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Diffstat (limited to 'arch/s390/purgatory/head.S')
| -rw-r--r-- | arch/s390/purgatory/head.S | 96 |
1 files changed, 96 insertions, 0 deletions
diff --git a/arch/s390/purgatory/head.S b/arch/s390/purgatory/head.S new file mode 100644 index 000000000000..8735409d0280 --- /dev/null +++ b/arch/s390/purgatory/head.S @@ -0,0 +1,96 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Purgatory setup code + * + * Copyright IBM Corp. 2018 + * + * Author(s): Philipp Rudo <prudo@linux.vnet.ibm.com> + */ + +#include <linux/linkage.h> +#include <asm/asm-offsets.h> +#include <asm/page.h> +#include <asm/sigp.h> + +/* The purgatory is the code running between two kernels. It's main purpose + * is to verify that the next kernel was not corrupted after load and to + * start it. + */ + +.macro START_NEXT_KERNEL base + lg %r4,kernel_entry-\base(%r13) + lg %r5,load_psw_mask-\base(%r13) + ogr %r4,%r5 + stg %r4,0(%r0) + + xgr %r0,%r0 + diag %r0,%r0,0x308 +.endm + +.text +.align PAGE_SIZE +ENTRY(purgatory_start) + /* The purgatory might be called after a diag308 so better set + * architecture and addressing mode. + */ + lhi %r1,1 + sigp %r1,%r0,SIGP_SET_ARCHITECTURE + sam64 + + larl %r5,gprregs + stmg %r6,%r15,0(%r5) + + basr %r13,0 +.base_crash: + + /* Setup stack */ + larl %r15,purgatory_end + aghi %r15,-160 + +.do_checksum_verification: + brasl %r14,verify_sha256_digest + + cghi %r2,0 /* checksum match */ + jne .disabled_wait + + /* start normal kernel */ + START_NEXT_KERNEL .base_crash + +.disabled_wait: + lpswe disabled_wait_psw-.base_crash(%r13) + + +load_psw_mask: + .long 0x00080000,0x80000000 + + .align 8 +disabled_wait_psw: + .quad 0x0002000180000000 + .quad 0x0000000000000000 + .do_checksum_verification + +gprregs: + .rept 10 + .quad 0 + .endr + +purgatory_sha256_digest: + .global purgatory_sha256_digest + .rept 32 /* SHA256_DIGEST_SIZE */ + .byte 0 + .endr + +purgatory_sha_regions: + .global purgatory_sha_regions + .rept 16 * __KEXEC_SHA_REGION_SIZE /* KEXEC_SEGMENTS_MAX */ + .byte 0 + .endr + +kernel_entry: + .global kernel_entry + .quad 0 + + .align PAGE_SIZE +stack: + .skip PAGE_SIZE + .align PAGE_SIZE +purgatory_end: |