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authorLinus Torvalds <torvalds@linux-foundation.org>2011-03-16 19:03:06 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-03-16 19:03:06 -0700
commit16d8775700f1815076f879719ce14b33f50a3171 (patch)
tree8525e6e6f12b6acf7cf2746853cc65549f3dbf4c /arch/arm/include/asm/fncpy.h
parente34551339a195aa548eaf698523714a8fe7f1984 (diff)
parent05e34754518b6a90d5c392790c032575fab12d66 (diff)
Merge branch 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm
* 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm: (91 commits) ARM: 6806/1: irq: introduce entry and exit functions for chained handlers ARM: 6781/1: Thumb-2: Work around buggy Thumb-2 short branch relocations in gas ARM: 6747/1: P2V: Thumb2 support ARM: 6798/1: aout-core: zero thread debug registers in a.out core dump ARM: 6796/1: Footbridge: Fix I/O mappings for NOMMU mode ARM: 6784/1: errata: no automatic Store Buffer drain on Cortex-A9 ARM: 6772/1: errata: possible fault MMU translations following an ASID switch ARM: 6776/1: mach-ux500: activate fix for errata 753970 ARM: 6794/1: SPEAr: Append UL to device address macros. ARM: 6793/1: SPEAr: Remove unused *_SIZE macros from spear*.h files ARM: 6792/1: SPEAr: Replace SIZE macro's with SZ_4K macros ARM: 6791/1: SPEAr3xx: Declare device structures after shirq code ARM: 6790/1: SPEAr: Clock Framework: Rename usbd clock and align apb_clk entry ARM: 6789/1: SPEAr3xx: Rename sdio to sdhci ARM: 6788/1: SPEAr: Include mach/hardware.h instead of mach/spear.h ARM: 6787/1: SPEAr: Reorder #includes in .h & .c files. ARM: 6681/1: SPEAr: add debugfs support to clk API ARM: 6703/1: SPEAr: update clk API support ARM: 6679/1: SPEAr: make clk API functions more generic ARM: 6737/1: SPEAr: formalized timer support ...
Diffstat (limited to 'arch/arm/include/asm/fncpy.h')
-rw-r--r--arch/arm/include/asm/fncpy.h94
1 files changed, 94 insertions, 0 deletions
diff --git a/arch/arm/include/asm/fncpy.h b/arch/arm/include/asm/fncpy.h
new file mode 100644
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+++ b/arch/arm/include/asm/fncpy.h
@@ -0,0 +1,94 @@
+/*
+ * 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.
+ *
+ * NOTE: in order for embedded literals and data to get referenced correctly,
+ * the alignment of functions must be preserved when copying. To ensure this,
+ * the source and destination addresses for fncpy() must be aligned to a
+ * multiple of 8 bytes: you will be get a BUG() if this condition is not met.
+ * You will typically need a ".align 3" directive in the assembler where the
+ * function to be copied is defined, and ensure that your allocator for the
+ * destination buffer returns 8-byte-aligned pointers.
+ *
+ * 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);
+ *
+ * ... 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 <linux/types.h>
+#include <linux/string.h>
+
+#include <asm/bug.h>
+#include <asm/cacheflush.h>
+
+/*
+ * Minimum alignment requirement for the source and destination addresses
+ * for function copying.
+ */
+#define FNCPY_ALIGN 8
+
+#define fncpy(dest_buf, funcp, size) ({ \
+ uintptr_t __funcp_address; \
+ typeof(funcp) __result; \
+ \
+ asm("" : "=r" (__funcp_address) : "0" (funcp)); \
+ \
+ /* \
+ * Ensure alignment of source and destination addresses, \
+ * disregarding the function's Thumb bit: \
+ */ \
+ BUG_ON((uintptr_t)(dest_buf) & (FNCPY_ALIGN - 1) || \
+ (__funcp_address & ~(uintptr_t)1 & (FNCPY_ALIGN - 1))); \
+ \
+ memcpy(dest_buf, (void const *)(__funcp_address & ~1), size); \
+ flush_icache_range((unsigned long)(dest_buf), \
+ (unsigned long)(dest_buf) + (size)); \
+ \
+ asm("" : "=r" (__result) \
+ : "0" ((uintptr_t)(dest_buf) | (__funcp_address & 1))); \
+ \
+ __result; \
+})
+
+#endif /* !__ASM_FNCPY_H */