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1c03ab9f4b
We factor out the arch-independent parts of the ARM semihosting implementation as a common library so that it can be shared with RISC-V. Signed-off-by: Kautuk Consul <kconsul@ventanamicro.com> Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
48 lines
1.2 KiB
C
48 lines
1.2 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Copyright (C) 2022 Sean Anderson <sean.anderson@seco.com>
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* Copyright 2014 Broadcom Corporation
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*/
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#include <common.h>
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/*
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* Macro to force the compiler to *populate* memory (for an array or struct)
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* before passing the pointer to an inline assembly call.
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*/
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#define USE_PTR(ptr) *(const char (*)[]) (ptr)
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#if defined(CONFIG_ARM64)
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#define SMH_TRAP "hlt #0xf000"
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#elif defined(CONFIG_CPU_V7M)
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#define SMH_TRAP "bkpt #0xAB"
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#elif defined(CONFIG_SYS_THUMB_BUILD)
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#define SMH_TRAP "svc #0xab"
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#else
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#define SMH_TRAP "svc #0x123456"
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#endif
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/*
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* Call the handler
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*/
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long smh_trap(unsigned int sysnum, void *addr)
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{
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register long result asm("r0");
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register void *_addr asm("r1") = addr;
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/*
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* We need a memory clobber (aka compiler barrier) for two reasons:
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* - The compiler needs to populate any data structures pointed to
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* by "addr" *before* the trap instruction is called.
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* - At least the SYSREAD function puts the result into memory pointed
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* to by "addr", so the compiler must not use a cached version of
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* the previous content, after the call has finished.
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*/
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asm volatile (SMH_TRAP
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: "=r" (result)
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: "0"(sysnum), "r"(USE_PTR(_addr))
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: "memory");
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return result;
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}
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