Merge tag 's390-6.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull more s390 updates from Vasily Gorbik:

 - Fix KMSAN build breakage caused by the conflict between s390 and
   mm-stable trees

 - Add KMSAN page markers for ptdump

 - Add runtime constant support

 - Fix __pa/__va for modules under non-GPL licenses by exporting
   necessary vm_layout struct with EXPORT_SYMBOL to prevent linkage
   problems

 - Fix an endless loop in the CF_DIAG event stop in the CPU Measurement
   Counter Facility code when the counter set size is zero

 - Remove the PROTECTED_VIRTUALIZATION_GUEST config option and enable
   its functionality by default

 - Support allocation of multiple MSI interrupts per device and improve
   logging of architecture-specific limitations

 - Add support for lowcore relocation as a debugging feature to catch
   all null ptr dereferences in the kernel address space, improving
   detection beyond the current implementation's limited write access
   protection

 - Clean up and rework CPU alternatives to allow for callbacks and early
   patching for the lowcore relocation

* tag 's390-6.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (39 commits)
  s390: Remove protvirt and kvm config guards for uv code
  s390/boot: Add cmdline option to relocate lowcore
  s390/kdump: Make kdump ready for lowcore relocation
  s390/entry: Make system_call() ready for lowcore relocation
  s390/entry: Make ret_from_fork() ready for lowcore relocation
  s390/entry: Make __switch_to() ready for lowcore relocation
  s390/entry: Make restart_int_handler() ready for lowcore relocation
  s390/entry: Make mchk_int_handler() ready for lowcore relocation
  s390/entry: Make int handlers ready for lowcore relocation
  s390/entry: Make pgm_check_handler() ready for lowcore relocation
  s390/entry: Add base register to CHECK_VMAP_STACK/CHECK_STACK macro
  s390/entry: Add base register to SIEEXIT macro
  s390/entry: Add base register to MBEAR macro
  s390/entry: Make __sie64a() ready for lowcore relocation
  s390/head64: Make startup code ready for lowcore relocation
  s390: Add infrastructure to patch lowcore accesses
  s390/atomic_ops: Disable flag outputs constraint for GCC versions below 14.2.0
  s390/entry: Move SIE indicator flag to thread info
  s390/nmi: Simplify ptregs setup
  s390/alternatives: Remove alternative facility list
  ...

Documentation/admin-guide/kernel-parameters.txt

@@ -3830,9 +3830,6 @@
 
 	noalign		[KNL,ARM]
 
-	noaltinstr	[S390,EARLY] Disables alternative instructions
-			patching (CPU alternatives feature).
-
 	noapic		[SMP,APIC,EARLY] Tells the kernel to not make use of any
 			IOAPICs that may be present in the system.
 

arch/s390/Kconfig

@@ -799,17 +799,6 @@ config HAVE_PNETID
 
 menu "Virtualization"
 
-config PROTECTED_VIRTUALIZATION_GUEST
-	def_bool n
-	prompt "Protected virtualization guest support"
-	help
-	  Select this option, if you want to be able to run this
-	  kernel as a protected virtualization KVM guest.
-	  Protected virtualization capable machines have a mini hypervisor
-	  located at machine level (an ultravisor). With help of the
-	  Ultravisor, KVM will be able to run "protected" VMs, special
-	  VMs whose memory and management data are unavailable to KVM.
-
 config PFAULT
 	def_bool y
 	prompt "Pseudo page fault support"

arch/s390/boot/Makefile

@@ -39,8 +39,7 @@ CFLAGS_sclp_early_core.o += -I$(srctree)/drivers/s390/char
 
 obj-y	:= head.o als.o startup.o physmem_info.o ipl_parm.o ipl_report.o vmem.o
 obj-y	+= string.o ebcdic.o sclp_early_core.o mem.o ipl_vmparm.o cmdline.o
-obj-y	+= version.o pgm_check_info.o ctype.o ipl_data.o relocs.o
-obj-$(findstring y, $(CONFIG_PROTECTED_VIRTUALIZATION_GUEST) $(CONFIG_PGSTE))	+= uv.o
+obj-y	+= version.o pgm_check_info.o ctype.o ipl_data.o relocs.o alternative.o uv.o
 obj-$(CONFIG_RANDOMIZE_BASE)	+= kaslr.o
 obj-y	+= $(if $(CONFIG_KERNEL_UNCOMPRESSED),,decompressor.o) info.o
 obj-$(CONFIG_KERNEL_ZSTD) += clz_ctz.o

