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Commit e9370ae1 authored by Paul Mackerras's avatar Paul Mackerras
Browse files

[PATCH] powerpc: Implement PR_[GS]ET_UNALIGN prctls for powerpc 



This gives the ability to control whether alignment exceptions get
fixed up or reported to the process as a SIGBUS, using the existing
PR_SET_UNALIGN and PR_GET_UNALIGN prctls.  We do not implement the
option of logging a message on alignment exceptions.

Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
parent fab5db97

arch/powerpc/kernel/process.c

+11 −0
Original line number Diff line number Diff line
@@ -752,6 +752,17 @@ int get_endian(struct task_struct *tsk, unsigned long adr) 
	return put_user(val, (unsigned int __user *)adr);

}



int set_unalign_ctl(struct task_struct *tsk, unsigned int val)

{

	tsk->thread.align_ctl = val;

	return 0;

}



int get_unalign_ctl(struct task_struct *tsk, unsigned long adr)

{

	return put_user(tsk->thread.align_ctl, (unsigned int __user *)adr);

}



#define TRUNC_PTR(x)	((typeof(x))(((unsigned long)(x)) & 0xffffffff))



int sys_clone(unsigned long clone_flags, unsigned long usp,

arch/powerpc/kernel/traps.c

+4 −2
Original line number Diff line number Diff line
@@ -805,8 +805,10 @@ void __kprobes program_check_exception(struct pt_regs *regs) 


void alignment_exception(struct pt_regs *regs)

{

	int fixed;

	int fixed = 0;



	/* we don't implement logging of alignment exceptions */

	if (!(current->thread.align_ctl & PR_UNALIGN_SIGBUS))

		fixed = fix_alignment(regs);



	if (fixed == 1) {

include/asm-powerpc/processor.h

+7 −0
Original line number Diff line number Diff line
@@ -149,6 +149,7 @@ struct thread_struct { 
		unsigned int val;	/* Floating point status */

	} fpscr;

	int		fpexc_mode;	/* floating-point exception mode */

	unsigned int	align_ctl;	/* alignment handling control */

#ifdef CONFIG_PPC64

	unsigned long	start_tb;	/* Start purr when proc switched in */

	unsigned long	accum_tb;	/* Total accumilated purr for process */
@@ -217,6 +218,12 @@ extern int set_fpexc_mode(struct task_struct *tsk, unsigned int val); 
extern int get_endian(struct task_struct *tsk, unsigned long adr);

extern int set_endian(struct task_struct *tsk, unsigned int val);



#define GET_UNALIGN_CTL(tsk, adr)	get_unalign_ctl((tsk), (adr))

#define SET_UNALIGN_CTL(tsk, val)	set_unalign_ctl((tsk), (val))



extern int get_unalign_ctl(struct task_struct *tsk, unsigned long adr);

extern int set_unalign_ctl(struct task_struct *tsk, unsigned int val);



static inline unsigned int __unpack_fe01(unsigned long msr_bits)

{

	return ((msr_bits & MSR_FE0) >> 10) | ((msr_bits & MSR_FE1) >> 8);