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

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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>
This commit is contained in:
Michael Holzheu 2010-03-24 11:49:50 +01:00 committed by Martin Schwidefsky
parent ae6be51ed0
commit 92fe31329c
4 changed files with 32 additions and 32 deletions
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1
arch/s390/include/asm/system.h
View File

@ -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); \

6
arch/s390/kernel/smp.c
View File

@ -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];

26
arch/s390/mm/maccess.c
View File

@ -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;
}

31
drivers/s390/char/zcore.c
View File

@ -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;