From b3e1a00c8fa41a80aa402e5ca7f8cc78efa4f50b Mon Sep 17 00:00:00 2001
From: Heiko Carstens <hca@linux.ibm.com>
Date: Wed, 28 Jul 2021 21:02:51 +0200
Subject: [PATCH] s390/mm: implement set_memory_4k()
Implement set_memory_4k() which will split any present large or huge
mapping in the given range to a 4k mapping.
Link: https://lore.kernel.org/r/20210728190254.3921642-2-hca@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
---
arch/s390/include/asm/set_memory.h | 6 ++++++
arch/s390/mm/pageattr.c | 14 ++++++++++++--
2 files changed, 18 insertions(+), 2 deletions(-)
diff --git a/arch/s390/include/asm/set_memory.h b/arch/s390/include/asm/set_memory.h
index a22a5a81811cf..950d87bd997a7 100644
--- a/arch/s390/include/asm/set_memory.h
+++ b/arch/s390/include/asm/set_memory.h
@@ -10,6 +10,7 @@ extern struct mutex cpa_mutex;
#define SET_MEMORY_RW 2UL
#define SET_MEMORY_NX 4UL
#define SET_MEMORY_X 8UL
+#define SET_MEMORY_4K 16UL
int __set_memory(unsigned long addr, int numpages, unsigned long flags);
@@ -33,4 +34,9 @@ static inline int set_memory_x(unsigned long addr, int numpages)
return __set_memory(addr, numpages, SET_MEMORY_X);
}
+static inline int set_memory_4k(unsigned long addr, int numpages)
+{
+ return __set_memory(addr, numpages, SET_MEMORY_4K);
+}
+
#endif
diff --git a/arch/s390/mm/pageattr.c b/arch/s390/mm/pageattr.c
index ed8e5b3575d59..2ad95e5c79c1b 100644
--- a/arch/s390/mm/pageattr.c
+++ b/arch/s390/mm/pageattr.c
@@ -85,6 +85,8 @@ static int walk_pte_level(pmd_t *pmdp, unsigned long addr, unsigned long end,
{
pte_t *ptep, new;
+ if ((flags & SET_MEMORY_4K) == SET_MEMORY_4K)
+ return 0;
ptep = pte_offset_kernel(pmdp, addr);
do {
new = *ptep;
@@ -155,6 +157,7 @@ static int walk_pmd_level(pud_t *pudp, unsigned long addr, unsigned long end,
unsigned long flags)
{
unsigned long next;
+ int need_split;
pmd_t *pmdp;
int rc = 0;
@@ -164,7 +167,10 @@ static int walk_pmd_level(pud_t *pudp, unsigned long addr, unsigned long end,
return -EINVAL;
next = pmd_addr_end(addr, end);
if (pmd_large(*pmdp)) {
- if (addr & ~PMD_MASK || addr + PMD_SIZE > next) {
+ need_split = !!(flags & SET_MEMORY_4K);
+ need_split |= !!(addr & ~PMD_MASK);
+ need_split |= !!(addr + PMD_SIZE > next);
+ if (need_split) {
rc = split_pmd_page(pmdp, addr);
if (rc)
return rc;
@@ -232,6 +238,7 @@ static int walk_pud_level(p4d_t *p4d, unsigned long addr, unsigned long end,
unsigned long flags)
{
unsigned long next;
+ int need_split;
pud_t *pudp;
int rc = 0;
@@ -241,7 +248,10 @@ static int walk_pud_level(p4d_t *p4d, unsigned long addr, unsigned long end,
return -EINVAL;
next = pud_addr_end(addr, end);
if (pud_large(*pudp)) {
- if (addr & ~PUD_MASK || addr + PUD_SIZE > next) {
+ need_split = !!(flags & SET_MEMORY_4K);
+ need_split |= !!(addr & ~PUD_MASK);
+ need_split |= !!(addr + PUD_SIZE > next);
+ if (need_split) {
rc = split_pud_page(pudp, addr);
if (rc)
break;
--
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