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
  ...

8 files changed, 33 insertions, 26 deletions

diff --git a/arch/s390/boot/Makefile b/arch/s390/boot/Makefile
index e7658997452b..4f476884d340 100644
--- a/arch/s390/boot/Makefile
+++ b/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
diff --git a/arch/s390/boot/alternative.c b/arch/s390/boot/alternative.c
new file mode 100644
index 000000000000..abc08d2c873d
--- /dev/null
+++ b/arch/s390/boot/alternative.c
@@ -0,0 +1,3 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "../kernel/alternative.c"
diff --git a/arch/s390/boot/boot.h b/arch/s390/boot/boot.h
index 18027fdc92b0..83e2ce050b6c 100644
--- a/arch/s390/boot/boot.h
+++ b/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)
diff --git a/arch/s390/boot/ipl_parm.c b/arch/s390/boot/ipl_parm.c
index a21f301acd29..1773b72a6a7b 100644
--- a/arch/s390/boot/ipl_parm.c
+++ b/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;
 	}
 }
diff --git a/arch/s390/boot/startup.c b/arch/s390/boot/startup.c
index c59014945af0..ce232552bc1c 100644
--- a/arch/s390/boot/startup.c
+++ b/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.
diff --git a/arch/s390/boot/uv.c b/arch/s390/boot/uv.c
index 1e66d2cbb096..318e6ba95bfd 100644
--- a/arch/s390/boot/uv.c
+++ b/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
diff --git a/arch/s390/boot/uv.h b/arch/s390/boot/uv.h
index 0f3070856f8d..da4a4a8d48e0 100644
--- a/arch/s390/boot/uv.h
+++ b/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 */
diff --git a/arch/s390/boot/vmem.c b/arch/s390/boot/vmem.c
index a255ca189aaa..2847cc059ab7 100644
--- a/arch/s390/boot/vmem.c
+++ b/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),