[S390] Extra Kernel Parameters via VMPARM

Now it is possible to specify additional kernel parameters on the IPL
command line using the IPL PARM option.
If the Linux system is already running, the new reipl sysfs attribute
'parm' can be used to change kernel parameters for the next reboot.
Examples:
  IPL    C PARM dasd=1234 root=/dev/dasda1
  IPL 1234 PARM savesys=mylnxnss
  echo "init=/bin/bash" > /sys/firmware/reipl/ccw/parm

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

1 files changed, 72 insertions, 8 deletions

diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c
index b2226e41f067..e22473993dc9 100644
--- a/arch/s390/kernel/early.c
+++ b/arch/s390/kernel/early.c
@@ -14,6 +14,7 @@
 #include <linux/module.h>
 #include <linux/pfn.h>
 #include <linux/uaccess.h>
+#include <asm/ebcdic.h>
 #include <asm/ipl.h>
 #include <asm/lowcore.h>
 #include <asm/processor.h>
@@ -26,12 +27,40 @@
 /*
  * Create a Kernel NSS if the SAVESYS= parameter is defined
  */
-#define DEFSYS_CMD_SIZE         96
+#define DEFSYS_CMD_SIZE         128
 #define SAVESYS_CMD_SIZE        32
 
 char kernel_nss_name[NSS_NAME_SIZE + 1];
 
+static void __init setup_boot_command_line(void);
+
+
 #ifdef CONFIG_SHARED_KERNEL
+int __init savesys_ipl_nss(char *cmd, const int cmdlen);
+
+asm(
+        "       .section .init.text,\"ax\",@progbits\n"
+        "       .align  4\n"
+        "       .type   savesys_ipl_nss, @function\n"
+        "savesys_ipl_nss:\n"
+#ifdef CONFIG_64BIT
+        "       stmg    6,15,48(15)\n"
+        "       lgr     14,3\n"
+        "       sam31\n"
+        "       diag    2,14,0x8\n"
+        "       sam64\n"
+        "       lgr     2,14\n"
+        "       lmg     6,15,48(15)\n"
+#else
+        "       stm     6,15,24(15)\n"
+        "       lr      14,3\n"
+        "       diag    2,14,0x8\n"
+        "       lr      2,14\n"
+        "       lm      6,15,24(15)\n"
+#endif
+        "       br      14\n"
+        "       .size   savesys_ipl_nss, .-savesys_ipl_nss\n");
+
 static noinline __init void create_kernel_nss(void)
 {
         unsigned int i, stext_pfn, eshared_pfn, end_pfn, min_size;
@@ -39,6 +68,7 @@ static noinline __init void create_kernel_nss(void)
         unsigned int sinitrd_pfn, einitrd_pfn;
 #endif
         int response;
+        size_t len;
         char *savesys_ptr;
         char upper_command_line[COMMAND_LINE_SIZE];
         char defsys_cmd[DEFSYS_CMD_SIZE];
@@ -49,8 +79,8 @@ static noinline __init void create_kernel_nss(void)
                 return;
 
         /* Convert COMMAND_LINE to upper case */
-        for (i = 0; i < strlen(COMMAND_LINE); i++)
-                upper_command_line[i] = toupper(COMMAND_LINE[i]);
+        for (i = 0; i < strlen(boot_command_line); i++)
+                upper_command_line[i] = toupper(boot_command_line[i]);
 
         savesys_ptr = strstr(upper_command_line, "SAVESYS=");
 
@@ -83,7 +113,8 @@ static noinline __init void create_kernel_nss(void)
         }
 #endif
 
-        sprintf(defsys_cmd, "%s EW MINSIZE=%.7iK", defsys_cmd, min_size);
+        sprintf(defsys_cmd, "%s EW MINSIZE=%.7iK PARMREGS=0-13",
+                defsys_cmd, min_size);
         sprintf(savesys_cmd, "SAVESYS %s \n IPL %s",
                 kernel_nss_name, kernel_nss_name);
 
@@ -94,13 +125,24 @@ static noinline __init void create_kernel_nss(void)
                 return;
         }
 
-        __cpcmd(savesys_cmd, NULL, 0, &response);
+        len = strlen(savesys_cmd);
+        ASCEBC(savesys_cmd, len);
+        response = savesys_ipl_nss(savesys_cmd, len);
 
-        if (response != strlen(savesys_cmd)) {
+        /* On success: response is equal to the command size,
+         *             max SAVESYS_CMD_SIZE
+         * On error: response contains the numeric portion of cp error message.
+         *           for SAVESYS it will be >= 263
+         */
+        if (response > SAVESYS_CMD_SIZE) {
                 kernel_nss_name[0] = '\0';
                 return;
         }
 
+        /* re-setup boot command line with new ipl vm parms */
+        ipl_update_parameters();
+        setup_boot_command_line();
+
         ipl_flags = IPL_NSS_VALID;
 }
 
@@ -397,6 +439,26 @@ static __init void rescue_initrd(void)
 #endif
 }
 
+/* Set up boot command line */
+static void __init setup_boot_command_line(void)
+{
+        char *parm = NULL;
+
+        /* copy arch command line */
+        strlcpy(boot_command_line, COMMAND_LINE, ARCH_COMMAND_LINE_SIZE);
+        boot_command_line[ARCH_COMMAND_LINE_SIZE - 1] = 0;
+
+        /* append IPL PARM data to the boot command line */
+        if (MACHINE_IS_VM) {
+                parm = boot_command_line + strlen(boot_command_line);
+                *parm++ = ' ';
+                get_ipl_vmparm(parm);
+                if (parm[0] == '=')
+                        memmove(boot_command_line, parm + 1, strlen(parm));
+        }
+}
+
+
 /*
  * Save ipl parameters, clear bss memory, initialize storage keys
  * and create a kernel NSS at startup if the SAVESYS= parm is defined
@@ -411,10 +473,12 @@ void __init startup_init(void)
         init_kernel_storage_key();
         lockdep_init();
         lockdep_off();
-        detect_machine_type();
-        create_kernel_nss();
         sort_main_extable();
         setup_lowcore_early();
+        detect_machine_type();
+        ipl_update_parameters();
+        setup_boot_command_line();
+        create_kernel_nss();
         detect_mvpg();
         detect_ieee();
         detect_csp();