[RFC PATCH 04/11] asm-generic: fncpy: Add function copying macros
From: Russ Dill
Date: Tue Sep 17 2013 - 08:44:11 EST
Under certain arches (ARM) function pointers cannot be
used naively. Specifically, for thumb functions, their 0 bit
is set, but they are contained on a word aligned address.
Add a fncpy macro to perform function copies correctly
along with two helpers, fnptr_to_address, and fnptr_translate.
Signed-off-by: Russ Dill <Russ.Dill@xxxxxx>
---
arch/alpha/include/asm/fncpy.h | 1 +
arch/arc/include/asm/fncpy.h | 1 +
arch/arm/include/asm/fncpy.h | 76 +++++++-------------------
arch/arm/plat-omap/sram.c | 2 +-
arch/arm64/include/asm/fncpy.h | 1 +
arch/avr32/include/asm/fncpy.h | 1 +
arch/blackfin/include/asm/fncpy.h | 1 +
arch/c6x/include/asm/fncpy.h | 1 +
arch/cris/include/asm/fncpy.h | 1 +
arch/frv/include/asm/fncpy.h | 1 +
arch/h8300/include/asm/fncpy.h | 1 +
arch/hexagon/include/asm/fncpy.h | 1 +
arch/ia64/include/asm/fncpy.h | 1 +
arch/m32r/include/asm/fncpy.h | 1 +
arch/m68k/include/asm/fncpy.h | 1 +
arch/metag/include/asm/fncpy.h | 1 +
arch/microblaze/include/asm/fncpy.h | 1 +
arch/mips/include/asm/fncpy.h | 1 +
arch/mn10300/include/asm/fncpy.h | 1 +
arch/openrisc/include/asm/fncpy.h | 1 +
arch/parisc/include/asm/fncpy.h | 1 +
arch/powerpc/include/asm/fncpy.h | 1 +
arch/s390/include/asm/fncpy.h | 1 +
arch/score/include/asm/fncpy.h | 1 +
arch/sh/include/asm/fncpy.h | 1 +
arch/sparc/include/asm/fncpy.h | 1 +
arch/tile/include/asm/fncpy.h | 1 +
arch/um/include/asm/fncpy.h | 1 +
arch/unicore32/include/asm/fncpy.h | 1 +
arch/x86/include/asm/fncpy.h | 1 +
arch/xtensa/include/asm/fncpy.h | 1 +
include/asm-generic/fncpy.h | 104 ++++++++++++++++++++++++++++++++++++
32 files changed, 154 insertions(+), 57 deletions(-)
create mode 100644 arch/alpha/include/asm/fncpy.h
create mode 100644 arch/arc/include/asm/fncpy.h
create mode 100644 arch/arm64/include/asm/fncpy.h
create mode 100644 arch/avr32/include/asm/fncpy.h
create mode 100644 arch/blackfin/include/asm/fncpy.h
create mode 100644 arch/c6x/include/asm/fncpy.h
create mode 100644 arch/cris/include/asm/fncpy.h
create mode 100644 arch/frv/include/asm/fncpy.h
create mode 100644 arch/h8300/include/asm/fncpy.h
create mode 100644 arch/hexagon/include/asm/fncpy.h
create mode 100644 arch/ia64/include/asm/fncpy.h
create mode 100644 arch/m32r/include/asm/fncpy.h
create mode 100644 arch/m68k/include/asm/fncpy.h
create mode 100644 arch/metag/include/asm/fncpy.h
create mode 100644 arch/microblaze/include/asm/fncpy.h
create mode 100644 arch/mips/include/asm/fncpy.h
create mode 100644 arch/mn10300/include/asm/fncpy.h
create mode 100644 arch/openrisc/include/asm/fncpy.h
create mode 100644 arch/parisc/include/asm/fncpy.h
create mode 100644 arch/powerpc/include/asm/fncpy.h
create mode 100644 arch/s390/include/asm/fncpy.h
create mode 100644 arch/score/include/asm/fncpy.h
create mode 100644 arch/sh/include/asm/fncpy.h
create mode 100644 arch/sparc/include/asm/fncpy.h
create mode 100644 arch/tile/include/asm/fncpy.h
create mode 100644 arch/um/include/asm/fncpy.h
create mode 100644 arch/unicore32/include/asm/fncpy.h
create mode 100644 arch/x86/include/asm/fncpy.h
create mode 100644 arch/xtensa/include/asm/fncpy.h
create mode 100644 include/asm-generic/fncpy.h
diff --git a/arch/alpha/include/asm/fncpy.h b/arch/alpha/include/asm/fncpy.h
new file mode 100644
index 0000000..ee4741c
--- /dev/null
+++ b/arch/alpha/include/asm/fncpy.h
@@ -0,0 +1 @@
+#include <asm-generic/fncpy.h>
diff --git a/arch/arc/include/asm/fncpy.h b/arch/arc/include/asm/fncpy.h
new file mode 100644
index 0000000..ee4741c
--- /dev/null
+++ b/arch/arc/include/asm/fncpy.h
@@ -0,0 +1 @@
+#include <asm-generic/fncpy.h>
diff --git a/arch/arm/include/asm/fncpy.h b/arch/arm/include/asm/fncpy.h
index de53547..f165f20 100644
--- a/arch/arm/include/asm/fncpy.h
+++ b/arch/arm/include/asm/fncpy.h
@@ -17,16 +17,12 @@
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
+#ifndef __ASM_FNCPY_H
+#define __ASM_FNCPY_H
+
+#include <linux/types.h>
+
/*
- * 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
@@ -34,61 +30,29 @@
* 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.
