Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull s390 updates from Martin Schwidefsky:
 "The most notable change for this pull request is the ftrace rework
  from Heiko.  It brings a small performance improvement and the ground
  work to support a new gcc option to replace the mcount blocks with a
  single nop.

  Two new s390 specific system calls are added to emulate user space
  mmio for PCI, an artifact of the how PCI memory is accessed.

  Two patches for the memory management with changes to common code.
  For KVM mm_forbids_zeropage is added which disables the empty zero
  page for an mm that is used by a KVM process.  And an optimization,
  pmdp_get_and_clear_full is added analog to ptep_get_and_clear_full.

  Some micro optimization for the cmpxchg and the spinlock code.

  And as usual bug fixes and cleanups"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (46 commits)
  s390/cputime: fix 31-bit compile
  s390/scm_block: make the number of reqs per HW req configurable
  s390/scm_block: handle multiple requests in one HW request
  s390/scm_block: allocate aidaw pages only when necessary
  s390/scm_block: use mempool to manage aidaw requests
  s390/eadm: change timeout value
  s390/mm: fix memory leak of ptlock in pmd_free_tlb
  s390: use local symbol names in entry[64].S
  s390/ptrace: always include vector registers in core files
  s390/simd: clear vector register pointer on fork/clone
  s390: translate cputime magic constants to macros
  s390/idle: convert open coded idle time seqcount
  s390/idle: add missing irq off lockdep annotation
  s390/debug: avoid function call for debug_sprintf_*
  s390/kprobes: fix instruction copy for out of line execution
  s390: remove diag 44 calls from cpu_relax()
  s390/dasd: retry partition detection
  s390/dasd: fix list corruption for sleep_on requests
  s390/dasd: fix infinite term I/O loop
  s390/dasd: remove unused code
  ...

1 files changed, 119 insertions, 59 deletions

diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c
index 014d4729b134..1e4c710dfb92 100644
--- a/arch/s390/kernel/kprobes.c
+++ b/arch/s390/kernel/kprobes.c
@@ -29,6 +29,7 @@
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/hardirq.h>
+#include <linux/ftrace.h>
 #include <asm/cacheflush.h>
 #include <asm/sections.h>
 #include <asm/dis.h>
@@ -58,12 +59,23 @@ struct kprobe_insn_cache kprobe_dmainsn_slots = {
 	.insn_size = MAX_INSN_SIZE,
 };
 
-static void __kprobes copy_instruction(struct kprobe *p)
+static void copy_instruction(struct kprobe *p)
 {
+	unsigned long ip = (unsigned long) p->addr;
 	s64 disp, new_disp;
 	u64 addr, new_addr;
 
-	memcpy(p->ainsn.insn, p->addr, insn_length(p->opcode >> 8));
+	if (ftrace_location(ip) == ip) {
+		/*
+		 * If kprobes patches the instruction that is morphed by
+		 * ftrace make sure that kprobes always sees the branch
+		 * "jg .+24" that skips the mcount block
+		 */
+		ftrace_generate_nop_insn((struct ftrace_insn *)p->ainsn.insn);
+		p->ainsn.is_ftrace_insn = 1;
+	} else
+		memcpy(p->ainsn.insn, p->addr, insn_length(*p->addr >> 8));
+	p->opcode = p->ainsn.insn[0];
 	if (!probe_is_insn_relative_long(p->ainsn.insn))
 		return;
 	/*
@@ -79,25 +91,14 @@ static void __kprobes copy_instruction(struct kprobe *p)
 	new_disp = ((addr + (disp * 2)) - new_addr) / 2;
 	*(s32 *)&p->ainsn.insn[1] = new_disp;
 }
+NOKPROBE_SYMBOL(copy_instruction);
 
 static inline int is_kernel_addr(void *addr)
 {
 	return addr < (void *)_end;
 }
 
-static inline int is_module_addr(void *addr)
-{
-#ifdef CONFIG_64BIT
-	BUILD_BUG_ON(MODULES_LEN > (1UL << 31));
-	if (addr < (void *)MODULES_VADDR)
-		return 0;
-	if (addr > (void *)MODULES_END)
-		return 0;
-#endif
-	return 1;
-}
-
-static int __kprobes s390_get_insn_slot(struct kprobe *p)
+static int s390_get_insn_slot(struct kprobe *p)
 {
 	/*
 	 * Get an insn slot that is within the same 2GB area like the original
@@ -111,8 +112,9 @@ static int __kprobes s390_get_insn_slot(struct kprobe *p)
 		p->ainsn.insn = get_insn_slot();
 	return p->ainsn.insn ? 0 : -ENOMEM;
 }
+NOKPROBE_SYMBOL(s390_get_insn_slot);
 