arch/s390/boot/alternative.c

@@ -0,0 +1,3 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "../kernel/alternative.c"

arch/s390/boot/boot.h

@@ -30,6 +30,8 @@ struct vmlinux_info {
 	unsigned long init_mm_off;
 	unsigned long swapper_pg_dir_off;
 	unsigned long invalid_pg_dir_off;
+	unsigned long alt_instructions;
+	unsigned long alt_instructions_end;
 #ifdef CONFIG_KASAN
 	unsigned long kasan_early_shadow_page_off;
 	unsigned long kasan_early_shadow_pte_off;
@@ -89,8 +91,10 @@ extern char _end[], _decompressor_end[];
 extern unsigned char _compressed_start[];
 extern unsigned char _compressed_end[];
 extern struct vmlinux_info _vmlinux_info;
+
 #define vmlinux _vmlinux_info
 
+#define __lowcore_pa(x)		((unsigned long)(x) % sizeof(struct lowcore))
 #define __abs_lowcore_pa(x)	(((unsigned long)(x) - __abs_lowcore) % sizeof(struct lowcore))
 #define __kernel_va(x)		((void *)((unsigned long)(x) - __kaslr_offset_phys + __kaslr_offset))
 #define __kernel_pa(x)		((unsigned long)(x) - __kaslr_offset + __kaslr_offset_phys)

arch/s390/boot/ipl_parm.c

@@ -3,6 +3,7 @@
 #include <linux/init.h>
 #include <linux/ctype.h>
 #include <linux/pgtable.h>
+#include <asm/abs_lowcore.h>
 #include <asm/page-states.h>
 #include <asm/ebcdic.h>
 #include <asm/sclp.h>
@@ -310,5 +311,7 @@ void parse_boot_command_line(void)
 				prot_virt_host = 1;
 		}
 #endif
+		if (!strcmp(param, "relocate_lowcore") && test_facility(193))
+			relocate_lowcore = 1;
 	}
 }

arch/s390/boot/startup.c

@@ -30,6 +30,7 @@ unsigned long __bootdata_preserved(vmemmap_size);
 unsigned long __bootdata_preserved(MODULES_VADDR);
 unsigned long __bootdata_preserved(MODULES_END);
 unsigned long __bootdata_preserved(max_mappable);
+int __bootdata_preserved(relocate_lowcore);
 
 u64 __bootdata_preserved(stfle_fac_list[16]);
 struct oldmem_data __bootdata_preserved(oldmem_data);
@@ -376,6 +377,8 @@ static void kaslr_adjust_vmlinux_info(long offset)
 	vmlinux.init_mm_off += offset;
 	vmlinux.swapper_pg_dir_off += offset;
 	vmlinux.invalid_pg_dir_off += offset;
+	vmlinux.alt_instructions += offset;
+	vmlinux.alt_instructions_end += offset;
 #ifdef CONFIG_KASAN
 	vmlinux.kasan_early_shadow_page_off += offset;
 	vmlinux.kasan_early_shadow_pte_off += offset;
@@ -478,8 +481,12 @@ void startup_kernel(void)
 	 * before the kernel started. Therefore, in case the two sections
 	 * overlap there is no risk of corrupting any data.
 	 */
-	if (kaslr_enabled())
-		amode31_lma = randomize_within_range(vmlinux.amode31_size, PAGE_SIZE, 0, SZ_2G);
+	if (kaslr_enabled()) {
+		unsigned long amode31_min;
+
+		amode31_min = (unsigned long)_decompressor_end;
+		amode31_lma = randomize_within_range(vmlinux.amode31_size, PAGE_SIZE, amode31_min, SZ_2G);
+	}
 	if (!amode31_lma)
 		amode31_lma = __kaslr_offset_phys - vmlinux.amode31_size;
 	physmem_reserve(RR_AMODE31, amode31_lma, vmlinux.amode31_size);
@@ -503,6 +510,9 @@ void startup_kernel(void)
 	kaslr_adjust_got(__kaslr_offset);
 	setup_vmem(__kaslr_offset, __kaslr_offset + kernel_size, asce_limit);
 	copy_bootdata();
+	__apply_alternatives((struct alt_instr *)_vmlinux_info.alt_instructions,
+			     (struct alt_instr *)_vmlinux_info.alt_instructions_end,
+			     ALT_CTX_EARLY);
 
