From 1f231e295024d88950c7e4b91f91a47bbeff1637 Mon Sep 17 00:00:00 2001
From: Alexander Gordeev <agordeev@linux.ibm.com>
Date: Fri, 21 Jan 2022 10:44:25 +0100
Subject: [PATCH] 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: Sven Schnelle <svens@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>
---
arch/s390/mm/maccess.c | 17 +++++++++--------
1 file changed, 9 insertions(+), 8 deletions(-)
diff --git a/arch/s390/mm/maccess.c b/arch/s390/mm/maccess.c
index c1ed1f51c25d8..d4d311cb2bb5e 100644
--- a/arch/s390/mm/maccess.c
+++ b/arch/s390/mm/maccess.c
@@ -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);
}
--
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