s390: raise minimum supported machine generation to z10

Machine generations up to z9 (released in May 2006) have been officially
out of service for several years now (z9 end of service - January 31, 2019).
No distributions build kernels supporting those old machine generations
anymore, except Debian, which seems to pick the oldest supported
generation. The team supporting Debian on s390 has been notified about
the change.

Raising minimum supported machine generation to z10 helps to reduce
maintenance cost and effectively remove code, which is not getting
enough testing coverage due to lack of older hardware and distributions
support. Besides that this unblocks some optimization opportunities and
allows to use wider instruction set in asm files for future features
implementation. Due to this change spectre mitigation and usercopy
implementations could be drastically simplified and many newer instructions
could be converted from ".insn" encoding to instruction names.

Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

Author: Vasily Gorbik

arch/s390/Kconfig

@@ -120,7 +120,6 @@ config S390
 	select ARCH_WANT_IPC_PARSE_VERSION
 	select BUILDTIME_TABLE_SORT
 	select CLONE_BACKWARDS2
-	select CPU_NO_EFFICIENT_FFS if !HAVE_MARCH_Z9_109_FEATURES
 	select DMA_OPS if PCI
 	select DYNAMIC_FTRACE if FUNCTION_TRACER
 	select GENERIC_ALLOCATOR
@@ -230,20 +229,8 @@ source "kernel/livepatch/Kconfig"
 
 menu "Processor type and features"
 
-config HAVE_MARCH_Z900_FEATURES
-	def_bool n
-
-config HAVE_MARCH_Z990_FEATURES
-	def_bool n
-	select HAVE_MARCH_Z900_FEATURES
-
-config HAVE_MARCH_Z9_109_FEATURES
-	def_bool n
-	select HAVE_MARCH_Z990_FEATURES
-
 config HAVE_MARCH_Z10_FEATURES
 	def_bool n
-	select HAVE_MARCH_Z9_109_FEATURES
 
 config HAVE_MARCH_Z196_FEATURES
 	def_bool n
@@ -269,41 +256,13 @@ choice
 	prompt "Processor type"
 	default MARCH_Z196
 
-config MARCH_Z900
-	bool "IBM zSeries model z800 and z900"
-	select HAVE_MARCH_Z900_FEATURES
-	depends on $(cc-option,-march=z900)
-	help
-	  Select this to enable optimizations for model z800/z900 (2064 and
-	  2066 series). This will enable some optimizations that are not
-	  available on older ESA/390 (31 Bit) only CPUs.
-
-config MARCH_Z990
-	bool "IBM zSeries model z890 and z990"
-	select HAVE_MARCH_Z990_FEATURES
-	depends on $(cc-option,-march=z990)
-	help
-	  Select this to enable optimizations for model z890/z990 (2084 and
-	  2086 series). The kernel will be slightly faster but will not work
-	  on older machines.
-
-config MARCH_Z9_109
-	bool "IBM System z9"
-	select HAVE_MARCH_Z9_109_FEATURES
-	depends on $(cc-option,-march=z9-109)
-	help
-	  Select this to enable optimizations for IBM System z9 (2094 and
-	  2096 series). The kernel will be slightly faster but will not work
-	  on older machines.
-
 config MARCH_Z10
 	bool "IBM System z10"
 	select HAVE_MARCH_Z10_FEATURES
 	depends on $(cc-option,-march=z10)
 	help
-	  Select this to enable optimizations for IBM System z10 (2097 and
-	  2098 series). The kernel will be slightly faster but will not work
-	  on older machines.
+	  Select this to enable optimizations for IBM System z10 (2097 and 2098
+	  series). This is the oldest machine generation currently supported.
 
 config MARCH_Z196
 	bool "IBM zEnterprise 114 and 196"
@@ -352,15 +311,6 @@ config MARCH_Z15
 
 endchoice
 
-config MARCH_Z900_TUNE
-	def_bool TUNE_Z900 || MARCH_Z900 && TUNE_DEFAULT
-
-config MARCH_Z990_TUNE
-	def_bool TUNE_Z990 || MARCH_Z990 && TUNE_DEFAULT
-
-config MARCH_Z9_109_TUNE
-	def_bool TUNE_Z9_109 || MARCH_Z9_109 && TUNE_DEFAULT
-
 config MARCH_Z10_TUNE
 	def_bool TUNE_Z10 || MARCH_Z10 && TUNE_DEFAULT
 
@@ -396,21 +346,8 @@ config TUNE_DEFAULT
 	  Tune the generated code for the target processor for which the kernel
 	  will be compiled.
 
