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Commit 9fff2fa0 authored by Al Viro's avatar Al Viro
Browse files

arm: switch to saner kernel_execve() semantics 



Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 22e2430d

arch/arm/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -50,6 +50,7 @@ config ARM 
	select GENERIC_STRNLEN_USER

	select DCACHE_WORD_ACCESS if (CPU_V6 || CPU_V6K || CPU_V7) && !CPU_BIG_ENDIAN

	select GENERIC_KERNEL_THREAD

	select GENERIC_KERNEL_EXECVE

	help

	  The ARM series is a line of low-power-consumption RISC chip designs

	  licensed by ARM Ltd and targeted at embedded applications and

arch/arm/include/asm/unistd.h

+0 −1
Original line number Diff line number Diff line
@@ -470,7 +470,6 @@ 
#define __ARCH_WANT_SYS_SOCKETCALL

#endif

#define __ARCH_WANT_SYS_EXECVE

#define __ARCH_WANT_KERNEL_EXECVE



/*

 * "Conditional" syscalls

arch/arm/kernel/entry-common.S

+4 −25
Original line number Diff line number Diff line
@@ -86,35 +86,14 @@ ENDPROC(ret_to_user) 
 */

ENTRY(ret_from_fork)

	bl	schedule_tail

	cmp	r5, #0

	movne	r0, r4

	movne	lr, pc

	movne	pc, r5

	get_thread_info tsk

	mov	why, #1

	b	ret_slow_syscall

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

#define CALL(x) .equ NR_syscalls,NR_syscalls+1

#include "calls.S"

arch/arm/kernel/process.c

+2 −3
Original line number Diff line number Diff line
@@ -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_kernel_thread(void) __asm__("ret_from_kernel_thread");



int

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->ARM_r0 = 0;

		childregs->ARM_sp = stack_start;

		thread->cpu_context.pc = (unsigned long)ret_from_fork;

	} else {

		memset(childregs, 0, sizeof(struct pt_regs));

		thread->cpu_context.r4 = stk_sz;

		thread->cpu_context.r5 = stack_start;

		thread->cpu_context.pc = (unsigned long)ret_from_kernel_thread;

		childregs->ARM_cpsr = SVC_MODE;

	}

	thread->cpu_context.pc = (unsigned long)ret_from_fork;

	thread->cpu_context.sp = (unsigned long)childregs;



	clear_ptrace_hw_breakpoint(p);