sh: Always fixup unaligned userspace accesses on sh64.

sh64 has traditionally had this configurable via a Kconfig option
(CONFIG_SH64_USER_MISALIGNED_FIXUP). In practice it has never really been
terribly useful to turn this off, so just get rid of the option entirely.

We leave the sysctl around so we don't end up breaking existing root
file systems, and to allow folks that really want this off to do so at
their own risk.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/Kconfig.cpu

@@ -76,11 +76,6 @@ config SPECULATIVE_EXECUTION
 
 	  If unsure, say N.
 
-config SH64_USER_MISALIGNED_FIXUP
-	def_bool y
-	prompt "Fixup misaligned loads/stores occurring in user mode"
-	depends on SUPERH64
-
 config SH64_ID2815_WORKAROUND
 	bool "Include workaround for SH5-101 cut2 silicon defect ID2815"
 	depends on CPU_SUBTYPE_SH5_101

arch/sh/kernel/traps_64.c

@@ -370,7 +370,6 @@ static int generate_and_check_address(struct pt_regs *regs,
 		return -1;
 	}
 
-#if defined(CONFIG_SH64_USER_MISALIGNED_FIXUP)
 	/* Check accessible.  For misaligned access in the kernel, assume the
 	   address is always accessible (and if not, just fault when the
 	   load/store gets done.) */
@@ -380,18 +379,13 @@ static int generate_and_check_address(struct pt_regs *regs,
 		}
 		/* Do access_ok check later - it depends on whether it's a load or a store. */
 	}
-#endif
 
 	*address = addr;
 	return 0;
 }
 
-/* Default value as for sh */
-#if defined(CONFIG_SH64_USER_MISALIGNED_FIXUP)
 static int user_mode_unaligned_fixup_count = 10;
 static int user_mode_unaligned_fixup_enable = 1;
-#endif
-
 static int kernel_mode_unaligned_fixup_count = 32;
 
 static void misaligned_kernel_word_load(__u64 address, int do_sign_extend, __u64 *result)
@@ -440,7 +434,6 @@ static int misaligned_load(struct pt_regs *regs,
 	}
 
 	destreg = (opcode >> 4) & 0x3f;
-#if defined(CONFIG_SH64_USER_MISALIGNED_FIXUP)
 	if (user_mode(regs)) {
 		__u64 buffer;
 
@@ -470,9 +463,7 @@ static int misaligned_load(struct pt_regs *regs,
 				width_shift, (unsigned long) regs->pc);
 			break;
 		}
-	} else
-#endif
-	{
+	} else {
 		/* kernel mode - we can take short cuts since if we fault, it's a genuine bug */
 		__u64 lo, hi;
 
@@ -519,7 +510,6 @@ static int misaligned_store(struct pt_regs *regs,
 	}
 
 	srcreg = (opcode >> 4) & 0x3f;
-#if defined(CONFIG_SH64_USER_MISALIGNED_FIXUP)
 	if (user_mode(regs)) {
 		__u64 buffer;
 
@@ -546,9 +536,7 @@ static int misaligned_store(struct pt_regs *regs,
 		if (__copy_user((void *)(int)address, &buffer, (1 << width_shift)) > 0) {
 			return -1; /* fault */
 		}
-	} else
-#endif
-	{
+	} else {
 		/* kernel mode - we can take short cuts since if we fault, it's a genuine bug */
 		__u64 val = regs->regs[srcreg];
 
@@ -576,7 +564,6 @@ static int misaligned_store(struct pt_regs *regs,
 
 }
 
-#if defined(CONFIG_SH64_USER_MISALIGNED_FIXUP)
 /* Never need to fix up misaligned FPU accesses within the kernel since that's a real
    error. */
 static int misaligned_fpu_load(struct pt_regs *regs,
@@ -727,20 +714,15 @@ static int misaligned_fpu_store(struct pt_regs *regs,
 		return -1;
 	}
 }
-#endif
 
 static int misaligned_fixup(struct pt_regs *regs)
 {
 	unsigned long opcode;
 	int error;
 	int major, minor;
 
-#if !defined(CONFIG_SH64_USER_MISALIGNED_FIXUP)
-	/* Never fixup user mode misaligned accesses without this option enabled. */
-	return -1;
-#else
-	if (!user_mode_unaligned_fixup_enable) return -1;
-#endif
+	if (!user_mode_unaligned_fixup_enable)
+		return -1;
 
 	error = read_opcode(regs->pc, &opcode, user_mode(regs));
 	if (error < 0) {
@@ -749,15 +731,12 @@ static int misaligned_fixup(struct pt_regs *regs)
 	major = (opcode >> 26) & 0x3f;
 	minor = (opcode >> 16) & 0xf;
 
-#if defined(CONFIG_SH64_USER_MISALIGNED_FIXUP)
 	if (user_mode(regs) && (user_mode_unaligned_fixup_count > 0)) {
 		--user_mode_unaligned_fixup_count;
 		/* Only do 'count' worth of these reports, to remove a potential DoS against syslog */
 		printk("Fixing up unaligned userspace access in \"%s\" pid=%d pc=0x%08x ins=0x%08lx\n",
 		       current->comm, task_pid_nr(current), (__u32)regs->pc, opcode);
-	} else
-#endif
-	if (!user_mode(regs) && (kernel_mode_unaligned_fixup_count > 0)) {
+	} else if (!user_mode(regs) && (kernel_mode_unaligned_fixup_count > 0)) {
 		--kernel_mode_unaligned_fixup_count;
 		if (in_interrupt()) {
 			printk("Fixing up unaligned kernelspace access in interrupt pc=0x%08x ins=0x%08lx\n",
@@ -830,7 +809,6 @@ static int misaligned_fixup(struct pt_regs *regs)
 			}
 			break;
 
-#if defined(CONFIG_SH64_USER_MISALIGNED_FIXUP)
 		case (0x94>>2): /* FLD.S */
 			error = misaligned_fpu_load(regs, opcode, 1, 2, 0);
 			break;
@@ -881,7 +859,6 @@ static int misaligned_fixup(struct pt_regs *regs)
 				break;
 			}
 			break;
-#endif
 
 		default:
 			/* Fault */
@@ -907,7 +884,6 @@ static ctl_table unaligned_table[] = {
 		.mode		= 0644,
 		.proc_handler	= &proc_dointvec
 	},
-#if defined(CONFIG_SH64_USER_MISALIGNED_FIXUP)
 	{
 		.ctl_name	= CTL_UNNUMBERED,
 		.procname	= "user_reports",
@@ -923,7 +899,6 @@ static ctl_table unaligned_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= &proc_dointvec},
-#endif
 	{}
 };