-static void __kprobes s390_free_insn_slot(struct kprobe *p)
+static void s390_free_insn_slot(struct kprobe *p)
 {
 	if (!p->ainsn.insn)
 		return;
@@ -122,8 +124,9 @@ static void __kprobes s390_free_insn_slot(struct kprobe *p)
 		free_insn_slot(p->ainsn.insn, 0);
 	p->ainsn.insn = NULL;
 }
+NOKPROBE_SYMBOL(s390_free_insn_slot);
 
-int __kprobes arch_prepare_kprobe(struct kprobe *p)
+int arch_prepare_kprobe(struct kprobe *p)
 {
 	if ((unsigned long) p->addr & 0x01)
 		return -EINVAL;
@@ -132,54 +135,79 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
 		return -EINVAL;
 	if (s390_get_insn_slot(p))
 		return -ENOMEM;
-	p->opcode = *p->addr;
 	copy_instruction(p);
 	return 0;
 }
+NOKPROBE_SYMBOL(arch_prepare_kprobe);
 
-struct ins_replace_args {
-	kprobe_opcode_t *ptr;
-	kprobe_opcode_t opcode;
+int arch_check_ftrace_location(struct kprobe *p)
+{
+	return 0;
+}
+
+struct swap_insn_args {
+	struct kprobe *p;
+	unsigned int arm_kprobe : 1;
 };
 
-static int __kprobes swap_instruction(void *aref)
+static int swap_instruction(void *data)
 {
 	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
 	unsigned long status = kcb->kprobe_status;
-	struct ins_replace_args *args = aref;
-
+	struct swap_insn_args *args = data;
+	struct ftrace_insn new_insn, *insn;
+	struct kprobe *p = args->p;
+	size_t len;
+
+	new_insn.opc = args->arm_kprobe ? BREAKPOINT_INSTRUCTION : p->opcode;
+	len = sizeof(new_insn.opc);
+	if (!p->ainsn.is_ftrace_insn)
+		goto skip_ftrace;
+	len = sizeof(new_insn);
+	insn = (struct ftrace_insn *) p->addr;
+	if (args->arm_kprobe) {
+		if (is_ftrace_nop(insn))
+			new_insn.disp = KPROBE_ON_FTRACE_NOP;
+		else
+			new_insn.disp = KPROBE_ON_FTRACE_CALL;
+	} else {
+		ftrace_generate_call_insn(&new_insn, (unsigned long)p->addr);
+		if (insn->disp == KPROBE_ON_FTRACE_NOP)
+			ftrace_generate_nop_insn(&new_insn);
+	}
+skip_ftrace:
 	kcb->kprobe_status = KPROBE_SWAP_INST;
-	probe_kernel_write(args->ptr, &args->opcode, sizeof(args->opcode));
+	probe_kernel_write(p->addr, &new_insn, len);
 	kcb->kprobe_status = status;
 	return 0;
 }
+NOKPROBE_SYMBOL(swap_instruction);
 
-void __kprobes arch_arm_kprobe(struct kprobe *p)
+void arch_arm_kprobe(struct kprobe *p)
 {
-	struct ins_replace_args args;
+	struct swap_insn_args args = {.p = p, .arm_kprobe = 1};
 
-	args.ptr = p->addr;
-	args.opcode = BREAKPOINT_INSTRUCTION;
 	stop_machine(swap_instruction, &args, NULL);
 }
+NOKPROBE_SYMBOL(arch_arm_kprobe);
 
-void __kprobes arch_disarm_kprobe(struct kprobe *p)
+void arch_disarm_kprobe(struct kprobe *p)
 {
-	struct ins_replace_args args;
+	struct swap_insn_args args = {.p = p, .arm_kprobe = 0};
 
-	args.ptr = p->addr;
-	args.opcode = p->opcode;
 	stop_machine(swap_instruction, &args, NULL);
 }
+NOKPROBE_SYMBOL(arch_disarm_kprobe);
 
-void __kprobes arch_remove_kprobe(struct kprobe *p)
+void arch_remove_kprobe(struct kprobe *p)
 {
 	s390_free_insn_slot(p);
 }
+NOKPROBE_SYMBOL(arch_remove_kprobe);
 
-static void __kprobes enable_singlestep(struct kprobe_ctlblk *kcb,
-					struct pt_regs *regs,
-					unsigned long ip)
+static void enable_singlestep(struct kprobe_ctlblk *kcb,
+			      struct pt_regs *regs,
+			      unsigned long ip)
 {
 	struct per_regs per_kprobe;
 
