s390/sclp: Determine HSA size dynamically for zfcpdump

Currently we have hardcoded the HSA size to 32 MiB. With this patch the
HSA size is determined dynamically via SCLP in early.c.

Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/include/asm/sclp.h

@@ -57,5 +57,7 @@ bool sclp_has_vt220(void);
 int sclp_pci_configure(u32 fid);
 int sclp_pci_deconfigure(u32 fid);
 int memcpy_hsa(void *dest, unsigned long src, size_t count, int mode);
+void sclp_hsa_size_detect(void);
+unsigned long sclp_get_hsa_size(void);
 
 #endif /* _ASM_S390_SCLP_H */

arch/s390/include/asm/setup.h

@@ -107,9 +107,6 @@ void create_mem_hole(struct mem_chunk mem_chunk[], unsigned long addr,
 #define MACHINE_HAS_RRBM	(S390_lowcore.machine_flags & MACHINE_FLAG_RRBM)
 #endif /* CONFIG_64BIT */
 
-#define ZFCPDUMP_HSA_SIZE	(32UL<<20)
-#define ZFCPDUMP_HSA_SIZE_MAX	(64UL<<20)
-
 /*
  * Console mode. Override with conmode=
  */

arch/s390/kernel/crash_dump.c

@@ -95,7 +95,7 @@ static void *elfcorehdr_newmem;
 /*
  * Copy one page from zfcpdump "oldmem"
  *
- * For pages below ZFCPDUMP_HSA_SIZE memory from the HSA is copied. Otherwise
+ * For pages below HSA size memory from the HSA is copied. Otherwise
  * real memory copy is used.
  */
 static ssize_t copy_oldmem_page_zfcpdump(char *buf, size_t csize,
@@ -103,7 +103,7 @@ static ssize_t copy_oldmem_page_zfcpdump(char *buf, size_t csize,
 {
 	int rc;
 
-	if (src < ZFCPDUMP_HSA_SIZE) {
+	if (src < sclp_get_hsa_size()) {
 		rc = memcpy_hsa(buf, src, csize, userbuf);
 	} else {
 		if (userbuf)
@@ -188,18 +188,19 @@ static int remap_oldmem_pfn_range_kdump(struct vm_area_struct *vma,
 /*
  * Remap "oldmem" for zfcpdump
  *
- * We only map available memory above ZFCPDUMP_HSA_SIZE. Memory below
- * ZFCPDUMP_HSA_SIZE is read on demand using the copy_oldmem_page() function.
+ * We only map available memory above HSA size. Memory below HSA size
+ * is read on demand using the copy_oldmem_page() function.
  */
 static int remap_oldmem_pfn_range_zfcpdump(struct vm_area_struct *vma,
 					   unsigned long from,
 					   unsigned long pfn,
 					   unsigned long size, pgprot_t prot)
 {
+	unsigned long hsa_end = sclp_get_hsa_size();
 	unsigned long size_hsa;
 
-	if (pfn < ZFCPDUMP_HSA_SIZE >> PAGE_SHIFT) {
-		size_hsa = min(size, ZFCPDUMP_HSA_SIZE - (pfn << PAGE_SHIFT));
+	if (pfn < hsa_end >> PAGE_SHIFT) {
+		size_hsa = min(size, hsa_end - (pfn << PAGE_SHIFT));
 		if (size == size_hsa)
 			return 0;
 		size -= size_hsa;
@@ -238,9 +239,9 @@ int copy_from_oldmem(void *dest, void *src, size_t count)
 				return rc;
 		}
 	} else {
-		if ((unsigned long) src < ZFCPDUMP_HSA_SIZE) {
-			copied = min(count,
-				     ZFCPDUMP_HSA_SIZE - (unsigned long) src);
+		unsigned long hsa_end = sclp_get_hsa_size();
+		if ((unsigned long) src < hsa_end) {
+			copied = min(count, hsa_end - (unsigned long) src);
 			rc = memcpy_hsa(dest, (unsigned long) src, copied, 0);
 			if (rc)
 				return rc;
@@ -580,6 +581,9 @@ int elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size)
 	/* If elfcorehdr= has been passed via cmdline, we use that one */
 	if (elfcorehdr_addr != ELFCORE_ADDR_MAX)
 		return 0;
+	/* If we cannot get HSA size for zfcpdump return error */
+	if (ipl_info.type == IPL_TYPE_FCP_DUMP && !sclp_get_hsa_size())
+		return -ENODEV;
 	mem_chunk_cnt = get_mem_chunk_cnt();
 
 	alloc_size = 0x1000 + get_cpu_cnt() * 0x300 +

arch/s390/kernel/early.c

@@ -484,6 +484,7 @@ void __init startup_init(void)
 	detect_machine_facilities();
 	setup_topology();
 	sclp_facilities_detect();
+	sclp_hsa_size_detect();
 #ifdef CONFIG_DYNAMIC_FTRACE
 	S390_lowcore.ftrace_func = (unsigned long)ftrace_caller;
 #endif

arch/s390/kernel/setup.c

@@ -471,8 +471,9 @@ static void __init setup_memory_end(void)
 
