alpha: drop pre-EV56 support

All EV4 machines are already gone, and the remaining EV5 based machines
all support the slightly more modern EV56 generation as well.
Debian only supports EV56 and later.

Drop both of these and build kernels optimized for EV56 and higher
when the "generic" options is selected, tuning for an out-of-order
EV6 pipeline, same as Debian userspace.

Since this was the only supported architecture without 8-bit and
16-bit stores, common kernel code no longer has to worry about
aligning struct members, and existing workarounds from the block
and tty layers can be removed.

The alpha memory management code no longer needs an abstraction
for the differences between EV4 and EV5+.

Link: https://lists.debian.org/debian-alpha/2023/05/msg00009.html
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Acked-by: Matt Turner <mattst88@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

11 files changed, 15 insertions, 301 deletions

diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig
index 7987bb548652..50ff06d5b799 100644
--- a/arch/alpha/Kconfig
+++ b/arch/alpha/Kconfig
@@ -240,29 +240,14 @@ config ISA_DMA_API
 	bool
 	default y
 
-config ALPHA_EV4
-	bool
-
-config ALPHA_EV5
-	bool
-	default y if ALPHA_RX164 || ALPHA_RAWHIDE || ALPHA_MIATA || ALPHA_LX164 || ALPHA_SX164 || ALPHA_RUFFIAN || ALPHA_SABLE || ALPHA_NORITAKE || ALPHA_MIKASA || ALPHA_PC164 || ALPHA_TAKARA || ALPHA_EB164 || ALPHA_ALCOR
-
 config ALPHA_CIA
 	bool
 	depends on ALPHA_MIATA || ALPHA_LX164 || ALPHA_SX164 || ALPHA_RUFFIAN || ALPHA_NORITAKE || ALPHA_MIKASA || ALPHA_PC164 || ALPHA_TAKARA || ALPHA_ALCOR
 	default y
 
 config ALPHA_EV56
-	bool "EV56 CPU (speed >= 366MHz)?" if ALPHA_ALCOR
-	default y if ALPHA_RX164 || ALPHA_MIATA || ALPHA_LX164 || ALPHA_SX164 || ALPHA_RUFFIAN || ALPHA_PC164 || ALPHA_TAKARA
-
-config ALPHA_EV56
-	prompt "EV56 CPU (speed >= 333MHz)?"
-	depends on ALPHA_NORITAKE || ALPHA_MIKASA
-
-config ALPHA_EV56
-	prompt "EV56 CPU (speed >= 400MHz)?"
-	depends on ALPHA_RAWHIDE
+	bool
+	default y if ALPHA_ALCOR || ALPHA_RX164 || ALPHA_MIATA || ALPHA_LX164 || ALPHA_SX164 || ALPHA_RUFFIAN || ALPHA_PC164 || ALPHA_TAKARA || ALPHA_NORITAKE || ALPHA_MIKASA || ALPHA_RAWHIDE || ALPHA_SABLE
 
 config ALPHA_T2
 	bool
@@ -403,7 +388,7 @@ config ARCH_SPARSEMEM_ENABLE
 config ALPHA_WTINT
 	bool "Use WTINT" if ALPHA_SRM || ALPHA_GENERIC
 	default y if ALPHA_QEMU
-	default n if ALPHA_EV5 || ALPHA_EV56
+	default n if ALPHA_EV56
 	default n if !ALPHA_SRM && !ALPHA_GENERIC
 	default y if SMP
 	help
diff --git a/arch/alpha/Makefile b/arch/alpha/Makefile
index 45158024085e..35445ff2e489 100644
--- a/arch/alpha/Makefile
+++ b/arch/alpha/Makefile
@@ -15,18 +15,14 @@ CHECKFLAGS	+= -D__alpha__
 cflags-y	:= -pipe -mno-fp-regs -ffixed-8
 cflags-y	+= $(call cc-option, -fno-jump-tables)
 
