92 lines
2.5 KiB
C
92 lines
2.5 KiB
C
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/*
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* QEMU s390-ccw firmware - jump to IPL code
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or (at
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* your option) any later version. See the COPYING file in the top-level
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* directory.
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*/
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#include "libc.h"
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#include "s390-ccw.h"
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#define KERN_IMAGE_START 0x010000UL
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#define PSW_MASK_64 0x0000000100000000ULL
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#define PSW_MASK_32 0x0000000080000000ULL
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#define IPL_PSW_MASK (PSW_MASK_32 | PSW_MASK_64)
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typedef struct ResetInfo {
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uint32_t ipl_mask;
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uint32_t ipl_addr;
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uint32_t ipl_continue;
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} ResetInfo;
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static ResetInfo save;
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static void jump_to_IPL_2(void)
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{
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ResetInfo *current = 0;
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void (*ipl)(void) = (void *) (uint64_t) current->ipl_continue;
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*current = save;
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ipl(); /* should not return */
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}
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void jump_to_IPL_code(uint64_t address)
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{
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/* store the subsystem information _after_ the bootmap was loaded */
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write_subsystem_identification();
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/* prevent unknown IPL types in the guest */
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if (iplb.pbt == S390_IPL_TYPE_QEMU_SCSI) {
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iplb.pbt = S390_IPL_TYPE_CCW;
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set_iplb(&iplb);
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}
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/*
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* The IPL PSW is at address 0. We also must not overwrite the
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* content of non-BIOS memory after we loaded the guest, so we
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* save the original content and restore it in jump_to_IPL_2.
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*/
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ResetInfo *current = 0;
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save = *current;
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current->ipl_addr = (uint32_t) (uint64_t) &jump_to_IPL_2;
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current->ipl_continue = address & 0x7fffffff;
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debug_print_int("set IPL addr to", current->ipl_continue);
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/* Ensure the guest output starts fresh */
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sclp_print("\n");
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/*
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* HACK ALERT.
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* We use the load normal reset to keep r15 unchanged. jump_to_IPL_2
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* can then use r15 as its stack pointer.
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*/
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asm volatile("lghi 1,1\n\t"
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"diag 1,1,0x308\n\t"
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: : : "1", "memory");
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panic("\n! IPL returns !\n");
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}
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void jump_to_low_kernel(void)
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{
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/*
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* If it looks like a Linux binary, i.e. there is the "S390EP" magic from
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* arch/s390/kernel/head.S here, then let's jump to the well-known Linux
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* kernel start address (when jumping to the PSW-at-zero address instead,
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* the kernel startup code fails when we booted from a network device).
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*/
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if (!memcmp((char *)0x10008, "S390EP", 6)) {
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jump_to_IPL_code(KERN_IMAGE_START);
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}
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/* Trying to get PSW at zero address */
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if (*((uint64_t *)0) & IPL_PSW_MASK) {
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jump_to_IPL_code((*((uint64_t *)0)) & 0x7fffffff);
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}
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/* No other option left, so use the Linux kernel start address */
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jump_to_IPL_code(KERN_IMAGE_START);
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}
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