.version) }
-	.gnu.version_d	: { *(.gnu.version_d) }
-	.gnu.version_r	: { *(.gnu.version_r) }
-
-	.note		: { *(.note.*) }		:text	:note
-
-	. = ALIGN(16);
-	.text		: {
-		*(.text .stub .text.* .gnu.linkonce.t.*)
-	} :text
-	PROVIDE(__etext = .);
-	PROVIDE(_etext = .);
-	PROVIDE(etext = .);
-
-	/*
-	 * Other stuff is appended to the text segment:
-	 */
-	.rodata		: { *(.rodata .rodata.* .gnu.linkonce.r.*) }
-	.rodata1	: { *(.rodata1) }
-
-	.dynamic	: { *(.dynamic) }		:text	:dynamic
-
-	.eh_frame_hdr	: { *(.eh_frame_hdr) }		:text	:eh_frame_hdr
-	.eh_frame	: { KEEP (*(.eh_frame)) }	:text
-	.gcc_except_table : { *(.gcc_except_table .gcc_except_table.*) }
-
-	.rela.dyn ALIGN(8) : { *(.rela.dyn) }
-	.got ALIGN(8)	: { *(.got .toc) }
-
-	_end = .;
-	PROVIDE(end = .);
-
-	/*
-	 * Stabs debugging sections are here too.
-	 */
-	.stab	       0 : { *(.stab) }
-	.stabstr       0 : { *(.stabstr) }
-	.stab.excl     0 : { *(.stab.excl) }
-	.stab.exclstr  0 : { *(.stab.exclstr) }
-	.stab.index    0 : { *(.stab.index) }
-	.stab.indexstr 0 : { *(.stab.indexstr) }
-	.comment       0 : { *(.comment) }
-
-	/*
-	 * DWARF debug sections.
-	 * Symbols in the DWARF debugging sections are relative to the
-	 * beginning of the section so we begin them at 0.
-	 */
-	/* DWARF 1 */
-	.debug		0 : { *(.debug) }
-	.line		0 : { *(.line) }
-	/* GNU DWARF 1 extensions */
-	.debug_srcinfo	0 : { *(.debug_srcinfo) }
-	.debug_sfnames	0 : { *(.debug_sfnames) }
-	/* DWARF 1.1 and DWARF 2 */
-	.debug_aranges	0 : { *(.debug_aranges) }
-	.debug_pubnames 0 : { *(.debug_pubnames) }
-	/* DWARF 2 */
-	.debug_info	0 : { *(.debug_info .gnu.linkonce.wi.*) }
-	.debug_abbrev	0 : { *(.debug_abbrev) }
-	.debug_line	0 : { *(.debug_line) }
-	.debug_frame	0 : { *(.debug_frame) }
-	.debug_str	0 : { *(.debug_str) }
-	.debug_loc	0 : { *(.debug_loc) }
-	.debug_macinfo	0 : { *(.debug_macinfo) }
-	/* SGI/MIPS DWARF 2 extensions */
-	.debug_weaknames 0 : { *(.debug_weaknames) }
-	.debug_funcnames 0 : { *(.debug_funcnames) }
-	.debug_typenames 0 : { *(.debug_typenames) }
-	.debug_varnames  0 : { *(.debug_varnames) }
-	/* DWARF 3 */
-	.debug_pubtypes 0 : { *(.debug_pubtypes) }
-	.debug_ranges	0 : { *(.debug_ranges) }
-	.gnu.attributes 0 : { KEEP (*(.gnu.attributes)) }
-
-	. = ALIGN(PAGE_SIZE);
-	PROVIDE(_vdso_data = .);
-
-	/DISCARD/	: {
-		*(.note.GNU-stack)
-		*(.branch_lt)
-		*(.data .data.* .gnu.linkonce.d.* .sdata*)
-		*(.bss .sbss .dynbss .dynsbss)
-	}
-}
-
-/*
- * Very old versions of ld do not recognize this name token; use the constant.
- */
-#define PT_GNU_EH_FRAME	0x6474e550
-
-/*
- * We must supply the ELF program headers explicitly to get just one
- * PT_LOAD segment, and set the flags explicitly to make segments read-only.
- */
-PHDRS
-{
-	text		PT_LOAD FILEHDR PHDRS FLAGS(5);	/* PF_R|PF_X */
-	dynamic		PT_DYNAMIC FLAGS(4);		/* PF_R */
-	note		PT_NOTE FLAGS(4);		/* PF_R */
-	eh_frame_hdr	PT_GNU_EH_FRAME;
-}
-
-/*
- * This controls what symbols we export from the DSO.
- */
-VERSION
-{
-	VDSO_VERSION_STRING {
-	global:
-		/*
-		 * Has to be there for the kernel to find
-		 */
-		__kernel_gettimeofday;
-		__kernel_clock_gettime;
-		__kernel_clock_getres;
-		__kernel_getcpu;
-
-	local: *;
-	};
-}

