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-rw-r--r--arch/s390/mm/page-states.c231
1 files changed, 231 insertions, 0 deletions
diff --git a/arch/s390/mm/page-states.c b/arch/s390/mm/page-states.c
new file mode 100644
index 000000000..7bea3be8b
--- /dev/null
+++ b/arch/s390/mm/page-states.c
@@ -0,0 +1,231 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright IBM Corp. 2008
+ *
+ * Guest page hinting for unused pages.
+ *
+ * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/mm.h>
+#include <linux/memblock.h>
+#include <linux/gfp.h>
+#include <linux/init.h>
+#include <asm/asm-extable.h>
+#include <asm/facility.h>
+#include <asm/page-states.h>
+
+static int cmma_flag = 1;
+
+static int __init cmma(char *str)
+{
+ bool enabled;
+
+ if (!kstrtobool(str, &enabled))
+ cmma_flag = enabled;
+ return 1;
+}
+__setup("cmma=", cmma);
+
+static inline int cmma_test_essa(void)
+{
+ unsigned long tmp = 0;
+ int rc = -EOPNOTSUPP;
+
+ /* test ESSA_GET_STATE */
+ asm volatile(
+ " .insn rrf,0xb9ab0000,%[tmp],%[tmp],%[cmd],0\n"
+ "0: la %[rc],0\n"
+ "1:\n"
+ EX_TABLE(0b,1b)
+ : [rc] "+&d" (rc), [tmp] "+&d" (tmp)
+ : [cmd] "i" (ESSA_GET_STATE));
+ return rc;
+}
+
+void __init cmma_init(void)
+{
+ if (!cmma_flag)
+ return;
+ if (cmma_test_essa()) {
+ cmma_flag = 0;
+ return;
+ }
+ if (test_facility(147))
+ cmma_flag = 2;
+}
+
+static inline unsigned char get_page_state(struct page *page)
+{
+ unsigned char state;
+
+ asm volatile(" .insn rrf,0xb9ab0000,%0,%1,%2,0"
+ : "=&d" (state)
+ : "a" (page_to_phys(page)),
+ "i" (ESSA_GET_STATE));
+ return state & 0x3f;
+}
+
+static inline void set_page_unused(struct page *page, int order)
+{
+ int i, rc;
+
+ for (i = 0; i < (1 << order); i++)
+ asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0"
+ : "=&d" (rc)
+ : "a" (page_to_phys(page + i)),
+ "i" (ESSA_SET_UNUSED));
+}
+
+static inline void set_page_stable_dat(struct page *page, int order)
+{
+ int i, rc;
+
+ for (i = 0; i < (1 << order); i++)
+ asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0"
+ : "=&d" (rc)
+ : "a" (page_to_phys(page + i)),
+ "i" (ESSA_SET_STABLE));
+}
+
+static inline void set_page_stable_nodat(struct page *page, int order)
+{
+ int i, rc;
+
+ for (i = 0; i < (1 << order); i++)
+ asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0"
+ : "=&d" (rc)
+ : "a" (page_to_phys(page + i)),
+ "i" (ESSA_SET_STABLE_NODAT));
+}
+
+static void mark_kernel_pmd(pud_t *pud, unsigned long addr, unsigned long end)
+{
+ unsigned long next;
+ struct page *page;
+ pmd_t *pmd;
+
+ pmd = pmd_offset(pud, addr);
+ do {
+ next = pmd_addr_end(addr, end);
+ if (pmd_none(*pmd) || pmd_large(*pmd))
+ continue;
+ page = phys_to_page(pmd_val(*pmd));
+ set_bit(PG_arch_1, &page->flags);
+ } while (pmd++, addr = next, addr != end);
+}
+
+static void mark_kernel_pud(p4d_t *p4d, unsigned long addr, unsigned long end)
+{
+ unsigned long next;
+ struct page *page;
+ pud_t *pud;
+ int i;
+
+ pud = pud_offset(p4d, addr);
+ do {
+ next = pud_addr_end(addr, end);
+ if (pud_none(*pud) || pud_large(*pud))
+ continue;
+ if (!pud_folded(*pud)) {
+ page = phys_to_page(pud_val(*pud));
+ for (i = 0; i < 4; i++)
+ set_bit(PG_arch_1, &page[i].flags);
+ }
+ mark_kernel_pmd(pud, addr, next);
+ } while (pud++, addr = next, addr != end);
+}
+
+static void mark_kernel_p4d(pgd_t *pgd, unsigned long addr, unsigned long end)
+{
+ unsigned long next;
+ struct page *page;
+ p4d_t *p4d;
+ int i;
+
+ p4d = p4d_offset(pgd, addr);
+ do {
+ next = p4d_addr_end(addr, end);
+ if (p4d_none(*p4d))
+ continue;
+ if (!p4d_folded(*p4d)) {
+ page = phys_to_page(p4d_val(*p4d));
+ for (i = 0; i < 4; i++)
+ set_bit(PG_arch_1, &page[i].flags);
+ }
+ mark_kernel_pud(p4d, addr, next);
+ } while (p4d++, addr = next, addr != end);
+}
+
+static void mark_kernel_pgd(void)
+{
+ unsigned long addr, next;
+ struct page *page;
+ pgd_t *pgd;
+ int i;
+
+ addr = 0;
+ pgd = pgd_offset_k(addr);
+ do {
+ next = pgd_addr_end(addr, MODULES_END);
+ if (pgd_none(*pgd))
+ continue;
+ if (!pgd_folded(*pgd)) {
+ page = phys_to_page(pgd_val(*pgd));
+ for (i = 0; i < 4; i++)
+ set_bit(PG_arch_1, &page[i].flags);
+ }
+ mark_kernel_p4d(pgd, addr, next);
+ } while (pgd++, addr = next, addr != MODULES_END);
+}
+
+void __init cmma_init_nodat(void)
+{
+ struct page *page;
+ unsigned long start, end, ix;
+ int i;
+
+ if (cmma_flag < 2)
+ return;
+ /* Mark pages used in kernel page tables */
+ mark_kernel_pgd();
+
+ /* Set all kernel pages not used for page tables to stable/no-dat */
+ for_each_mem_pfn_range(i, MAX_NUMNODES, &start, &end, NULL) {
+ page = pfn_to_page(start);
+ for (ix = start; ix < end; ix++, page++) {
+ if (__test_and_clear_bit(PG_arch_1, &page->flags))
+ continue; /* skip page table pages */
+ if (!list_empty(&page->lru))
+ continue; /* skip free pages */
+ set_page_stable_nodat(page, 0);
+ }
+ }
+}
+
+void arch_free_page(struct page *page, int order)
+{
+ if (!cmma_flag)
+ return;
+ set_page_unused(page, order);
+}
+
+void arch_alloc_page(struct page *page, int order)
+{
+ if (!cmma_flag)
+ return;
+ if (cmma_flag < 2)
+ set_page_stable_dat(page, order);
+ else
+ set_page_stable_nodat(page, order);
+}
+
+void arch_set_page_dat(struct page *page, int order)
+{
+ if (!cmma_flag)
+ return;
+ set_page_stable_dat(page, order);
+}