sh64: Attempt to make reserved insn trap handler resemble C.

This has been long overdue. No functional changes.

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

arch/sh/kernel/traps_64.c

@@ -32,195 +32,6 @@
 #include <asm/pgtable.h>
 #include <asm/fpu.h>
 
-static void do_unhandled_exception(int trapnr, int signr, char *str, char *fn_name,
-		unsigned long error_code, struct pt_regs *regs, struct task_struct *tsk);
-
-#define DO_ERROR(trapnr, signr, str, name, tsk) \
-asmlinkage void do_##name(unsigned long error_code, struct pt_regs *regs) \
-{ \
-	do_unhandled_exception(trapnr, signr, str, __stringify(name), error_code, regs, current); \
-}
-
-DO_ERROR(13, SIGILL,  "illegal slot instruction", illegal_slot_inst, current)
-DO_ERROR(87, SIGSEGV, "address error (exec)", address_error_exec, current)
-
-
-/* Implement misaligned load/store handling for kernel (and optionally for user
-   mode too).  Limitation : only SHmedia mode code is handled - there is no
-   handling at all for misaligned accesses occurring in SHcompact code yet. */
-
-static int misaligned_fixup(struct pt_regs *regs);
-
-asmlinkage void do_address_error_load(unsigned long error_code, struct pt_regs *regs)
-{
-	if (misaligned_fixup(regs) < 0) {
-		do_unhandled_exception(7, SIGSEGV, "address error(load)",
-				"do_address_error_load",
-				error_code, regs, current);
-	}
-	return;
-}
-
-asmlinkage void do_address_error_store(unsigned long error_code, struct pt_regs *regs)
-{
-	if (misaligned_fixup(regs) < 0) {
-		do_unhandled_exception(8, SIGSEGV, "address error(store)",
-				"do_address_error_store",
-				error_code, regs, current);
-	}
-	return;
-}
-
-#if defined(CONFIG_SH64_ID2815_WORKAROUND)
-
-#define OPCODE_INVALID      0
-#define OPCODE_USER_VALID   1
-#define OPCODE_PRIV_VALID   2
-
-/* getcon/putcon - requires checking which control register is referenced. */
-#define OPCODE_CTRL_REG     3
-
-/* Table of valid opcodes for SHmedia mode.
-   Form a 10-bit value by concatenating the major/minor opcodes i.e.
-   opcode[31:26,20:16].  The 6 MSBs of this value index into the following
-   array.  The 4 LSBs select the bit-pair in the entry (bits 1:0 correspond to
-   LSBs==4'b0000 etc). */
-static unsigned long shmedia_opcode_table[64] = {
-	0x55554044,0x54445055,0x15141514,0x14541414,0x00000000,0x10001000,0x01110055,0x04050015,
-	0x00000444,0xc0000000,0x44545515,0x40405555,0x55550015,0x10005555,0x55555505,0x04050000,
-	0x00000555,0x00000404,0x00040445,0x15151414,0x00000000,0x00000000,0x00000000,0x00000000,
-	0x00000055,0x40404444,0x00000404,0xc0009495,0x00000000,0x00000000,0x00000000,0x00000000,
-	0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,
-	0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,
-	0x80005050,0x04005055,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,
-	0x81055554,0x00000404,0x55555555,0x55555555,0x00000000,0x00000000,0x00000000,0x00000000
-};
-
-void do_reserved_inst(unsigned long error_code, struct pt_regs *regs)
-{
-	/* Workaround SH5-101 cut2 silicon defect #2815 :
-	   in some situations, inter-mode branches from SHcompact -> SHmedia
-	   which should take ITLBMISS or EXECPROT exceptions at the target
-	   falsely take RESINST at the target instead. */
-
-	unsigned long opcode = 0x6ff4fff0; /* guaranteed reserved opcode */
-	unsigned long pc, aligned_pc;
-	int get_user_error;
-	int trapnr = 12;
-	int signr = SIGILL;
-	char *exception_name = "reserved_instruction";
-
-	pc = regs->pc;
-	if ((pc & 3) == 1) {
-		/* SHmedia : check for defect.  This requires executable vmas
-		   to be readable too. */
-		aligned_pc = pc & ~3;
-		if (!access_ok(VERIFY_READ, aligned_pc, sizeof(unsigned long))) {
-			get_user_error = -EFAULT;
-		} else {
-			get_user_error = __get_user(opcode, (unsigned long *)aligned_pc);
-		}
-		if (get_user_error >= 0) {
-			unsigned long index, shift;
-			unsigned long major, minor, combined;
-			unsigned long reserved_field;