 	/*
 	 * Save KASLR offset for early dumps, before vmcore_info is set.

arch/s390/boot/uv.c

@@ -8,12 +8,8 @@
 #include "uv.h"
 
 /* will be used in arch/s390/kernel/uv.c */
-#ifdef CONFIG_PROTECTED_VIRTUALIZATION_GUEST
 int __bootdata_preserved(prot_virt_guest);
-#endif
-#if IS_ENABLED(CONFIG_KVM)
 int __bootdata_preserved(prot_virt_host);
-#endif
 struct uv_info __bootdata_preserved(uv_info);
 
 void uv_query_info(void)
@@ -53,14 +49,11 @@ void uv_query_info(void)
 		uv_info.max_secrets = uvcb.max_secrets;
 	}
 
-#ifdef CONFIG_PROTECTED_VIRTUALIZATION_GUEST
 	if (test_bit_inv(BIT_UVC_CMD_SET_SHARED_ACCESS, (unsigned long *)uvcb.inst_calls_list) &&
 	    test_bit_inv(BIT_UVC_CMD_REMOVE_SHARED_ACCESS, (unsigned long *)uvcb.inst_calls_list))
 		prot_virt_guest = 1;
-#endif
 }
 
-#if IS_ENABLED(CONFIG_KVM)
 unsigned long adjust_to_uv_max(unsigned long limit)
 {
 	if (is_prot_virt_host() && uv_info.max_sec_stor_addr)
@@ -92,4 +85,3 @@ void sanitize_prot_virt_host(void)
 {
 	prot_virt_host = is_prot_virt_host_capable();
 }
-#endif

arch/s390/boot/uv.h

@@ -2,21 +2,8 @@
 #ifndef BOOT_UV_H
 #define BOOT_UV_H
 
-#if IS_ENABLED(CONFIG_KVM)
 unsigned long adjust_to_uv_max(unsigned long limit);
 void sanitize_prot_virt_host(void);
-#else
-static inline unsigned long adjust_to_uv_max(unsigned long limit)
-{
-	return limit;
-}
-static inline void sanitize_prot_virt_host(void) {}
-#endif
-
-#if defined(CONFIG_PROTECTED_VIRTUALIZATION_GUEST) || IS_ENABLED(CONFIG_KVM)
 void uv_query_info(void);
-#else
-static inline void uv_query_info(void) {}
-#endif
 
 #endif /* BOOT_UV_H */

arch/s390/boot/vmem.c

@@ -26,6 +26,7 @@ atomic_long_t __bootdata_preserved(direct_pages_count[PG_DIRECT_MAP_MAX]);
 enum populate_mode {
 	POPULATE_NONE,
 	POPULATE_DIRECT,
+	POPULATE_LOWCORE,
 	POPULATE_ABS_LOWCORE,
 	POPULATE_IDENTITY,
 	POPULATE_KERNEL,
@@ -242,6 +243,8 @@ static unsigned long _pa(unsigned long addr, unsigned long size, enum populate_m
 		return -1;
 	case POPULATE_DIRECT:
 		return addr;
+	case POPULATE_LOWCORE:
+		return __lowcore_pa(addr);
 	case POPULATE_ABS_LOWCORE:
 		return __abs_lowcore_pa(addr);
 	case POPULATE_KERNEL:
@@ -418,6 +421,7 @@ static void pgtable_populate(unsigned long addr, unsigned long end, enum populat
 
 void setup_vmem(unsigned long kernel_start, unsigned long kernel_end, unsigned long asce_limit)
 {
+	unsigned long lowcore_address = 0;
 	unsigned long start, end;
 	unsigned long asce_type;
 	unsigned long asce_bits;
@@ -455,12 +459,17 @@ void setup_vmem(unsigned long kernel_start, unsigned long kernel_end, unsigned l
 	__arch_set_page_dat((void *)swapper_pg_dir, 1UL << CRST_ALLOC_ORDER);
 	__arch_set_page_dat((void *)invalid_pg_dir, 1UL << CRST_ALLOC_ORDER);
 