arch/s390/kernel/vdso32/vdso32_wrapper.S

@@ -1,15 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#include <linux/init.h>
-#include <linux/linkage.h>
-#include <asm/page.h>
-
-	__PAGE_ALIGNED_DATA
-
-	.globl vdso32_start, vdso32_end
-	.balign PAGE_SIZE
-vdso32_start:
-	.incbin "arch/s390/kernel/vdso32/vdso32.so"
-	.balign PAGE_SIZE
-vdso32_end:
-
-	.previous

arch/s390/kernel/vdso64/getcpu.S

@@ -16,10 +16,8 @@
 	.type  __kernel_getcpu,@function
 __kernel_getcpu:
 	CFI_STARTPROC
-	la	%r4,0
 	sacf	256
-	l	%r5,__VDSO_CPU_NR(%r4)
+	lm	%r4,%r5,__VDSO_GETCPU_VAL(%r0)
-	l	%r4,__VDSO_NODE_ID(%r4)
 	sacf	0
 	ltgr	%r2,%r2
 	jz	2f

arch/s390/lib/Makefile

@@ -11,3 +11,6 @@ lib-$(CONFIG_UPROBES) += probes.o
 # Instrumenting memory accesses to __user data (in different address space)
 # produce false positives
 KASAN_SANITIZE_uaccess.o := n
+
+obj-$(CONFIG_S390_UNWIND_SELFTEST) += test_unwind.o
+CFLAGS_test_unwind.o += -fno-optimize-sibling-calls