@@ -199,10 +227,11 @@ static void __kprobes enable_singlestep(struct kprobe_ctlblk *kcb,
 	regs->psw.mask &= ~(PSW_MASK_IO | PSW_MASK_EXT);
 	regs->psw.addr = ip | PSW_ADDR_AMODE;
 }
+NOKPROBE_SYMBOL(enable_singlestep);
 
-static void __kprobes disable_singlestep(struct kprobe_ctlblk *kcb,
-					 struct pt_regs *regs,
-					 unsigned long ip)
+static void disable_singlestep(struct kprobe_ctlblk *kcb,
+			       struct pt_regs *regs,
+			       unsigned long ip)
 {
 	/* Restore control regs and psw mask, set new psw address */
 	__ctl_load(kcb->kprobe_saved_ctl, 9, 11);
@@ -210,41 +239,43 @@ static void __kprobes disable_singlestep(struct kprobe_ctlblk *kcb,
 	regs->psw.mask |= kcb->kprobe_saved_imask;
 	regs->psw.addr = ip | PSW_ADDR_AMODE;
 }
+NOKPROBE_SYMBOL(disable_singlestep);
 
 /*
  * Activate a kprobe by storing its pointer to current_kprobe. The
  * previous kprobe is stored in kcb->prev_kprobe. A stack of up to
  * two kprobes can be active, see KPROBE_REENTER.
  */
-static void __kprobes push_kprobe(struct kprobe_ctlblk *kcb, struct kprobe *p)
+static void push_kprobe(struct kprobe_ctlblk *kcb, struct kprobe *p)
 {
 	kcb->prev_kprobe.kp = __this_cpu_read(current_kprobe);
 	kcb->prev_kprobe.status = kcb->kprobe_status;
 	__this_cpu_write(current_kprobe, p);
 }
+NOKPROBE_SYMBOL(push_kprobe);
 
 /*
  * Deactivate a kprobe by backing up to the previous state. If the
  * current state is KPROBE_REENTER prev_kprobe.kp will be non-NULL,
  * for any other state prev_kprobe.kp will be NULL.
  */
-static void __kprobes pop_kprobe(struct kprobe_ctlblk *kcb)
+static void pop_kprobe(struct kprobe_ctlblk *kcb)
 {
 	__this_cpu_write(current_kprobe, kcb->prev_kprobe.kp);
 	kcb->kprobe_status = kcb->prev_kprobe.status;
 }
+NOKPROBE_SYMBOL(pop_kprobe);
 
-void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
-					struct pt_regs *regs)
+void arch_prepare_kretprobe(struct kretprobe_instance *ri, struct pt_regs *regs)
 {
 	ri->ret_addr = (kprobe_opcode_t *) regs->gprs[14];
 
 	/* Replace the return addr with trampoline addr */
 	regs->gprs[14] = (unsigned long) &kretprobe_trampoline;
 }
+NOKPROBE_SYMBOL(arch_prepare_kretprobe);
 
-static void __kprobes kprobe_reenter_check(struct kprobe_ctlblk *kcb,
-					   struct kprobe *p)
+static void kprobe_reenter_check(struct kprobe_ctlblk *kcb, struct kprobe *p)
 {
 	switch (kcb->kprobe_status) {
 	case KPROBE_HIT_SSDONE:
@@ -264,8 +295,9 @@ static void __kprobes kprobe_reenter_check(struct kprobe_ctlblk *kcb,
 		BUG();
 	}
 }
+NOKPROBE_SYMBOL(kprobe_reenter_check);
 
-static int __kprobes kprobe_handler(struct pt_regs *regs)
+static int kprobe_handler(struct pt_regs *regs)
 {
 	struct kprobe_ctlblk *kcb;
 	struct kprobe *p;
@@ -339,6 +371,7 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
 	preempt_enable_no_resched();
 	return 0;
 }
+NOKPROBE_SYMBOL(kprobe_handler);
 
 /*
  * Function return probe trampoline:
@@ -355,8 +388,7 @@ static void __used kretprobe_trampoline_holder(void)
 /*
  * Called when the probe at kretprobe trampoline is hit
  */
-static int __kprobes trampoline_probe_handler(struct kprobe *p,
-					      struct pt_regs *regs)
+static int trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
 {
 	struct kretprobe_instance *ri;
 	struct hlist_head *head, empty_rp;
@@ -444,6 +476,7 @@ static int __kprobes trampoline_probe_handler(struct kprobe *p,
 	 */
 	return 1;
 }
+NOKPROBE_SYMBOL(trampoline_probe_handler);
 
