[S390] Convert memory detection into C code.

Hopefully this will make it more maintainable and less error prone.
Code makes use of search_exception_tables(). Since it calls this
function before the kernel exeception table is sorted, there is an
early call to sort_main_extable().

This way it's easy to use the already present infrastructure of fixup
sections. Also this would allows to easily convert the rest of
head[31|64].S into C code.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 307 insertions, 0 deletions

diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c
new file mode 100644
index 00000000000..40dd47970a3
--- /dev/null
+++ b/arch/s390/kernel/early.c
@@ -0,0 +1,307 @@
+/*
+ *  arch/s390/kernel/early.c
+ *
+ *    Copyright IBM Corp. 2007
+ *    Author(s): Hongjie Yang <hongjie@us.ibm.com>,
+ *		 Heiko Carstens <heiko.carstens@de.ibm.com>
+ */
+
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/ctype.h>
+#include <linux/lockdep.h>
+#include <linux/module.h>
+#include <linux/pfn.h>
+#include <linux/uaccess.h>
+#include <asm/lowcore.h>
+#include <asm/processor.h>
+#include <asm/sections.h>
+#include <asm/setup.h>
+#include <asm/cpcmd.h>
+#include <asm/sclp.h>
+
+/*
+ * Create a Kernel NSS if the SAVESYS= parameter is defined
+ */
+#define DEFSYS_CMD_SIZE		96
+#define SAVESYS_CMD_SIZE	32
+
+extern int _eshared;
+char kernel_nss_name[NSS_NAME_SIZE + 1];
+
+#ifdef CONFIG_SHARED_KERNEL
+static noinline __init void create_kernel_nss(void)
+{
+	unsigned int i, stext_pfn, eshared_pfn, end_pfn, min_size;
+#ifdef CONFIG_BLK_DEV_INITRD
+	unsigned int sinitrd_pfn, einitrd_pfn;
+#endif
+	int response;
+	char *savesys_ptr;
+	char upper_command_line[COMMAND_LINE_SIZE];
+	char defsys_cmd[DEFSYS_CMD_SIZE];
+	char savesys_cmd[SAVESYS_CMD_SIZE];
+
+	/* Do nothing if we are not running under VM */
+	if (!MACHINE_IS_VM)
+		return;
+
+	/* Convert COMMAND_LINE to upper case */
+	for (i = 0; i < strlen(COMMAND_LINE); i++)
+		upper_command_line[i] = toupper(COMMAND_LINE[i]);
+
+	savesys_ptr = strstr(upper_command_line, "SAVESYS=");
+
+	if (!savesys_ptr)
+		return;
+
+	savesys_ptr += 8;    /* Point to the beginning of the NSS name */
+	for (i = 0; i < NSS_NAME_SIZE; i++) {
+		if (savesys_ptr[i] == ' ' || savesys_ptr[i] == '\0')
+			break;
+		kernel_nss_name[i] = savesys_ptr[i];
+	}
+
+	stext_pfn = PFN_DOWN(__pa(&_stext));
+	eshared_pfn = PFN_DOWN(__pa(&_eshared));
+	end_pfn = PFN_UP(__pa(&_end));
+	min_size = end_pfn << 2;
+
+	sprintf(defsys_cmd, "DEFSYS %s 00000-%.5X EW %.5X-%.5X SR %.5X-%.5X",
+		kernel_nss_name, stext_pfn - 1, stext_pfn, eshared_pfn - 1,
+		eshared_pfn, end_pfn);
+
+#ifdef CONFIG_BLK_DEV_INITRD
+	if (INITRD_START && INITRD_SIZE) {
+		sinitrd_pfn = PFN_DOWN(__pa(INITRD_START));
+		einitrd_pfn = PFN_UP(__pa(INITRD_START + INITRD_SIZE));
+		min_size = einitrd_pfn << 2;
+		sprintf(defsys_cmd, "%s EW %.5X-%.5X", defsys_cmd,
+		sinitrd_pfn, einitrd_pfn);
+	}
+#endif
+
+	sprintf(defsys_cmd, "%s EW MINSIZE=%.7iK", defsys_cmd, min_size);
+	sprintf(savesys_cmd, "SAVESYS %s \n IPL %s",
+		kernel_nss_name, kernel_nss_name);
+
+	__cpcmd(defsys_cmd, NULL, 0, &response);
+
+	if (response != 0)
+		return;
+
+	__cpcmd(savesys_cmd, NULL, 0, &response);
+
+	if (response != strlen(savesys_cmd))
+		return;
+
+	ipl_flags = IPL_NSS_VALID;
+}
+
+#else /* CONFIG_SHARED_KERNEL */
+
+static inline void create_kernel_nss(void) { }
+
+#endif /* CONFIG_SHARED_KERNEL */
+
+/*
+ * Clear bss memory
+ */
+static noinline __init void clear_bss_section(void)
+{
+	memset(__bss_start, 0, _end - __bss_start);
+}
+
+/*
+ * Initialize storage key for kernel pages
+ */
+static noinline __init void init_kernel_storage_key(void)
+{
+	unsigned long end_pfn, init_pfn;
+
+	end_pfn = PFN_UP(__pa(&_end));
+
+	for (init_pfn = 0 ; init_pfn < end_pfn; init_pfn++)
+		page_set_storage_key(init_pfn << PAGE_SHIFT, PAGE_DEFAULT_KEY);
+}
+
+static noinline __init void detect_machine_type(void)
+{
+	struct cpuinfo_S390 *cpuinfo = &S390_lowcore.cpu_data;
+
