s390/kernel: Introduce memcpy_absolute() function

This patch introduces the new function memcpy_absolute() that allows to
copy memory using absolute addressing. This means that the prefix swap
does not apply when this function is used.

With this patch also all s390 kernel code that accesses absolute zero
now uses the new memcpy_absolute() function. The old and less generic
copy_to_absolute_zero() function is removed.

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/arch/s390/include/asm/uaccess.h b/arch/s390/include/asm/uaccess.h
index 8f2cada4f7c916d9d88fb87cbb390cf99e4b793e..8e83da66df0d60f451ba9086d61a6b58556bf747 100644 (file)
--- a/arch/s390/include/asm/uaccess.h
+++ b/arch/s390/include/asm/uaccess.h
@@ -377,7 +377,7 @@ clear_user(void __user *to, unsigned long n)
 }
 
 extern int memcpy_real(void *, void *, size_t);
-extern void copy_to_absolute_zero(void *dest, void *src, size_t count);
+extern void memcpy_absolute(void *, void *, size_t);
 extern int copy_to_user_real(void __user *dest, void *src, size_t count);
 extern int copy_from_user_real(void *dest, void __user *src, size_t count);
 

diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c
index dcfdcb3ea1637e9a93dbca03e625ed3c1971f18b..2f6cfd460cb6ad5a04fd033ea7f515b49ba3e487 100644 (file)
--- a/arch/s390/kernel/ipl.c
+++ b/arch/s390/kernel/ipl.c
@@ -1528,12 +1528,15 @@ static struct shutdown_action __refdata dump_action = {
 
 static void dump_reipl_run(struct shutdown_trigger *trigger)
 {
-       u32 csum;
-
-       csum = csum_partial(reipl_block_actual, reipl_block_actual->hdr.len, 0);
-       copy_to_absolute_zero(&S390_lowcore.ipib_checksum, &csum, sizeof(csum));
-       copy_to_absolute_zero(&S390_lowcore.ipib, &reipl_block_actual,
-                             sizeof(reipl_block_actual));
+       struct {
+               void    *addr;
+               __u32   csum;
+       } __packed ipib;
+
+       ipib.csum = csum_partial(reipl_block_actual,
+                                reipl_block_actual->hdr.len, 0);
+       ipib.addr = reipl_block_actual;
+       memcpy_absolute(&S390_lowcore.ipib, &ipib, sizeof(ipib));
        dump_run(trigger);
 }
 

diff --git a/arch/s390/kernel/os_info.c b/arch/s390/kernel/os_info.c
index f2fe18f3f01fc6b095c06687a8afee073e8ee225..95fa5ac6c4cedbf6d287ca25708b906cb1f35c4c 100644 (file)
--- a/arch/s390/kernel/os_info.c
+++ b/arch/s390/kernel/os_info.c
@@ -60,7 +60,7 @@ void __init os_info_init(void)
        os_info.version_minor = OS_INFO_VERSION_MINOR;
        os_info.magic = OS_INFO_MAGIC;
        os_info.csum = os_info_csum(&os_info);
-       copy_to_absolute_zero(&S390_lowcore.os_info, &ptr, sizeof(ptr));
+       memcpy_absolute(&S390_lowcore.os_info, &ptr, sizeof(ptr));
 }
 
 #ifdef CONFIG_CRASH_DUMP

diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index 06264ae8ccd9e05fd54f166d4d2bdaa37df18441..489d1d8d96b068f63b61886ee3c55d50f52b3913 100644 (file)
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -428,10 +428,12 @@ static void __init setup_lowcore(void)
        lc->restart_fn = (unsigned long) do_restart;
        lc->restart_data = 0;
        lc->restart_source = -1UL;
-       memcpy(&S390_lowcore.restart_stack, &lc->restart_stack,
-              4*sizeof(unsigned long));
-       copy_to_absolute_zero(&S390_lowcore.restart_psw,
-                             &lc->restart_psw, sizeof(psw_t));
+
+       /* Setup absolute zero lowcore */
+       memcpy_absolute(&S390_lowcore.restart_stack, &lc->restart_stack,
+                       4 * sizeof(unsigned long));
+       memcpy_absolute(&S390_lowcore.restart_psw, &lc->restart_psw,
+                       sizeof(lc->restart_psw));
 
        set_prefix((u32)(unsigned long) lc);
        lowcore_ptr[0] = lc;
@@ -598,7 +600,7 @@ static void __init setup_vmcoreinfo(void)
 #ifdef CONFIG_KEXEC
        unsigned long ptr = paddr_vmcoreinfo_note();
 
-       copy_to_absolute_zero(&S390_lowcore.vmcore_info, &ptr, sizeof(ptr));
+       memcpy_absolute(&S390_lowcore.vmcore_info, &ptr, sizeof(ptr));
 #endif
 }
 

diff --git a/arch/s390/mm/maccess.c b/arch/s390/mm/maccess.c
index 795a0a9bb2eba72875aa3a300f98929daa1c6c12..921fa541dc0431050dfc6b429b4836b94972d6a0 100644 (file)
--- a/arch/s390/mm/maccess.c
+++ b/arch/s390/mm/maccess.c
@@ -101,19 +101,27 @@ int memcpy_real(void *dest, void *src, size_t count)
 }
 
 /*
- * Copy memory to absolute zero
+ * Copy memory in absolute mode (kernel to kernel)
  */
-void copy_to_absolute_zero(void *dest, void *src, size_t count)
+void memcpy_absolute(void *dest, void *src, size_t count)
 {
-       unsigned long cr0;
+       unsigned long cr0, flags, prefix;
 
-       BUG_ON((unsigned long) dest + count >= sizeof(struct _lowcore));
-       preempt_disable();
+       flags = arch_local_irq_save();
        __ctl_store(cr0, 0, 0);
        __ctl_clear_bit(0, 28); /* disable lowcore protection */
-       memcpy_real(dest + store_prefix(), src, count);
+       prefix = store_prefix();
+       if (prefix) {
+               local_mcck_disable();
+               set_prefix(0);
+               memcpy(dest, src, count);
+               set_prefix(prefix);
+               local_mcck_enable();
+       } else {
+               memcpy(dest, src, count);
+       }
        __ctl_load(cr0, 0, 0);
-       preempt_enable();
+       arch_local_irq_restore(flags);
 }
 
 /*
@@ -187,20 +195,6 @@ static int is_swapped(unsigned long addr)
        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
  *
@@ -218,7 +212,7 @@ void *xlate_dev_mem_ptr(unsigned long addr)
                size = PAGE_SIZE - (addr & ~PAGE_MASK);
                bounce = (void *) __get_free_page(GFP_ATOMIC);
                if (bounce)
-                       memcpy_real(bounce, (void *) get_swapped(addr), size);
+                       memcpy_absolute(bounce, (void *) addr, size);
        }
        preempt_enable();
        put_online_cpus();