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-rw-r--r--arch/mips/fw/lib/call_o32.S104
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diff --git a/arch/mips/fw/lib/call_o32.S b/arch/mips/fw/lib/call_o32.S
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+++ b/arch/mips/fw/lib/call_o32.S
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+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * O32 interface for the 64 (or N32) ABI.
+ *
+ * Copyright (C) 2002, 2014 Maciej W. Rozycki
+ */
+
+#include <asm/asm.h>
+#include <asm/regdef.h>
+
+/* O32 register size. */
+#define O32_SZREG 4
+/* Maximum number of arguments supported. Must be even! */
+#define O32_ARGC 32
+/* Number of static registers we save. */
+#define O32_STATC 11
+/* Argument area frame size. */
+#define O32_ARGSZ (O32_SZREG * O32_ARGC)
+/* Static register save area frame size. */
+#define O32_STATSZ (SZREG * O32_STATC)
+/* Stack pointer register save area frame size. */
+#define O32_SPSZ SZREG
+/* Combined area frame size. */
+#define O32_FRAMESZ (O32_ARGSZ + O32_SPSZ + O32_STATSZ)
+/* Switched stack frame size. */
+#define O32_NFRAMESZ (O32_ARGSZ + O32_SPSZ)
+
+ .text
+
+/*
+ * O32 function call dispatcher, for interfacing 32-bit ROM routines.
+ *
+ * The standard 64 (N32) calling sequence is supported, with a0 holding
+ * a function pointer, a1 a pointer to the new stack to call the
+ * function with or 0 if no stack switching is requested, a2-a7 -- the
+ * function call's first six arguments, and the stack -- the remaining
+ * arguments (up to O32_ARGC, including a2-a7). Static registers, gp
+ * and fp are preserved, v0 holds the result. This code relies on the
+ * called o32 function for sp and ra restoration and this dispatcher has
+ * to be placed in a KSEGx (or KUSEG) address space. Any pointers
+ * passed have to point to addresses within one of these spaces as well.
+ */
+NESTED(call_o32, O32_FRAMESZ, ra)
+ REG_SUBU sp,O32_FRAMESZ
+
+ REG_S ra,O32_FRAMESZ-1*SZREG(sp)
+ REG_S fp,O32_FRAMESZ-2*SZREG(sp)
+ REG_S gp,O32_FRAMESZ-3*SZREG(sp)
+ REG_S s7,O32_FRAMESZ-4*SZREG(sp)
+ REG_S s6,O32_FRAMESZ-5*SZREG(sp)
+ REG_S s5,O32_FRAMESZ-6*SZREG(sp)
+ REG_S s4,O32_FRAMESZ-7*SZREG(sp)
+ REG_S s3,O32_FRAMESZ-8*SZREG(sp)
+ REG_S s2,O32_FRAMESZ-9*SZREG(sp)
+ REG_S s1,O32_FRAMESZ-10*SZREG(sp)
+ REG_S s0,O32_FRAMESZ-11*SZREG(sp)
+
+ move jp,a0
+
+ move fp,sp
+ beqz a1,0f
+ REG_SUBU fp,a1,O32_NFRAMESZ
+0:
+ REG_S sp,O32_NFRAMESZ-1*SZREG(fp)
+
+ sll a0,a2,zero
+ sll a1,a3,zero
+ sll a2,a4,zero
+ sll a3,a5,zero
+ sw a6,4*O32_SZREG(fp)
+ sw a7,5*O32_SZREG(fp)
+
+ PTR_LA t0,O32_FRAMESZ(sp)
+ PTR_LA t1,6*O32_SZREG(fp)
+ li t2,O32_ARGC-6
+1:
+ lw t3,(t0)
+ REG_ADDU t0,SZREG
+ sw t3,(t1)
+ REG_SUBU t2,1
+ REG_ADDU t1,O32_SZREG
+ bnez t2,1b
+
+ move sp,fp
+
+ jalr jp
+
+ REG_L sp,O32_NFRAMESZ-1*SZREG(sp)
+
+ REG_L s0,O32_FRAMESZ-11*SZREG(sp)
+ REG_L s1,O32_FRAMESZ-10*SZREG(sp)
+ REG_L s2,O32_FRAMESZ-9*SZREG(sp)
+ REG_L s3,O32_FRAMESZ-8*SZREG(sp)
+ REG_L s4,O32_FRAMESZ-7*SZREG(sp)
+ REG_L s5,O32_FRAMESZ-6*SZREG(sp)
+ REG_L s6,O32_FRAMESZ-5*SZREG(sp)
+ REG_L s7,O32_FRAMESZ-4*SZREG(sp)
+ REG_L gp,O32_FRAMESZ-3*SZREG(sp)
+ REG_L fp,O32_FRAMESZ-2*SZREG(sp)
+ REG_L ra,O32_FRAMESZ-1*SZREG(sp)
+
+ REG_ADDU sp,O32_FRAMESZ
+ jr ra
+END(call_o32)