1/*
2 * ESI call stub.
3 *
4 * Copyright (C) 2005 Hewlett-Packard Co
5 *	Alex Williamson <alex.williamson@hp.com>
6 *
7 * Based on EFI call stub by David Mosberger.  The stub is virtually
8 * identical to the one for EFI phys-mode calls, except that ESI
9 * calls may have up to 8 arguments, so they get passed to this routine
10 * through memory.
11 *
12 * This stub allows us to make ESI calls in physical mode with interrupts
13 * turned off.  ESI calls may not support calling from virtual mode.
14 *
15 * Google for "Extensible SAL specification" for a document describing the
16 * ESI standard.
17 */
18
19/*
20 * PSR settings as per SAL spec (Chapter 8 in the "IA-64 System
21 * Abstraction Layer Specification", revision 2.6e).  Note that
22 * psr.dfl and psr.dfh MUST be cleared, despite what this manual says.
23 * Otherwise, SAL dies whenever it's trying to do an IA-32 BIOS call
24 * (the br.ia instruction fails unless psr.dfl and psr.dfh are
25 * cleared).  Fortunately, SAL promises not to touch the floating
26 * point regs, so at least we don't have to save f2-f127.
27 */
28#define PSR_BITS_TO_CLEAR						\
29	(IA64_PSR_I | IA64_PSR_IT | IA64_PSR_DT | IA64_PSR_RT |		\
30	 IA64_PSR_DD | IA64_PSR_SS | IA64_PSR_RI | IA64_PSR_ED |	\
31	 IA64_PSR_DFL | IA64_PSR_DFH)
32
33#define PSR_BITS_TO_SET							\
34	(IA64_PSR_BN)
35
36#include <asm/processor.h>
37#include <asm/asmmacro.h>
38
39/*
40 * Inputs:
41 *	in0 = address of function descriptor of ESI routine to call
42 *	in1 = address of array of ESI parameters
43 *
44 * Outputs:
45 *	r8 = result returned by called function
46 */
47GLOBAL_ENTRY(esi_call_phys)
48	.prologue ASM_UNW_PRLG_RP|ASM_UNW_PRLG_PFS, ASM_UNW_PRLG_GRSAVE(2)
49	alloc loc1=ar.pfs,2,7,8,0
50	ld8 r2=[in0],8			// load ESI function's entry point
51	mov loc0=rp
52	.body
53	;;
54	ld8 out0=[in1],8		// ESI params loaded from array
55	;;				// passing all as inputs doesn't work
56	ld8 out1=[in1],8
57	;;
58	ld8 out2=[in1],8
59	;;
60	ld8 out3=[in1],8
61	;;
62	ld8 out4=[in1],8
63	;;
64	ld8 out5=[in1],8
65	;;
66	ld8 out6=[in1],8
67	;;
68	ld8 out7=[in1]
69	mov loc2=gp			// save global pointer
70	mov loc4=ar.rsc			// save RSE configuration
71	mov ar.rsc=0			// put RSE in enforced lazy, LE mode
72	;;
73	ld8 gp=[in0]			// load ESI function's global pointer
74	movl r16=PSR_BITS_TO_CLEAR
75	mov loc3=psr			// save processor status word
76	movl r17=PSR_BITS_TO_SET
77	;;
78	or loc3=loc3,r17
79	mov b6=r2
80	;;
81	andcm r16=loc3,r16	// get psr with IT, DT, and RT bits cleared
82	br.call.sptk.many rp=ia64_switch_mode_phys
83.ret0:	mov loc5=r19			// old ar.bsp
84	mov loc6=r20			// old sp
85	br.call.sptk.many rp=b6		// call the ESI function
86.ret1:	mov ar.rsc=0			// put RSE in enforced lazy, LE mode
87	mov r16=loc3			// save virtual mode psr
88	mov r19=loc5			// save virtual mode bspstore
89	mov r20=loc6			// save virtual mode sp
90	br.call.sptk.many rp=ia64_switch_mode_virt // return to virtual mode
91.ret2:	mov ar.rsc=loc4			// restore RSE configuration
92	mov ar.pfs=loc1
93	mov rp=loc0
94	mov gp=loc2
95	br.ret.sptk.many rp
96END(esi_call_phys)
97