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

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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: Paul Mackerras <paulus@samba.org>
This commit is contained in:
Paul Mackerras 2006-06-07 16:15:39 +10:00
parent fab5db97e4
commit e9370ae15d
3 changed files with 22 additions and 2 deletions
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11
arch/powerpc/kernel/process.c
View file

@ -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,

6
arch/powerpc/kernel/traps.c
View file

@ -805,9 +805,11 @@ void __kprobes program_check_exception(struct pt_regs *regs)
void alignment_exception(struct pt_regs *regs)
{
int fixed;
int fixed = 0;
fixed = fix_alignment(regs);
/* we don't implement logging of alignment exceptions */
if (!(current->thread.align_ctl & PR_UNALIGN_SIGBUS))
fixed = fix_alignment(regs);
if (fixed == 1) {
regs->nip += 4; /* skip over emulated instruction */

7
include/asm-powerpc/processor.h
View file

@ -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);