+	if (relocate_lowcore)
+		lowcore_address = LOWCORE_ALT_ADDRESS;
+
 	/*
 	 * To allow prefixing the lowcore must be mapped with 4KB pages.
 	 * To prevent creation of a large page at address 0 first map
 	 * the lowcore and create the identity mapping only afterwards.
 	 */
-	pgtable_populate(0, sizeof(struct lowcore), POPULATE_DIRECT);
+	pgtable_populate(lowcore_address,
+			 lowcore_address + sizeof(struct lowcore),
+			 POPULATE_LOWCORE);
 	for_each_physmem_usable_range(i, &start, &end) {
 		pgtable_populate((unsigned long)__identity_va(start),
 				 (unsigned long)__identity_va(end),

arch/s390/configs/debug_defconfig

@@ -55,7 +55,6 @@ CONFIG_EXPOLINE_AUTO=y
 CONFIG_CHSC_SCH=y
 CONFIG_VFIO_CCW=m
 CONFIG_VFIO_AP=m
-CONFIG_PROTECTED_VIRTUALIZATION_GUEST=y
 CONFIG_CMM=m
 CONFIG_APPLDATA_BASE=y
 CONFIG_S390_HYPFS_FS=y

arch/s390/configs/defconfig

@@ -53,7 +53,6 @@ CONFIG_EXPOLINE_AUTO=y
 CONFIG_CHSC_SCH=y
 CONFIG_VFIO_CCW=m
 CONFIG_VFIO_AP=m
-CONFIG_PROTECTED_VIRTUALIZATION_GUEST=y
 CONFIG_CMM=m
 CONFIG_APPLDATA_BASE=y
 CONFIG_S390_HYPFS_FS=y

arch/s390/include/asm/abs_lowcore.h

@@ -2,6 +2,7 @@
 #ifndef _ASM_S390_ABS_LOWCORE_H
 #define _ASM_S390_ABS_LOWCORE_H
 
+#include <asm/sections.h>
 #include <asm/lowcore.h>
 
 #define ABS_LOWCORE_MAP_SIZE	(NR_CPUS * sizeof(struct lowcore))
@@ -24,4 +25,11 @@ static inline void put_abs_lowcore(struct lowcore *lc)
 	put_cpu();
 }
 
+extern int __bootdata_preserved(relocate_lowcore);
+
+static inline int have_relocated_lowcore(void)
+{
+	return relocate_lowcore;
+}
+
 #endif /* _ASM_S390_ABS_LOWCORE_H */