arch/s390/lib/test_unwind.c

@@ -0,0 +1,347 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Test module for unwind_for_each_frame
+ */
+
+#define pr_fmt(fmt) "test_unwind: " fmt
+#include <asm/unwind.h>
+#include <linux/completion.h>
+#include <linux/kallsyms.h>
+#include <linux/kthread.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/kprobes.h>
+#include <linux/wait.h>
+#include <asm/irq.h>
+#include <asm/delay.h>
+
+#define BT_BUF_SIZE (PAGE_SIZE * 4)
+
+/*
+ * To avoid printk line limit split backtrace by lines
+ */
+static void print_backtrace(char *bt)
+{
+	char *p;
+
+	while (true) {
+		p = strsep(&bt, "\n");
+		if (!p)
+			break;
+		pr_err("%s\n", p);
+	}
+}
+
+/*
+ * Calls unwind_for_each_frame(task, regs, sp) and verifies that the result
+ * contains unwindme_func2 followed by unwindme_func1.
+ */
+static noinline int test_unwind(struct task_struct *task, struct pt_regs *regs,
+				unsigned long sp)
+{
+	int frame_count, prev_is_func2, seen_func2_func1;
+	const int max_frames = 128;
+	struct unwind_state state;
+	size_t bt_pos = 0;
+	int ret = 0;
+	char *bt;
+
+	bt = kmalloc(BT_BUF_SIZE, GFP_ATOMIC);
+	if (!bt) {
+		pr_err("failed to allocate backtrace buffer\n");
+		return -ENOMEM;
+	}
+	/* Unwind. */
+	frame_count = 0;
+	prev_is_func2 = 0;
+	seen_func2_func1 = 0;
+	unwind_for_each_frame(&state, task, regs, sp) {
+		unsigned long addr = unwind_get_return_address(&state);
+		char sym[KSYM_SYMBOL_LEN];
+
+		if (frame_count++ == max_frames)
+			break;
+		if (state.reliable && !addr) {
+			pr_err("unwind state reliable but addr is 0\n");
+			return -EINVAL;
+		}
+		sprint_symbol(sym, addr);
+		if (bt_pos < BT_BUF_SIZE) {
+			bt_pos += snprintf(bt + bt_pos, BT_BUF_SIZE - bt_pos,
+					   state.reliable ? " [%-7s%px] %pSR\n" :
+							    "([%-7s%px] %pSR)\n",
+					   stack_type_name(state.stack_info.type),
+					   (void *)state.sp, (void *)state.ip);
+			if (bt_pos >= BT_BUF_SIZE)
+				pr_err("backtrace buffer is too small\n");
+		}
+		frame_count += 1;
+		if (prev_is_func2 && str_has_prefix(sym, "unwindme_func1"))
+			seen_func2_func1 = 1;
+		prev_is_func2 = str_has_prefix(sym, "unwindme_func2");
+	}
+
+	/* Check the results. */
+	if (unwind_error(&state)) {
+		pr_err("unwind error\n");
+		ret = -EINVAL;
+	}
+	if (!seen_func2_func1) {
+		pr_err("unwindme_func2 and unwindme_func1 not found\n");
+		ret = -EINVAL;
+	}
+	if (frame_count == max_frames) {
+		pr_err("Maximum number of frames exceeded\n");
+		ret = -EINVAL;
+	}
+	if (ret)
+		print_backtrace(bt);
+	kfree(bt);
+	return ret;
+}
+
+/* State of the task being unwound. */
+struct unwindme {
+	int flags;
+	int ret;
+	struct task_struct *task;
+	struct completion task_ready;
+	wait_queue_head_t task_wq;
+	unsigned long sp;
+};
+
+static struct unwindme *unwindme;
+
+/* Values of unwindme.flags. */
+#define UWM_DEFAULT		0x0
+#define UWM_THREAD		0x1	/* Unwind a separate task. */
+#define UWM_REGS		0x2	/* Pass regs to test_unwind(). */
+#define UWM_SP			0x4	/* Pass sp to test_unwind(). */
+#define UWM_CALLER		0x8	/* Unwind starting from caller. */
+#define UWM_SWITCH_STACK	0x10	/* Use CALL_ON_STACK. */
+#define UWM_IRQ			0x20	/* Unwind from irq context. */
+#define UWM_PGM			0x40	/* Unwind from program check handler. */
+
+static __always_inline unsigned long get_psw_addr(void)
+{
+	unsigned long psw_addr;
+
+	asm volatile(
+		"basr	%[psw_addr],0\n"
+		: [psw_addr] "=d" (psw_addr));
+	return psw_addr;
+}
+
+#ifdef CONFIG_KPROBES
+static int pgm_pre_handler(struct kprobe *p, struct pt_regs *regs)
+{
+	struct unwindme *u = unwindme;
+
+	u->ret = test_unwind(NULL, (u->flags & UWM_REGS) ? regs : NULL,
+			     (u->flags & UWM_SP) ? u->sp : 0);
+	return 0;
+}
+#endif
+
+/* This function may or may not appear in the backtrace. */
+static noinline int unwindme_func4(struct unwindme *u)
+{
+	if (!(u->flags & UWM_CALLER))
+		u->sp = current_frame_address();
+	if (u->flags & UWM_THREAD) {
+		complete(&u->task_ready);
+		wait_event(u->task_wq, kthread_should_park());
+		kthread_parkme();
+		return 0;
+#ifdef CONFIG_KPROBES
+	} else if (u->flags & UWM_PGM) {
+		struct kprobe kp;
+		int ret;
+
+		unwindme = u;
+		memset(&kp, 0, sizeof(kp));
+		kp.symbol_name = "do_report_trap";
+		kp.pre_handler = pgm_pre_handler;
+		ret = register_kprobe(&kp);
+		if (ret < 0) {
