Commit 1f231e29 authored by Alexander Gordeev's avatar Alexander Gordeev Committed by Vasily Gorbik
Browse files

s390/maccess: fix absolute lowcore virtual vs physical address confusion 



Due to historical reasons memcpy_absolute() and friend functions
misuse the notion of physical vs virtual addresses difference.

Note: this does not fix a bug currently, since virtual and physical
addresses are identical.

Reviewed-by: default avatarSven Schnelle <svens@linux.ibm.com>
Reviewed-by: default avatarHeiko Carstens <hca@linux.ibm.com>
Signed-off-by: default avatarAlexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
parent 98c0d24d

arch/s390/mm/maccess.c

+9 −8
Original line number Diff line number Diff line
@@ -199,15 +199,15 @@ int copy_to_user_real(void __user *dest, void *src, unsigned long count) 
/*

 * Check if physical address is within prefix or zero page

 */

static int is_swapped(unsigned long addr)

static int is_swapped(phys_addr_t addr)

{

	unsigned long lc;

	phys_addr_t lc;

	int cpu;



	if (addr < sizeof(struct lowcore))

		return 1;

	for_each_online_cpu(cpu) {

		lc = (unsigned long) lowcore_ptr[cpu];

		lc = virt_to_phys(lowcore_ptr[cpu]);

		if (addr > lc + sizeof(struct lowcore) - 1 || addr < lc)

			continue;

		return 1;
@@ -223,7 +223,8 @@ static int is_swapped(unsigned long addr) 
 */

void *xlate_dev_mem_ptr(phys_addr_t addr)

{

	void *bounce = (void *) addr;

	void *ptr = phys_to_virt(addr);

	void *bounce = ptr;

	unsigned long size;



	cpus_read_lock();
@@ -232,7 +233,7 @@ void *xlate_dev_mem_ptr(phys_addr_t addr) 
		size = PAGE_SIZE - (addr & ~PAGE_MASK);

		bounce = (void *) __get_free_page(GFP_ATOMIC);

		if (bounce)

			memcpy_absolute(bounce, (void *) addr, size);

			memcpy_absolute(bounce, ptr, size);

	}

	preempt_enable();

	cpus_read_unlock();
@@ -242,8 +243,8 @@ void *xlate_dev_mem_ptr(phys_addr_t addr) 
/*

 * Free converted buffer for /dev/mem access (if necessary)

 */

void unxlate_dev_mem_ptr(phys_addr_t addr, void *buf)

void unxlate_dev_mem_ptr(phys_addr_t addr, void *ptr)

{

	if ((void *) addr != buf)

		free_page((unsigned long) buf);

	if (addr != virt_to_phys(ptr))

		free_page((unsigned long)ptr);

}