 
 #ifdef CONFIG_ZFCPDUMP
-	if (ipl_info.type == IPL_TYPE_FCP_DUMP && !OLDMEM_BASE) {
-		memory_end = ZFCPDUMP_HSA_SIZE;
+	if (ipl_info.type == IPL_TYPE_FCP_DUMP &&
+	    !OLDMEM_BASE && sclp_get_hsa_size()) {
+		memory_end = sclp_get_hsa_size();
 		memory_end_set = 1;
 	}
 #endif
@@ -586,7 +587,7 @@ static unsigned long __init find_crash_base(unsigned long crash_size,
 		crash_base = (chunk->addr + chunk->size) - crash_size;
 		if (crash_base < crash_size)
 			continue;
-		if (crash_base < ZFCPDUMP_HSA_SIZE_MAX)
+		if (crash_base < sclp_get_hsa_size())
 			continue;
 		if (crash_base < (unsigned long) INITRD_START + INITRD_SIZE)
 			continue;

drivers/s390/char/Makefile

@@ -3,7 +3,8 @@
 #
 
 obj-y += ctrlchar.o keyboard.o defkeymap.o sclp.o sclp_rw.o sclp_quiesce.o \
-	 sclp_cmd.o sclp_config.o sclp_cpi_sys.o sclp_ocf.o sclp_ctl.o
+	 sclp_cmd.o sclp_config.o sclp_cpi_sys.o sclp_ocf.o sclp_ctl.o \
+	 sclp_early.o
 
 obj-$(CONFIG_TN3270) += raw3270.o
 obj-$(CONFIG_TN3270_CONSOLE) += con3270.o

drivers/s390/char/sclp.h

@@ -172,6 +172,7 @@ int sclp_deactivate(void);
 int sclp_reactivate(void);
 int sclp_service_call(sclp_cmdw_t command, void *sccb);
 int sclp_sync_request(sclp_cmdw_t command, void *sccb);
+int __init sclp_cmd_sync_early(sclp_cmdw_t cmd, void *sccb);
 
 int sclp_sdias_init(void);
 void sclp_sdias_exit(void);

drivers/s390/char/sclp_cmd.c

@@ -59,7 +59,7 @@ static u8 sclp_fac84;
 static unsigned long long rzm;
 static unsigned long long rnmax;
 
-static int __init sclp_cmd_sync_early(sclp_cmdw_t cmd, void *sccb)
+int __init sclp_cmd_sync_early(sclp_cmdw_t cmd, void *sccb)
 {
 	int rc;
 

