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[POWERPC] mpic: Fix use of uninitialized variable 

Compiling ppc64_defconfig with gcc 4.3 gives thes warnings:

arch/powerpc/sysdev/mpic.c: In function 'mpic_irq_get_priority':
arch/powerpc/sysdev/mpic.c:1351: warning: 'is_ipi' may be used uninitialized in this function
arch/powerpc/sysdev/mpic.c: In function 'mpic_irq_set_priority':
arch/powerpc/sysdev/mpic.c:1328: warning: 'is_ipi' may be used uninitialized in this function

It turns out that in the cases where is_ipi is uninitialized, another
variable (mpic) will be NULL and it is dereferenced.  Protect against
this by returning if mpic is NULL in mpic_irq_set_priority, and removing
mpic_irq_get_priority completely as it has no in tree callers.

This has the nice side effect of making the warning go away.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This commit is contained in:
Stephen Rothwell 2008-05-21 16:24:31 +10:00 committed by Paul Mackerras
parent d1e8d50d5a
commit 06a901c562
2 changed files with 4 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
arch/powerpc/sysdev/mpic.c
View File

@ -1331,6 +1331,9 @@ void mpic_irq_set_priority(unsigned int irq, unsigned int pri)
unsigned long flags;
u32 reg;
if (!mpic)
return;
spin_lock_irqsave(&mpic_lock, flags);
if (is_ipi) {
reg = mpic_ipi_read(src - mpic->ipi_vecs[0]) &
@ -1346,23 +1349,6 @@ void mpic_irq_set_priority(unsigned int irq, unsigned int pri)
spin_unlock_irqrestore(&mpic_lock, flags);
}
unsigned int mpic_irq_get_priority(unsigned int irq)
{
unsigned int is_ipi;
struct mpic *mpic = mpic_find(irq, &is_ipi);
unsigned int src = mpic_irq_to_hw(irq);
unsigned long flags;
u32 reg;
spin_lock_irqsave(&mpic_lock, flags);
if (is_ipi)
reg = mpic_ipi_read(src = mpic->ipi_vecs[0]);
else
reg = mpic_irq_read(src, MPIC_INFO(IRQ_VECTOR_PRI));
spin_unlock_irqrestore(&mpic_lock, flags);
return (reg & MPIC_VECPRI_PRIORITY_MASK) >> MPIC_VECPRI_PRIORITY_SHIFT;
}
void mpic_setup_this_cpu(void)
{
#ifdef CONFIG_SMP

3
include/asm-powerpc/mpic.h
View File

@ -428,12 +428,11 @@ extern void mpic_init(struct mpic *mpic);
*/
/* Change/Read the priority of an interrupt. Default is 8 for irqs and
/* Change the priority of an interrupt. Default is 8 for irqs and
* 10 for IPIs. You can call this on both IPIs and IRQ numbers, but the
* IPI number is then the offset'ed (linux irq number mapped to the IPI)
*/
extern void mpic_irq_set_priority(unsigned int irq, unsigned int pri);
extern unsigned int mpic_irq_get_priority(unsigned int irq);
/* Setup a non-boot CPU */
extern void mpic_setup_this_cpu(void);