diff options
Diffstat (limited to 'arch/s390/mm/maccess.c')
-rw-r--r-- | arch/s390/mm/maccess.c | 218 |
1 files changed, 80 insertions, 138 deletions
diff --git a/arch/s390/mm/maccess.c b/arch/s390/mm/maccess.c index 421efa46946b..632c3a55feed 100644 --- a/arch/s390/mm/maccess.c +++ b/arch/s390/mm/maccess.c @@ -12,10 +12,17 @@ #include <linux/errno.h> #include <linux/gfp.h> #include <linux/cpu.h> +#include <linux/uio.h> +#include <linux/io.h> #include <asm/asm-extable.h> -#include <asm/ctl_reg.h> -#include <asm/io.h> +#include <asm/abs_lowcore.h> #include <asm/stacktrace.h> +#include <asm/maccess.h> +#include <asm/ctlreg.h> + +unsigned long __bootdata_preserved(__memcpy_real_area); +pte_t *__bootdata_preserved(memcpy_real_ptep); +static DEFINE_MUTEX(memcpy_real_mutex); static notrace long s390_kernel_write_odd(void *dst, const void *src, size_t size) { @@ -61,159 +68,77 @@ notrace void *s390_kernel_write(void *dst, const void *src, size_t size) long copied; spin_lock_irqsave(&s390_kernel_write_lock, flags); - if (!(flags & PSW_MASK_DAT)) { - memcpy(dst, src, size); - } else { - while (size) { - copied = s390_kernel_write_odd(tmp, src, size); - tmp += copied; - src += copied; - size -= copied; - } + while (size) { + copied = s390_kernel_write_odd(tmp, src, size); + tmp += copied; + src += copied; + size -= copied; } spin_unlock_irqrestore(&s390_kernel_write_lock, flags); return dst; } -static int __no_sanitize_address __memcpy_real(void *dest, void *src, size_t count) -{ - union register_pair _dst, _src; - int rc = -EFAULT; - - _dst.even = (unsigned long) dest; - _dst.odd = (unsigned long) count; - _src.even = (unsigned long) src; - _src.odd = (unsigned long) count; - asm volatile ( - "0: mvcle %[dst],%[src],0\n" - "1: jo 0b\n" - " lhi %[rc],0\n" - "2:\n" - EX_TABLE(1b,2b) - : [rc] "+&d" (rc), [dst] "+&d" (_dst.pair), [src] "+&d" (_src.pair) - : : "cc", "memory"); - return rc; -} - -static unsigned long __no_sanitize_address _memcpy_real(unsigned long dest, - unsigned long src, - unsigned long count) -{ - int irqs_disabled, rc; - unsigned long flags; - - if (!count) - return 0; - flags = arch_local_irq_save(); - irqs_disabled = arch_irqs_disabled_flags(flags); - if (!irqs_disabled) - trace_hardirqs_off(); - __arch_local_irq_stnsm(0xf8); // disable DAT - rc = __memcpy_real((void *) dest, (void *) src, (size_t) count); - if (flags & PSW_MASK_DAT) - __arch_local_irq_stosm(0x04); // enable DAT - if (!irqs_disabled) - trace_hardirqs_on(); - __arch_local_irq_ssm(flags); - return rc; -} - -/* - * Copy memory in real mode (kernel to kernel) - */ -int memcpy_real(void *dest, unsigned long src, size_t count) +size_t memcpy_real_iter(struct iov_iter *iter, unsigned long src, size_t count) { - unsigned long _dest = (unsigned long)dest; - unsigned long _src = (unsigned long)src; - unsigned long _count = (unsigned long)count; - int rc; - - if (S390_lowcore.nodat_stack != 0) { - preempt_disable(); - rc = call_on_stack(3, S390_lowcore.nodat_stack, - unsigned long, _memcpy_real, - unsigned long, _dest, - unsigned long, _src, - unsigned long, _count); - preempt_enable(); - return rc; - } - /* - * This is a really early memcpy_real call, the stacks are - * not set up yet. Just call _memcpy_real on the early boot - * stack - */ - return _memcpy_real(_dest, _src, _count); -} - -/* - * Copy memory in absolute mode (kernel to kernel) - */ -void