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Merge branch 'dat-enhancement-1'

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Heiko Carstens says:

====================

Add the Dat-Enhancement facility 1 to the list of facilities which are
required to start the kernel. The facility provides the CSPG and IDTE
instructions. In particular the CSPG instruction can be used to replace a
valid page table entry with a different page table entry, which also
differs in the page frame real address.

Without the CSPG instruction it is possible to use the CSP instruction to
change valid page table entries, however it only allows to change the lower
or higher 32 bits of such entries, which means it cannot be used to change
the page frame real address of valid page table entries.

Given that there is code around (e.g. HugeTLB vmemmap optimization) which
requires to change valid page table entries of the kernel mapping, without
the detour over an invalid page table entry, make the CSPG instruction
unconditionally available.

The Dat-Enhancement facility 1 is available since z990, which is older than
the currently supported minimum architecture (z10). Therefore adding this
the architecture level set shouldn't cause any problems.

====================

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
This commit is contained in:
Heiko Carstens 2025-11-06 14:14:00 +01:00
commit 547e9feb0e
7 changed files with 16 additions and 62 deletions
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1
arch/s390/include/asm/cpufeature.h
View File

@ -27,7 +27,6 @@ int cpu_have_feature(unsigned int nr);
#define cpu_has_edat1() test_facility(8)
#define cpu_has_edat2() test_facility(78)
#define cpu_has_gs() test_facility(133)
#define cpu_has_idte() test_facility(3)
#define cpu_has_nx() test_facility(130)
#define cpu_has_rdp() test_facility(194)
#define cpu_has_seq_insn() test_facility(85)

19
arch/s390/include/asm/pgtable.h
View File

@ -648,18 +648,6 @@ static inline int mm_uses_skeys(struct mm_struct *mm)
return 0;
}
static inline void csp(unsigned int *ptr, unsigned int old, unsigned int new)
{
union register_pair r1 = { .even = old, .odd = new, };
unsigned long address = (unsigned long)ptr | 1;
asm volatile(
" csp %[r1],%[address]"
: [r1] "+&d" (r1.pair), "+m" (*ptr)
: [address] "d" (address)
: "cc");
}
/**
* cspg() - Compare and Swap and Purge (CSPG)
* @ptr: Pointer to the value to be exchanged
@ -1402,7 +1390,6 @@ int set_pgste_bits(struct mm_struct *mm, unsigned long addr,
int get_pgste(struct mm_struct *mm, unsigned long hva, unsigned long *pgstep);
int pgste_perform_essa(struct mm_struct *mm, unsigned long hva, int orc,
unsigned long *oldpte, unsigned long *oldpgste);
void gmap_pmdp_csp(struct mm_struct *mm, unsigned long vmaddr);
void gmap_pmdp_invalidate(struct mm_struct *mm, unsigned long vmaddr);
void gmap_pmdp_idte_local(struct mm_struct *mm, unsigned long vmaddr);
void gmap_pmdp_idte_global(struct mm_struct *mm, unsigned long vmaddr);
@ -1692,10 +1679,10 @@ static inline pmd_t mk_pmd_phys(unsigned long physpage, pgprot_t pgprot)
#endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLB_PAGE */
static inline void __pmdp_csp(pmd_t *pmdp)
static inline void __pmdp_cspg(pmd_t *pmdp)
{
csp((unsigned int *)pmdp + 1, pmd_val(*pmdp),
pmd_val(*pmdp) | _SEGMENT_ENTRY_INVALID);
cspg((unsigned long *)pmdp, pmd_val(*pmdp),
pmd_val(*pmdp) | _SEGMENT_ENTRY_INVALID);
}
#define IDTE_GLOBAL 0

11
arch/s390/include/asm/tlbflush.h
View File

@ -35,9 +35,9 @@ static inline void __tlb_flush_idte(unsigned long asce)
*/
static inline void __tlb_flush_global(void)
{
unsigned int dummy = 0;
unsigned long dummy = 0;
csp(&dummy, 0, 0);
cspg(&dummy, 0, 0);
}
/*
@ -54,7 +54,7 @@ static inline void __tlb_flush_mm(struct mm_struct *mm)
cpumask_copy(mm_cpumask(mm), &mm->context.cpu_attach_mask);
barrier();
gmap_asce = READ_ONCE(mm->context.gmap_asce);
if (cpu_has_idte() && gmap_asce != -1UL) {
if (gmap_asce != -1UL) {
if (gmap_asce)
__tlb_flush_idte(gmap_asce);
__tlb_flush_idte(mm->context.asce);
@ -68,10 +68,7 @@ static inline void __tlb_flush_mm(struct mm_struct *mm)
static inline void __tlb_flush_kernel(void)
{
if (cpu_has_idte())
__tlb_flush_idte(init_mm.context.asce);
else
__tlb_flush_global();
__tlb_flush_idte(init_mm.context.asce);
}
static inline void __tlb_flush_mm_lazy(struct mm_struct * mm)

