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-rw-r--r--arch/s390/mm/maccess.c94
1 files changed, 85 insertions, 9 deletions
diff --git a/arch/s390/mm/maccess.c b/arch/s390/mm/maccess.c
index 7bb15fcca75e..795a0a9bb2eb 100644
--- a/arch/s390/mm/maccess.c
+++ b/arch/s390/mm/maccess.c
@@ -12,6 +12,7 @@
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/gfp.h>
+#include <linux/cpu.h>
#include <asm/ctl_reg.h>
/*
@@ -61,21 +62,14 @@ long probe_kernel_write(void *dst, const void *src, size_t size)
return copied < 0 ? -EFAULT : 0;
}
-/*
- * Copy memory in real mode (kernel to kernel)
- */
-int memcpy_real(void *dest, void *src, size_t count)
+static int __memcpy_real(void *dest, void *src, size_t count)
{
register unsigned long _dest asm("2") = (unsigned long) dest;
register unsigned long _len1 asm("3") = (unsigned long) count;
register unsigned long _src asm("4") = (unsigned long) src;
register unsigned long _len2 asm("5") = (unsigned long) count;
- unsigned long flags;
int rc = -EFAULT;
- if (!count)
- return 0;
- flags = __arch_local_irq_stnsm(0xf8UL);
asm volatile (
"0: mvcle %1,%2,0x0\n"
"1: jo 0b\n"
@@ -86,7 +80,23 @@ int memcpy_real(void *dest, void *src, size_t count)
"+d" (_len2), "=m" (*((long *) dest))
: "m" (*((long *) src))
: "cc", "memory");
- arch_local_irq_restore(flags);
+ return rc;
+}
+
+/*
+ * Copy memory in real mode (kernel to kernel)
+ */
+int memcpy_real(void *dest, void *src, size_t count)
+{
+ unsigned long flags;
+ int rc;
+
+ if (!count)
+ return 0;
+ local_irq_save(flags);
+ __arch_local_irq_stnsm(0xfbUL);
+ rc = __memcpy_real(dest, src, count);
+ local_irq_restore(flags);
return rc;
}
@@ -157,3 +167,69 @@ out:
free_page((unsigned long) buf);
return rc;
}
+
+/*
+ * Check if physical address is within prefix or zero page
+ */
+static int is_swapped(unsigned long addr)
+{
+ unsigned long lc;
+ int cpu;
+
+ if (addr < sizeof(struct _lowcore))
+ return 1;
+ for_each_online_cpu(cpu) {
+ lc = (unsigned long) lowcore_ptr[cpu];
+ if (addr > lc + sizeof(struct _lowcore) - 1 || addr < lc)
+ continue;
+ return 1;
+ }
+ return 0;
+}
+
+/*
+ * Return swapped prefix or zero page address
+ */
+static unsigned long get_swapped(unsigned long addr)
+{
+ unsigned long prefix = store_prefix();
+
+ if (addr < sizeof(struct _lowcore))
+ return addr + prefix;
+ if (addr >= prefix && addr < prefix + sizeof(struct _lowcore))
+ return addr - prefix;
+ return addr;
+}
+
+/*
+ * Convert a physical pointer for /dev/mem access
+ *
+ * For swapped prefix pages a new buffer is returned that contains a copy of
+ * the absolute memory. The buffer size is maximum one page large.
+ */
+void *xlate_dev_mem_ptr(unsigned long addr)
+{
+ void *bounce = (void *) addr;
+ unsigned long size;
+
+ get_online_cpus();
+ preempt_disable();
+ if (is_swapped(addr)) {
+ size = PAGE_SIZE - (addr & ~PAGE_MASK);
+ bounce = (void *) __get_free_page(GFP_ATOMIC);
+ if (bounce)
+ memcpy_real(bounce, (void *) get_swapped(addr), size);
+ }
+ preempt_enable();
+ put_online_cpus();
+ return bounce;
+}
+
+/*
+ * Free converted buffer for /dev/mem access (if necessary)
+ */
+void unxlate_dev_mem_ptr(unsigned long addr, void *buf)
+{
+ if ((void *) addr != buf)
+ free_page((unsigned long) buf);
+}