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authorHeiko Carstens <heiko.carstens@de.ibm.com>2017-08-07 15:16:15 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2017-08-09 09:09:35 -0400
commitcd4386a931b6310b05559d2e28efda04d30ab593 (patch)
treed1fbc2a6a8e86af9308ce8713e842e6717471c8e
parent267239cc10f18251892a0783104df3dc22b620d5 (diff)
s390/cpcmd,vmcp: avoid GFP_DMA allocations
According to the CP Programming Services manual Diagnose Code 8 "Virtual Console Function" can be used in all addressing modes. Also the input and output buffers do not have a limitation which specifies they need to be below the 2GB line. This is true at least since z/VM 5.4. Therefore remove the sam31/64 instructions and allow for simple GFP_KERNEL allocations. This makes it easier to allocate a 1MB page if the user requested such a large return buffer. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
-rw-r--r--arch/s390/include/asm/cpcmd.h7
-rw-r--r--arch/s390/kernel/cpcmd.c13
-rw-r--r--drivers/s390/char/vmcp.c2
3 files changed, 8 insertions, 14 deletions
diff --git a/arch/s390/include/asm/cpcmd.h b/arch/s390/include/asm/cpcmd.h
index 3dfadb5d648f..ca2b0624ad46 100644
--- a/arch/s390/include/asm/cpcmd.h
+++ b/arch/s390/include/asm/cpcmd.h
@@ -10,9 +10,8 @@
/*
* the lowlevel function for cpcmd
- * the caller of __cpcmd has to ensure that the response buffer is below 2 GB
*/
-extern int __cpcmd(const char *cmd, char *response, int rlen, int *response_code);
+int __cpcmd(const char *cmd, char *response, int rlen, int *response_code);
/*
* cpcmd is the in-kernel interface for issuing CP commands
@@ -25,8 +24,8 @@ extern int __cpcmd(const char *cmd, char *response, int rlen, int *response_code
* response_code: return pointer for VM's error code
* return value: the size of the response. The caller can check if the buffer
* was large enough by comparing the return value and rlen
- * NOTE: If the response buffer is not below 2 GB, cpcmd can sleep
+ * NOTE: If the response buffer is not in real storage, cpcmd can sleep
*/
-extern int cpcmd(const char *cmd, char *response, int rlen, int *response_code);
+int cpcmd(const char *cmd, char *response, int rlen, int *response_code);
#endif /* _ASM_S390_CPCMD_H */
diff --git a/arch/s390/kernel/cpcmd.c b/arch/s390/kernel/cpcmd.c
index 9f0e4a2785f7..63bc6603e0ed 100644
--- a/arch/s390/kernel/cpcmd.c
+++ b/arch/s390/kernel/cpcmd.c
@@ -14,6 +14,7 @@
#include <linux/spinlock.h>
#include <linux/stddef.h>
#include <linux/string.h>
+#include <linux/mm.h>
#include <asm/diag.h>
#include <asm/ebcdic.h>
#include <asm/cpcmd.h>
@@ -28,9 +29,7 @@ static int diag8_noresponse(int cmdlen)
register unsigned long reg3 asm ("3") = cmdlen;
asm volatile(
- " sam31\n"
" diag %1,%0,0x8\n"
- " sam64\n"
: "+d" (reg3) : "d" (reg2) : "cc");
return reg3;
}
@@ -43,9 +42,7 @@ static int diag8_response(int cmdlen, char *response, int *rlen)
register unsigned long reg5 asm ("5") = *rlen;
asm volatile(
- " sam31\n"
" diag %2,%0,0x8\n"
- " sam64\n"
" brc 8,1f\n"
" agr %1,%4\n"
"1:\n"
@@ -57,7 +54,6 @@ static int diag8_response(int cmdlen, char *response, int *rlen)
/*
* __cpcmd has some restrictions over cpcmd
- * - the response buffer must reside below 2GB (if any)
* - __cpcmd is unlocked and therefore not SMP-safe
*/
int __cpcmd(const char *cmd, char *response, int rlen, int *response_code)
@@ -88,13 +84,12 @@ EXPORT_SYMBOL(__cpcmd);
int cpcmd(const char *cmd, char *response, int rlen, int *response_code)
{
+ unsigned long flags;
char *lowbuf;
int len;
- unsigned long flags;
- if ((virt_to_phys(response) != (unsigned long) response) ||
- (((unsigned long)response + rlen) >> 31)) {
- lowbuf = kmalloc(rlen, GFP_KERNEL | GFP_DMA);
+ if (is_vmalloc_or_module_addr(response)) {
+ lowbuf = kmalloc(rlen, GFP_KERNEL);
if (!lowbuf) {
pr_warn("The cpcmd kernel function failed to allocate a response buffer\n");
return -ENOMEM;
diff --git a/drivers/s390/char/vmcp.c b/drivers/s390/char/vmcp.c
index 66d5e9f83e0d..b5e3a49745f9 100644
--- a/drivers/s390/char/vmcp.c
+++ b/drivers/s390/char/vmcp.c
@@ -98,7 +98,7 @@ vmcp_write(struct file *file, const char __user *buff, size_t count,
}
if (!session->response)
session->response = (char *)__get_free_pages(GFP_KERNEL
- | __GFP_RETRY_MAYFAIL | GFP_DMA,
+ | __GFP_RETRY_MAYFAIL,
get_order(session->bufsize));
if (!session->response) {
mutex_unlock(&session->mutex);