+	asm volatile("stidp %0" : "=m" (S390_lowcore.cpu_data.cpu_id));
+
+	/* Running under z/VM ? */
+	if (cpuinfo->cpu_id.version == 0xff)
+		machine_flags |= 1;
+
+	/* Running on a P/390 ? */
+	if (cpuinfo->cpu_id.machine == 0x7490)
+		machine_flags |= 4;
+}
+
+static noinline __init int memory_fast_detect(void)
+{
+
+	unsigned long val0 = 0;
+	unsigned long val1 = 0xc;
+	int ret = -ENOSYS;
+
+	if (ipl_flags & IPL_NSS_VALID)
+		return -ENOSYS;
+
+	asm volatile(
+		"	diag	%1,%2,0x260\n"
+		"0:	lhi	%0,0\n"
+		"1:\n"
+		EX_TABLE(0b,1b)
+		: "+d" (ret), "+d" (val0), "+d" (val1) : : "cc");
+
+	if (ret || val0 != val1)
+		return -ENOSYS;
+
+	memory_chunk[0].size = val0;
+	return 0;
+}
+
+#define ADDR2G	(1UL << 31)
+
+static noinline __init unsigned long sclp_memory_detect(void)
+{
+	struct sclp_readinfo_sccb *sccb;
+	unsigned long long memsize;
+
+	sccb = &s390_readinfo_sccb;
+
+	if (sccb->header.response_code != 0x10)
+		return 0;
+
+	if (sccb->rnsize)
+		memsize = sccb->rnsize << 20;
+	else
+		memsize = sccb->rnsize2 << 20;
+	if (sccb->rnmax)
+		memsize *= sccb->rnmax;
+	else
+		memsize *= sccb->rnmax2;
+#ifndef CONFIG_64BIT
+	/*
+	 * Can't deal with more than 2G in 31 bit addressing mode, so
+	 * limit the value in order to avoid strange side effects.
+	 */
+	if (memsize > ADDR2G)
+		memsize = ADDR2G;
+#endif
+	return (unsigned long) memsize;
+}
+
+static inline __init unsigned long __tprot(unsigned long addr)
+{
+	int cc = -1;
+
+	asm volatile(
+		"	tprot	0(%1),0\n"
+		"0:	ipm	%0\n"
+		"	srl	%0,28\n"
+		"1:\n"
+		EX_TABLE(0b,1b)
+		: "+d" (cc) : "a" (addr) : "cc");
+	return (unsigned long)cc;
+}
+
+/* Checking memory in 128KB increments. */
+#define CHUNK_INCR	(1UL << 17)
+
+static noinline __init void find_memory_chunks(unsigned long memsize)
+{
+	unsigned long addr = 0, old_addr = 0;
+	unsigned long old_cc = CHUNK_READ_WRITE;
+	unsigned long cc;
+	int chunk = 0;
+
+	while (chunk < MEMORY_CHUNKS) {
+		cc = __tprot(addr);
+		while (cc == old_cc) {
+			addr += CHUNK_INCR;
+			cc = __tprot(addr);
+#ifndef CONFIG_64BIT
+			if (addr == ADDR2G)
+				break;
+#endif
+		}
+
+		if (old_addr != addr &&
+		    (old_cc == CHUNK_READ_WRITE || old_cc == CHUNK_READ_ONLY)) {
+			memory_chunk[chunk].addr = old_addr;
+			memory_chunk[chunk].size = addr - old_addr;
+			memory_chunk[chunk].type = old_cc;
+			chunk++;
+		}
+
+		old_addr = addr;
+		old_cc = cc;
+
+#ifndef CONFIG_64BIT
+		if (addr == ADDR2G)
+			break;
+#endif
+		/*
+		 * Finish memory detection at the first hole, unless
+		 * - we reached the hsa -> skip it.
+		 * - we know there must be more.
+		 */
+		if (cc == -1UL && !memsize && old_addr != ADDR2G)
+			break;
+		if (memsize && addr >= memsize)
+			break;
+	}
+}
+
+static __init void early_pgm_check_handler(void)
+{
+	unsigned long addr;
+	const struct exception_table_entry *fixup;
+
+	addr = S390_lowcore.program_old_psw.addr;
+	fixup = search_exception_tables(addr & PSW_ADDR_INSN);
+	if (!fixup)
+		disabled_wait(0);
+	S390_lowcore.program_old_psw.addr = fixup->fixup | PSW_ADDR_AMODE;
+}
+
+static noinline __init void setup_lowcore_early(void)
+{
+	psw_t psw;
+
+	psw.mask = PSW_BASE_BITS | PSW_DEFAULT_KEY;
+	psw.addr = PSW_ADDR_AMODE | (unsigned long) s390_base_ext_handler;
+	S390_lowcore.external_new_psw = psw;
+	psw.addr = PSW_ADDR_AMODE | (unsigned long) s390_base_pgm_handler;
+	S390_lowcore.program_new_psw = psw;
+	s390_base_pgm_handler_fn = early_pgm_check_handler;
+}
+
+/*
+ * Save ipl parameters, clear bss memory, initialize storage keys
+ * and create a kernel NSS at startup if the SAVESYS= parm is defined
+ */
+void __init startup_init(void)
+{
+	unsigned long memsize;
+
+	ipl_save_parameters();
+	clear_bss_section();
+	init_kernel_storage_key();
+	lockdep_init();
+	lockdep_off();
+	detect_machine_type();
+	create_kernel_nss();
+	sort_main_extable();
+	setup_lowcore_early();
+	sclp_readinfo_early();
+	memsize = sclp_memory_detect();
+	if (memory_fast_detect() < 0)
+		find_memory_chunks(memsize);
+	lockdep_on();
+}