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Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to the free software foundation inc 59 temple place suite 330 boston ma 02111 1307 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 136 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Alexios Zavras <alexios.zavras@intel.com> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190530000436.384967451@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
83 lines
2.5 KiB
C
83 lines
2.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* arch/arm/include/asm/fncpy.h - helper macros for function body copying
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*
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* Copyright (C) 2011 Linaro Limited
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*/
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/*
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* These macros are intended for use when there is a need to copy a low-level
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* function body into special memory.
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*
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* For example, when reconfiguring the SDRAM controller, the code doing the
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* reconfiguration may need to run from SRAM.
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*
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* NOTE: that the copied function body must be entirely self-contained and
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* position-independent in order for this to work properly.
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*
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* NOTE: in order for embedded literals and data to get referenced correctly,
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* the alignment of functions must be preserved when copying. To ensure this,
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* the source and destination addresses for fncpy() must be aligned to a
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* multiple of 8 bytes: you will be get a BUG() if this condition is not met.
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* You will typically need a ".align 3" directive in the assembler where the
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* function to be copied is defined, and ensure that your allocator for the
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* destination buffer returns 8-byte-aligned pointers.
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*
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* Typical usage example:
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*
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* extern int f(args);
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* extern uint32_t size_of_f;
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* int (*copied_f)(args);
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* void *sram_buffer;
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*
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* copied_f = fncpy(sram_buffer, &f, size_of_f);
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*
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* ... later, call the function: ...
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*
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* copied_f(args);
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*
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* The size of the function to be copied can't be determined from C:
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* this must be determined by other means, such as adding assmbler directives
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* in the file where f is defined.
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*/
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#ifndef __ASM_FNCPY_H
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#define __ASM_FNCPY_H
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#include <linux/types.h>
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#include <linux/string.h>
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#include <asm/bug.h>
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#include <asm/cacheflush.h>
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/*
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* Minimum alignment requirement for the source and destination addresses
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* for function copying.
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*/
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#define FNCPY_ALIGN 8
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#define fncpy(dest_buf, funcp, size) ({ \
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uintptr_t __funcp_address; \
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typeof(funcp) __result; \
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\
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asm("" : "=r" (__funcp_address) : "0" (funcp)); \
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\
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/* \
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* Ensure alignment of source and destination addresses, \
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* disregarding the function's Thumb bit: \
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*/ \
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BUG_ON((uintptr_t)(dest_buf) & (FNCPY_ALIGN - 1) || \
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(__funcp_address & ~(uintptr_t)1 & (FNCPY_ALIGN - 1))); \
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\
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memcpy(dest_buf, (void const *)(__funcp_address & ~1), size); \
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flush_icache_range((unsigned long)(dest_buf), \
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(unsigned long)(dest_buf) + (size)); \
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\
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asm("" : "=r" (__result) \
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: "0" ((uintptr_t)(dest_buf) | (__funcp_address & 1))); \
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\
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__result; \
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})
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#endif /* !__ASM_FNCPY_H */
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