 /*
  * Called after single-stepping.  p->addr is the address of the
@@ -453,12 +486,30 @@ static int __kprobes trampoline_probe_handler(struct kprobe *p,
  * single-stepped a copy of the instruction.  The address of this
  * copy is p->ainsn.insn.
  */
-static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)
+static void resume_execution(struct kprobe *p, struct pt_regs *regs)
 {
 	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
 	unsigned long ip = regs->psw.addr & PSW_ADDR_INSN;
 	int fixup = probe_get_fixup_type(p->ainsn.insn);
 
+	/* Check if the kprobes location is an enabled ftrace caller */
+	if (p->ainsn.is_ftrace_insn) {
+		struct ftrace_insn *insn = (struct ftrace_insn *) p->addr;
+		struct ftrace_insn call_insn;
+
+		ftrace_generate_call_insn(&call_insn, (unsigned long) p->addr);
+		/*
+		 * A kprobe on an enabled ftrace call site actually single
+		 * stepped an unconditional branch (ftrace nop equivalent).
+		 * Now we need to fixup things and pretend that a brasl r0,...
+		 * was executed instead.
+		 */
+		if (insn->disp == KPROBE_ON_FTRACE_CALL) {
+			ip += call_insn.disp * 2 - MCOUNT_INSN_SIZE;
+			regs->gprs[0] = (unsigned long)p->addr + sizeof(*insn);
+		}
+	}
+
 	if (fixup & FIXUP_PSW_NORMAL)
 		ip += (unsigned long) p->addr - (unsigned long) p->ainsn.insn;
 
@@ -476,8 +527,9 @@ static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)
 
 	disable_singlestep(kcb, regs, ip);
 }
+NOKPROBE_SYMBOL(resume_execution);
 
-static int __kprobes post_kprobe_handler(struct pt_regs *regs)
+static int post_kprobe_handler(struct pt_regs *regs)
 {
 	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
 	struct kprobe *p = kprobe_running();
@@ -504,8 +556,9 @@ static int __kprobes post_kprobe_handler(struct pt_regs *regs)
 
 	return 1;
 }
+NOKPROBE_SYMBOL(post_kprobe_handler);
 
-static int __kprobes kprobe_trap_handler(struct pt_regs *regs, int trapnr)
+static int kprobe_trap_handler(struct pt_regs *regs, int trapnr)
 {
 	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
 	struct kprobe *p = kprobe_running();
@@ -567,8 +620,9 @@ static int __kprobes kprobe_trap_handler(struct pt_regs *regs, int trapnr)
 	}
 	return 0;
 }
+NOKPROBE_SYMBOL(kprobe_trap_handler);
 
-int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
+int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 {
 	int ret;
 
@@ -579,12 +633,13 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 		local_irq_restore(regs->psw.mask & ~PSW_MASK_PER);
 	return ret;
 }
+NOKPROBE_SYMBOL(kprobe_fault_handler);
 
 /*
  * Wrapper routine to for handling exceptions.
  */
-int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
-				       unsigned long val, void *data)
+int kprobe_exceptions_notify(struct notifier_block *self,
+			     unsigned long val, void *data)
 {
 	struct die_args *args = (struct die_args *) data;
 	struct pt_regs *regs = args->regs;
@@ -616,8 +671,9 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
 
 	return ret;
 }
+NOKPROBE_SYMBOL(kprobe_exceptions_notify);
 
-int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
+int setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
 {
 	struct jprobe *jp = container_of(p, struct jprobe, kp);
 	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
@@ -635,13 +691,15 @@ int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
 	memcpy(kcb->jprobes_stack, (void *) stack, MIN_STACK_SIZE(stack));
 	return 1;
 }
+NOKPROBE_SYMBOL(setjmp_pre_handler);
 
-void __kprobes jprobe_return(void)
+void jprobe_return(void)
 {
 	asm volatile(".word 0x0002");
 }
+NOKPROBE_SYMBOL(jprobe_return);
 
-int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
+int longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
 {
 	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
 	unsigned long stack;
@@ -655,6 +713,7 @@ int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
 	preempt_enable_no_resched();
 	return 1;
 }
+NOKPROBE_SYMBOL(longjmp_break_handler);
 
 static struct kprobe trampoline = {
 	.addr = (kprobe_opcode_t *) &kretprobe_trampoline,
@@ -666,7 +725,8 @@ int __init arch_init_kprobes(void)
 	return register_kprobe(&trampoline);
 }
 
-int __kprobes arch_trampoline_kprobe(struct kprobe *p)
+int arch_trampoline_kprobe(struct kprobe *p)
 {
 	return p->addr == (kprobe_opcode_t *) &kretprobe_trampoline;
 }
+NOKPROBE_SYMBOL(arch_trampoline_kprobe);