-			reserved_field = opcode & 0xf; /* These bits are currently reserved as zero in all valid opcodes */
-			major = (opcode >> 26) & 0x3f;
-			minor = (opcode >> 16) & 0xf;
-			combined = (major << 4) | minor;
-			index = major;
-			shift = minor << 1;
-			if (reserved_field == 0) {
-				int opcode_state = (shmedia_opcode_table[index] >> shift) & 0x3;
-				switch (opcode_state) {
-					case OPCODE_INVALID:
-						/* Trap. */
-						break;
-					case OPCODE_USER_VALID:
-						/* Restart the instruction : the branch to the instruction will now be from an RTE
-						   not from SHcompact so the silicon defect won't be triggered. */
-						return;
-					case OPCODE_PRIV_VALID:
-						if (!user_mode(regs)) {
-							/* Should only ever get here if a module has
-							   SHcompact code inside it.  If so, the same fix up is needed. */
-							return; /* same reason */
-						}
-						/* Otherwise, user mode trying to execute a privileged instruction -
-						   fall through to trap. */
-						break;
-					case OPCODE_CTRL_REG:
-						/* If in privileged mode, return as above. */
-						if (!user_mode(regs)) return;
-						/* In user mode ... */
-						if (combined == 0x9f) { /* GETCON */
-							unsigned long regno = (opcode >> 20) & 0x3f;
-							if (regno >= 62) {
-								return;
-							}
-							/* Otherwise, reserved or privileged control register, => trap */
-						} else if (combined == 0x1bf) { /* PUTCON */
-							unsigned long regno = (opcode >> 4) & 0x3f;
-							if (regno >= 62) {
-								return;
-							}
-							/* Otherwise, reserved or privileged control register, => trap */
-						} else {
-							/* Trap */
-						}
-						break;
-					default:
-						/* Fall through to trap. */
-						break;
-				}
-			}
-			/* fall through to normal resinst processing */
-		} else {
-			/* Error trying to read opcode.  This typically means a
-			   real fault, not a RESINST any more.  So change the
-			   codes. */
-			trapnr = 87;
-			exception_name = "address error (exec)";
-			signr = SIGSEGV;
-		}
-	}
-
-	do_unhandled_exception(trapnr, signr, exception_name, "do_reserved_inst", error_code, regs, current);
-}
-
-#else /* CONFIG_SH64_ID2815_WORKAROUND */
-
-/* If the workaround isn't needed, this is just a straightforward reserved
-   instruction */
-DO_ERROR(12, SIGILL,  "reserved instruction", reserved_inst, current)
-
-#endif /* CONFIG_SH64_ID2815_WORKAROUND */
-
-/* Called with interrupts disabled */
-asmlinkage void do_exception_error(unsigned long ex, struct pt_regs *regs)
-{
-	die_if_kernel("exception", regs, ex);
-}
-
-int do_unknown_trapa(unsigned long scId, struct pt_regs *regs)
-{
-	/* Syscall debug */
-        printk("System call ID error: [0x1#args:8 #syscall:16  0x%lx]\n", scId);
-
-	die_if_kernel("unknown trapa", regs, scId);
-
-	return -ENOSYS;
-}
-
-static void do_unhandled_exception(int trapnr, int signr, char *str, char *fn_name,
-		unsigned long error_code, struct pt_regs *regs, struct task_struct *tsk)
-{
-	if (user_mode(regs))
-		force_sig(signr, tsk);
-
-	die_if_no_fixup(str, regs, error_code);
-}
-
 static int read_opcode(reg_size_t pc, insn_size_t *result_opcode, int from_user_mode)
 {
 	int get_user_error;
@@ -784,7 +595,201 @@ static int misaligned_fixup(struct pt_regs *regs)
 		regs->pc += 4; /* Skip the instruction that's just been emulated */
 		return 0;
 	}
+}
+
+static void do_unhandled_exception(int signr, char *str, unsigned long error,
+				   struct pt_regs *regs)
+{
+	if (user_mode(regs))
+		force_sig(signr, current);
+
+	die_if_no_fixup(str, regs, error);
+}
+
+#define DO_ERROR(signr, str, name) \
+asmlinkage void do_##name(unsigned long error_code, struct pt_regs *regs) \
+{ \
+	do_unhandled_exception(signr, str, error_code, regs); \
+}
+
+DO_ERROR(SIGILL,  "illegal slot instruction", illegal_slot_inst)
+DO_ERROR(SIGSEGV, "address error (exec)", address_error_exec)
+
+#if defined(CONFIG_SH64_ID2815_WORKAROUND)
+
+#define OPCODE_INVALID      0
+#define OPCODE_USER_VALID   1
+#define OPCODE_PRIV_VALID   2