drivers/s390/char/sclp_early.c

@@ -0,0 +1,111 @@
+/*
+ * SCLP early driver
+ *
+ * Copyright IBM Corp. 2013
+ */
+
+#define KMSG_COMPONENT "sclp_early"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <asm/sclp.h>
+#include <asm/ipl.h>
+#include "sclp_sdias.h"
+#include "sclp.h"
+
+static __initdata char sccb_early[PAGE_SIZE] __aligned(PAGE_SIZE);
+static unsigned long sclp_hsa_size;
+
+static int __init sclp_cmd_early(sclp_cmdw_t cmd, void *sccb)
+{
+	int rc;
+
+	do {
+		rc = sclp_cmd_sync_early(cmd, sccb);
+	} while (rc == -EBUSY);
+
+	if (rc)
+		return -EIO;
+	if (((struct sccb_header *) sccb)->response_code != 0x0020)
+		return -EIO;
+	return 0;
+}
+
+static void __init sccb_init_eq_size(struct sdias_sccb *sccb)
+{
+	memset(sccb, 0, sizeof(*sccb));
+
+	sccb->hdr.length = sizeof(*sccb);
+	sccb->evbuf.hdr.length = sizeof(struct sdias_evbuf);
+	sccb->evbuf.hdr.type = EVTYP_SDIAS;
+	sccb->evbuf.event_qual = SDIAS_EQ_SIZE;
+	sccb->evbuf.data_id = SDIAS_DI_FCP_DUMP;
+	sccb->evbuf.event_id = 4712;
+	sccb->evbuf.dbs = 1;
+}
+
+static int __init sclp_set_event_mask(unsigned long receive_mask,
+				      unsigned long send_mask)
+{
+	struct init_sccb *sccb = (void *) &sccb_early;
+
+	memset(sccb, 0, sizeof(*sccb));
+	sccb->header.length = sizeof(*sccb);
+	sccb->mask_length = sizeof(sccb_mask_t);
+	sccb->receive_mask = receive_mask;
+	sccb->send_mask = send_mask;
+	return sclp_cmd_early(SCLP_CMDW_WRITE_EVENT_MASK, sccb);
+}
+
+static long __init sclp_hsa_size_init(void)
+{
+	struct sdias_sccb *sccb = (void *) &sccb_early;
+
+	sccb_init_eq_size(sccb);
+	if (sclp_cmd_early(SCLP_CMDW_WRITE_EVENT_DATA, sccb))
+		return -EIO;
+	if (sccb->evbuf.blk_cnt != 0)
+		return (sccb->evbuf.blk_cnt - 1) * PAGE_SIZE;
+	return 0;
+}
+
+static long __init sclp_hsa_copy_wait(void)
+{
+	struct sccb_header *sccb = (void *) &sccb_early;
+
+	memset(sccb, 0, PAGE_SIZE);
+	sccb->length = PAGE_SIZE;
+	if (sclp_cmd_early(SCLP_CMDW_READ_EVENT_DATA, sccb))
+		return -EIO;
+	return (((struct sdias_sccb *) sccb)->evbuf.blk_cnt - 1) * PAGE_SIZE;
+}
+
+unsigned long sclp_get_hsa_size(void)
+{
+	return sclp_hsa_size;
+}
+
+void __init sclp_hsa_size_detect(void)
+{
+	long size;
+
+	/* First try synchronous interface (LPAR) */
+	if (sclp_set_event_mask(0, 0x40000010))
+		return;
+	size = sclp_hsa_size_init();
+	if (size < 0)
+		return;
+	if (size != 0)
+		goto out;
+	/* Then try asynchronous interface (z/VM) */
+	if (sclp_set_event_mask(0x00000010, 0x40000010))
+		return;
+	size = sclp_hsa_size_init();
+	if (size < 0)
+		return;
+	size = sclp_hsa_copy_wait();
+	if (size < 0)
+		return;
+out:
+	sclp_set_event_mask(0, 0);
+	sclp_hsa_size = size;
+}

drivers/s390/char/zcore.c

@@ -328,9 +328,9 @@ static ssize_t zcore_read(struct file *file, char __user *buf, size_t count,
 	mem_offs = 0;
 
 	/* Copy from HSA data */
-	if (*ppos < (ZFCPDUMP_HSA_SIZE + HEADER_SIZE)) {
-		size = min((count - hdr_count), (size_t) (ZFCPDUMP_HSA_SIZE
-			   - mem_start));
+	if (*ppos < sclp_get_hsa_size() + HEADER_SIZE) {
+		size = min((count - hdr_count),
+			   (size_t) (sclp_get_hsa_size() - mem_start));
 		rc = memcpy_hsa_user(buf + hdr_count, mem_start, size);
 		if (rc)
 			goto fail;
@@ -490,7 +490,7 @@ static ssize_t zcore_hsa_read(struct file *filp, char __user *buf,
 	static char str[18];
 
 	if (hsa_available)
-		snprintf(str, sizeof(str), "%lx\n", ZFCPDUMP_HSA_SIZE);
+		snprintf(str, sizeof(str), "%lx\n", sclp_get_hsa_size());
 	else
 		snprintf(str, sizeof(str), "0\n");
 	return simple_read_from_buffer(buf, count, ppos, str, strlen(str));
@@ -584,17 +584,9 @@ static int __init sys_info_init(enum arch_id arch, unsigned long mem_end)
 
 static int __init check_sdias(void)
 {
-	int rc, act_hsa_size;
-
-	rc = sclp_sdias_blk_count();
-	if (rc < 0) {
+	if (!sclp_get_hsa_size()) {
 		TRACE("Could not determine HSA size\n");
-		return rc;
-	}
-	act_hsa_size = (rc - 1) * PAGE_SIZE;
-	if (act_hsa_size < ZFCPDUMP_HSA_SIZE) {
-		TRACE("HSA size too small: %i\n", act_hsa_size);
-		return -EINVAL;
+		return -ENODEV;
 	}
 	return 0;
 }
@@ -662,7 +654,7 @@ static int __init zcore_reipl_init(void)
 	ipl_block = (void *) __get_free_page(GFP_KERNEL);
 	if (!ipl_block)
 		return -ENOMEM;
-	if (ipib_info.ipib < ZFCPDUMP_HSA_SIZE)
+	if (ipib_info.ipib < sclp_get_hsa_size())
 		rc = memcpy_hsa_kernel(ipl_block, ipib_info.ipib, PAGE_SIZE);
 	else
 		rc = memcpy_real(ipl_block, (void *) ipib_info.ipib, PAGE_SIZE);