diff options
| -rw-r--r-- | arch/s390/include/asm/io.h | 7 | ||||
| -rw-r--r-- | arch/s390/mm/maccess.c | 67 |
2 files changed, 69 insertions, 5 deletions
diff --git a/arch/s390/include/asm/io.h b/arch/s390/include/asm/io.h index b7ff6afc3ca..27216d31799 100644 --- a/arch/s390/include/asm/io.h +++ b/arch/s390/include/asm/io.h @@ -38,11 +38,8 @@ static inline void * phys_to_virt(unsigned long address) return (void *) address; } -/* - * Convert a physical pointer to a virtual kernel pointer for /dev/mem - * access - */ -#define xlate_dev_mem_ptr(p) __va(p) +void *xlate_dev_mem_ptr(unsigned long phys); +void unxlate_dev_mem_ptr(unsigned long phys, void *addr); /* * Convert a virtual cached pointer to an uncached pointer diff --git a/arch/s390/mm/maccess.c b/arch/s390/mm/maccess.c index e1335dc2b1b..795a0a9bb2e 100644 --- a/arch/s390/mm/maccess.c +++ b/arch/s390/mm/maccess.c @@ -12,6 +12,7 @@ #include <linux/types.h> #include <linux/errno.h> #include <linux/gfp.h> +#include <linux/cpu.h> #include <asm/ctl_reg.h> /* @@ -166,3 +167,69 @@ out: free_page((unsigned long) buf); return rc; } + +/* + * Check if physical address is within prefix or zero page + */ +static int is_swapped(unsigned long addr) +{ + unsigned long lc; + int cpu; + + if (addr < sizeof(struct _lowcore)) + return 1; + for_each_online_cpu(cpu) { + lc = (unsigned long) lowcore_ptr[cpu]; + if (addr > lc + sizeof(struct _lowcore) - 1 || addr < lc) + continue; + return 1; + } + return 0; +} + +/* + * Return swapped prefix or zero page address + */ +static unsigned long get_swapped(unsigned long addr) +{ + unsigned long prefix = store_prefix(); + + if (addr < sizeof(struct _lowcore)) + return addr + prefix; + if (addr >= prefix && addr < prefix + sizeof(struct _lowcore)) + return addr - prefix; + return addr; +} + +/* + * Convert a physical pointer for /dev/mem access + * + * For swapped prefix pages a new buffer is returned that contains a copy of + * the absolute memory. The buffer size is maximum one page large. + */ +void *xlate_dev_mem_ptr(unsigned long addr) +{ + void *bounce = (void *) addr; + unsigned long size; + + get_online_cpus(); + preempt_disable(); + if (is_swapped(addr)) { + size = PAGE_SIZE - (addr & ~PAGE_MASK); + bounce = (void *) __get_free_page(GFP_ATOMIC); + if (bounce) + memcpy_real(bounce, (void *) get_swapped(addr), size); + } + preempt_enable(); + put_online_cpus(); + return bounce; +} + +/* + * Free converted buffer for /dev/mem access (if necessary) + */ +void unxlate_dev_mem_ptr(unsigned long addr, void *buf) +{ + if ((void *) addr != buf) + free_page((unsigned long) buf); +} |