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arm: introduce ret_from_kernel_execve(), switch to generic kernel_execve()

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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2012-08-02 11:46:39 +04:00
parent 9e14f828ee
commit 583d632fb3
3 changed files with 13 additions and 42 deletions
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1
arch/arm/include/asm/unistd.h
View File

@ -469,6 +469,7 @@
#define __ARCH_WANT_OLD_READDIR
#define __ARCH_WANT_SYS_SOCKETCALL
#endif
#define __ARCH_WANT_KERNEL_EXECVE
/*
* "Conditional" syscalls

12
arch/arm/kernel/entry-common.S
View File

@ -103,6 +103,18 @@ ENTRY(ret_from_kernel_thread)
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
#define CALL(x) .equ NR_syscalls,NR_syscalls+1
#include "calls.S"

42
arch/arm/kernel/sys_arm.c
View File

@ -79,48 +79,6 @@ out:
return error;
}
int kernel_execve(const char *filename,
const char *const argv[],
const char *const envp[])
{
struct pt_regs regs;
int ret;
memset(&regs, 0, sizeof(struct pt_regs));
ret = do_execve(filename,
(const char __user *const __user *)argv,
(const char __user *const __user *)envp, &regs);
if (ret < 0)
goto out;
/*
* Save argc to the register structure for userspace.
*/
regs.ARM_r0 = ret;
/*
* We were successful. We won't be returning to our caller, but
* instead to user space by manipulating the kernel stack.
*/
asm( "add r0, %0, %1\n\t"
"mov r1, %2\n\t"
"mov r2, %3\n\t"
"bl memmove\n\t" /* copy regs to top of stack */
"mov r8, #0\n\t" /* not a syscall */
"mov r9, %0\n\t" /* thread structure */
"mov sp, r0\n\t" /* reposition stack pointer */
"b ret_to_user"
:
: "r" (current_thread_info()),
"Ir" (THREAD_START_SP - sizeof(regs)),
"r" (&regs),
"Ir" (sizeof(regs))
: "r0", "r1", "r2", "r3", "r8", "r9", "ip", "lr", "memory");
out:
return ret;
}
/*
* Since loff_t is a 64 bit type we avoid a lot of ABI hassle
* with a different argument ordering.