/* * arch/s390/mm/page-states.c * * 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/init.h> #define ESSA_SET_STABLE 1 #define ESSA_SET_UNUSED 2 static int cmma_flag; static int __init cmma(char *str) { char *parm; parm = strstrip(str); if (strcmp(parm, "yes") == 0 || strcmp(parm, "on") == 0) { cmma_flag = 1; return 1; } cmma_flag = 0; if (strcmp(parm, "no") == 0 || strcmp(parm, "off") == 0) return 1; return 0; } __setup("cmma=", cmma); void __init cmma_init(void) { register unsigned long tmp asm("0") = 0; register int rc asm("1") = -EOPNOTSUPP; if (!cmma_flag) return; asm volatile( " .insn rrf,0xb9ab0000,%1,%1,0,0\n" "0: la %0,0\n" "1:\n" EX_TABLE(0b,1b) : "+&d" (rc), "+&d" (tmp)); if (rc) cmma_flag = 0; } void arch_free_page(struct page *page, int order) { int i, rc; if (!cmma_flag) return; for (i = 0; i < (1 << order); i++) asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0" : "=&d" (rc) : "a" ((page_to_pfn(page) + i) << PAGE_SHIFT), "i" (ESSA_SET_UNUSED)); } void arch_alloc_page(struct page *page, int order) { int i, rc; if (!cmma_flag) return; for (i = 0; i < (1 << order); i++) asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0" : "=&d" (rc) : "a" ((page_to_pfn(page) + i) << PAGE_SHIFT), "i" (ESSA_SET_STABLE)); }