1 files changed, 39 insertions, 26 deletions

diff --git a/arch/arm/kernel/swp_emulate.c b/arch/arm/kernel/swp_emulate.c
index 7a576092291..b1b89882b11 100644
--- a/arch/arm/kernel/swp_emulate.c
+++ b/arch/arm/kernel/swp_emulate.c
@@ -21,10 +21,12 @@
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/proc_fs.h>
+#include <linux/seq_file.h>
 #include <linux/sched.h>
 #include <linux/syscalls.h>
 #include <linux/perf_event.h>
 
+#include <asm/opcodes.h>
 #include <asm/traps.h>
 #include <asm/uaccess.h>
 
@@ -78,27 +80,27 @@ static unsigned long abtcounter;
 static pid_t         previous_pid;
 
 #ifdef CONFIG_PROC_FS
-static int proc_read_status(char *page, char **start, off_t off, int count,
-			    int *eof, void *data)
+static int proc_status_show(struct seq_file *m, void *v)
 {
-	char *p = page;
-	int len;
-
-	p += sprintf(p, "Emulated SWP:\t\t%lu\n", swpcounter);
-	p += sprintf(p, "Emulated SWPB:\t\t%lu\n", swpbcounter);
-	p += sprintf(p, "Aborted SWP{B}:\t\t%lu\n", abtcounter);
+	seq_printf(m, "Emulated SWP:\t\t%lu\n", swpcounter);
+	seq_printf(m, "Emulated SWPB:\t\t%lu\n", swpbcounter);
+	seq_printf(m, "Aborted SWP{B}:\t\t%lu\n", abtcounter);
 	if (previous_pid != 0)
-		p += sprintf(p, "Last process:\t\t%d\n", previous_pid);
-
-	len = (p - page) - off;
-	if (len < 0)
-		len = 0;
-
-	*eof = (len <= count) ? 1 : 0;
-	*start = page + off;
+		seq_printf(m, "Last process:\t\t%d\n", previous_pid);
+	return 0;
+}
 
-	return len;
+static int proc_status_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, proc_status_show, PDE_DATA(inode));
 }
+
+static const struct file_operations proc_status_fops = {
+	.open		= proc_status_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
 #endif
 
 /*
@@ -108,10 +110,12 @@ static void set_segfault(struct pt_regs *regs, unsigned long addr)
 {
 	siginfo_t info;
 
+	down_read(&current->mm->mmap_sem);
 	if (find_vma(current->mm, addr) == NULL)
 		info.si_code = SEGV_MAPERR;
 	else
 		info.si_code = SEGV_ACCERR;
+	up_read(&current->mm->mmap_sem);
 
 	info.si_signo = SIGSEGV;
 	info.si_errno = 0;
@@ -158,7 +162,7 @@ static int emulate_swpX(unsigned int address, unsigned int *data,
 
 	if (res == 0) {
 		/*
-		 * Barrier also required between aquiring a lock for a
+		 * Barrier also required between acquiring a lock for a
 		 * protected resource and accessing the resource. Inserted for
 		 * same reason as above.
 		 */
@@ -183,7 +187,22 @@ static int swp_handler(struct pt_regs *regs, unsigned int instr)
 	unsigned int address, destreg, data, type;
 	unsigned int res = 0;
 
-	perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, 0, regs, regs->ARM_pc);
+	perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, regs->ARM_pc);
+
+	res = arm_check_condition(instr, regs->ARM_cpsr);
+	switch (res) {
+	case ARM_OPCODE_CONDTEST_PASS:
+		break;
+	case ARM_OPCODE_CONDTEST_FAIL:
+		/* Condition failed - return to next instruction */
+		regs->ARM_pc += 4;
+		return 0;
+	case ARM_OPCODE_CONDTEST_UNCOND:
+		/* If unconditional encoding - not a SWP, undef */
+		return -EFAULT;
+	default:
+		return -EINVAL;
+	}
 
 	if (current->pid != previous_pid) {
 		pr_debug("\"%s\" (%ld) uses deprecated SWP{B} instruction\n",
@@ -248,14 +267,8 @@ static struct undef_hook swp_hook = {
 static int __init swp_emulation_init(void)
 {
 #ifdef CONFIG_PROC_FS
-	struct proc_dir_entry *res;
-
-	res = create_proc_entry("cpu/swp_emulation", S_IRUGO, NULL);
-
-	if (!res)
+	if (!proc_create("cpu/swp_emulation", S_IRUGO, NULL, &proc_status_fops))
 		return -ENOMEM;
-
-	res->read_proc = proc_read_status;
 #endif /* CONFIG_PROC_FS */
 
 	printk(KERN_NOTICE "Registering SWP/SWPB emulation handler\n");