1 /* 2 * QEMU s390-ccw firmware - jump to IPL code 3 * 4 * This work is licensed under the terms of the GNU GPL, version 2 or (at 5 * your option) any later version. See the COPYING file in the top-level 6 * directory. 7 */ 8 9 #include <string.h> 10 #include <stdio.h> 11 #include "s390-ccw.h" 12 #include "s390-arch.h" 13 14 #define KERN_IMAGE_START 0x010000UL 15 #define RESET_PSW_MASK (PSW_MASK_SHORTPSW | PSW_MASK_64) 16 #define RESET_PSW ((uint64_t)&jump_to_IPL_addr | RESET_PSW_MASK) 17 18 static uint64_t *reset_psw = 0, save_psw, ipl_continue; 19 20 void write_reset_psw(uint64_t psw) 21 { 22 *reset_psw = psw; 23 } 24 25 static void jump_to_IPL_addr(void) 26 { 27 __attribute__((noreturn)) void (*ipl)(void) = (void *)ipl_continue; 28 29 /* Restore reset PSW */ 30 write_reset_psw(save_psw); 31 32 ipl(); 33 /* should not return */ 34 } 35 36 int jump_to_IPL_code(uint64_t address) 37 { 38 /* store the subsystem information _after_ the bootmap was loaded */ 39 write_subsystem_identification(); 40 write_iplb_location(); 41 42 /* 43 * The IPLB for QEMU SCSI type devices must be rebuilt during re-ipl. The 44 * iplb.devno is set to the boot position of the target SCSI device. 45 */ 46 if (iplb.pbt == S390_IPL_TYPE_QEMU_SCSI) { 47 iplb.devno = qipl.index; 48 } 49 50 if (have_iplb && !set_iplb(&iplb)) { 51 panic("Failed to set IPLB"); 52 } 53 54 /* 55 * The IPL PSW is at address 0. We also must not overwrite the 56 * content of non-BIOS memory after we loaded the guest, so we 57 * save the original content and restore it in jump_to_IPL_2. 58 */ 59 if (address) { 60 save_psw = *reset_psw; 61 write_reset_psw(RESET_PSW); 62 ipl_continue = address; 63 } 64 debug_print_int("set IPL addr to", address ?: *reset_psw & PSW_MASK_SHORT_ADDR); 65 66 /* Ensure the guest output starts fresh */ 67 printf("\n"); 68 69 /* 70 * HACK ALERT. 71 * We use the load normal reset to keep r15 unchanged. jump_to_IPL_2 72 * can then use r15 as its stack pointer. 73 */ 74 asm volatile("lghi %%r1,1\n\t" 75 "diag %%r1,%%r1,0x308\n\t" 76 : : : "1", "memory"); 77 puts("IPL code jump failed"); 78 return -1; 79 } 80 81 void jump_to_low_kernel(void) 82 { 83 /* 84 * If it looks like a Linux binary, i.e. there is the "S390EP" magic from 85 * arch/s390/kernel/head.S here, then let's jump to the well-known Linux 86 * kernel start address (when jumping to the PSW-at-zero address instead, 87 * the kernel startup code fails when we booted from a network device). 88 */ 89 if (!memcmp((char *)S390EP, "S390EP", 6)) { 90 jump_to_IPL_code(KERN_IMAGE_START); 91 } 92 93 /* Trying to get PSW at zero address (pointed to by reset_psw) */ 94 if (*reset_psw & RESET_PSW_MASK) { 95 /* 96 * Surely nobody will try running directly from lowcore, so 97 * let's use 0 as an indication that we want to load the reset 98 * psw at 0x0 and not jump to the entry. 99 */ 100 jump_to_IPL_code(0); 101 } 102 103 /* No other option left, so use the Linux kernel start address */ 104 jump_to_IPL_code(KERN_IMAGE_START); 105 } 106