28
arch/s390/mm/gmap.c
View File

@ -138,10 +138,7 @@ EXPORT_SYMBOL_GPL(gmap_create);
static void gmap_flush_tlb(struct gmap *gmap)
{
if (cpu_has_idte())
__tlb_flush_idte(gmap->asce);
else
__tlb_flush_global();
__tlb_flush_idte(gmap->asce);
}
static void gmap_radix_tree_free(struct radix_tree_root *root)
@ -1988,10 +1985,8 @@ static void gmap_pmdp_xchg(struct gmap *gmap, pmd_t *pmdp, pmd_t new,
if (machine_has_tlb_guest())
__pmdp_idte(gaddr, (pmd_t *)pmdp, IDTE_GUEST_ASCE, gmap->asce,
IDTE_GLOBAL);
else if (cpu_has_idte())
__pmdp_idte(gaddr, (pmd_t *)pmdp, 0, 0, IDTE_GLOBAL);
else
__pmdp_csp(pmdp);
__pmdp_idte(gaddr, (pmd_t *)pmdp, 0, 0, IDTE_GLOBAL);
set_pmd(pmdp, new);
}
@ -2012,7 +2007,7 @@ static void gmap_pmdp_clear(struct mm_struct *mm, unsigned long vmaddr,
_SEGMENT_ENTRY_GMAP_UC |
_SEGMENT_ENTRY));
if (purge)
__pmdp_csp(pmdp);
__pmdp_cspg(pmdp);
set_pmd(pmdp, __pmd(_SEGMENT_ENTRY_EMPTY));
}
spin_unlock(&gmap->guest_table_lock);
@ -2032,17 +2027,6 @@ void gmap_pmdp_invalidate(struct mm_struct *mm, unsigned long vmaddr)
}
EXPORT_SYMBOL_GPL(gmap_pmdp_invalidate);
/**
* gmap_pmdp_csp - csp all affected guest pmd entries
* @mm: pointer to the process mm_struct
* @vmaddr: virtual address in the process address space
*/
void gmap_pmdp_csp(struct mm_struct *mm, unsigned long vmaddr)
{
gmap_pmdp_clear(mm, vmaddr, 1);
}
EXPORT_SYMBOL_GPL(gmap_pmdp_csp);
/**
* gmap_pmdp_idte_local - invalidate and clear a guest pmd entry
* @mm: pointer to the process mm_struct
@ -2066,7 +2050,7 @@ void gmap_pmdp_idte_local(struct mm_struct *mm, unsigned long vmaddr)
if (machine_has_tlb_guest())
__pmdp_idte(gaddr, pmdp, IDTE_GUEST_ASCE,
gmap->asce, IDTE_LOCAL);
else if (cpu_has_idte())
else
__pmdp_idte(gaddr, pmdp, 0, 0, IDTE_LOCAL);
*pmdp = __pmd(_SEGMENT_ENTRY_EMPTY);
}
@ -2099,10 +2083,8 @@ void gmap_pmdp_idte_global(struct mm_struct *mm, unsigned long vmaddr)
if (machine_has_tlb_guest())
__pmdp_idte(gaddr, pmdp, IDTE_GUEST_ASCE,
gmap->asce, IDTE_GLOBAL);
else if (cpu_has_idte())
__pmdp_idte(gaddr, pmdp, 0, 0, IDTE_GLOBAL);
else
__pmdp_csp(pmdp);
__pmdp_idte(gaddr, pmdp, 0, 0, IDTE_GLOBAL);
*pmdp = __pmd(_SEGMENT_ENTRY_EMPTY);
}
spin_unlock(&gmap->guest_table_lock);

4
arch/s390/mm/pageattr.c
View File

@ -78,10 +78,8 @@ static void pgt_set(unsigned long *old, unsigned long new, unsigned long addr,
}
table = (unsigned long *)((unsigned long)old & mask);
crdte(*old, new, table, dtt, addr, get_lowcore()->kernel_asce.val);
} else if (cpu_has_idte()) {
cspg(old, *old, new);
} else {
csp((unsigned int *)old + 1, *old, new);
cspg(old, *old, new);
}
}

14
arch/s390/mm/pgtable.c
View File

@ -360,14 +360,10 @@ static inline void pmdp_idte_global(struct mm_struct *mm,
mm->context.asce, IDTE_GLOBAL);
if (mm_has_pgste(mm) && mm->context.allow_gmap_hpage_1m)
gmap_pmdp_idte_global(mm, addr);
} else if (cpu_has_idte()) {
} else {
__pmdp_idte(addr, pmdp, 0, 0, IDTE_GLOBAL);
if (mm_has_pgste(mm) && mm->context.allow_gmap_hpage_1m)
gmap_pmdp_idte_global(mm, addr);
} else {
__pmdp_csp(pmdp);
if (mm_has_pgste(mm) && mm->context.allow_gmap_hpage_1m)
gmap_pmdp_csp(mm, addr);
}
}
@ -487,14 +483,8 @@ static inline void pudp_idte_global(struct mm_struct *mm,
if (machine_has_tlb_guest())
__pudp_idte(addr, pudp, IDTE_NODAT | IDTE_GUEST_ASCE,
mm->context.asce, IDTE_GLOBAL);
else if (cpu_has_idte())
__pudp_idte(addr, pudp, 0, 0, IDTE_GLOBAL);
else
/*
* Invalid bit position is the same for pmd and pud, so we can
* reuse _pmd_csp() here
*/
__pmdp_csp((pmd_t *) pudp);
__pudp_idte(addr, pudp, 0, 0, IDTE_GLOBAL);
}
static inline pud_t pudp_flush_direct(struct mm_struct *mm,

1
arch/s390/tools/gen_facilities.c
View File

@ -29,6 +29,7 @@ static struct facility_def facility_defs[] = {
.bits = (int[]){
0, /* N3 instructions */
1, /* z/Arch mode installed */
3, /* dat-enhancement 1 */
18, /* long displacement facility */
21, /* extended-immediate facility */
25, /* store clock fast */