[PATCH] kexec: s390 support

Add kexec support for s390 architecture.

From: Milton Miller <miltonm@bga.com>

- Fix passing of first argument to relocate_kernel assembly.
- Fix Kconfig description.
- Remove wrong comment and comments that describe obvious things.
- Allow only KEXEC_TYPE_DEFAULT as image type -> dump not supported.

Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 81 insertions, 0 deletions

diff --git a/arch/s390/kernel/relocate_kernel.S b/arch/s390/kernel/relocate_kernel.S
new file mode 100644
index 000000000000..d5e4a62fbb79
--- /dev/null
+++ b/arch/s390/kernel/relocate_kernel.S
@@ -0,0 +1,81 @@
+/*
+ * arch/s390/kernel/relocate_kernel.S
+ *
+ * (C) Copyright IBM Corp. 2005
+ *
+ * Author(s): Rolf Adelsberger <adelsberger@de.ibm.com>
+ *
+ */
+
+/*
+ * moves the new kernel to its destination...
+ * %r2 = pointer to first kimage_entry_t
+ * %r3 = start address - where to jump to after the job is done...
+ *
+ * %r5 will be used as temp. storage
+ * %r6 holds the destination address
+ * %r7 = PAGE_SIZE
+ * %r8 holds the source address
+ * %r9 = PAGE_SIZE
+ * %r10 is a page mask
+ */
+
+        .text
+        .globl          relocate_kernel
+        relocate_kernel:
+                basr    %r13,0          #base address
+        .base:
+                spx     zero64-.base(%r13)      #absolute addressing mode
+                stnsm   sys_msk-.base(%r13),0xf8        #disable DAT and IRQ (external)
+                lhi     %r10,-1         #preparing the mask
+                sll     %r10,12         #shift it such that it becomes 0xf000
+        .top:
+                lhi     %r7,4096        #load PAGE_SIZE in r7
+                lhi     %r9,4096        #load PAGE_SIZE in r9
+                l       %r5,0(%r2)      #read another word for indirection page
+                ahi     %r2,4           #increment pointer
+                tml     %r5,0x1         #is it a destination page?
+                je      .indir_check    #NO, goto "indir_check"
+                lr      %r6,%r5         #r6 = r5
+                nr      %r6,%r10        #mask it out and...
+                j       .top            #...next iteration
+        .indir_check:
+                tml     %r5,0x2         #is it a indirection page?
+                je      .done_test      #NO, goto "done_test"
+                nr      %r5,%r10        #YES, mask out,
+                lr      %r2,%r5         #move it into the right register,
+                j       .top            #and read next...
+        .done_test:
+                tml     %r5,0x4         #is it the done indicator?
+                je      .source_test    #NO! Well, then it should be the source indicator...
+                j       .done           #ok, lets finish it here...
+        .source_test:
+                tml     %r5,0x8         #it should be a source indicator...
+                je      .top            #NO, ignore it...
+                lr      %r8,%r5         #r8 = r5
+                nr      %r8,%r10        #masking
+        0:      mvcle   %r6,%r8,0x0     #copy PAGE_SIZE bytes from r8 to r6 - pad with 0
+                jo      0b
+                j       .top
+        .done:
+                sr      %r0,%r0         #clear register r0
+                la      %r4,load_psw-.base(%r13)        #load psw-address into the register
+                o       %r3,4(%r4)      #or load address into psw
+                st      %r3,4(%r4)
+                mvc     0(8,%r0),0(%r4) #copy psw to absolute address 0
+                sr      %r1,%r1         #clear %r1
+                sr      %r2,%r2         #clear %r2
+                sigp    %r1,%r2,0x12    #set cpuid to zero
+                lpsw    0               #hopefully start new kernel...
+
+                .align  8
+        zero64:
+                .quad   0
+        load_psw:
+                .long   0x00080000,0x80000000
+        sys_msk:
+                .quad   0
+        relocate_kernel_end:
+        .globl  relocate_kernel_len
+        relocate_kernel_len:
+                .quad   relocate_kernel_end - relocate_kernel