-config TUNE_Z900
-	bool "IBM zSeries model z800 and z900"
-	depends on $(cc-option,-mtune=z900)
-
-config TUNE_Z990
-	bool "IBM zSeries model z890 and z990"
-	depends on $(cc-option,-mtune=z990)
-
-config TUNE_Z9_109
-	bool "IBM System z9"
-	depends on $(cc-option,-mtune=z9-109)
-
 config TUNE_Z10
 	bool "IBM System z10"
-	depends on $(cc-option,-mtune=z10)
 
 config TUNE_Z196
 	bool "IBM zEnterprise 114 and 196"
@@ -599,7 +536,6 @@ config EXPOLINE
 config EXPOLINE_EXTERN
 	def_bool n
 	depends on EXPOLINE
-	depends on HAVE_MARCH_Z10_FEATURES
 	depends on CC_IS_GCC && GCC_VERSION >= 110200
 	depends on $(success,$(srctree)/arch/s390/tools/gcc-thunk-extern.sh $(CC))
 	prompt "Generate expolines as extern functions."

arch/s390/Makefile

@@ -36,9 +36,6 @@ CHECKFLAGS	+= -D__s390__ -D__s390x__
 
 export LD_BFD
 
-mflags-$(CONFIG_MARCH_Z900)   := -march=z900
-mflags-$(CONFIG_MARCH_Z990)   := -march=z990
-mflags-$(CONFIG_MARCH_Z9_109) := -march=z9-109
 mflags-$(CONFIG_MARCH_Z10)    := -march=z10
 mflags-$(CONFIG_MARCH_Z196)   := -march=z196
 mflags-$(CONFIG_MARCH_ZEC12)  := -march=zEC12
@@ -51,9 +48,6 @@ export CC_FLAGS_MARCH := $(mflags-y)
 aflags-y += $(mflags-y)
 cflags-y += $(mflags-y)
 
-cflags-$(CONFIG_MARCH_Z900_TUNE)	+= -mtune=z900
-cflags-$(CONFIG_MARCH_Z990_TUNE)	+= -mtune=z990
-cflags-$(CONFIG_MARCH_Z9_109_TUNE)	+= -mtune=z9-109
 cflags-$(CONFIG_MARCH_Z10_TUNE)		+= -mtune=z10
 cflags-$(CONFIG_MARCH_Z196_TUNE)	+= -mtune=z196
 cflags-$(CONFIG_MARCH_ZEC12_TUNE)	+= -mtune=zEC12

arch/s390/include/asm/bitops.h

@@ -256,8 +256,6 @@ static inline bool test_bit_inv(unsigned long nr,
 	return test_bit(nr ^ (BITS_PER_LONG - 1), ptr);
 }
 
-#ifdef CONFIG_HAVE_MARCH_Z9_109_FEATURES
-
 /**
  * __flogr - find leftmost one
  * @word - The word to search
@@ -376,16 +374,6 @@ static inline int fls(unsigned int word)
 	return fls64(word);
 }
 
-#else /* CONFIG_HAVE_MARCH_Z9_109_FEATURES */
-
-#include <asm-generic/bitops/__ffs.h>
-#include <asm-generic/bitops/ffs.h>
-#include <asm-generic/bitops/__fls.h>
-#include <asm-generic/bitops/fls.h>
-#include <asm-generic/bitops/fls64.h>
-
-#endif /* CONFIG_HAVE_MARCH_Z9_109_FEATURES */
-
 #include <asm-generic/bitops/ffz.h>
 #include <asm-generic/bitops/hweight.h>
 #include <asm-generic/bitops/sched.h>

arch/s390/include/asm/lowcore.h

@@ -163,11 +163,9 @@ struct lowcore {
 	__u64	gmap;				/* 0x03d0 */
 	__u8	pad_0x03d8[0x0400-0x03d8];	/* 0x03d8 */
 