memcpy_absolute(void *dest, void *src, size_t count) -{ - unsigned long cr0, flags, prefix; - - flags = arch_local_irq_save(); - __ctl_store(cr0, 0, 0); - __ctl_clear_bit(0, 28); /* disable lowcore protection */ - 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); + size_t len, copied, res = 0; + unsigned long phys, offset; + void *chunk; + pte_t pte; + + BUILD_BUG_ON(MEMCPY_REAL_SIZE != PAGE_SIZE); + while (count) { + phys = src & MEMCPY_REAL_MASK; + offset = src & ~MEMCPY_REAL_MASK; + chunk = (void *)(__memcpy_real_area + offset); + len = min(count, MEMCPY_REAL_SIZE - offset); + pte = mk_pte_phys(phys, PAGE_KERNEL_RO); + + mutex_lock(&memcpy_real_mutex); + if (pte_val(pte) != pte_val(*memcpy_real_ptep)) { + __ptep_ipte(__memcpy_real_area, memcpy_real_ptep, 0, 0, IPTE_GLOBAL); + set_pte(memcpy_real_ptep, pte); + } + copied = copy_to_iter(chunk, len, iter); + mutex_unlock(&memcpy_real_mutex); + + count -= copied; + src += copied; + res += copied; + if (copied < len) + break; } - __ctl_load(cr0, 0, 0); - arch_local_irq_restore(flags); + return res; } -/* - * Copy memory from kernel (real) to user (virtual) - */ -int copy_to_user_real(void __user *dest, unsigned long src, unsigned long count) +int memcpy_real(void *dest, unsigned long src, size_t count) { - int offs = 0, size, rc; - char *buf; - - buf = (char *) __get_free_page(GFP_KERNEL); - if (!buf) - return -ENOMEM; - rc = -EFAULT; - while (offs < count) { - size = min(PAGE_SIZE, count - offs); - if (memcpy_real(buf, src + offs, size)) - goto out; - if (copy_to_user(dest + offs, buf, size)) - goto out; - offs += size; - } - rc = 0; -out: - free_page((unsigned long) buf); - return rc; + struct iov_iter iter; + struct kvec kvec; + + kvec.iov_base = dest; + kvec.iov_len = count; + iov_iter_kvec(&iter, ITER_DEST, &kvec, 1, count); + if (memcpy_real_iter(&iter, src, count) < count) + return -EFAULT; + return 0; } /* - * Check if physical address is within prefix or zero page + * Find CPU that owns swapped prefix page */ -static int is_swapped(phys_addr_t addr) +static int get_swapped_owner(phys_addr_t addr) { phys_addr_t lc; int cpu; - if (addr < sizeof(struct lowcore)) - return 1; for_each_online_cpu(cpu) { lc = virt_to_phys(lowcore_ptr[cpu]); if (addr > lc + sizeof(struct lowcore) - 1 || addr < lc) continue; - return 1; + return cpu; } - return 0; + return -1; } /* @@ -226,17 +151,34 @@ void *xlate_dev_mem_ptr(phys_addr_t addr) { void *ptr = phys_to_virt(addr); void *bounce = ptr; + struct lowcore *abs_lc; unsigned long size; + int this_cpu, cpu; cpus_read_lock(); - preempt_disable(); - if (is_swapped(addr)) { - size = PAGE_SIZE - (addr & ~PAGE_MASK); - bounce = (void *) __get_free_page(GFP_ATOMIC); - if (bounce) - memcpy_absolute(bounce, ptr, size); + this_cpu = get_cpu(); + if (addr >= sizeof(struct lowcore)) { + cpu = get_swapped_owner(addr); + if (cpu < 0) + goto out; + } + bounce = (void *)__get_free_page(GFP_ATOMIC); + if (!bounce) + goto out; + size = PAGE_SIZE - (addr & ~PAGE_MASK); + if (addr < sizeof(struct lowcore)) { + abs_lc = get_abs_lowcore(); + ptr = (void *)abs_lc + addr; + memcpy(bounce, ptr, size); + put_abs_lowcore(abs_lc); + } else if (cpu == this_cpu) { + ptr = (void *)(addr - virt_to_phys(lowcore_ptr[cpu])); + memcpy(bounce, ptr, size); + } else { + memcpy(bounce, ptr, size); } - preempt_enable(); +out: + put_cpu(); cpus_read_unlock(); return bounce; } |