1 files changed, 96 insertions, 0 deletions

diff --git a/arch/ia64/kernel/esi_stub.S b/arch/ia64/kernel/esi_stub.S
new file mode 100644
index 000000000000..6b3d6c1f99b6
--- /dev/null
+++ b/arch/ia64/kernel/esi_stub.S
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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)