[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: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 2d35d83..e473245 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -752,6 +752,17 @@
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,
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 03def57..91a6e04 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -805,9 +805,11 @@
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 */
diff --git a/include/asm-powerpc/processor.h b/include/asm-powerpc/processor.h
index fa61632..d2c2c95 100644
--- a/include/asm-powerpc/processor.h
+++ b/include/asm-powerpc/processor.h
@@ -149,6 +149,7 @@
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 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);