summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
-rw-r--r--arch/arm/kernel/Makefile3
-rw-r--r--arch/arm/kernel/signal.c24
-rw-r--r--arch/arm/kernel/sigreturn_codes.S80
3 files changed, 83 insertions, 24 deletions
diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index 5140df5f23aa..39c9834461b4 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -17,7 +17,8 @@ CFLAGS_REMOVE_return_address.o = -pg
obj-y := elf.o entry-common.o irq.o opcodes.o \
process.o ptrace.o return_address.o \
- setup.o signal.o stacktrace.o sys_arm.o time.o traps.o
+ setup.o signal.o sigreturn_codes.o \
+ stacktrace.o sys_arm.o time.o traps.o
obj-$(CONFIG_ATAGS) += atags_parse.o
obj-$(CONFIG_ATAGS_PROC) += atags_proc.o
diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
index ab3304225272..64845fc4152a 100644
--- a/arch/arm/kernel/signal.c
+++ b/arch/arm/kernel/signal.c
@@ -21,29 +21,7 @@
#include <asm/unistd.h>
#include <asm/vfp.h>
-/*
- * For ARM syscalls, we encode the syscall number into the instruction.
- */
-#define SWI_SYS_SIGRETURN (0xef000000|(__NR_sigreturn)|(__NR_OABI_SYSCALL_BASE))
-#define SWI_SYS_RT_SIGRETURN (0xef000000|(__NR_rt_sigreturn)|(__NR_OABI_SYSCALL_BASE))
-
-/*
- * With EABI, the syscall number has to be loaded into r7.
- */
-#define MOV_R7_NR_SIGRETURN (0xe3a07000 | (__NR_sigreturn - __NR_SYSCALL_BASE))
-#define MOV_R7_NR_RT_SIGRETURN (0xe3a07000 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE))
-
-/*
- * For Thumb syscalls, we pass the syscall number via r7. We therefore
- * need two 16-bit instructions.
- */
-#define SWI_THUMB_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_sigreturn - __NR_SYSCALL_BASE))
-#define SWI_THUMB_RT_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE))
-
-static const unsigned long sigreturn_codes[7] = {
- MOV_R7_NR_SIGRETURN, SWI_SYS_SIGRETURN, SWI_THUMB_SIGRETURN,
- MOV_R7_NR_RT_SIGRETURN, SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN,
-};
+extern const unsigned long sigreturn_codes[7];
static unsigned long signal_return_offset;
diff --git a/arch/arm/kernel/sigreturn_codes.S b/arch/arm/kernel/sigreturn_codes.S
new file mode 100644
index 000000000000..3c5d0f2170fd
--- /dev/null
+++ b/arch/arm/kernel/sigreturn_codes.S
@@ -0,0 +1,80 @@
+/*
+ * sigreturn_codes.S - code sinpets for sigreturn syscalls
+ *
+ * Created by: Victor Kamensky, 2013-08-13
+ * Copyright: (C) 2013 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.
+ */
+
+#include <asm/unistd.h>
+
+/*
+ * For ARM syscalls, we encode the syscall number into the instruction.
+ * With EABI, the syscall number has to be loaded into r7. As result
+ * ARM syscall sequence snippet will have move and svc in .arm encoding
+ *
+ * For Thumb syscalls, we pass the syscall number via r7. We therefore
+ * need two 16-bit instructions in .thumb encoding
+ *
+ * Please note sigreturn_codes code are not executed in place. Instead
+ * they just copied by kernel into appropriate places. Code inside of
+ * arch/arm/kernel/signal.c is very sensitive to layout of these code
+ * snippets.
+ */
+
+#if __LINUX_ARM_ARCH__ <= 4
+ /*
+ * Note we manually set minimally required arch that supports
+ * required thumb opcodes for early arch versions. It is OK
+ * for this file to be used in combination with other
+ * lower arch variants, since these code snippets are only
+ * used as input data.
+ */
+ .arch armv4t
+#endif
+
+ .section .rodata
+ .global sigreturn_codes
+ .type sigreturn_codes, #object
+
+ .arm
+
+sigreturn_codes:
+
+ /* ARM sigreturn syscall code snippet */
+ mov r7, #(__NR_sigreturn - __NR_SYSCALL_BASE)
+ swi #(__NR_sigreturn)|(__NR_OABI_SYSCALL_BASE)
+
+ /* Thumb sigreturn syscall code snippet */
+ .thumb
+ movs r7, #(__NR_sigreturn - __NR_SYSCALL_BASE)
+ swi #0
+
+ /* ARM sigreturn_rt syscall code snippet */
+ .arm
+ mov r7, #(__NR_rt_sigreturn - __NR_SYSCALL_BASE)
+ swi #(__NR_rt_sigreturn)|(__NR_OABI_SYSCALL_BASE)
+
+ /* Thumb sigreturn_rt syscall code snippet */
+ .thumb
+ movs r7, #(__NR_rt_sigreturn - __NR_SYSCALL_BASE)
+ swi #0
+
+ /*
+ * Note on addtional space: setup_return in signal.c
+ * algorithm uses two words copy regardless whether
+ * it is thumb case or not, so we need additional
+ * word after real last entry.
+ */
+ .arm
+ .space 4
+
+ .size sigreturn_codes, . - sigreturn_codes