arch/s390/include/asm/alternative-asm.h

@@ -1,57 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _ASM_S390_ALTERNATIVE_ASM_H
-#define _ASM_S390_ALTERNATIVE_ASM_H
-
-#ifdef __ASSEMBLY__
-
-/*
- * Issue one struct alt_instr descriptor entry (need to put it into
- * the section .altinstructions, see below). This entry contains
- * enough information for the alternatives patching code to patch an
- * instruction. See apply_alternatives().
- */
-.macro alt_entry orig_start, orig_end, alt_start, alt_end, feature
-	.long	\orig_start - .
-	.long	\alt_start - .
-	.word	\feature
-	.byte	\orig_end - \orig_start
-	.org	. - ( \orig_end - \orig_start ) & 1
-	.org	. - ( \orig_end - \orig_start ) + ( \alt_end - \alt_start )
-	.org	. - ( \alt_end - \alt_start ) + ( \orig_end - \orig_start )
-.endm
-
-/*
- * Define an alternative between two instructions. If @feature is
- * present, early code in apply_alternatives() replaces @oldinstr with
- * @newinstr.
- */
-.macro ALTERNATIVE oldinstr, newinstr, feature
-	.pushsection .altinstr_replacement,"ax"
-770:	\newinstr
-771:	.popsection
-772:	\oldinstr
-773:	.pushsection .altinstructions,"a"
-	alt_entry 772b, 773b, 770b, 771b, \feature
-	.popsection
-.endm
-
-/*
- * Define an alternative between two instructions. If @feature is
- * present, early code in apply_alternatives() replaces @oldinstr with
- * @newinstr.
- */
-.macro ALTERNATIVE_2 oldinstr, newinstr1, feature1, newinstr2, feature2
-	.pushsection .altinstr_replacement,"ax"
-770:	\newinstr1
-771:	\newinstr2
-772:	.popsection
-773:	\oldinstr
-774:	.pushsection .altinstructions,"a"
-	alt_entry 773b, 774b, 770b, 771b,\feature1
-	alt_entry 773b, 774b, 771b, 772b,\feature2
-	.popsection
-.endm
-
-#endif	/*  __ASSEMBLY__  */
-
-#endif /* _ASM_S390_ALTERNATIVE_ASM_H */

arch/s390/include/asm/alternative.h

@@ -2,6 +2,58 @@
 #ifndef _ASM_S390_ALTERNATIVE_H
 #define _ASM_S390_ALTERNATIVE_H
 
+/*
+ * Each alternative comes with a 32 bit feature field:
+ *	union {
+ *		u32 feature;
+ *		struct {
+ *			u32 ctx	 : 4;
+ *			u32 type : 8;
+ *			u32 data : 20;
+ *		};
+ *	}
+ *
+ * @ctx is a bitfield, where only one bit must be set. Each bit defines
+ * in which context an alternative is supposed to be applied to the
+ * kernel image:
+ *
+ * - from the decompressor before the kernel itself is executed
+ * - from early kernel code from within the kernel
+ *
+ * @type is a number which defines the type and with that the type
+ * specific alternative patching.
+ *
+ * @data is additional type specific information which defines if an
+ * alternative should be applied.
+ */
+
+#define ALT_CTX_EARLY		1
+#define ALT_CTX_LATE		2
+#define ALT_CTX_ALL		(ALT_CTX_EARLY | ALT_CTX_LATE)
+
+#define ALT_TYPE_FACILITY	0
+#define ALT_TYPE_SPEC		1
+#define ALT_TYPE_LOWCORE	2
+
+#define ALT_DATA_SHIFT		0
+#define ALT_TYPE_SHIFT		20
+#define ALT_CTX_SHIFT		28
+
+#define ALT_FACILITY_EARLY(facility)	(ALT_CTX_EARLY << ALT_CTX_SHIFT		| \
+					 ALT_TYPE_FACILITY << ALT_TYPE_SHIFT	| \
+					 (facility) << ALT_DATA_SHIFT)
+
+#define ALT_FACILITY(facility)		(ALT_CTX_LATE << ALT_CTX_SHIFT		| \
+					 ALT_TYPE_FACILITY << ALT_TYPE_SHIFT	| \
+					 (facility) << ALT_DATA_SHIFT)
+
+#define ALT_SPEC(facility)		(ALT_CTX_LATE << ALT_CTX_SHIFT		| \
+					 ALT_TYPE_SPEC << ALT_TYPE_SHIFT	| \
+					 (facility) << ALT_DATA_SHIFT)
+
+#define ALT_LOWCORE			(ALT_CTX_EARLY << ALT_CTX_SHIFT		| \
+					 ALT_TYPE_LOWCORE << ALT_TYPE_SHIFT)
+
 #ifndef __ASSEMBLY__
 
 #include <linux/types.h>
@@ -11,12 +63,30 @@
 struct alt_instr {
 	s32 instr_offset;	/* original instruction */
 	s32 repl_offset;	/* offset to replacement instruction */
-	u16 facility;		/* facility bit set for replacement */
+	union {
+		u32 feature;	/* feature required for replacement */
+		struct {
+			u32 ctx	 : 4;  /* context */
+			u32 type : 8;  /* type of alternative */
+			u32 data : 20; /* patching information */
+		};
+	};
 	u8  instrlen;		/* length of original instruction */
 } __packed;
 
