s390/smp: make absolute lowcore / cpu restart parameter accesses more robust
Setting the cpu restart parameters is done in three different fashions:
- directly setting the four parameters individually
- copying the four parameters with memcpy (using 4 * sizeof(long))
- copying the four parameters using a private structure
In addition code in entry*.S relies on a certain order of the restart
members of struct _lowcore.
Make all of this more robust to future changes by adding a
mem_absolute_assign(dest, val) define, which assigns val to dest
using absolute addressing mode. Also the load multiple instructions
in entry*.S have been split into separate load instruction so the
order of the struct _lowcore members doesn't matter anymore.
In addition move the prototypes of memcpy_real/absolute from uaccess.h
to processor.h. These memcpy* variants are not related to uaccess at all.
string.h doesn't seem to match as well, so lets use processor.h.
Also replace the eight byte array in struct _lowcore which represents a
misaliged u64 with a u64. The compiler will always create code that
handles the misaligned u64 correctly.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/kernel/asm-offsets.c b/arch/s390/kernel/asm-offsets.c
index 83e6edf..0e974dd 100644
--- a/arch/s390/kernel/asm-offsets.c
+++ b/arch/s390/kernel/asm-offsets.c
@@ -131,6 +131,8 @@
DEFINE(__LC_PANIC_STACK, offsetof(struct _lowcore, panic_stack));
DEFINE(__LC_RESTART_STACK, offsetof(struct _lowcore, restart_stack));
DEFINE(__LC_RESTART_FN, offsetof(struct _lowcore, restart_fn));
+ DEFINE(__LC_RESTART_DATA, offsetof(struct _lowcore, restart_data));
+ DEFINE(__LC_RESTART_SOURCE, offsetof(struct _lowcore, restart_source));
DEFINE(__LC_USER_ASCE, offsetof(struct _lowcore, user_asce));
DEFINE(__LC_INT_CLOCK, offsetof(struct _lowcore, int_clock));
DEFINE(__LC_MCCK_CLOCK, offsetof(struct _lowcore, mcck_clock));
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
index 3787f9e..4ea53cd 100644
--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S
@@ -724,7 +724,9 @@
mvc __PT_PSW(8,%r15),__LC_RST_OLD_PSW # store restart old psw
ahi %r15,-STACK_FRAME_OVERHEAD # create stack frame on stack
xc 0(STACK_FRAME_OVERHEAD,%r15),0(%r15)
- lm %r1,%r3,__LC_RESTART_FN # load fn, parm & source cpu
+ l %r1,__LC_RESTART_FN # load fn, parm & source cpu
+ l %r2,__LC_RESTART_DATA
+ l %r3,__LC_RESTART_SOURCE
ltr %r3,%r3 # test source cpu address
jm 1f # negative -> skip source stop
0: sigp %r4,%r3,SIGP_SENSE # sigp sense to source cpu
diff --git a/arch/s390/kernel/entry64.S b/arch/s390/kernel/entry64.S
index d5f02e4..2813e83 100644
--- a/arch/s390/kernel/entry64.S
+++ b/arch/s390/kernel/entry64.S
@@ -751,7 +751,9 @@
mvc __PT_PSW(16,%r15),__LC_RST_OLD_PSW # store restart old psw
aghi %r15,-STACK_FRAME_OVERHEAD # create stack frame on stack
xc 0(STACK_FRAME_OVERHEAD,%r15),0(%r15)
- lmg %r1,%r3,__LC_RESTART_FN # load fn, parm & source cpu
+ lg %r1,__LC_RESTART_FN # load fn, parm & source cpu
+ lg %r2,__LC_RESTART_DATA
+ lg %r3,__LC_RESTART_SOURCE
ltgr %r3,%r3 # test source cpu address
jm 1f # negative -> skip source stop
0: sigp %r4,%r3,SIGP_SENSE # sigp sense to source cpu
diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c
index 2f6cfd4..25241cd 100644
--- a/arch/s390/kernel/ipl.c