-cpuflags-$(CONFIG_ALPHA_EV4)		:= -mcpu=ev4
-cpuflags-$(CONFIG_ALPHA_EV5)		:= -mcpu=ev5
 cpuflags-$(CONFIG_ALPHA_EV56)		:= -mcpu=ev56
 cpuflags-$(CONFIG_ALPHA_POLARIS)	:= -mcpu=pca56
 cpuflags-$(CONFIG_ALPHA_SX164)		:= -mcpu=pca56
 cpuflags-$(CONFIG_ALPHA_EV6)		:= -mcpu=ev6
 cpuflags-$(CONFIG_ALPHA_EV67)		:= -mcpu=ev67
 # If GENERIC, make sure to turn off any instruction set extensions that
-# the host compiler might have on by default.  Given that EV4 and EV5
-# have the same instruction set, prefer EV5 because an EV5 schedule is
-# more likely to keep an EV4 processor busy than vice-versa.
-cpuflags-$(CONFIG_ALPHA_GENERIC)	:= -mcpu=ev5
+# the host compiler might have on by default.
+cpuflags-$(CONFIG_ALPHA_GENERIC)	:= -mcpu=ev56 -mtune=ev6
 
 cflags-y				+= $(cpuflags-y)
 
diff --git a/arch/alpha/include/asm/elf.h b/arch/alpha/include/asm/elf.h
index e6da23f1da83..4d7c46f50382 100644
--- a/arch/alpha/include/asm/elf.h
+++ b/arch/alpha/include/asm/elf.h
@@ -133,9 +133,7 @@ extern int dump_elf_task(elf_greg_t *dest, struct task_struct *task);
 #define ELF_PLATFORM				\
 ({						\
 	enum implver_enum i_ = implver();	\
-	( i_ == IMPLVER_EV4 ? "ev4"		\
-	: i_ == IMPLVER_EV5			\
-	  ? (amask(AMASK_BWX) ? "ev5" : "ev56")	\
+	( i_ == IMPLVER_EV5 ? "ev56"			\
 	: amask (AMASK_CIX) ? "ev6" : "ev67");	\
 })
 
diff --git a/arch/alpha/include/asm/machvec.h b/arch/alpha/include/asm/machvec.h
index 8623f995d34c..490fc880bb3f 100644
--- a/arch/alpha/include/asm/machvec.h
+++ b/arch/alpha/include/asm/machvec.h
@@ -72,15 +72,6 @@ struct alpha_machine_vector
 	int (*mv_is_ioaddr)(unsigned long);
 	int (*mv_is_mmio)(const volatile void __iomem *);
 
-	void (*mv_switch_mm)(struct mm_struct *, struct mm_struct *,
-			     struct task_struct *);
-	void (*mv_activate_mm)(struct mm_struct *, struct mm_struct *);
-
-	void (*mv_flush_tlb_current)(struct mm_struct *);
-	void (*mv_flush_tlb_current_page)(struct mm_struct * mm,
-					  struct vm_area_struct *vma,
-					  unsigned long addr);
-
 	void (*update_irq_hw)(unsigned long, unsigned long, int);
 	void (*ack_irq)(unsigned long);
 	void (*device_interrupt)(unsigned long vector);
diff --git a/arch/alpha/include/asm/mmu_context.h b/arch/alpha/include/asm/mmu_context.h
index 29a3e3a1f02b..eee8fe836a59 100644
--- a/arch/alpha/include/asm/mmu_context.h
+++ b/arch/alpha/include/asm/mmu_context.h
@@ -71,9 +71,7 @@ __reload_thread(struct pcb_struct *pcb)
 #ifdef CONFIG_ALPHA_GENERIC
 # define MAX_ASN	(alpha_mv.max_asn)
 #else
-# ifdef CONFIG_ALPHA_EV4
-#  define MAX_ASN	EV4_MAX_ASN
-# elif defined(CONFIG_ALPHA_EV5)
+# if defined(CONFIG_ALPHA_EV56)
 #  define MAX_ASN	EV5_MAX_ASN
 # else
 #  define MAX_ASN	EV6_MAX_ASN
@@ -162,26 +160,6 @@ ev5_switch_mm(struct mm_struct *prev_mm, struct mm_struct *next_mm,
 	task_thread_info(next)->pcb.asn = mmc & HARDWARE_ASN_MASK;
 }
 
