2 * Copyright (C) 2009-2011 Nathan Whitehorn
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28 #include <sys/syscall.h>
30 #include <machine/trap.h>
31 #include <machine/param.h>
32 #include <machine/spr.h>
33 #include <machine/asm.h>
35 #define OFWSTKSZ 4096 /* 4K Open Firmware stack */
42 .long 0, 0, 0, 0, 0 /* msr/sprg0-3 used in Open Firmware */
45 GLOBAL(openfirmware_entry)
46 .long 0 /* Open Firmware entry point */
48 .long 0 /* RTAS entry point */
57 * Open Firmware Entry Point. May need to enter real mode.
59 * C prototype: int ofwcall(void *callbuffer);
66 /* Record the old MSR */
69 /* GOT pointer in r7 */
73 addis %r7,%r7,(_GLOBAL_OFFSET_TABLE_-1b)@ha
74 addi %r7,%r7,(_GLOBAL_OFFSET_TABLE_-1b)@l
76 /* read client interface handler */
77 lwz %r4,openfirmware_entry@got(%r7)
81 * Set the MSR to the OF value. This has the side effect of disabling
82 * exceptions, which prevents preemption later.
85 lwz %r5,ofmsr@got(%r7)
91 * Set up OF stack. This needs to be potentially accessible in real mode
92 * The pointer to the current kernel stack is placed at the very
93 * top of the stack along with the old MSR so we can get them back
97 lwz %r1,ofwstk@got(%r7)
98 addi %r1,%r1,(OFWSTKSZ-32)
99 stw %r5,20(%r1) /* Save real stack pointer */
100 stw %r2,24(%r1) /* Save curthread */
101 stw %r6,28(%r1) /* Save old MSR */
106 /* Finally, branch to OF */
110 /* Reload stack pointer and MSR from the OFW stack */
115 /* Now set the real MSR */
125 * RTAS Entry Point. Similar to the OF one, but simpler (no separate stack)
127 * C prototype: int rtascall(void *callbuffer, void *rtas_privdat);
134 /* GOT pointer in r7 */
138 addis %r7,%r7,(_GLOBAL_OFFSET_TABLE_-1b)@ha
139 addi %r7,%r7,(_GLOBAL_OFFSET_TABLE_-1b)@l
141 /* Record the old MSR to real-mode-accessible area */
143 lwz %r5,rtas_regsave@got(%r7)
146 /* read client interface handler */
147 lwz %r5,rtas_entry@got(%r7)
150 /* Set the MSR to the RTAS value */
151 lwz %r6,rtasmsr@got(%r7)
160 /* GOT pointer in r7 */
164 addis %r7,%r7,(_GLOBAL_OFFSET_TABLE_-1b)@ha
165 addi %r7,%r7,(_GLOBAL_OFFSET_TABLE_-1b)@l
167 /* Now set the MSR back */
168 lwz %r6,rtas_regsave@got(%r7)