Merge branch 'dat-enhancement-1'

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>

3 files changed, 7 insertions, 24 deletions

diff --git a/arch/s390/include/asm/cpufeature.h b/arch/s390/include/asm/cpufeature.h
index 6c6a99660e78..d6fb999c8c6d 100644
--- a/arch/s390/include/asm/cpufeature.h
+++ b/arch/s390/include/asm/cpufeature.h
@@ -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)
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index b7100c6a4054..bb915cbffc7b 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -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
diff --git a/arch/s390/include/asm/tlbflush.h b/arch/s390/include/asm/tlbflush.h
index 75491baa2197..be8ca0d854d3 100644
--- a/arch/s390/include/asm/tlbflush.h
+++ b/arch/s390/include/asm/tlbflush.h
@@ -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)