-__EXTERN_INLINE void
-ev4_switch_mm(struct mm_struct *prev_mm, struct mm_struct *next_mm,
-	      struct task_struct *next)
-{
-	/* As described, ASN's are broken for TLB usage.  But we can
-	   optimize for switching between threads -- if the mm is
-	   unchanged from current we needn't flush.  */
-	/* ??? May not be needed because EV4 PALcode recognizes that
-	   ASN's are broken and does a tbiap itself on swpctx, under
-	   the "Must set ASN or flush" rule.  At least this is true
-	   for a 1992 SRM, reports Joseph Martin (jmartin@hlo.dec.com).
-	   I'm going to leave this here anyway, just to Be Sure.  -- r~  */
-	if (prev_mm != next_mm)
-		tbiap();
-
-	/* Do continue to allocate ASNs, because we can still use them
-	   to avoid flushing the icache.  */
-	ev5_switch_mm(prev_mm, next_mm, next);
-}
-
 extern void __load_new_mm_context(struct mm_struct *);
 asmlinkage void do_page_fault(unsigned long address, unsigned long mmcsr,
 			      long cause, struct pt_regs *regs);
@@ -209,25 +187,8 @@ ev5_activate_mm(struct mm_struct *prev_mm, struct mm_struct *next_mm)
 	__load_new_mm_context(next_mm);
 }
 
-__EXTERN_INLINE void
-ev4_activate_mm(struct mm_struct *prev_mm, struct mm_struct *next_mm)
-{
-	__load_new_mm_context(next_mm);
-	tbiap();
-}
-
-#ifdef CONFIG_ALPHA_GENERIC
-# define switch_mm(a,b,c)	alpha_mv.mv_switch_mm((a),(b),(c))
-# define activate_mm(x,y)	alpha_mv.mv_activate_mm((x),(y))
-#else
-# ifdef CONFIG_ALPHA_EV4
-#  define switch_mm(a,b,c)	ev4_switch_mm((a),(b),(c))
-#  define activate_mm(x,y)	ev4_activate_mm((x),(y))
-# else
-#  define switch_mm(a,b,c)	ev5_switch_mm((a),(b),(c))
-#  define activate_mm(x,y)	ev5_activate_mm((x),(y))
-# endif
-#endif
+#define switch_mm(a,b,c)	ev5_switch_mm((a),(b),(c))
+#define activate_mm(x,y)	ev5_activate_mm((x),(y))
 
 #define init_new_context init_new_context
 static inline int
diff --git a/arch/alpha/include/asm/special_insns.h b/arch/alpha/include/asm/special_insns.h
index ca2c5c30b22e..798d0bdb11f9 100644
--- a/arch/alpha/include/asm/special_insns.h
+++ b/arch/alpha/include/asm/special_insns.h
@@ -15,10 +15,7 @@ enum implver_enum {
    (enum implver_enum) __implver; })
 #else
 /* Try to eliminate some dead code.  */
-#ifdef CONFIG_ALPHA_EV4
-#define implver() IMPLVER_EV4
-#endif
-#ifdef CONFIG_ALPHA_EV5
+#ifdef CONFIG_ALPHA_EV56
 #define implver() IMPLVER_EV5
 #endif
 #if defined(CONFIG_ALPHA_EV6)
diff --git a/arch/alpha/include/asm/tlbflush.h b/arch/alpha/include/asm/tlbflush.h
index 94dc37cf873a..ba4b359d6c39 100644
--- a/arch/alpha/include/asm/tlbflush.h
+++ b/arch/alpha/include/asm/tlbflush.h
@@ -14,16 +14,6 @@
 extern void __load_new_mm_context(struct mm_struct *);
 
 
-/* Use a few helper functions to hide the ugly broken ASN
-   numbers on early Alphas (ev4 and ev45).  */
-
-__EXTERN_INLINE void
-ev4_flush_tlb_current(struct mm_struct *mm)
-{
-	__load_new_mm_context(mm);
-	tbiap();
-}
-
 __EXTERN_INLINE void
 ev5_flush_tlb_current(struct mm_struct *mm)
 {
@@ -35,19 +25,6 @@ ev5_flush_tlb_current(struct mm_struct *mm)
    specific icache page.  */
 
 __EXTERN_INLINE void
-ev4_flush_tlb_current_page(struct mm_struct * mm,
-			   struct vm_area_struct *vma,
-			   unsigned long addr)
-{
-	int tbi_flag = 2;
-	if (vma->vm_flags & VM_EXEC) {
-		__load_new_mm_context(mm);
-		tbi_flag = 3;
-	}
-	tbi(tbi_flag, addr);
-}
-
-__EXTERN_INLINE void
 ev5_flush_tlb_current_page(struct mm_struct * mm,
 			   struct vm_area_struct *vma,
 			   unsigned long addr)
@@ -59,18 +36,8 @@ ev5_flush_tlb_current_page(struct mm_struct * mm,
 }
 
