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arm: switch to saner kernel_execve() semantics

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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2012-10-10 22:23:29 -04:00
parent 22e2430d60
commit 9fff2fa0db
4 changed files with 7 additions and 29 deletions
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1
arch/arm/Kconfig
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@ -50,6 +50,7 @@ config ARM
select GENERIC_STRNLEN_USER select GENERIC_STRNLEN_USER
select DCACHE_WORD_ACCESS if (CPU_V6 || CPU_V6K || CPU_V7) && !CPU_BIG_ENDIAN select DCACHE_WORD_ACCESS if (CPU_V6 || CPU_V6K || CPU_V7) && !CPU_BIG_ENDIAN
select GENERIC_KERNEL_THREAD select GENERIC_KERNEL_THREAD
select GENERIC_KERNEL_EXECVE
help help
The ARM series is a line of low-power-consumption RISC chip designs The ARM series is a line of low-power-consumption RISC chip designs
licensed by ARM Ltd and targeted at embedded applications and licensed by ARM Ltd and targeted at embedded applications and

1
arch/arm/include/asm/unistd.h
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@ -470,7 +470,6 @@
#define __ARCH_WANT_SYS_SOCKETCALL #define __ARCH_WANT_SYS_SOCKETCALL
#endif #endif
#define __ARCH_WANT_SYS_EXECVE #define __ARCH_WANT_SYS_EXECVE
#define __ARCH_WANT_KERNEL_EXECVE
/* /*
* "Conditional" syscalls * "Conditional" syscalls

29
arch/arm/kernel/entry-common.S
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@ -86,35 +86,14 @@ ENDPROC(ret_to_user)
*/ */
ENTRY(ret_from_fork) ENTRY(ret_from_fork)
bl schedule_tail bl schedule_tail
cmp r5, #0
movne r0, r4
movne lr, pc
movne pc, r5
get_thread_info tsk get_thread_info tsk
mov why, #1
b ret_slow_syscall b ret_slow_syscall
ENDPROC(ret_from_fork) ENDPROC(ret_from_fork)
ENTRY(ret_from_kernel_thread)
UNWIND(.fnstart)
UNWIND(.cantunwind)
bl schedule_tail
mov r0, r4
adr lr, BSYM(1f) @ kernel threads should not exit
mov pc, r5
1: bl do_exit
nop
UNWIND(.fnend)
ENDPROC(ret_from_kernel_thread)
/*
* turn a kernel thread into userland process
* use: ret_from_kernel_execve(struct pt_regs *normal)
*/
ENTRY(ret_from_kernel_execve)
mov why, #0 @ not a syscall
str why, [r0, #S_R0] @ ... and we want 0 in ->ARM_r0 as well
get_thread_info tsk @ thread structure
mov sp, r0 @ stack pointer just under pt_regs
b ret_slow_syscall
ENDPROC(ret_from_kernel_execve)
.equ NR_syscalls,0 .equ NR_syscalls,0
#define CALL(x) .equ NR_syscalls,NR_syscalls+1 #define CALL(x) .equ NR_syscalls,NR_syscalls+1
#include "calls.S" #include "calls.S"

5
arch/arm/kernel/process.c
View File

@ -373,7 +373,6 @@ void release_thread(struct task_struct *dead_task)
} }
asmlinkage void ret_from_fork(void) __asm__("ret_from_fork"); asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
asmlinkage void ret_from_kernel_thread(void) __asm__("ret_from_kernel_thread");
int int
copy_thread(unsigned long clone_flags, unsigned long stack_start, copy_thread(unsigned long clone_flags, unsigned long stack_start,
@ -388,13 +387,13 @@ copy_thread(unsigned long clone_flags, unsigned long stack_start,
*childregs = *regs; *childregs = *regs;
childregs->ARM_r0 = 0; childregs->ARM_r0 = 0;
childregs->ARM_sp = stack_start; childregs->ARM_sp = stack_start;
thread->cpu_context.pc = (unsigned long)ret_from_fork;
} else { } else {
memset(childregs, 0, sizeof(struct pt_regs));
thread->cpu_context.r4 = stk_sz; thread->cpu_context.r4 = stk_sz;
thread->cpu_context.r5 = stack_start; thread->cpu_context.r5 = stack_start;
thread->cpu_context.pc = (unsigned long)ret_from_kernel_thread;
childregs->ARM_cpsr = SVC_MODE; childregs->ARM_cpsr = SVC_MODE;
} }
thread->cpu_context.pc = (unsigned long)ret_from_fork;
thread->cpu_context.sp = (unsigned long)childregs; thread->cpu_context.sp = (unsigned long)childregs;
clear_ptrace_hw_breakpoint(p); clear_ptrace_hw_breakpoint(p);