| 1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
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| 2 | /* |
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| 3 | * arch/arm/lib/call_with_stack.S |
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| 4 | * |
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| 5 | * Copyright (C) 2011 ARM Ltd. |
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| 6 | * Written by Will Deacon <will.deacon@arm.com> |
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| 7 | */ |
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| 8 | |
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| 9 | #include <linux/linkage.h> |
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| 10 | #include <asm/assembler.h> |
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| 11 | #include <asm/unwind.h> |
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| 12 | |
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| 13 | /* |
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| 14 | * void call_with_stack(void (*fn)(void *), void *arg, void *sp) |
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| 15 | * |
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| 16 | * Change the stack to that pointed at by sp, then invoke fn(arg) with |
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| 17 | * the new stack. |
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| 18 | * |
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| 19 | * The sequence below follows the APCS frame convention for frame pointer |
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| 20 | * unwinding, and implements the unwinder annotations needed by the EABI |
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| 21 | * unwinder. |
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| 22 | */ |
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| 23 | |
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| 24 | ENTRY(call_with_stack) |
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| 25 | #if defined(CONFIG_UNWINDER_FRAME_POINTER) && defined(CONFIG_CC_IS_GCC) |
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| 26 | mov ip, sp |
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| 27 | push {fp, ip, lr, pc} |
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| 28 | sub fp, ip, #4 |
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| 29 | #else |
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| 30 | UNWIND( .fnstart ) |
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| 31 | UNWIND( .save {fpreg, lr} ) |
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| 32 | push {fpreg, lr} |
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| 33 | UNWIND( .setfp fpreg, sp ) |
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| 34 | mov fpreg, sp |
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| 35 | #endif |
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| 36 | mov sp, r2 |
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| 37 | mov r2, r0 |
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| 38 | mov r0, r1 |
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| 39 | |
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| 40 | bl_r r2 |
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| 41 | |
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| 42 | #if defined(CONFIG_UNWINDER_FRAME_POINTER) && defined(CONFIG_CC_IS_GCC) |
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| 43 | ldmdb fp, {fp, sp, pc} |
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| 44 | #else |
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| 45 | mov sp, fpreg |
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| 46 | pop {fpreg, pc} |
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| 47 | UNWIND( .fnend ) |
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| 48 | #endif |
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| 49 | .globl call_with_stack_end |
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| 50 | call_with_stack_end: |
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| 51 | ENDPROC(call_with_stack) |
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| 52 | |
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