-void apply_alternative_instructions(void);
-void apply_alternatives(struct alt_instr *start, struct alt_instr *end);
+extern struct alt_instr __alt_instructions[], __alt_instructions_end[];
+
+void __apply_alternatives(struct alt_instr *start, struct alt_instr *end, unsigned int ctx);
+
+static inline void apply_alternative_instructions(void)
+{
+	__apply_alternatives(__alt_instructions, __alt_instructions_end, ALT_CTX_LATE);
+}
+
+static inline void apply_alternatives(struct alt_instr *start, struct alt_instr *end)
+{
+	__apply_alternatives(start, end, ALT_CTX_ALL);
+}
 
 /*
  * +---------------------------------+
@@ -48,10 +118,10 @@ void apply_alternatives(struct alt_instr *start, struct alt_instr *end);
 #define OLDINSTR(oldinstr) \
 	"661:\n\t" oldinstr "\n662:\n"
 
-#define ALTINSTR_ENTRY(facility, num)					\
+#define ALTINSTR_ENTRY(feature, num)					\
 	"\t.long 661b - .\n"			/* old instruction */	\
 	"\t.long " b_altinstr(num)"b - .\n"	/* alt instruction */	\
-	"\t.word " __stringify(facility) "\n"	/* facility bit    */	\
+	"\t.long " __stringify(feature) "\n"	/* feature	   */	\
 	"\t.byte " oldinstr_len "\n"		/* instruction len */	\
 	"\t.org . - (" oldinstr_len ") & 1\n"				\
 	"\t.org . - (" oldinstr_len ") + (" altinstr_len(num) ")\n"	\
@@ -61,24 +131,24 @@ void apply_alternatives(struct alt_instr *start, struct alt_instr *end);
 	b_altinstr(num)":\n\t" altinstr "\n" e_altinstr(num) ":\n"
 
 /* alternative assembly primitive: */
-#define ALTERNATIVE(oldinstr, altinstr, facility) \
+#define ALTERNATIVE(oldinstr, altinstr, feature) \
 	".pushsection .altinstr_replacement, \"ax\"\n"			\
 	ALTINSTR_REPLACEMENT(altinstr, 1)				\
 	".popsection\n"							\
 	OLDINSTR(oldinstr)						\
 	".pushsection .altinstructions,\"a\"\n"				\
-	ALTINSTR_ENTRY(facility, 1)					\
+	ALTINSTR_ENTRY(feature, 1)					\
 	".popsection\n"
 
-#define ALTERNATIVE_2(oldinstr, altinstr1, facility1, altinstr2, facility2)\
+#define ALTERNATIVE_2(oldinstr, altinstr1, feature1, altinstr2, feature2)\
 	".pushsection .altinstr_replacement, \"ax\"\n"			\
 	ALTINSTR_REPLACEMENT(altinstr1, 1)				\
 	ALTINSTR_REPLACEMENT(altinstr2, 2)				\
 	".popsection\n"							\
 	OLDINSTR(oldinstr)						\
 	".pushsection .altinstructions,\"a\"\n"				\
-	ALTINSTR_ENTRY(facility1, 1)					\
-	ALTINSTR_ENTRY(facility2, 2)					\
+	ALTINSTR_ENTRY(feature1, 1)					\
+	ALTINSTR_ENTRY(feature2, 2)					\
 	".popsection\n"
 
 /*
@@ -93,12 +163,12 @@ void apply_alternatives(struct alt_instr *start, struct alt_instr *end);
  * For non barrier like inlines please define new variants
  * without volatile and memory clobber.
  */
-#define alternative(oldinstr, altinstr, facility)			\
-	asm_inline volatile(ALTERNATIVE(oldinstr, altinstr, facility) : : : "memory")
+#define alternative(oldinstr, altinstr, feature)			\
+	asm_inline volatile(ALTERNATIVE(oldinstr, altinstr, feature) : : : "memory")
 
