From cd4386a931b6310b05559d2e28efda04d30ab593 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Mon, 7 Aug 2017 15:16:15 +0200 Subject: [PATCH] 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 Signed-off-by: Martin Schwidefsky --- arch/s390/include/asm/cpcmd.h | 7 +++---- arch/s390/kernel/cpcmd.c | 13 ++++--------- drivers/s390/char/vmcp.c | 2 +- 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 #include #include +#include #include #include #include @@ -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);