diff options
| author | Heiko Carstens <heiko.carstens@de.ibm.com> | 2017-08-07 15:16:15 +0200 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2017-08-09 15:09:35 +0200 |
| commit | cd4386a931b6310b05559d2e28efda04d30ab593 (patch) | |
| tree | d1fbc2a6a8e86af9308ce8713e842e6717471c8e /arch/s390/kernel/cpcmd.c | |
| parent | s390/vmcp: fix uaccess check and avoid undefined behavior (diff) | |
| download | linux-cd4386a931b6310b05559d2e28efda04d30ab593.tar.xz linux-cd4386a931b6310b05559d2e28efda04d30ab593.zip | |
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>
Diffstat (limited to 'arch/s390/kernel/cpcmd.c')
| -rw-r--r-- | arch/s390/kernel/cpcmd.c | 13 |
1 files changed, 4 insertions, 9 deletions
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; |