 
-#ifdef CONFIG_ALPHA_GENERIC
-# define flush_tlb_current		alpha_mv.mv_flush_tlb_current
-# define flush_tlb_current_page		alpha_mv.mv_flush_tlb_current_page
-#else
-# ifdef CONFIG_ALPHA_EV4
-#  define flush_tlb_current		ev4_flush_tlb_current
-#  define flush_tlb_current_page	ev4_flush_tlb_current_page
-# else
-#  define flush_tlb_current		ev5_flush_tlb_current
-#  define flush_tlb_current_page	ev5_flush_tlb_current_page
-# endif
-#endif
+#define flush_tlb_current	ev5_flush_tlb_current
+#define flush_tlb_current_page	ev5_flush_tlb_current_page
 
 #ifdef __MMU_EXTERN_INLINE
 #undef __EXTERN_INLINE
diff --git a/arch/alpha/include/asm/uaccess.h b/arch/alpha/include/asm/uaccess.h
index c32c2584c0b7..ef295cbb797c 100644
--- a/arch/alpha/include/asm/uaccess.h
+++ b/arch/alpha/include/asm/uaccess.h
@@ -96,9 +96,6 @@ struct __large_struct { unsigned long buf[100]; };
 		: "=r"(__gu_val), "=r"(__gu_err)	\
 		: "m"(__m(addr)), "1"(__gu_err))
 
-#ifdef __alpha_bwx__
-/* Those lucky bastards with ev56 and later CPUs can do byte/word moves.  */
-
 #define __get_user_16(addr)				\
 	__asm__("1: ldwu %0,%2\n"			\
 	"2:\n"						\
@@ -112,33 +109,6 @@ struct __large_struct { unsigned long buf[100]; };
 	EXC(1b,2b,%0,%1)				\
 		: "=r"(__gu_val), "=r"(__gu_err)	\
 		: "m"(__m(addr)), "1"(__gu_err))
-#else
-/* Unfortunately, we can't get an unaligned access trap for the sub-word
-   load, so we have to do a general unaligned operation.  */
-
-#define __get_user_16(addr)						\
-{									\
-	long __gu_tmp;							\
-	__asm__("1: ldq_u %0,0(%3)\n"					\
-	"2:	ldq_u %1,1(%3)\n"					\
-	"	extwl %0,%3,%0\n"					\
-	"	extwh %1,%3,%1\n"					\
-	"	or %0,%1,%0\n"						\
-	"3:\n"								\
-	EXC(1b,3b,%0,%2)						\
-	EXC(2b,3b,%0,%2)						\
-		: "=&r"(__gu_val), "=&r"(__gu_tmp), "=r"(__gu_err)	\
-		: "r"(addr), "2"(__gu_err));				\
-}
-
-#define __get_user_8(addr)						\
-	__asm__("1: ldq_u %0,0(%2)\n"					\
-	"	extbl %0,%2,%0\n"					\
-	"2:\n"								\
-	EXC(1b,2b,%0,%1)						\
-		: "=&r"(__gu_val), "=r"(__gu_err)			\
-		: "r"(addr), "1"(__gu_err))
-#endif
 
 extern void __put_user_unknown(void);
 
@@ -192,9 +162,6 @@ __asm__ __volatile__("1: stl %r2,%1\n"				\
 		: "=r"(__pu_err)				\
 		: "m"(__m(addr)), "rJ"(x), "0"(__pu_err))
 
