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+/*
+ * ESI call stub.
+ *
+ * Copyright (C) 2005 Hewlett-Packard Co
+ * Alex Williamson <alex.williamson@hp.com>
+ *
+ * Based on EFI call stub by David Mosberger. The stub is virtually
+ * identical to the one for EFI phys-mode calls, except that ESI
+ * calls may have up to 8 arguments, so they get passed to this routine
+ * through memory.
+ *
+ * This stub allows us to make ESI calls in physical mode with interrupts
+ * turned off. ESI calls may not support calling from virtual mode.
+ *
+ * Google for "Extensible SAL specification" for a document describing the
+ * ESI standard.
+ */
+
+/*
+ * PSR settings as per SAL spec (Chapter 8 in the "IA-64 System
+ * Abstraction Layer Specification", revision 2.6e). Note that
+ * psr.dfl and psr.dfh MUST be cleared, despite what this manual says.
+ * Otherwise, SAL dies whenever it's trying to do an IA-32 BIOS call
+ * (the br.ia instruction fails unless psr.dfl and psr.dfh are
+ * cleared). Fortunately, SAL promises not to touch the floating
+ * point regs, so at least we don't have to save f2-f127.
+ */
+#define PSR_BITS_TO_CLEAR \
+ (IA64_PSR_I | IA64_PSR_IT | IA64_PSR_DT | IA64_PSR_RT | \
+ IA64_PSR_DD | IA64_PSR_SS | IA64_PSR_RI | IA64_PSR_ED | \
+ IA64_PSR_DFL | IA64_PSR_DFH)
+
+#define PSR_BITS_TO_SET \
+ (IA64_PSR_BN)
+
+#include <asm/processor.h>
+#include <asm/asmmacro.h>
+
+/*
+ * Inputs:
+ * in0 = address of function descriptor of ESI routine to call
+ * in1 = address of array of ESI parameters
+ *
+ * Outputs:
+ * r8 = result returned by called function
+ */
+GLOBAL_ENTRY(esi_call_phys)
+ .prologue ASM_UNW_PRLG_RP|ASM_UNW_PRLG_PFS, ASM_UNW_PRLG_GRSAVE(2)
+ alloc loc1=ar.pfs,2,7,8,0
+ ld8 r2=[in0],8 // load ESI function's entry point
+ mov loc0=rp
+ .body
+ ;;
+ ld8 out0=[in1],8 // ESI params loaded from array
+ ;; // passing all as inputs doesn't work
+ ld8 out1=[in1],8
+ ;;
+ ld8 out2=[in1],8
+ ;;
+ ld8 out3=[in1],8
+ ;;
+ ld8 out4=[in1],8
+ ;;
+ ld8 out5=[in1],8
+ ;;
+ ld8 out6=[in1],8
+ ;;
+ ld8 out7=[in1]
+ mov loc2=gp // save global pointer
+ mov loc4=ar.rsc // save RSE configuration
+ mov ar.rsc=0 // put RSE in enforced lazy, LE mode
+ ;;
+ ld8 gp=[in0] // load ESI function's global pointer
+ movl r16=PSR_BITS_TO_CLEAR
+ mov loc3=psr // save processor status word
+ movl r17=PSR_BITS_TO_SET
+ ;;
+ or loc3=loc3,r17
+ mov b6=r2
+ ;;
+ andcm r16=loc3,r16 // get psr with IT, DT, and RT bits cleared
+ br.call.sptk.many rp=ia64_switch_mode_phys
+.ret0: mov loc5=r19 // old ar.bsp
+ mov loc6=r20 // old sp
+ br.call.sptk.many rp=b6 // call the ESI function
+.ret1: mov ar.rsc=0 // put RSE in enforced lazy, LE mode
+ mov r16=loc3 // save virtual mode psr
+ mov r19=loc5 // save virtual mode bspstore
+ mov r20=loc6 // save virtual mode sp
+ br.call.sptk.many rp=ia64_switch_mode_virt // return to virtual mode
+.ret2: mov ar.rsc=loc4 // restore RSE configuration
+ mov ar.pfs=loc1
+ mov rp=loc0
+ mov gp=loc2
+ br.ret.sptk.many rp
+END(esi_call_phys)