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-rw-r--r--arch/s390/boot/boot.h2
-rw-r--r--arch/s390/boot/ipl_parm.c1
-rw-r--r--arch/s390/boot/startup.c1
-rw-r--r--arch/s390/boot/vmem.c11
-rw-r--r--arch/s390/include/asm/abs_lowcore.h8
-rw-r--r--arch/s390/include/asm/alternative.h4
-rw-r--r--arch/s390/include/asm/lowcore.h23
-rw-r--r--arch/s390/kernel/abs_lowcore.c1
-rw-r--r--arch/s390/kernel/alternative.c4
-rw-r--r--arch/s390/kernel/alternative.h0
-rw-r--r--arch/s390/kernel/early.c1
-rw-r--r--arch/s390/kernel/setup.c3
12 files changed, 57 insertions, 2 deletions
diff --git a/arch/s390/boot/boot.h b/arch/s390/boot/boot.h
index ed2f0ec24f0d..83e2ce050b6c 100644
--- a/arch/s390/boot/boot.h
+++ b/arch/s390/boot/boot.h
@@ -91,8 +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..337c14931ccb 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>
diff --git a/arch/s390/boot/startup.c b/arch/s390/boot/startup.c
index cca2f1bad33c..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);
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),
diff --git a/arch/s390/include/asm/abs_lowcore.h b/arch/s390/include/asm/abs_lowcore.h
index 6f264b79e377..d20df8c923fc 100644
--- a/arch/s390/include/asm/abs_lowcore.h
+++ b/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 */
diff --git a/arch/s390/include/asm/alternative.h b/arch/s390/include/asm/alternative.h
index 3ddd6dbe5635..de980c938a3e 100644
--- a/arch/s390/include/asm/alternative.h
+++ b/arch/s390/include/asm/alternative.h
@@ -33,6 +33,7 @@
#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
@@ -50,6 +51,9 @@
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>
diff --git a/arch/s390/include/asm/lowcore.h b/arch/s390/include/asm/lowcore.h
index bce3a69ab2a3..52c90b65a2b8 100644
--- a/arch/s390/include/asm/lowcore.h
+++ b/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];
};
@@ -214,7 +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[];
@@ -224,4 +236,13 @@ 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
+
+#endif /* __ASSEMBLY__ */
#endif /* _ASM_S390_LOWCORE_H */
diff --git a/arch/s390/kernel/abs_lowcore.c b/arch/s390/kernel/abs_lowcore.c
index f9efc54ec4b7..09cd24cbe74e 100644
--- a/arch/s390/kernel/abs_lowcore.c
+++ b/arch/s390/kernel/abs_lowcore.c
@@ -4,6 +4,7 @@
#include <asm/abs_lowcore.h>
unsigned long __bootdata_preserved(__abs_lowcore);
+int __bootdata_preserved(relocate_lowcore);
int abs_lowcore_map(int cpu, struct lowcore *lc, bool alloc)
{
diff --git a/arch/s390/kernel/alternative.c b/arch/s390/kernel/alternative.c
index eae254466192..8d5d0de35de0 100644
--- a/arch/s390/kernel/alternative.c
+++ b/arch/s390/kernel/alternative.c
@@ -2,6 +2,7 @@
#include <linux/uaccess.h>
#include <asm/nospec-branch.h>
+#include <asm/abs_lowcore.h>
#include <asm/alternative.h>
#include <asm/facility.h>
@@ -25,6 +26,9 @@ void __apply_alternatives(struct alt_instr *start, struct alt_instr *end, unsign
case ALT_TYPE_SPEC:
replace = nobp_enabled();
break;
+ case ALT_TYPE_LOWCORE:
+ replace = have_relocated_lowcore();
+ break;
default:
replace = false;
}
diff --git a/arch/s390/kernel/alternative.h b/arch/s390/kernel/alternative.h
new file mode 100644
index 000000000000..e69de29bb2d1
--- /dev/null
+++ b/arch/s390/kernel/alternative.h
diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c
index 3ce77cee272d..14d324865e33 100644
--- a/arch/s390/kernel/early.c
+++ b/arch/s390/kernel/early.c
@@ -48,6 +48,7 @@ decompressor_handled_param(dfltcc);
decompressor_handled_param(facilities);
decompressor_handled_param(nokaslr);
decompressor_handled_param(cmma);
+decompressor_handled_param(relocate_lowcore);
#if IS_ENABLED(CONFIG_KVM)
decompressor_handled_param(prot_virt);
#endif
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index 700003e1bc76..4ec99f73fa27 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -889,6 +889,9 @@ void __init setup_arch(char **cmdline_p)
else
pr_info("Linux is running as a guest in 64-bit mode\n");
+ if (have_relocated_lowcore())
+ pr_info("Lowcore relocated to 0x%px\n", get_lowcore());
+
log_component_list();
/* Have one command line that is parsed and saved in /proc/cmdline */
generated by cgit v1.2.3-70-g09d2 (git 2.48.1) at 2025-04-16 19:03:18 +0000