- */
+*/
+#define ARCH_FNCPY_ALIGN 3
-#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) ({ \
+/* Clear the Thumb bit */
+#define fnptr_to_addr(funcp) ({ \
uintptr_t __funcp_address; \
- typeof(funcp) __result; \
\
asm("" : "=r" (__funcp_address) : "0" (funcp)); \
+ __funcp_address & ~1; \
+})
+
+/* Put the Thumb bit back */
+#define fnptr_translate(orig_funcp, new_addr) ({ \
+ uintptr_t __funcp_address; \
+ typeof(orig_funcp) __result; \
\
- /* \
- * 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" (__funcp_address) : "0" (orig_funcp)); \
asm("" : "=r" (__result) \
- : "0" ((uintptr_t)(dest_buf) | (__funcp_address & 1))); \
+ : "0" ((uintptr_t)(new_addr) | (__funcp_address & 1))); \
\
__result; \
})
+#include <asm-generic/fncpy.h>
+
#endif /* !__ASM_FNCPY_H */
diff --git a/arch/arm/plat-omap/sram.c b/arch/arm/plat-omap/sram.c
index a5bc92d..90ccd74 100644
--- a/arch/arm/plat-omap/sram.c
+++ b/arch/arm/plat-omap/sram.c
@@ -54,7 +54,7 @@ void *omap_sram_push_address(unsigned long size)
}
new_ceil -= size;
- new_ceil = ROUND_DOWN(new_ceil, FNCPY_ALIGN);
+ new_ceil = ROUND_DOWN(new_ceil, 1 << ARCH_FNCPY_ALIGN);
omap_sram_ceil = IOMEM(new_ceil);
return (void *)omap_sram_ceil;
diff --git a/arch/arm64/include/asm/fncpy.h b/arch/arm64/include/asm/fncpy.h
new file mode 100644
index 0000000..ee4741c
--- /dev/null
+++ b/arch/arm64/include/asm/fncpy.h
@@ -0,0 +1 @@
+#include <asm-generic/fncpy.h>
diff --git a/arch/avr32/include/asm/fncpy.h b/arch/avr32/include/asm/fncpy.h
new file mode 100644
index 0000000..ee4741c
--- /dev/null
+++ b/arch/avr32/include/asm/fncpy.h
@@ -0,0 +1 @@
+#include <asm-generic/fncpy.h>
diff --git a/arch/blackfin/include/asm/fncpy.h b/arch/blackfin/include/asm/fncpy.h
new file mode 100644
index 0000000..ee4741c
--- /dev/null
+++ b/arch/blackfin/include/asm/fncpy.h
@@ -0,0 +1 @@
+#include <asm-generic/fncpy.h>
diff --git a/arch/c6x/include/asm/fncpy.h b/arch/c6x/include/asm/fncpy.h
new file mode 100644
index 0000000..ee4741c
--- /dev/null
+++ b/arch/c6x/include/asm/fncpy.h
@@ -0,0 +1 @@
+#include <asm-generic/fncpy.h>
diff --git a/arch/cris/include/asm/fncpy.h b/arch/cris/include/asm/fncpy.h
new file mode 100644
index 0000000..ee4741c
--- /dev/null
+++ b/arch/cris/include/asm/fncpy.h
@@ -0,0 +1 @@
+#include <asm-generic/fncpy.h>
diff --git a/arch/frv/include/asm/fncpy.h b/arch/frv/include/asm/fncpy.h
new file mode 100644
index 0000000..ee4741c
--- /dev/null
+++ b/arch/frv/include/asm/fncpy.h
@@ -0,0 +1 @@
+#include <asm-generic/fncpy.h>
diff --git a/arch/h8300/include/asm/fncpy.h b/arch/h8300/include/asm/fncpy.h
new file mode 100644
index 0000000..ee4741c
--- /dev/null
+++ b/arch/h8300/include/asm/fncpy.h
@@ -0,0 +1 @@
+#include <asm-generic/fncpy.h>
diff --git a/arch/hexagon/include/asm/fncpy.h b/arch/hexagon/include/asm/fncpy.h
new file mode 100644
index 0000000..ee4741c
--- /dev/null
