Commit 7f0bf656 authored by Michael Holzheu's avatar Michael Holzheu Committed by Martin Schwidefsky
Browse files

[S390] Add real memory access functions 



Add access function for real memory needed by s390 kdump backend.

Signed-off-by: default avatarMichael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 1943f53c

arch/s390/include/asm/system.h

+2 −0
Original line number Diff line number Diff line
@@ -114,6 +114,8 @@ extern void pfault_fini(void); 
extern void cmma_init(void);

extern int memcpy_real(void *, void *, size_t);

extern void copy_to_absolute_zero(void *dest, void *src, size_t count);

extern int copy_to_user_real(void __user *dest, void *src, size_t count);

extern int copy_from_user_real(void *dest, void __user *src, size_t count);



#define finish_arch_switch(prev) do {					     \

	set_fs(current->thread.mm_segment);				     \

arch/s390/mm/maccess.c

+56 −0
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
#include <linux/kernel.h>

#include <linux/types.h>

#include <linux/errno.h>

#include <linux/gfp.h>

#include <asm/system.h>



/*
@@ -60,6 +61,9 @@ long probe_kernel_write(void *dst, const void *src, size_t size) 
	return copied < 0 ? -EFAULT : 0;

}



/*

 * Copy memory in real mode (kernel to kernel)

 */

int memcpy_real(void *dest, void *src, size_t count)

{

	register unsigned long _dest asm("2") = (unsigned long) dest;
@@ -101,3 +105,55 @@ void copy_to_absolute_zero(void *dest, void *src, size_t count) 
	__ctl_load(cr0, 0, 0);

	preempt_enable();

}



/*

 * Copy memory from kernel (real) to user (virtual)

 */

int copy_to_user_real(void __user *dest, void *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;

}



/*

 * Copy memory from user (virtual) to kernel (real)

 */

int copy_from_user_real(void *dest, void __user *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 (copy_from_user(buf, src + offs, size))

			goto out;

		if (memcpy_real(dest + offs, buf, size))

			goto out;

		offs += size;

	}

	rc = 0;

out:

	free_page((unsigned long) buf);

	return rc;

}

drivers/s390/char/zcore.c

+2 −18
Original line number Diff line number Diff line
@@ -142,22 +142,6 @@ static int memcpy_hsa_kernel(void *dest, unsigned long src, size_t count) 
	return memcpy_hsa(dest, src, count, TO_KERNEL);

}



static int memcpy_real_user(void __user *dest, unsigned long src, size_t count)

{

	static char buf[4096];

	int offs = 0, size;



	while (offs < count) {

		size = min(sizeof(buf), count - offs);

		if (memcpy_real(buf, (void *) src + offs, size))

			return -EFAULT;

		if (copy_to_user(dest + offs, buf, size))

			return -EFAULT;

		offs += size;

	}

	return 0;

}



static int __init init_cpu_info(enum arch_id arch)

{

	struct save_area *sa;
@@ -346,8 +330,8 @@ static ssize_t zcore_read(struct file *file, char __user *buf, size_t count, 


	/* Copy from real mem */

	size = count - mem_offs - hdr_count;

	rc = memcpy_real_user(buf + hdr_count + mem_offs, mem_start + mem_offs,

			      size);

	rc = copy_to_user_real(buf + hdr_count + mem_offs,

			       (void *) mem_start + mem_offs, size);

	if (rc)

		goto fail;