[S390] kdump backend code

This patch provides the architecture specific part of the s390 kdump
support.

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 119 insertions, 0 deletions

diff --git a/arch/s390/kernel/head_kdump.S b/arch/s390/kernel/head_kdump.S
new file mode 100644
index 000000000000..e1ac3893e972
--- /dev/null
+++ b/arch/s390/kernel/head_kdump.S
@@ -0,0 +1,119 @@
+/*
+ * S390 kdump lowlevel functions (new kernel)
+ *
+ * Copyright IBM Corp. 2011
+ * Author(s): Michael Holzheu <holzheu@linux.vnet.ibm.com>
+ */
+
+#define DATAMOVER_ADDR  0x4000
+#define COPY_PAGE_ADDR  0x6000
+
+#ifdef CONFIG_CRASH_DUMP
+
+#
+# kdump entry (new kernel - not yet relocated)
+#
+# Note: This code has to be position independent
+#
+
+.align 2
+.Lep_startup_kdump:
+        lhi     %r1,2                           # mode 2 = esame (dump)
+        sigp    %r1,%r0,0x12                    # Switch to esame mode
+        sam64                                   # Switch to 64 bit addressing
+        basr    %r13,0
+.Lbase:
+        larl    %r2,.Lbase_addr                 # Check, if we have been
+        lg      %r2,0(%r2)                      # already relocated:
+        clgr    %r2,%r13                        #
+        jne     .Lrelocate                      # No : Start data mover
+        lghi    %r2,0                           # Yes: Start kdump kernel
+        brasl   %r14,startup_kdump_relocated
+
+.Lrelocate:
+        larl    %r4,startup
+        lg      %r2,0x418(%r4)                  # Get kdump base
+        lg      %r3,0x420(%r4)                  # Get kdump size
+
+        larl    %r10,.Lcopy_start               # Source of data mover
+        lghi    %r8,DATAMOVER_ADDR              # Target of data mover
+        mvc     0(256,%r8),0(%r10)              # Copy data mover code
+
+        agr     %r8,%r2                         # Copy data mover to
+        mvc     0(256,%r8),0(%r10)              # reserved mem
+
+        lghi    %r14,DATAMOVER_ADDR             # Jump to copied data mover
+        basr    %r14,%r14
+.Lbase_addr:
+        .quad   .Lbase
+
+#
+# kdump data mover code (runs at address DATAMOVER_ADDR)
+#
+# r2: kdump base address
+# r3: kdump size
+#
+.Lcopy_start:
+        basr    %r13,0                          # Base
+0:
+        lgr     %r11,%r2                        # Save kdump base address
+        lgr     %r12,%r2
+        agr     %r12,%r3                        # Compute kdump end address
+
+        lghi    %r5,0
+        lghi    %r10,COPY_PAGE_ADDR             # Load copy page address
+1:
+        mvc     0(256,%r10),0(%r5)              # Copy old kernel to tmp
+        mvc     0(256,%r5),0(%r11)              # Copy new kernel to old
+        mvc     0(256,%r11),0(%r10)             # Copy tmp to new
+        aghi    %r11,256
+        aghi    %r5,256
+        clgr    %r11,%r12
+        jl      1b
+
+        lg      %r14,.Lstartup_kdump-0b(%r13)
+        basr    %r14,%r14                       # Start relocated kernel
+.Lstartup_kdump:
+        .long   0x00000000,0x00000000 + startup_kdump_relocated
+.Lcopy_end:
+
+#
+# Startup of kdump (relocated new kernel)
+#
+.align 2
+startup_kdump_relocated:
+        basr    %r13,0
+0:
+        mvc     0(8,%r0),.Lrestart_psw-0b(%r13) # Setup restart PSW
+        mvc     464(16,%r0),.Lpgm_psw-0b(%r13)  # Setup pgm check PSW
+        lhi     %r1,1                           # Start new kernel
+        diag    %r1,%r1,0x308                   # with diag 308
+
+.Lno_diag308:                                   # No diag 308
+        sam31                                   # Switch to 31 bit addr mode
+        sr      %r1,%r1                         # Erase register r1
+        sr      %r2,%r2                         # Erase register r2
+        sigp    %r1,%r2,0x12                    # Switch to 31 bit arch mode
+        lpsw    0                               # Start new kernel...
+.align  8
+.Lrestart_psw:
+        .long   0x00080000,0x80000000 + startup
+.Lpgm_psw:
+        .quad   0x0000000180000000,0x0000000000000000 + .Lno_diag308
+#else
+.align 2
+.Lep_startup_kdump:
+#ifdef CONFIG_64BIT
+        larl    %r13,startup_kdump_crash
+        lpswe   0(%r13)
+.align 8
+startup_kdump_crash:
+        .quad   0x0002000080000000,0x0000000000000000 + startup_kdump_crash
+#else
+        basr    %r13,0
+0:      lpsw    startup_kdump_crash-0b(%r13)
+.align 8
+startup_kdump_crash:
+        .long   0x000a0000,0x00000000 + startup_kdump_crash
+#endif /* CONFIG_64BIT */
+#endif /* CONFIG_CRASH_DUMP */