[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>
diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c
new file mode 100644
index 0000000..40dd479
--- /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();
+}