+			pr_err("register_kprobe failed %d\n", ret);
+			return -EINVAL;
+		}
+
+		/*
+		 * trigger specification exception
+		 */
+		asm volatile(
+			"	mvcl	%%r1,%%r1\n"
+			"0:	nopr	%%r7\n"
+			EX_TABLE(0b, 0b)
+			:);
+
+		unregister_kprobe(&kp);
+		unwindme = NULL;
+		return u->ret;
+#endif
+	} else {
+		struct pt_regs regs;
+
+		memset(&regs, 0, sizeof(regs));
+		regs.psw.addr = get_psw_addr();
+		regs.gprs[15] = current_stack_pointer();
+		return test_unwind(NULL,
+				   (u->flags & UWM_REGS) ? &regs : NULL,
+				   (u->flags & UWM_SP) ? u->sp : 0);
+	}
+}
+
+/* This function may or may not appear in the backtrace. */
+static noinline int unwindme_func3(struct unwindme *u)
+{
+	u->sp = current_frame_address();
+	return unwindme_func4(u);
+}
+
+/* This function must appear in the backtrace. */
+static noinline int unwindme_func2(struct unwindme *u)
+{
+	int rc;
+
+	if (u->flags & UWM_SWITCH_STACK) {
+		preempt_disable();
+		rc = CALL_ON_STACK(unwindme_func3, S390_lowcore.nodat_stack, 1, u);
+		preempt_enable();
+		return rc;
+	} else {
+		return unwindme_func3(u);
+	}
+}
+
+/* This function must follow unwindme_func2 in the backtrace. */
+static noinline int unwindme_func1(void *u)
+{
+	return unwindme_func2((struct unwindme *)u);
+}
+
+static void unwindme_irq_handler(struct ext_code ext_code,
+				       unsigned int param32,
+				       unsigned long param64)
+{
+	struct unwindme *u = READ_ONCE(unwindme);
+
+	if (u && u->task == current) {
+		unwindme = NULL;
+		u->task = NULL;
+		u->ret = unwindme_func1(u);
+	}
+}
+
+static int test_unwind_irq(struct unwindme *u)
+{
+	preempt_disable();
+	if (register_external_irq(EXT_IRQ_CLK_COMP, unwindme_irq_handler)) {
+		pr_info("Couldn't reqister external interrupt handler");
+		return -1;
+	}
+	u->task = current;
+	unwindme = u;
+	udelay(1);
+	unregister_external_irq(EXT_IRQ_CLK_COMP, unwindme_irq_handler);
+	preempt_enable();
+	return u->ret;
+}
+
+/* Spawns a task and passes it to test_unwind(). */
+static int test_unwind_task(struct unwindme *u)
+{
+	struct task_struct *task;
+	int ret;
+
+	/* Initialize thread-related fields. */
+	init_completion(&u->task_ready);
+	init_waitqueue_head(&u->task_wq);
+
+	/*
+	 * Start the task and wait until it reaches unwindme_func4() and sleeps
+	 * in (task_ready, unwind_done] range.
+	 */
+	task = kthread_run(unwindme_func1, u, "%s", __func__);
+	if (IS_ERR(task)) {
+		pr_err("kthread_run() failed\n");
+		return PTR_ERR(task);
+	}
+	/*
+	 * Make sure task reaches unwindme_func4 before parking it,
+	 * we might park it before kthread function has been executed otherwise
+	 */
+	wait_for_completion(&u->task_ready);
+	kthread_park(task);
+	/* Unwind. */
+	ret = test_unwind(task, NULL, (u->flags & UWM_SP) ? u->sp : 0);
+	kthread_stop(task);
+	return ret;
+}
+
+static int test_unwind_flags(int flags)
+{
+	struct unwindme u;
+
+	u.flags = flags;
+	if (u.flags & UWM_THREAD)
+		return test_unwind_task(&u);
+	else if (u.flags & UWM_IRQ)
+		return test_unwind_irq(&u);
+	else
+		return unwindme_func1(&u);
+}
+
+static int test_unwind_init(void)
+{
+	int ret = 0;
+
+#define TEST(flags)							\
+do {									\
+	pr_info("[ RUN      ] " #flags "\n");				\
+	if (!test_unwind_flags((flags))) {				\
+		pr_info("[       OK ] " #flags "\n");			\
+	} else {							\
+		pr_err("[  FAILED  ] " #flags "\n");			\
+		ret = -EINVAL;						\
+	}								\
+} while (0)
+
+	TEST(UWM_DEFAULT);
+	TEST(UWM_SP);
+	TEST(UWM_REGS);
+	TEST(UWM_SWITCH_STACK);
+	TEST(UWM_SP | UWM_REGS);
+	TEST(UWM_CALLER | UWM_SP);
+	TEST(UWM_CALLER | UWM_SP | UWM_REGS);
+	TEST(UWM_CALLER | UWM_SP | UWM_REGS | UWM_SWITCH_STACK);
+	TEST(UWM_THREAD);
+	TEST(UWM_THREAD | UWM_SP);
+	TEST(UWM_THREAD | UWM_CALLER | UWM_SP);
+	TEST(UWM_IRQ);
+	TEST(UWM_IRQ | UWM_SWITCH_STACK);
+	TEST(UWM_IRQ | UWM_SP);
+	TEST(UWM_IRQ | UWM_REGS);
+	TEST(UWM_IRQ | UWM_SP | UWM_REGS);
+	TEST(UWM_IRQ | UWM_CALLER | UWM_SP);
+	TEST(UWM_IRQ | UWM_CALLER | UWM_SP | UWM_REGS);
+	TEST(UWM_IRQ | UWM_CALLER | UWM_SP | UWM_REGS | UWM_SWITCH_STACK);
+#ifdef CONFIG_KPROBES
+	TEST(UWM_PGM);
+	TEST(UWM_PGM | UWM_SP);
+	TEST(UWM_PGM | UWM_REGS);
+	TEST(UWM_PGM | UWM_SP | UWM_REGS);
+#endif
+#undef TEST
+
+	return ret;
+}
+
+static void test_unwind_exit(void)
+{
+}
+
+module_init(test_unwind_init);
+module_exit(test_unwind_exit);
+MODULE_LICENSE("GPL");