-	/* br %r1 trampoline */
-	__u16	br_r1_trampoline;		/* 0x0400 */
-	__u32	return_lpswe;			/* 0x0402 */
-	__u32	return_mcck_lpswe;		/* 0x0406 */
-	__u8	pad_0x040a[0x0e00-0x040a];	/* 0x040a */
+	__u32	return_lpswe;			/* 0x0400 */
+	__u32	return_mcck_lpswe;		/* 0x0404 */
+	__u8	pad_0x040a[0x0e00-0x0408];	/* 0x0408 */
 
 	/*
 	 * 0xe00 contains the address of the IPL Parameter Information

arch/s390/include/asm/nospec-insn.h

@@ -10,8 +10,6 @@
 
 #ifdef CC_USING_EXPOLINE
 
-_LC_BR_R1 = __LC_BR_R1
-
 /*
  * The expoline macros are used to create thunks in the same format
  * as gcc generates them. The 'comdat' section flag makes sure that
@@ -39,7 +37,6 @@ _LC_BR_R1 = __LC_BR_R1
 	.popsection
 	.endm
 
-#ifdef CONFIG_HAVE_MARCH_Z10_FEATURES
 	.macro __THUNK_PROLOG_BR r1,r2
 	__THUNK_PROLOG_NAME __s390_indirect_jump_r\r1
 	.endm
@@ -55,23 +52,6 @@ _LC_BR_R1 = __LC_BR_R1
 	.macro __THUNK_BRASL r1,r2,r3
 	brasl	\r1,__s390_indirect_jump_r\r2
 	.endm
-#else
-	.macro __THUNK_PROLOG_BR r1,r2
-	__THUNK_PROLOG_NAME __s390_indirect_jump_r\r2\()use_r\r1
-	.endm
-
-	.macro __THUNK_EPILOG_BR r1,r2
-	__THUNK_EPILOG_NAME __s390_indirect_jump_r\r2\()use_r\r1
-	.endm
-
-	.macro __THUNK_BR r1,r2
-	jg	__s390_indirect_jump_r\r2\()use_r\r1
-	.endm
-
-	.macro __THUNK_BRASL r1,r2,r3
-	brasl	\r1,__s390_indirect_jump_r\r3\()use_r\r2
-	.endm
-#endif
 
 	.macro	__DECODE_RR expand,reg,ruse
 	.set __decode_fail,1
@@ -112,22 +92,8 @@ _LC_BR_R1 = __LC_BR_R1
 	.endm
 
 	.macro __THUNK_EX_BR reg,ruse
-	# Be very careful when adding instructions to this macro!
-	# The ALTERNATIVE replacement code has a .+10 which targets
-	# the "br \reg" after the code has been patched.
-#ifdef CONFIG_HAVE_MARCH_Z10_FEATURES
 	exrl	0,555f
 	j	.
-#else
-	.ifc \reg,%r1
-	ALTERNATIVE "ex %r0,_LC_BR_R1", ".insn ril,0xc60000000000,0,.+10", 35
-	j	.
-	.else
-	larl	\ruse,555f
-	ex	0,0(\ruse)
-	j	.
-	.endif
-#endif
 555:	br	\reg
 	.endm
 

arch/s390/include/asm/timex.h

@@ -187,14 +187,10 @@ static inline unsigned long get_tod_clock(void)
 
 static inline unsigned long get_tod_clock_fast(void)
 {
-#ifdef CONFIG_HAVE_MARCH_Z9_109_FEATURES
 	unsigned long clk;
 
 	asm volatile("stckf %0" : "=Q" (clk) : : "cc");
 	return clk;
-#else
-	return get_tod_clock();
-#endif
 }
 
 static inline cycles_t get_cycles(void)

arch/s390/include/asm/uaccess.h

@@ -92,8 +92,6 @@ union oac {
 	};
 };
 
-#ifdef CONFIG_HAVE_MARCH_Z10_FEATURES
-
 #define __put_get_user_asm(to, from, size, oac_spec)			\
 ({									\
 	int __rc;							\
@@ -187,22 +185,6 @@ static __always_inline int __get_user_fn(void *x, const void __user *ptr, unsign
 	return rc;
 }
 
