From patchwork Thu Jan 13 22:41:43 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: tip-bot for Dave Martin X-Patchwork-Id: 476891 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter1.kernel.org (8.14.4/8.14.3) with ESMTP id p0DMfrEB005984 for ; Thu, 13 Jan 2011 22:42:24 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756705Ab1AMWlx (ORCPT ); Thu, 13 Jan 2011 17:41:53 -0500 Received: from mail-yw0-f46.google.com ([209.85.213.46]:56643 "EHLO mail-yw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752260Ab1AMWlw (ORCPT ); Thu, 13 Jan 2011 17:41:52 -0500 Received: by mail-yw0-f46.google.com with SMTP id 5so645851ywl.19 for ; Thu, 13 Jan 2011 14:41:52 -0800 (PST) Received: by 10.91.67.10 with SMTP id u10mr282098agk.187.1294958512542; Thu, 13 Jan 2011 14:41:52 -0800 (PST) Received: from LinaroE102765 ([63.133.153.66]) by mx.google.com with ESMTPS id b27sm551530ana.28.2011.01.13.14.41.51 (version=SSLv3 cipher=RC4-MD5); Thu, 13 Jan 2011 14:41:51 -0800 (PST) From: Dave Martin To: linux-arm-kernel@lists.infradead.org Cc: linux-omap@vger.kernel.org, Jean Pihet Subject: [PATCH v3 1/1] ARM: Thumb-2: Symbol manipulation macros for function body copying Date: Thu, 13 Jan 2011 16:41:43 -0600 Message-Id: <1294958503-6537-2-git-send-email-dave.martin@linaro.org> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1294958503-6537-1-git-send-email-dave.martin@linaro.org> References: <1294958503-6537-1-git-send-email-dave.martin@linaro.org> Sender: linux-omap-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter1.kernel.org [140.211.167.41]); Thu, 13 Jan 2011 22:42:24 +0000 (UTC) diff --git a/arch/arm/include/asm/fncpy.h b/arch/arm/include/asm/fncpy.h new file mode 100644 index 0000000..6399265 --- /dev/null +++ b/arch/arm/include/asm/fncpy.h @@ -0,0 +1,110 @@ +/* + * arch/arm/include/asm/fncpy.h - helper macros for function body copying + * + * Copyright (C) 2011 Linaro Limited + * + * 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 + */ + +/* + * These macros are intended for use when there is a need to copy a low-level + * function body into special memory. + * + * For example, when reconfiguring the SDRAM controller, the code doing the + * reconfiguration may need to run from SRAM. + * + * NOTE: that the copied function body must be entirely self-contained and + * position-independent in order for this to work properly. + * + * + * Typical usage example: + * + * extern int f(args); + * extern uint32_t size_of_f; + * int (*copied_f)(args); + * void *sram_buffer; + * + * copied_f = fncpy(sram_buffer, &f, size_of_f); + * + * ... do any required D-side/I-side synchronisation ... + * + * ... later, call the function: ... + * + * copied_f(args); + * + * The size of the function to be copied can't be determined from C: + * this must be determined by other means, such as adding assmbler directives + * in the file where f is defined. + */ + +#ifndef __ASM_FNCPY_H +#define __ASM_FNCPY_H + +#include +#include + +#include + +/* Function pointer casting macros */ + +/* Cast function pointer to integer: */ +#define __funcp_to_uint(funcp) ({ \ + uintptr_t __result; \ + \ + asm("" : "=r" (__result) : "0" (funcp)); \ + __result; \ + }) + +/* Cast integer to function pointer with type matching funcp: */ +#define __uint_to_funcp(i, funcp) ({ \ + typeof(funcp) __result; \ + \ + asm("" : "=r" (__result) : "0" (i)); \ + __result; \ + }) + + +/* Function symbol manipulation macros */ + +/* + * FSYM_REBASE: Determine the correct function pointer for funcp, + * after the function has been copied to dest_buf: + */ +#define FSYM_REBASE(funcp, dest_buf) \ + __uint_to_funcp((uintptr_t)(dest_buf) | FSYM_TYPE(funcp), funcp) + +/* + * FSYM_BASE: Determine the base address in memory of the function funcp + * FSYM_TYPE: Determine the instruction set type (ARM/Thumb) of funcp + * (both defined below) + */ + +#ifdef CONFIG_THUMB2_KERNEL +#define FSYM_BASE(funcp) ((void *)(__funcp_to_uint(funcp) & ~(uintptr_t)1)) +#define FSYM_TYPE(funcp) (__funcp_to_uint(funcp) & 1) +#else /* !CONFIG_THUMB2_KERNEL */ +#define FSYM_BASE(funcp) ((void *)__funcp_to_uint(funcp)) +#define FSYM_TYPE(funcp) 0 +#endif /* !CONFIG_THUMB2_KERNEL */ + +/* Function copy helper */ +#define fncpy(dest_buf, funcp, size) ({ \ + memcpy(dest_buf, FSYM_BASE(funcp), size); \ + flush_icache_range((unsigned long)(dest_buf), \ + (unsigned long)(dest_buf) + (size)); \ + \ + FSYM_REBASE(funcp, dest_buf); \ + }) + +#endif /* !__ASM_FNCPY_H */