+++ b/arch/s390/kernel/ipl.c
@@ -1528,15 +1528,12 @@
static void dump_reipl_run(struct shutdown_trigger *trigger)
{
- struct {
- void *addr;
- __u32 csum;
- } __packed ipib;
+ unsigned long ipib = (unsigned long) &reipl_block_actual;
+ unsigned int csum;
- 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));
+ csum = csum_partial(reipl_block_actual, reipl_block_actual->hdr.len, 0);
+ mem_assign_absolute(S390_lowcore.ipib, ipib);
+ mem_assign_absolute(S390_lowcore.ipib_checksum, csum);
dump_run(trigger);
}
diff --git a/arch/s390/kernel/os_info.c b/arch/s390/kernel/os_info.c
index 95fa5ac..46480d8 100644
--- a/arch/s390/kernel/os_info.c
+++ b/arch/s390/kernel/os_info.c
@@ -60,7 +60,7 @@
os_info.version_minor = OS_INFO_VERSION_MINOR;
os_info.magic = OS_INFO_MAGIC;
os_info.csum = os_info_csum(&os_info);
- memcpy_absolute(&S390_lowcore.os_info, &ptr, sizeof(ptr));
+ mem_assign_absolute(S390_lowcore.os_info, (unsigned long) ptr);
}
#ifdef CONFIG_CRASH_DUMP
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index 489d1d8..49158cb 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -430,10 +430,11 @@
lc->restart_source = -1UL;
/* 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));
+ mem_assign_absolute(S390_lowcore.restart_stack, lc->restart_stack);
+ mem_assign_absolute(S390_lowcore.restart_fn, lc->restart_fn);
+ mem_assign_absolute(S390_lowcore.restart_data, lc->restart_data);
+ mem_assign_absolute(S390_lowcore.restart_source, lc->restart_source);
+ mem_assign_absolute(S390_lowcore.restart_psw, lc->restart_psw);
set_prefix((u32)(unsigned long) lc);
lowcore_ptr[0] = lc;
@@ -598,9 +599,7 @@
static void __init setup_vmcoreinfo(void)
{
#ifdef CONFIG_KEXEC
- unsigned long ptr = paddr_vmcoreinfo_note();
-
- memcpy_absolute(&S390_lowcore.vmcore_info, &ptr, sizeof(ptr));
+ mem_assign_absolute(S390_lowcore.vmcore_info, paddr_vmcoreinfo_note());
#endif
}
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index e014084..dc602a6 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -273,26 +273,24 @@
void *data, unsigned long stack)
{
struct _lowcore *lc = lowcore_ptr[pcpu - pcpu_devices];
- struct {
- unsigned long stack;
- void *func;
- void *data;
- unsigned long source;
- } restart = { stack, func, data, stap() };
+ unsigned long source_cpu = stap();
__load_psw_mask(psw_kernel_bits);
- if (pcpu->address == restart.source)
+ if (pcpu->address == source_cpu)
func(data); /* should not return */
/* Stop target cpu (if func returns this stops the current cpu). */
pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
/* Restart func on the target cpu and stop the current cpu. */
- memcpy_absolute(&lc->restart_stack, &restart, sizeof(restart));
+ mem_assign_absolute(lc->restart_stack, stack);
+ mem_assign_absolute(lc->restart_fn, (unsigned long) func);
+ mem_assign_absolute(lc->restart_data, (unsigned long) data);
+ mem_assign_absolute(lc->restart_source, source_cpu);
asm volatile(
"0: sigp 0,%0,%2 # sigp restart to target cpu\n"
" brc 2,0b # busy, try again\n"
"1: sigp 0,%1,%3 # sigp stop to current cpu\n"
" brc 2,1b # busy, try again\n"
- : : "d" (pcpu->address), "d" (restart.source),
+ : : "d" (pcpu->address), "d" (source_cpu),
"K" (SIGP_RESTART), "K" (SIGP_STOP)
: "0", "1", "cc");
for (;;) ;