+++ b/arch/hexagon/include/asm/fncpy.h
@@ -0,0 +1 @@
+#include <asm-generic/fncpy.h>
diff --git a/arch/ia64/include/asm/fncpy.h b/arch/ia64/include/asm/fncpy.h
new file mode 100644
index 0000000..ee4741c
--- /dev/null
+++ b/arch/ia64/include/asm/fncpy.h
@@ -0,0 +1 @@
+#include <asm-generic/fncpy.h>
diff --git a/arch/m32r/include/asm/fncpy.h b/arch/m32r/include/asm/fncpy.h
new file mode 100644
index 0000000..ee4741c
--- /dev/null
+++ b/arch/m32r/include/asm/fncpy.h
@@ -0,0 +1 @@
+#include <asm-generic/fncpy.h>
diff --git a/arch/m68k/include/asm/fncpy.h b/arch/m68k/include/asm/fncpy.h
new file mode 100644
index 0000000..ee4741c
--- /dev/null
+++ b/arch/m68k/include/asm/fncpy.h
@@ -0,0 +1 @@
+#include <asm-generic/fncpy.h>
diff --git a/arch/metag/include/asm/fncpy.h b/arch/metag/include/asm/fncpy.h
new file mode 100644
index 0000000..ee4741c
--- /dev/null
+++ b/arch/metag/include/asm/fncpy.h
@@ -0,0 +1 @@
+#include <asm-generic/fncpy.h>
diff --git a/arch/microblaze/include/asm/fncpy.h b/arch/microblaze/include/asm/fncpy.h
new file mode 100644
index 0000000..ee4741c
--- /dev/null
+++ b/arch/microblaze/include/asm/fncpy.h
@@ -0,0 +1 @@
+#include <asm-generic/fncpy.h>
diff --git a/arch/mips/include/asm/fncpy.h b/arch/mips/include/asm/fncpy.h
new file mode 100644
index 0000000..ee4741c
--- /dev/null
+++ b/arch/mips/include/asm/fncpy.h
@@ -0,0 +1 @@
+#include <asm-generic/fncpy.h>
diff --git a/arch/mn10300/include/asm/fncpy.h b/arch/mn10300/include/asm/fncpy.h
new file mode 100644
index 0000000..ee4741c
--- /dev/null
+++ b/arch/mn10300/include/asm/fncpy.h
@@ -0,0 +1 @@
+#include <asm-generic/fncpy.h>
diff --git a/arch/openrisc/include/asm/fncpy.h b/arch/openrisc/include/asm/fncpy.h
new file mode 100644
index 0000000..ee4741c
--- /dev/null
+++ b/arch/openrisc/include/asm/fncpy.h
@@ -0,0 +1 @@
+#include <asm-generic/fncpy.h>
diff --git a/arch/parisc/include/asm/fncpy.h b/arch/parisc/include/asm/fncpy.h
new file mode 100644
index 0000000..ee4741c
--- /dev/null
+++ b/arch/parisc/include/asm/fncpy.h
@@ -0,0 +1 @@
+#include <asm-generic/fncpy.h>
diff --git a/arch/powerpc/include/asm/fncpy.h b/arch/powerpc/include/asm/fncpy.h
new file mode 100644
index 0000000..ee4741c
--- /dev/null
+++ b/arch/powerpc/include/asm/fncpy.h
@@ -0,0 +1 @@
+#include <asm-generic/fncpy.h>
diff --git a/arch/s390/include/asm/fncpy.h b/arch/s390/include/asm/fncpy.h
new file mode 100644
index 0000000..ee4741c
--- /dev/null
+++ b/arch/s390/include/asm/fncpy.h
@@ -0,0 +1 @@
+#include <asm-generic/fncpy.h>
diff --git a/arch/score/include/asm/fncpy.h b/arch/score/include/asm/fncpy.h
new file mode 100644
index 0000000..ee4741c
--- /dev/null
+++ b/arch/score/include/asm/fncpy.h
@@ -0,0 +1 @@
+#include <asm-generic/fncpy.h>
diff --git a/arch/sh/include/asm/fncpy.h b/arch/sh/include/asm/fncpy.h
new file mode 100644
index 0000000..ee4741c
--- /dev/null
+++ b/arch/sh/include/asm/fncpy.h