-#define alternative_2(oldinstr, altinstr1, facility1, altinstr2, facility2) \
-	asm_inline volatile(ALTERNATIVE_2(oldinstr, altinstr1, facility1,   \
-				   altinstr2, facility2) ::: "memory")
+#define alternative_2(oldinstr, altinstr1, feature1, altinstr2, feature2) \
+	asm_inline volatile(ALTERNATIVE_2(oldinstr, altinstr1, feature1,   \
+				   altinstr2, feature2) ::: "memory")
 
 /* Alternative inline assembly with input. */
 #define alternative_input(oldinstr, newinstr, feature, input...)	\
@@ -106,8 +176,8 @@ void apply_alternatives(struct alt_instr *start, struct alt_instr *end);
 		: : input)
 
 /* Like alternative_input, but with a single output argument */
-#define alternative_io(oldinstr, altinstr, facility, output, input...)	\
-	asm_inline volatile(ALTERNATIVE(oldinstr, altinstr, facility)	\
+#define alternative_io(oldinstr, altinstr, feature, output, input...)	\
+	asm_inline volatile(ALTERNATIVE(oldinstr, altinstr, feature)	\
 		: output : input)
 
 /* Use this macro if more than one output parameter is needed. */
@@ -116,6 +186,56 @@ void apply_alternatives(struct alt_instr *start, struct alt_instr *end);
 /* Use this macro if clobbers are needed without inputs. */
 #define ASM_NO_INPUT_CLOBBER(clobber...) : clobber
 
+#else  /* __ASSEMBLY__ */
+
+/*
+ * Issue one struct alt_instr descriptor entry (need to put it into
+ * the section .altinstructions, see below). This entry contains
+ * enough information for the alternatives patching code to patch an
+ * instruction. See apply_alternatives().
+ */
+.macro alt_entry orig_start, orig_end, alt_start, alt_end, feature
+	.long	\orig_start - .
+	.long	\alt_start - .
+	.long	\feature
+	.byte	\orig_end - \orig_start
+	.org	. - ( \orig_end - \orig_start ) & 1
+	.org	. - ( \orig_end - \orig_start ) + ( \alt_end - \alt_start )
+	.org	. - ( \alt_end - \alt_start ) + ( \orig_end - \orig_start )
+.endm
+
+/*
+ * Define an alternative between two instructions. If @feature is
+ * present, early code in apply_alternatives() replaces @oldinstr with
+ * @newinstr.
+ */
+.macro ALTERNATIVE oldinstr, newinstr, feature
+	.pushsection .altinstr_replacement,"ax"
+770:	\newinstr
+771:	.popsection
+772:	\oldinstr
+773:	.pushsection .altinstructions,"a"
+	alt_entry 772b, 773b, 770b, 771b, \feature
+	.popsection
+.endm
+
+/*
+ * Define an alternative between two instructions. If @feature is
+ * present, early code in apply_alternatives() replaces @oldinstr with
+ * @newinstr.
+ */
+.macro ALTERNATIVE_2 oldinstr, newinstr1, feature1, newinstr2, feature2
+	.pushsection .altinstr_replacement,"ax"
+770:	\newinstr1
+771:	\newinstr2
+772:	.popsection
+773:	\oldinstr
+774:	.pushsection .altinstructions,"a"
+	alt_entry 773b, 774b, 770b, 771b,\feature1
+	alt_entry 773b, 774b, 771b, 772b,\feature2
+	.popsection
+.endm
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* _ASM_S390_ALTERNATIVE_H */

arch/s390/include/asm/atomic_ops.h

@@ -188,7 +188,8 @@ static __always_inline long __atomic64_cmpxchg(long *ptr, long old, long new)
 	return old;
 }
 