-#ifdef __alpha_bwx__
-/* Those lucky bastards with ev56 and later CPUs can do byte/word moves.  */
-
 #define __put_user_16(x, addr)					\
 __asm__ __volatile__("1: stw %r2,%1\n"				\
 	"2:\n"							\
@@ -208,53 +175,6 @@ __asm__ __volatile__("1: stb %r2,%1\n"				\
 	EXC(1b,2b,$31,%0)					\
 		: "=r"(__pu_err)				\
 		: "m"(__m(addr)), "rJ"(x), "0"(__pu_err))
-#else
-/* Unfortunately, we can't get an unaligned access trap for the sub-word
-   write, so we have to do a general unaligned operation.  */
-
-#define __put_user_16(x, addr)					\
-{								\
-	long __pu_tmp1, __pu_tmp2, __pu_tmp3, __pu_tmp4;	\
-	__asm__ __volatile__(					\
-	"1:	ldq_u %2,1(%5)\n"				\
-	"2:	ldq_u %1,0(%5)\n"				\
-	"	inswh %6,%5,%4\n"				\
-	"	inswl %6,%5,%3\n"				\
-	"	mskwh %2,%5,%2\n"				\
-	"	mskwl %1,%5,%1\n"				\
-	"	or %2,%4,%2\n"					\
-	"	or %1,%3,%1\n"					\
-	"3:	stq_u %2,1(%5)\n"				\
-	"4:	stq_u %1,0(%5)\n"				\
-	"5:\n"							\
-	EXC(1b,5b,$31,%0)					\
-	EXC(2b,5b,$31,%0)					\
-	EXC(3b,5b,$31,%0)					\
-	EXC(4b,5b,$31,%0)					\
-		: "=r"(__pu_err), "=&r"(__pu_tmp1), 		\
-		  "=&r"(__pu_tmp2), "=&r"(__pu_tmp3), 		\
-		  "=&r"(__pu_tmp4)				\
-		: "r"(addr), "r"((unsigned long)(x)), "0"(__pu_err)); \
-}
-
-#define __put_user_8(x, addr)					\
-{								\
-	long __pu_tmp1, __pu_tmp2;				\
-	__asm__ __volatile__(					\
-	"1:	ldq_u %1,0(%4)\n"				\
-	"	insbl %3,%4,%2\n"				\
-	"	mskbl %1,%4,%1\n"				\
-	"	or %1,%2,%1\n"					\
-	"2:	stq_u %1,0(%4)\n"				\
-	"3:\n"							\
-	EXC(1b,3b,$31,%0)					\
-	EXC(2b,3b,$31,%0)					\
-		: "=r"(__pu_err), 				\
-	  	  "=&r"(__pu_tmp1), "=&r"(__pu_tmp2)		\
-		: "r"((unsigned long)(x)), "r"(addr), "0"(__pu_err)); \
-}
-#endif
-
 
 /*
  * Complex access routines
diff --git a/arch/alpha/include/uapi/asm/compiler.h b/arch/alpha/include/uapi/asm/compiler.h
index 0e00c0e13374..8c03740966b4 100644
--- a/arch/alpha/include/uapi/asm/compiler.h
+++ b/arch/alpha/include/uapi/asm/compiler.h
@@ -95,24 +95,6 @@
 #define __kernel_ldwu(mem)	(mem)
 #define __kernel_stb(val,mem)	((mem) = (val))
 #define __kernel_stw(val,mem)	((mem) = (val))
-#else
-#define __kernel_ldbu(mem)				\
-  ({ unsigned char __kir;				\
-     __asm__(".arch ev56;				\
-	      ldbu %0,%1" : "=r"(__kir) : "m"(mem));	\
-     __kir; })
-#define __kernel_ldwu(mem)				\
-  ({ unsigned short __kir;				\
-     __asm__(".arch ev56;				\
-	      ldwu %0,%1" : "=r"(__kir) : "m"(mem));	\
-     __kir; })
-#define __kernel_stb(val,mem)				\
-  __asm__(".arch ev56;					\
-	   stb %1,%0" : "=m"(mem) : "r"(val))
-#define __kernel_stw(val,mem)				\
-  __asm__(".arch ev56;					\
-	   stw %1,%0" : "=m"(mem) : "r"(val))
 #endif
 
-
 #endif /* _UAPI__ALPHA_COMPILER_H */
diff --git a/arch/alpha/kernel/machvec_impl.h b/arch/alpha/kernel/machvec_impl.h
index c2ebcb39e589..129ae36b8e6d 100644
--- a/arch/alpha/kernel/machvec_impl.h
+++ b/arch/alpha/kernel/machvec_impl.h
@@ -44,33 +44,14 @@
 
 #define DO_DEFAULT_RTC			.rtc_port = 0x70
 
-#define DO_EV4_MMU							\
-	.max_asn =			EV4_MAX_ASN,			\
-	.mv_switch_mm =			ev4_switch_mm,			\
-	.mv_activate_mm =		ev4_activate_mm,		\
-	.mv_flush_tlb_current =		ev4_flush_tlb_current,		\
-	.mv_flush_tlb_current_page =	ev4_flush_tlb_current_page
-
 #define DO_EV5_MMU							\
-	.max_asn =			EV5_MAX_ASN,			\
-	.mv_switch_mm =			ev5_switch_mm,			\
-	.mv_activate_mm =		ev5_activate_mm,		\
-	.mv_flush_tlb_current =		ev5_flush_tlb_current,		\
-	.mv_flush_tlb_current_page =	ev5_flush_tlb_current_page
+	.max_asn =			EV5_MAX_ASN			\
 