+
+/* getcon/putcon - requires checking which control register is referenced. */
+#define OPCODE_CTRL_REG     3
+
+/* Table of valid opcodes for SHmedia mode.
+   Form a 10-bit value by concatenating the major/minor opcodes i.e.
+   opcode[31:26,20:16].  The 6 MSBs of this value index into the following
+   array.  The 4 LSBs select the bit-pair in the entry (bits 1:0 correspond to
+   LSBs==4'b0000 etc). */
+static unsigned long shmedia_opcode_table[64] = {
+	0x55554044,0x54445055,0x15141514,0x14541414,0x00000000,0x10001000,0x01110055,0x04050015,
+	0x00000444,0xc0000000,0x44545515,0x40405555,0x55550015,0x10005555,0x55555505,0x04050000,
+	0x00000555,0x00000404,0x00040445,0x15151414,0x00000000,0x00000000,0x00000000,0x00000000,
+	0x00000055,0x40404444,0x00000404,0xc0009495,0x00000000,0x00000000,0x00000000,0x00000000,
+	0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,
+	0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,
+	0x80005050,0x04005055,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,
+	0x81055554,0x00000404,0x55555555,0x55555555,0x00000000,0x00000000,0x00000000,0x00000000
+};
+
+/* Workaround SH5-101 cut2 silicon defect #2815 :
+   in some situations, inter-mode branches from SHcompact -> SHmedia
+   which should take ITLBMISS or EXECPROT exceptions at the target
+   falsely take RESINST at the target instead. */
+void do_reserved_inst(unsigned long error_code, struct pt_regs *regs)
+{
+	insn_size_t opcode = 0x6ff4fff0; /* guaranteed reserved opcode */
+	unsigned long pc, aligned_pc;
+	unsigned long index, shift;
+	unsigned long major, minor, combined;
+	unsigned long reserved_field;
+	int opcode_state;
+	int get_user_error;
+	int signr = SIGILL;
+	char *exception_name = "reserved_instruction";
+
+	pc = regs->pc;
+
+	/* SHcompact is not handled */
+	if (unlikely((pc & 3) == 0))
+		goto out;
+
+	/* SHmedia : check for defect.  This requires executable vmas
+	   to be readable too. */
+	aligned_pc = pc & ~3;
+	if (!access_ok(VERIFY_READ, aligned_pc, sizeof(insn_size_t)))
+		get_user_error = -EFAULT;
+	else
+		get_user_error = __get_user(opcode, (insn_size_t *)aligned_pc);
+
+	if (get_user_error < 0) {
+		/*
+		 * Error trying to read opcode.  This typically means a
+		 * real fault, not a RESINST any more.  So change the
+		 * codes.
+		 */
+		exception_name = "address error (exec)";
+		signr = SIGSEGV;
+		goto out;
+	}
+
+	/* These bits are currently reserved as zero in all valid opcodes */
+	reserved_field = opcode & 0xf;
+	if (unlikely(reserved_field))
+		goto out;	/* invalid opcode */
+
+	major = (opcode >> 26) & 0x3f;
+	minor = (opcode >> 16) & 0xf;
+	combined = (major << 4) | minor;
+	index = major;
+	shift = minor << 1;
+	opcode_state = (shmedia_opcode_table[index] >> shift) & 0x3;
+	switch (opcode_state) {
+	case OPCODE_INVALID:
+		/* Trap. */
+		break;
+	case OPCODE_USER_VALID:
+		/*
+		 * Restart the instruction: the branch to the instruction
+		 * will now be from an RTE not from SHcompact so the
+		 * silicon defect won't be triggered.
+		 */
+		return;
+	case OPCODE_PRIV_VALID:
+		if (!user_mode(regs)) {
+			/*
+			 * Should only ever get here if a module has
+			 * SHcompact code inside it. If so, the same fix
+			 * up is needed.
+			 */
+			return; /* same reason */
+		}
+
+		/*
+		 * Otherwise, user mode trying to execute a privileged
+		 * instruction - fall through to trap.
+		 */
+		break;
+	case OPCODE_CTRL_REG:
+		/* If in privileged mode, return as above. */
+		if (!user_mode(regs))
+			return;
+
+		/* In user mode ... */
+		if (combined == 0x9f) { /* GETCON */
+			unsigned long regno = (opcode >> 20) & 0x3f;
+
+			if (regno >= 62)
+				return;
+
+			/* reserved/privileged control register => trap */
+		} else if (combined == 0x1bf) { /* PUTCON */
+			unsigned long regno = (opcode >> 4) & 0x3f;
+
+			if (regno >= 62)
+				return;
+
+			/* reserved/privileged control register => trap */
+		}
+
+		break;
+	default:
+		/* Fall through to trap. */
+		break;
+	}
 