-#ifdef __GCC_ASM_FLAG_OUTPUTS__
+/* GCC versions before 14.2.0 may die with an ICE in some configurations. */
+#if defined(__GCC_ASM_FLAG_OUTPUTS__) && !(IS_ENABLED(CONFIG_CC_IS_GCC) && (GCC_VERSION < 140200))
 
 static __always_inline bool __atomic_cmpxchg_bool(int *ptr, int old, int new)
 {

arch/s390/include/asm/facility.h

@@ -20,7 +20,6 @@
 #define MAX_FACILITY_BIT (sizeof(stfle_fac_list) * 8)
 
 extern u64 stfle_fac_list[16];
-extern u64 alt_stfle_fac_list[16];
 
 static inline void __set_facility(unsigned long nr, void *facilities)
 {

arch/s390/include/asm/kmsan.h

@@ -12,8 +12,8 @@
 
 static inline bool is_lowcore_addr(void *addr)
 {
-	return addr >= (void *)&S390_lowcore &&
-	       addr < (void *)(&S390_lowcore + 1);
+	return addr >= (void *)get_lowcore() &&
+	       addr < (void *)(get_lowcore() + 1);
 }
 
 static inline void *arch_kmsan_get_meta_or_null(void *addr, bool is_origin)
@@ -25,7 +25,7 @@ static inline void *arch_kmsan_get_meta_or_null(void *addr, bool is_origin)
 		 * order to get a distinct struct page.
 		 */
 		addr += (void *)lowcore_ptr[raw_smp_processor_id()] -
-			(void *)&S390_lowcore;
+			(void *)get_lowcore();
 		if (KMSAN_WARN_ON(is_lowcore_addr(addr)))
 			return NULL;
 		return kmsan_get_metadata(addr, is_origin);

arch/s390/include/asm/lowcore.h

@@ -14,10 +14,15 @@
 #include <asm/ctlreg.h>
 #include <asm/cpu.h>
 #include <asm/types.h>
+#include <asm/alternative.h>
 
 #define LC_ORDER 1
 #define LC_PAGES 2
 
+#define LOWCORE_ALT_ADDRESS	_AC(0x70000, UL)
+
+#ifndef __ASSEMBLY__
+
 struct pgm_tdb {
 	u64 data[32];
 };
@@ -97,8 +102,7 @@ struct lowcore {
 	__u64	save_area_async[8];		/* 0x0240 */
 	__u64	save_area_restart[1];		/* 0x0280 */
 
-	/* CPU flags. */
-	__u64	cpu_flags;			/* 0x0288 */
+	__u64	pcpu;				/* 0x0288 */
 
 	/* Return psws. */
 	psw_t	return_psw;			/* 0x0290 */
@@ -215,7 +219,14 @@ struct lowcore {
 
 static __always_inline struct lowcore *get_lowcore(void)
 {
-	return NULL;
+	struct lowcore *lc;
+
+	if (__is_defined(__DECOMPRESSOR))
+		return NULL;
+	asm(ALTERNATIVE("llilh %[lc],0", "llilh %[lc],%[alt]", ALT_LOWCORE)
+	    : [lc] "=d" (lc)
+	    : [alt] "i" (LOWCORE_ALT_ADDRESS >> 16));
+	return lc;
 }
 
 extern struct lowcore *lowcore_ptr[];
@@ -225,4 +236,19 @@ static inline void set_prefix(__u32 address)
 	asm volatile("spx %0" : : "Q" (address) : "memory");
 }
 
+#else /* __ASSEMBLY__ */
+
+.macro GET_LC reg
+	ALTERNATIVE "llilh	\reg,0",					\
+		__stringify(llilh	\reg, LOWCORE_ALT_ADDRESS >> 16),	\
+		ALT_LOWCORE
+.endm
+
+.macro STMG_LC start, end, savearea
+	ALTERNATIVE "stmg	\start, \end, \savearea",				\
+		__stringify(stmg	\start, \end, LOWCORE_ALT_ADDRESS + \savearea),	\
+		ALT_LOWCORE
+.endm
+
+#endif /* __ASSEMBLY__ */
 #endif /* _ASM_S390_LOWCORE_H */

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

@@ -5,8 +5,17 @@
 #ifndef __ASSEMBLY__
 
 #include <linux/types.h>
+#include <asm/facility.h>
 
 extern int nospec_disable;
+extern int nobp;
+
+static inline bool nobp_enabled(void)
+{
+	if (__is_defined(__DECOMPRESSOR))
+		return false;
+	return nobp && test_facility(82);
+}
 
 void nospec_init_branches(void);
 void nospec_auto_detect(void);