 #define DO_EV6_MMU							\
-	.max_asn =			EV6_MAX_ASN,			\
-	.mv_switch_mm =			ev5_switch_mm,			\
-	.mv_activate_mm =		ev5_activate_mm,		\
-	.mv_flush_tlb_current =		ev5_flush_tlb_current,		\
-	.mv_flush_tlb_current_page =	ev5_flush_tlb_current_page
+	.max_asn =			EV6_MAX_ASN			\
 
 #define DO_EV7_MMU							\
-	.max_asn =			EV6_MAX_ASN,			\
-	.mv_switch_mm =			ev5_switch_mm,			\
-	.mv_activate_mm =		ev5_activate_mm,		\
-	.mv_flush_tlb_current =		ev5_flush_tlb_current,		\
-	.mv_flush_tlb_current_page =	ev5_flush_tlb_current_page
+	.max_asn =			EV6_MAX_ASN			\
 
 #define IO_LITE(UP,low)							\
 	.hae_register =		(unsigned long *) CAT(UP,_HAE_ADDRESS),	\
diff --git a/arch/alpha/kernel/traps.c b/arch/alpha/kernel/traps.c
index 7fc72aeb7398..6afae65e9a8b 100644
--- a/arch/alpha/kernel/traps.c
+++ b/arch/alpha/kernel/traps.c
@@ -30,39 +30,6 @@
 
 #include "proto.h"
 
-/* Work-around for some SRMs which mishandle opDEC faults.  */
-
-static int opDEC_fix;
-
-static void
-opDEC_check(void)
-{
-	__asm__ __volatile__ (
-	/* Load the address of... */
-	"	br	$16, 1f\n"
-	/* A stub instruction fault handler.  Just add 4 to the
-	   pc and continue.  */
-	"	ldq	$16, 8($sp)\n"
-	"	addq	$16, 4, $16\n"
-	"	stq	$16, 8($sp)\n"
-	"	call_pal %[rti]\n"
-	/* Install the instruction fault handler.  */
-	"1:	lda	$17, 3\n"
-	"	call_pal %[wrent]\n"
-	/* With that in place, the fault from the round-to-minf fp
-	   insn will arrive either at the "lda 4" insn (bad) or one
-	   past that (good).  This places the correct fixup in %0.  */
-	"	lda %[fix], 0\n"
-	"	cvttq/svm $f31,$f31\n"
-	"	lda %[fix], 4"
-	: [fix] "=r" (opDEC_fix)
-	: [rti] "n" (PAL_rti), [wrent] "n" (PAL_wrent)
-	: "$0", "$1", "$16", "$17", "$22", "$23", "$24", "$25");
-
-	if (opDEC_fix)
-		printk("opDEC fixup enabled.\n");
-}
-
 void
 dik_show_regs(struct pt_regs *regs, unsigned long *r9_15)
 {
@@ -353,32 +320,6 @@ do_entIF(unsigned long type, struct pt_regs *regs)
 		return;
 
 	      case 4: /* opDEC */
-		if (implver() == IMPLVER_EV4) {
-			long si_code;
-
-			/* The some versions of SRM do not handle
-			   the opDEC properly - they return the PC of the
-			   opDEC fault, not the instruction after as the
-			   Alpha architecture requires.  Here we fix it up.
-			   We do this by intentionally causing an opDEC
-			   fault during the boot sequence and testing if
-			   we get the correct PC.  If not, we set a flag
-			   to correct it every time through.  */
-			regs->pc += opDEC_fix; 
-			
-			/* EV4 does not implement anything except normal
-			   rounding.  Everything else will come here as
-			   an illegal instruction.  Emulate them.  */
-			si_code = alpha_fp_emul(regs->pc - 4);
-			if (si_code == 0)
-				return;
-			if (si_code > 0) {
-				send_sig_fault_trapno(SIGFPE, si_code,
-						      (void __user *) regs->pc,
-						      0, current);
-				return;
-			}
-		}
 		break;
 
 	      case 5: /* illoc */
@@ -979,11 +920,6 @@ trap_init(void)
 	register unsigned long gptr __asm__("$29");
 	wrkgp(gptr);
 
-	/* Hack for Multia (UDB) and JENSEN: some of their SRMs have
-	   a bug in the handling of the opDEC fault.  Fix it up if so.  */
-	if (implver() == IMPLVER_EV4)
-		opDEC_check();
-
 	wrent(entArith, 1);
 	wrent(entMM, 2);
 	wrent(entIF, 3);