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-rw-r--r--arch/s390/kernel/text_amode31.S159
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diff --git a/arch/s390/kernel/text_amode31.S b/arch/s390/kernel/text_amode31.S
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+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Code that needs to run below 2 GB.
+ *
+ * Copyright IBM Corp. 2019
+ */
+
+#include <linux/linkage.h>
+#include <asm/asm-extable.h>
+#include <asm/errno.h>
+#include <asm/sigp.h>
+
+ .section .amode31.text,"ax"
+/*
+ * Simplified version of expoline thunk. The normal thunks can not be used here,
+ * because they might be more than 2 GB away, and not reachable by the relative
+ * branch. No comdat, exrl, etc. optimizations used here, because it only
+ * affects a few functions that are not performance-relevant.
+ */
+ .macro BR_EX_AMODE31_r14
+ larl %r1,0f
+ ex 0,0(%r1)
+ j .
+0: br %r14
+ .endm
+
+/*
+ * int _diag14_amode31(unsigned long rx, unsigned long ry1, unsigned long subcode)
+ */
+ENTRY(_diag14_amode31)
+ lgr %r1,%r2
+ lgr %r2,%r3
+ lgr %r3,%r4
+ lhi %r5,-EIO
+ sam31
+ diag %r1,%r2,0x14
+.Ldiag14_ex:
+ ipm %r5
+ srl %r5,28
+.Ldiag14_fault:
+ sam64
+ lgfr %r2,%r5
+ BR_EX_AMODE31_r14
+ EX_TABLE_AMODE31(.Ldiag14_ex, .Ldiag14_fault)
+ENDPROC(_diag14_amode31)
+
+/*
+ * int _diag210_amode31(struct diag210 *addr)
+ */
+ENTRY(_diag210_amode31)
+ lgr %r1,%r2
+ lhi %r2,-1
+ sam31
+ diag %r1,%r0,0x210
+.Ldiag210_ex:
+ ipm %r2
+ srl %r2,28
+.Ldiag210_fault:
+ sam64
+ lgfr %r2,%r2
+ BR_EX_AMODE31_r14
+ EX_TABLE_AMODE31(.Ldiag210_ex, .Ldiag210_fault)
+ENDPROC(_diag210_amode31)
+
+/*
+ * int _diag26c_amode31(void *req, void *resp, enum diag26c_sc subcode)
+ */
+ENTRY(_diag26c_amode31)
+ lghi %r5,-EOPNOTSUPP
+ sam31
+ diag %r2,%r4,0x26c
+.Ldiag26c_ex:
+ sam64
+ lgfr %r2,%r5
+ BR_EX_AMODE31_r14
+ EX_TABLE_AMODE31(.Ldiag26c_ex, .Ldiag26c_ex)
+ENDPROC(_diag26c_amode31)
+
+/*
+ * void _diag0c_amode31(struct hypfs_diag0c_entry *entry)
+ */
+ENTRY(_diag0c_amode31)
+ sam31
+ diag %r2,%r2,0x0c
+ sam64
+ BR_EX_AMODE31_r14
+ENDPROC(_diag0c_amode31)
+
+/*
+ * void _diag308_reset_amode31(void)
+ *
+ * Calls diag 308 subcode 1 and continues execution
+ */
+ENTRY(_diag308_reset_amode31)
+ larl %r4,.Lctlregs # Save control registers
+ stctg %c0,%c15,0(%r4)
+ lg %r2,0(%r4) # Disable lowcore protection
+ nilh %r2,0xefff
+ larl %r4,.Lctlreg0
+ stg %r2,0(%r4)
+ lctlg %c0,%c0,0(%r4)
+ larl %r4,.Lfpctl # Floating point control register
+ stfpc 0(%r4)
+ larl %r4,.Lprefix # Save prefix register
+ stpx 0(%r4)
+ larl %r4,.Lprefix_zero # Set prefix register to 0
+ spx 0(%r4)
+ larl %r4,.Lcontinue_psw # Save PSW flags
+ epsw %r2,%r3
+ stm %r2,%r3,0(%r4)
+ larl %r4,.Lrestart_part2 # Setup restart PSW at absolute 0
+ larl %r3,.Lrestart_diag308_psw
+ og %r4,0(%r3) # Save PSW
+ lghi %r3,0
+ sturg %r4,%r3 # Use sturg, because of large pages
+ lghi %r1,1
+ lghi %r0,0
+ diag %r0,%r1,0x308
+.Lrestart_part2:
+ lhi %r0,0 # Load r0 with zero
+ lhi %r1,2 # Use mode 2 = ESAME (dump)
+ sigp %r1,%r0,SIGP_SET_ARCHITECTURE # Switch to ESAME mode
+ sam64 # Switch to 64 bit addressing mode
+ larl %r4,.Lctlregs # Restore control registers
+ lctlg %c0,%c15,0(%r4)
+ larl %r4,.Lfpctl # Restore floating point ctl register
+ lfpc 0(%r4)
+ larl %r4,.Lprefix # Restore prefix register
+ spx 0(%r4)
+ larl %r4,.Lcontinue_psw # Restore PSW flags
+ larl %r2,.Lcontinue
+ stg %r2,8(%r4)
+ lpswe 0(%r4)
+.Lcontinue:
+ BR_EX_AMODE31_r14
+ENDPROC(_diag308_reset_amode31)
+
+ .section .amode31.data,"aw",@progbits
+.align 8
+.Lrestart_diag308_psw:
+ .long 0x00080000,0x80000000
+
+.align 8
+.Lcontinue_psw:
+ .quad 0,0
+
+.align 8
+.Lctlreg0:
+ .quad 0
+.Lctlregs:
+ .rept 16
+ .quad 0
+ .endr
+.Lfpctl:
+ .long 0
+.Lprefix:
+ .long 0
+.Lprefix_zero:
+ .long 0