diff options
| -rw-r--r-- | arch/arm/kernel/Makefile | 3 | ||||
| -rw-r--r-- | arch/arm/kernel/signal.c | 24 | ||||
| -rw-r--r-- | arch/arm/kernel/sigreturn_codes.S | 80 |
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 |