+out:
+	do_unhandled_exception(signr, exception_name, error_code, regs);
+}
+
+#else /* CONFIG_SH64_ID2815_WORKAROUND */
+
+/* If the workaround isn't needed, this is just a straightforward reserved
+   instruction */
+DO_ERROR(SIGILL, "reserved instruction", reserved_inst)
+
+#endif /* CONFIG_SH64_ID2815_WORKAROUND */
+
+/* Called with interrupts disabled */
+asmlinkage void do_exception_error(unsigned long ex, struct pt_regs *regs)
+{
+	die_if_kernel("exception", regs, ex);
+}
+
+asmlinkage int do_unknown_trapa(unsigned long scId, struct pt_regs *regs)
+{
+	/* Syscall debug */
+	printk("System call ID error: [0x1#args:8 #syscall:16  0x%lx]\n", scId);
+
+	die_if_kernel("unknown trapa", regs, scId);
+
+	return -ENOSYS;
+}
+
+/* Implement misaligned load/store handling for kernel (and optionally for user
+   mode too).  Limitation : only SHmedia mode code is handled - there is no
+   handling at all for misaligned accesses occurring in SHcompact code yet. */
+
+asmlinkage void do_address_error_load(unsigned long error_code, struct pt_regs *regs)
+{
+	if (misaligned_fixup(regs) < 0)
+		do_unhandled_exception(SIGSEGV, "address error(load)",
+				       error_code, regs);
+}
+
+asmlinkage void do_address_error_store(unsigned long error_code, struct pt_regs *regs)
+{
+	if (misaligned_fixup(regs) < 0)
+		do_unhandled_exception(SIGSEGV, "address error(store)",
+				error_code, regs);
 }
 
 asmlinkage void do_debug_interrupt(unsigned long code, struct pt_regs *regs)
@@ -797,10 +802,9 @@ asmlinkage void do_debug_interrupt(unsigned long code, struct pt_regs *regs)
 	   of access we make to them - just go direct to their physical
 	   addresses. */
 	exp_cause = peek_real_address_q(DM_EXP_CAUSE_PHY);
-	if (exp_cause & ~4) {
+	if (exp_cause & ~4)
 		printk("DM.EXP_CAUSE had unexpected bits set (=%08lx)\n",
 			(unsigned long)(exp_cause & 0xffffffff));
-	}
 	show_state();
 	/* Clear all DEBUGINT causes */
 	poke_real_address_q(DM_EXP_CAUSE_PHY, 0x0);