-#else /* CONFIG_HAVE_MARCH_Z10_FEATURES */
-
-static inline int __put_user_fn(void *x, void __user *ptr, unsigned long size)
-{
-	size = raw_copy_to_user(ptr, x, size);
-	return size ? -EFAULT : 0;
-}
-
-static inline int __get_user_fn(void *x, const void __user *ptr, unsigned long size)
-{
-	size = raw_copy_from_user(x, ptr, size);
-	return size ? -EFAULT : 0;
-}
-
-#endif /* CONFIG_HAVE_MARCH_Z10_FEATURES */
-
 /*
  * These are the main single-value transfer routines.  They automatically
  * use the right size if we just have the right pointer type.

arch/s390/kernel/asm-offsets.c

@@ -122,7 +122,6 @@ int main(void)
 	OFFSET(__LC_LPP, lowcore, lpp);
 	OFFSET(__LC_CURRENT_PID, lowcore, current_pid);
 	OFFSET(__LC_GMAP, lowcore, gmap);
-	OFFSET(__LC_BR_R1, lowcore, br_r1_trampoline);
 	OFFSET(__LC_LAST_BREAK, lowcore, last_break);
 	/* software defined ABI-relevant lowcore locations 0xe00 - 0xe20 */
 	OFFSET(__LC_DUMP_REIPL, lowcore, ipib);

arch/s390/kernel/cache.c

@@ -70,8 +70,6 @@ void show_cacheinfo(struct seq_file *m)
 	struct cacheinfo *cache;
 	int idx;
 
-	if (!test_facility(34))
-		return;
 	this_cpu_ci = get_cpu_cacheinfo(cpumask_any(cpu_online_mask));
 	for (idx = 0; idx < this_cpu_ci->num_leaves; idx++) {
 		cache = this_cpu_ci->info_list + idx;
@@ -131,8 +129,6 @@ int init_cache_level(unsigned int cpu)
 	union cache_topology ct;
 	enum cache_type ctype;
 
-	if (!test_facility(34))
-		return -EOPNOTSUPP;
 	if (!this_cpu_ci)
 		return -EINVAL;
 	ct.raw = ecag(EXTRACT_TOPOLOGY, 0, 0);
@@ -156,8 +152,6 @@ int populate_cache_leaves(unsigned int cpu)
 	union cache_topology ct;
 	enum cache_type ctype;
 
-	if (!test_facility(34))
-		return -EOPNOTSUPP;
 	ct.raw = ecag(EXTRACT_TOPOLOGY, 0, 0);
 	for (idx = 0, level = 0; level < this_cpu_ci->num_levels &&
 	     idx < this_cpu_ci->num_leaves; idx++, level++) {

arch/s390/kernel/ftrace.c

@@ -58,15 +58,6 @@ asm(
 );
 
 #ifdef CONFIG_EXPOLINE
-asm(
-	"	.align 16\n"
-	"ftrace_shared_hotpatch_trampoline_ex:\n"
-	"	lmg	%r0,%r1,2(%r1)\n"
-	"	ex	%r0," __stringify(__LC_BR_R1) "(%r0)\n"
-	"	j	.\n"
-	"ftrace_shared_hotpatch_trampoline_ex_end:\n"
-);
-
 asm(
 	"	.align 16\n"
 	"ftrace_shared_hotpatch_trampoline_exrl:\n"
@@ -90,12 +81,8 @@ static const char *ftrace_shared_hotpatch_trampoline(const char **end)
 	tend = ftrace_shared_hotpatch_trampoline_br_end;
 #ifdef CONFIG_EXPOLINE
 	if (!nospec_disable) {
-		tstart = ftrace_shared_hotpatch_trampoline_ex;
-		tend = ftrace_shared_hotpatch_trampoline_ex_end;
-		if (test_facility(35)) { /* exrl */
-			tstart = ftrace_shared_hotpatch_trampoline_exrl;
-			tend = ftrace_shared_hotpatch_trampoline_exrl_end;
-		}
+		tstart = ftrace_shared_hotpatch_trampoline_exrl;
+		tend = ftrace_shared_hotpatch_trampoline_exrl_end;
 	}
 #endif /* CONFIG_EXPOLINE */
 	if (end)