arch/s390/mm/maccess.c

@@ -119,9 +119,15 @@ static unsigned long __no_sanitize_address _memcpy_real(unsigned long dest,
  */
 int memcpy_real(void *dest, void *src, size_t count)
 {
-	if (S390_lowcore.nodat_stack != 0)
+	int rc;
-		return CALL_ON_STACK(_memcpy_real, S390_lowcore.nodat_stack,
+
-				     3, dest, src, count);
+	if (S390_lowcore.nodat_stack != 0) {
+		preempt_disable();
+		rc = CALL_ON_STACK(_memcpy_real, S390_lowcore.nodat_stack, 3,
+				   dest, src, count);
+		preempt_enable();
+		return rc;
+	}
 	/*
 	 * This is a really early memcpy_real call, the stacks are
 	 * not set up yet. Just call _memcpy_real on the early boot

arch/s390/pci/pci.c

@@ -27,6 +27,7 @@
 #include <linux/seq_file.h>
 #include <linux/jump_label.h>
 #include <linux/pci.h>
+#include <linux/printk.h>
 
 #include <asm/isc.h>
 #include <asm/airq.h>
@@ -659,6 +660,8 @@ static int zpci_alloc_domain(struct zpci_dev *zdev)
 		spin_lock(&zpci_domain_lock);
 		if (test_bit(zdev->domain, zpci_domain)) {
 			spin_unlock(&zpci_domain_lock);
+			pr_err("Adding PCI function %08x failed because domain %04x is already assigned\n",
+				zdev->fid, zdev->domain);
 			return -EEXIST;
 		}
 		set_bit(zdev->domain, zpci_domain);
@@ -670,6 +673,8 @@ static int zpci_alloc_domain(struct zpci_dev *zdev)
 	zdev->domain = find_first_zero_bit(zpci_domain, ZPCI_NR_DEVICES);
 	if (zdev->domain == ZPCI_NR_DEVICES) {
 		spin_unlock(&zpci_domain_lock);
+		pr_err("Adding PCI function %08x failed because the configured limit of %d is reached\n",
+			zdev->fid, ZPCI_NR_DEVICES);
 		return -ENOSPC;
 	}
 	set_bit(zdev->domain, zpci_domain);

drivers/s390/crypto/zcrypt_error.h

@@ -61,6 +61,7 @@ struct error_hdr {
 #define REP82_ERROR_EVEN_MOD_IN_OPND	    0x85
 #define REP82_ERROR_RESERVED_FIELD	    0x88
 #define REP82_ERROR_INVALID_DOMAIN_PENDING  0x8A
+#define REP82_ERROR_FILTERED_BY_HYPERVISOR  0x8B
 #define REP82_ERROR_TRANSPORT_FAIL	    0x90
 #define REP82_ERROR_PACKET_TRUNCATED	    0xA0
 #define REP82_ERROR_ZERO_BUFFER_LEN	    0xB0
@@ -91,6 +92,7 @@ static inline int convert_error(struct zcrypt_queue *zq,
 	case REP82_ERROR_INVALID_DOMAIN_PRECHECK:
 	case REP82_ERROR_INVALID_DOMAIN_PENDING:
 	case REP82_ERROR_INVALID_SPECIAL_CMD:
+	case REP82_ERROR_FILTERED_BY_HYPERVISOR:
 	//   REP88_ERROR_INVALID_KEY		// '82' CEX2A
 	//   REP88_ERROR_OPERAND		// '84' CEX2A
 	//   REP88_ERROR_OPERAND_EVEN_MOD	// '85' CEX2A