s390/maccess: rework absolute lowcore accessors

Macro mem_assign_absolute() is able to access the whole memory, but
is only used and makes sense when updating the absolute lowcore.
Instead, introduce get_abs_lowcore() and put_abs_lowcore() macros
that limit access to absolute lowcore addresses only.

Suggested-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

diff --git a/arch/s390/include/asm/processor.h b/arch/s390/include/asm/processor.h
index 84ec631..eee8d96 100644 (file)
--- a/arch/s390/include/asm/processor.h
+++ b/arch/s390/include/asm/processor.h
@@ -319,11 +319,18 @@ extern void (*s390_base_pgm_handler_fn)(struct pt_regs *regs);
 extern int memcpy_real(void *, unsigned long, size_t);
 extern void memcpy_absolute(void *, void *, size_t);
 
-#define mem_assign_absolute(dest, val) do {                    \
-       __typeof__(dest) __tmp = (val);                         \
-                                                               \
-       BUILD_BUG_ON(sizeof(__tmp) != sizeof(val));             \
-       memcpy_absolute(&(dest), &__tmp, sizeof(__tmp));        \
+#define put_abs_lowcore(member, x) do {                                        \
+       unsigned long __abs_address = offsetof(struct lowcore, member); \
+       __typeof__(((struct lowcore *)0)->member) __tmp = (x);          \
+                                                                       \
+       memcpy_absolute(__va(__abs_address), &__tmp, sizeof(__tmp));    \
+} while (0)
+
+#define get_abs_lowcore(x, member) do {                                        \
+       unsigned long __abs_address = offsetof(struct lowcore, member); \
+       __typeof__(((struct lowcore *)0)->member) *__ptr = &(x);        \
+                                                                       \
+       memcpy_absolute(__ptr, __va(__abs_address), sizeof(*__ptr));    \
 } while (0)
 
 extern int s390_isolate_bp(void);

diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c
index 28ae7df..1cc85b8 100644 (file)
--- a/arch/s390/kernel/ipl.c
+++ b/arch/s390/kernel/ipl.c
@@ -1646,8 +1646,8 @@ static void dump_reipl_run(struct shutdown_trigger *trigger)
 
        csum = (__force unsigned int)
               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);
+       put_abs_lowcore(ipib, ipib);
+       put_abs_lowcore(ipib_checksum, csum);
        dump_run(trigger);
 }
 

diff --git a/arch/s390/kernel/machine_kexec.c b/arch/s390/kernel/machine_kexec.c
index 088d57a..b2ef014 100644 (file)
--- a/arch/s390/kernel/machine_kexec.c
+++ b/arch/s390/kernel/machine_kexec.c
@@ -226,7 +226,7 @@ void arch_crash_save_vmcoreinfo(void)
        vmcoreinfo_append_str("SAMODE31=%lx\n", __samode31);
        vmcoreinfo_append_str("EAMODE31=%lx\n", __eamode31);
        vmcoreinfo_append_str("KERNELOFFSET=%lx\n", kaslr_offset());
-       mem_assign_absolute(S390_lowcore.vmcore_info, paddr_vmcoreinfo_note());
+       put_abs_lowcore(vmcore_info, paddr_vmcoreinfo_note());
 }
 
 void machine_shutdown(void)

diff --git a/arch/s390/kernel/os_info.c b/arch/s390/kernel/os_info.c
index 6b5b64e..1acc2e0 100644 (file)
--- a/arch/s390/kernel/os_info.c
+++ b/arch/s390/kernel/os_info.c
@@ -63,7 +63,7 @@ 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);
-       mem_assign_absolute(S390_lowcore.os_info, __pa(ptr));
+       put_abs_lowcore(os_info, __pa(ptr));
 }
 
 #ifdef CONFIG_CRASH_DUMP

diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index 84e23fc..d860ac3 100644 (file)
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -481,11 +481,11 @@ static void __init setup_lowcore_dat_off(void)
        lc->mcck_stack = mcck_stack + STACK_INIT_OFFSET;
 
        /* Setup absolute zero lowcore */
-       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);
+       put_abs_lowcore(restart_stack, lc->restart_stack);
+       put_abs_lowcore(restart_fn, lc->restart_fn);
+       put_abs_lowcore(restart_data, lc->restart_data);
+       put_abs_lowcore(restart_source, lc->restart_source);
+       put_abs_lowcore(restart_psw, lc->restart_psw);
 
        lc->spinlock_lockval = arch_spin_lockval(0);
        lc->spinlock_index = 0;
@@ -501,6 +501,7 @@ static void __init setup_lowcore_dat_off(void)
 static void __init setup_lowcore_dat_on(void)
 {
        struct lowcore *lc = lowcore_ptr[0];
+       int cr;
 
        __ctl_clear_bit(0, 28);
        S390_lowcore.external_new_psw.mask |= PSW_MASK_DAT;
@@ -509,10 +510,10 @@ static void __init setup_lowcore_dat_on(void)
        S390_lowcore.io_new_psw.mask |= PSW_MASK_DAT;
        __ctl_store(S390_lowcore.cregs_save_area, 0, 15);
        __ctl_set_bit(0, 28);
-       mem_assign_absolute(S390_lowcore.restart_flags, RESTART_FLAG_CTLREGS);
-       mem_assign_absolute(S390_lowcore.program_new_psw, lc->program_new_psw);
-       memcpy_absolute(&S390_lowcore.cregs_save_area, lc->cregs_save_area,
-                       sizeof(S390_lowcore.cregs_save_area));
+       put_abs_lowcore(restart_flags, RESTART_FLAG_CTLREGS);
+       put_abs_lowcore(program_new_psw, lc->program_new_psw);
+       for (cr = 0; cr < ARRAY_SIZE(lc->cregs_save_area); cr++)
+               put_abs_lowcore(cregs_save_area[cr], lc->cregs_save_area[cr]);
 }
 
 static struct resource code_resource = {

diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index cc6971a..51529c3 100644 (file)
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -332,10 +332,10 @@ static void pcpu_delegate(struct pcpu *pcpu,
                lc->restart_data = (unsigned long)data;
                lc->restart_source = source_cpu;
        } else {
-               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);
+               put_abs_lowcore(restart_stack, stack);
+               put_abs_lowcore(restart_fn, (unsigned long)func);
+               put_abs_lowcore(restart_data, (unsigned long)data);
+               put_abs_lowcore(restart_source, source_cpu);
        }
        __bpon();
        asm volatile(
@@ -591,9 +591,9 @@ void smp_ctl_set_clear_bit(int cr, int bit, bool set)
                parms.andval = ~(1UL << bit);
        }
        spin_lock(&ctl_lock);
-       memcpy_absolute(&ctlreg, &S390_lowcore.cregs_save_area[cr], sizeof(ctlreg));
+       get_abs_lowcore(ctlreg, cregs_save_area[cr]);
        ctlreg = (ctlreg & parms.andval) | parms.orval;
-       memcpy_absolute(&S390_lowcore.cregs_save_area[cr], &ctlreg, sizeof(ctlreg));
+       put_abs_lowcore(cregs_save_area[cr], ctlreg);
        spin_unlock(&ctl_lock);
        on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 }