3 files changed, 53 insertions, 30 deletions

diff --git a/arch/parisc/kernel/pci.c b/arch/parisc/kernel/pci.c
index 64f2764a8cef..c99f3dde455c 100644
--- a/arch/parisc/kernel/pci.c
+++ b/arch/parisc/kernel/pci.c
@@ -171,24 +171,6 @@ void pcibios_set_master(struct pci_dev *dev)
 }
 
 
-void __init pcibios_init_bus(struct pci_bus *bus)
-{
-	struct pci_dev *dev = bus->self;
-	unsigned short bridge_ctl;
-
-	/* We deal only with pci controllers and pci-pci bridges. */
-	if (!dev || (dev->class >> 8) != PCI_CLASS_BRIDGE_PCI)
-		return;
-
-	/* PCI-PCI bridge - set the cache line and default latency
-	   (32) for primary and secondary buses. */
-	pci_write_config_byte(dev, PCI_SEC_LATENCY_TIMER, 32);
-
-	pci_read_config_word(dev, PCI_BRIDGE_CONTROL, &bridge_ctl);
-	bridge_ctl |= PCI_BRIDGE_CTL_PARITY | PCI_BRIDGE_CTL_SERR;
-	pci_write_config_word(dev, PCI_BRIDGE_CONTROL, bridge_ctl);
-}
-
 /*
  * pcibios align resources() is called every time generic PCI code
  * wants to generate a new address. The process of looking for
diff --git a/arch/parisc/kernel/signal.c b/arch/parisc/kernel/signal.c
index dc1ea796fd60..2264f68f3c2f 100644
--- a/arch/parisc/kernel/signal.c
+++ b/arch/parisc/kernel/signal.c
@@ -435,6 +435,55 @@ handle_signal(struct ksignal *ksig, struct pt_regs *regs, int in_syscall)
 		regs->gr[28]);
 }
 
+/*
+ * Check how the syscall number gets loaded into %r20 within
+ * the delay branch in userspace and adjust as needed.
+ */
+
+static void check_syscallno_in_delay_branch(struct pt_regs *regs)
+{
+	u32 opcode, source_reg;
+	u32 __user *uaddr;
+	int err;
+
+	/* Usually we don't have to restore %r20 (the system call number)
+	 * because it gets loaded in the delay slot of the branch external
+	 * instruction via the ldi instruction.
+	 * In some cases a register-to-register copy instruction might have
+	 * been used instead, in which case we need to copy the syscall
+	 * number into the source register before returning to userspace.
+	 */
+
+	/* A syscall is just a branch, so all we have to do is fiddle the
+	 * return pointer so that the ble instruction gets executed again.
+	 */
+	regs->gr[31] -= 8; /* delayed branching */
+
+	/* Get assembler opcode of code in delay branch */
+	uaddr = (unsigned int *) ((regs->gr[31] & ~3) + 4);
+	err = get_user(opcode, uaddr);
+	if (err)
+		return;
+
+	/* Check if delay branch uses "ldi int,%r20" */
+	if ((opcode & 0xffff0000) == 0x34140000)
+		return;	/* everything ok, just return */
+
+	/* Check if delay branch uses "nop" */
+	if (opcode == INSN_NOP)
+		return;
+
+	/* Check if delay branch uses "copy %rX,%r20" */
+	if ((opcode & 0xffe0ffff) == 0x08000254) {
+		source_reg = (opcode >> 16) & 31;
+		regs->gr[source_reg] = regs->gr[20];
+		return;
+	}
+
+	pr_warn("syscall restart: %s (pid %d): unexpected opcode 0x%08x\n",
+		current->comm, task_pid_nr(current), opcode);
+}
+
 static inline void
 syscall_restart(struct pt_regs *regs, struct k_sigaction *ka)
 {
@@ -457,10 +506,7 @@ syscall_restart(struct pt_regs *regs, struct k_sigaction *ka)
 		}
 		/* fallthrough */
 	case -ERESTARTNOINTR:
-		/* A syscall is just a branch, so all
-		 * we have to do is fiddle the return pointer.
-		 */
-		regs->gr[31] -= 8; /* delayed branching */
+		check_syscallno_in_delay_branch(regs);
 		break;
 	}
 }
@@ -510,15 +556,9 @@ insert_restart_trampoline(struct pt_regs *regs)
 	}
 	case -ERESTARTNOHAND:
 	case -ERESTARTSYS:
-	case -ERESTARTNOINTR: {
-		/* Hooray for delayed branching.  We don't
-		 * have to restore %r20 (the system call
-		 * number) because it gets loaded in the delay
-		 * slot of the branch external instruction.
-		 */
-		regs->gr[31] -= 8;
+	case -ERESTARTNOINTR:
+		check_syscallno_in_delay_branch(regs);
 		return;
-	}
 	default:
 		break;
 	}
diff --git a/arch/parisc/kernel/syscall_table.S b/arch/parisc/kernel/syscall_table.S
index 78c3ef8c348d..d4ffcfbc9885 100644
--- a/arch/parisc/kernel/syscall_table.S
+++ b/arch/parisc/kernel/syscall_table.S
@@ -440,6 +440,7 @@
 	ENTRY_COMP(execveat)
 	ENTRY_SAME(membarrier)
 	ENTRY_SAME(userfaultfd)
+	ENTRY_SAME(mlock2)		/* 345 */
 
 
 .ifne (. - 90b) - (__NR_Linux_syscalls * (91b - 90b))