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>

2 files changed, 3 insertions, 86 deletions

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);