[S390] zcore: CPU registers are not saved under LPAR

To save the registers for all CPUs a sigp "store status" is done that
stores the registers to address absolute zero. To access storage at
absolute zero, normally the address of the prefix register of the
accessing CPU has to be used. This does not work when large pages are
active (currently only under LPAR). In order to fix that problem,
instead of memcpy memcpy_real is used, which switches to real mode
where prefixing works.

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/system.h b/arch/s390/include/asm/system.h
index 67ee6c3c6bb3aa352484c94449c135315b0763ec..12be42baa055fa2b7cd0a3e17c6ffa0fc8dad458 100644 (file)
--- a/arch/s390/include/asm/system.h
+++ b/arch/s390/include/asm/system.h
@@ -110,6 +110,7 @@ extern void pfault_fini(void);
 #endif /* CONFIG_PFAULT */
 
 extern void cmma_init(void);
+extern int memcpy_real(void *, void *, size_t);
 
 #define finish_arch_switch(prev) do {                                       \
        set_fs(current->thread.mm_segment);                                  \

diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 29f65bce55e1bea4cac1e9c00297a0fb7eda371a..d7d24fc3d6b73de8ebdee72126cb9b0f91db16e0 100644 (file)
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -292,9 +292,9 @@ static void __init smp_get_save_area(unsigned int cpu, unsigned int phy_cpu)
        zfcpdump_save_areas[cpu] = kmalloc(sizeof(struct save_area), GFP_KERNEL);
        while (raw_sigp(phy_cpu, sigp_stop_and_store_status) == sigp_busy)
                cpu_relax();
-       memcpy(zfcpdump_save_areas[cpu],
-              (void *)(unsigned long) store_prefix() + SAVE_AREA_BASE,
-              sizeof(struct save_area));
+       memcpy_real(zfcpdump_save_areas[cpu],
+                   (void *)(unsigned long) store_prefix() + SAVE_AREA_BASE,
+                   sizeof(struct save_area));
 }
 
 struct save_area *zfcpdump_save_areas[NR_CPUS + 1];

diff --git a/arch/s390/mm/maccess.c b/arch/s390/mm/maccess.c
index 81756271dc44a51848f26f93bab6c5b2a066982a..a8c2af8c650fabd9c96a4f9efaf3c0c4f530f294 100644 (file)
--- a/arch/s390/mm/maccess.c
+++ b/arch/s390/mm/maccess.c
@@ -59,3 +59,29 @@ long probe_kernel_write(void *dst, void *src, size_t size)
        }
        return copied < 0 ? -EFAULT : 0;
 }
+
+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 = __raw_local_irq_stnsm(0xf8UL);
+       asm volatile (
+               "0:     mvcle   %1,%2,0x0\n"
+               "1:     jo      0b\n"
+               "       lhi     %0,0x0\n"
+               "2:\n"
+               EX_TABLE(1b,2b)
+               : "+d" (rc), "+d" (_dest), "+d" (_src), "+d" (_len1),
+                 "+d" (_len2), "=m" (*((long *) dest))
+               : "m" (*((long *) src))
+               : "cc", "memory");
+       __raw_local_irq_ssm(flags);
+       return rc;
+}

diff --git a/drivers/s390/char/zcore.c b/drivers/s390/char/zcore.c
index 3438658b66b76fb7f7aaf261310fe3512fa1cc70..3166d85914f289aa41e34c7b31fcb067e284dd5b 100644 (file)
--- a/drivers/s390/char/zcore.c
+++ b/drivers/s390/char/zcore.c
@@ -141,33 +141,6 @@ static int memcpy_hsa_kernel(void *dest, unsigned long src, size_t count)
        return memcpy_hsa(dest, src, count, TO_KERNEL);
 }
 
-static int memcpy_real(void *dest, unsigned long src, size_t count)
-{
-       unsigned long flags;
-       int rc = -EFAULT;
-       register unsigned long _dest asm("2") = (unsigned long) dest;
-       register unsigned long _len1 asm("3") = (unsigned long) count;
-       register unsigned long _src  asm("4") = src;
-       register unsigned long _len2 asm("5") = (unsigned long) count;
-
-       if (count == 0)
-               return 0;
-       flags = __raw_local_irq_stnsm(0xf8UL); /* switch to real mode */
-       asm volatile (
-               "0:     mvcle   %1,%2,0x0\n"
-               "1:     jo      0b\n"
-               "       lhi     %0,0x0\n"
-               "2:\n"
-               EX_TABLE(1b,2b)
-               : "+d" (rc), "+d" (_dest), "+d" (_src), "+d" (_len1),
-                 "+d" (_len2), "=m" (*((long*)dest))
-               : "m" (*((long*)src))
-               : "cc", "memory");
-       __raw_local_irq_ssm(flags);
-
-       return rc;
-}
-
 static int memcpy_real_user(void __user *dest, unsigned long src, size_t count)
 {
        static char buf[4096];
@@ -175,7 +148,7 @@ static int memcpy_real_user(void __user *dest, unsigned long src, size_t count)
 
        while (offs < count) {
                size = min(sizeof(buf), count - offs);
-               if (memcpy_real(buf, src + offs, size))
+               if (memcpy_real(buf, (void *) src + offs, size))
                        return -EFAULT;
                if (copy_to_user(dest + offs, buf, size))
                        return -EFAULT;
@@ -663,7 +636,7 @@ static int __init zcore_reipl_init(void)
        if (ipib_info.ipib < ZFCPDUMP_HSA_SIZE)
                rc = memcpy_hsa_kernel(ipl_block, ipib_info.ipib, PAGE_SIZE);
        else
-               rc = memcpy_real(ipl_block, ipib_info.ipib, PAGE_SIZE);
+               rc = memcpy_real(ipl_block, (void *) ipib_info.ipib, PAGE_SIZE);
        if (rc) {
                free_page((unsigned long) ipl_block);
                return rc;