@@ -0,0 +1 @@
+#include <asm-generic/fncpy.h>
diff --git a/arch/sparc/include/asm/fncpy.h b/arch/sparc/include/asm/fncpy.h
new file mode 100644
index 0000000..ee4741c
--- /dev/null
+++ b/arch/sparc/include/asm/fncpy.h
@@ -0,0 +1 @@
+#include <asm-generic/fncpy.h>
diff --git a/arch/tile/include/asm/fncpy.h b/arch/tile/include/asm/fncpy.h
new file mode 100644
index 0000000..ee4741c
--- /dev/null
+++ b/arch/tile/include/asm/fncpy.h
@@ -0,0 +1 @@
+#include <asm-generic/fncpy.h>
diff --git a/arch/um/include/asm/fncpy.h b/arch/um/include/asm/fncpy.h
new file mode 100644
index 0000000..ee4741c
--- /dev/null
+++ b/arch/um/include/asm/fncpy.h
@@ -0,0 +1 @@
+#include <asm-generic/fncpy.h>
diff --git a/arch/unicore32/include/asm/fncpy.h b/arch/unicore32/include/asm/fncpy.h
new file mode 100644
index 0000000..ee4741c
--- /dev/null
+++ b/arch/unicore32/include/asm/fncpy.h
@@ -0,0 +1 @@
+#include <asm-generic/fncpy.h>
diff --git a/arch/x86/include/asm/fncpy.h b/arch/x86/include/asm/fncpy.h
new file mode 100644
index 0000000..ee4741c
--- /dev/null
+++ b/arch/x86/include/asm/fncpy.h
@@ -0,0 +1 @@
+#include <asm-generic/fncpy.h>
diff --git a/arch/xtensa/include/asm/fncpy.h b/arch/xtensa/include/asm/fncpy.h
new file mode 100644
index 0000000..ee4741c
--- /dev/null
+++ b/arch/xtensa/include/asm/fncpy.h
@@ -0,0 +1 @@
+#include <asm-generic/fncpy.h>
diff --git a/include/asm-generic/fncpy.h b/include/asm-generic/fncpy.h
new file mode 100644
index 0000000..1a25282
--- /dev/null
+++ b/include/asm-generic/fncpy.h
@@ -0,0 +1,104 @@
+/*
+ * include/asm-generic/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);
+ *
+ * ... 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_GENERIC_FNCPY_H
+#define __ASM_GENERIC_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.
+ */
+#ifndef ARCH_FNCPY_ALIGN
+#define ARCH_FNCPY_ALIGN 0
+#endif
+
+#define ARCH_FNCPY_MASK ((1 << (ARCH_FNCPY_ALIGN)) - 1)
+
+#ifndef fnptr_to_addr
+#define fnptr_to_addr(funcp) ({ \
+ (uintptr_t) (funcp); \
+})
+#endif
+
+#ifndef fnptr_translate
+#define fnptr_translate(orig_funcp, new_addr) ({ \
+ (typeof(orig_funcp)) (new_addr); \
+})
+#endif
+
+/* Ensure alignment of source and destination addresses */
+#ifndef fn_dest_invalid
+#define fn_dest_invalid(funcp, dest_buf) ({ \
+ uintptr_t __funcp_address; \
+ \
+ __funcp_address = fnptr_to_addr(funcp); \
+ \
+ ((uintptr_t)(dest_buf) & ARCH_FNCPY_MASK) || \
+ (__funcp_address & ARCH_FNCPY_MASK); \
+})
+#endif
+
+#ifndef fncpy
+#define fncpy(dest_buf, funcp, size) ({ \
+ BUG_ON(fn_dest_invalid(funcp, dest_buf)); \
+ \
+ memcpy(dest_buf, (void const *)(funcp), size); \
+ flush_icache_range((unsigned long)(dest_buf), \
+ (unsigned long)(dest_buf) + (size)); \
+ \
+ fnptr_translate(funcp, dest_buf); \
+})
+#endif
+
+#endif /* !__ASM_GENERIC_FNCPY_H */
+
--
1.8.3.2
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/