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authorJosh Boyer <jwboyer@linux.vnet.ibm.com>2009-03-25 06:23:59 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2009-03-27 16:58:24 +1100
commitefbda86098455da014be849713df6498cefc5a2a (patch)
treefb239d51dd521bb2976807eeedfacd17be9b6824 /arch/powerpc/include
parent82631f5dd114e52239fb3d1e270a49d37c088b46 (diff)
powerpc: Sanitize stack pointer in signal handling code
On powerpc64 machines running 32-bit userspace, we can get garbage bits in the stack pointer passed into the kernel. Most places handle this correctly, but the signal handling code uses the passed value directly for allocating signal stack frames. This fixes the issue by introducing a get_clean_sp function that returns a sanitized stack pointer. For 32-bit tasks on a 64-bit kernel, the stack pointer is masked correctly. In all other cases, the stack pointer is simply returned. Additionally, we pass an 'is_32' parameter to get_sigframe now in order to get the properly sanitized stack. The callers are know to be 32 or 64-bit statically. Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/include')
-rw-r--r--arch/powerpc/include/asm/processor.h19
1 files changed, 19 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
index d3466490104..9eed29eee60 100644
--- a/arch/powerpc/include/asm/processor.h
+++ b/arch/powerpc/include/asm/processor.h
@@ -313,6 +313,25 @@ static inline void prefetchw(const void *x)
#define HAVE_ARCH_PICK_MMAP_LAYOUT
#endif
+#ifdef CONFIG_PPC64
+static inline unsigned long get_clean_sp(struct pt_regs *regs, int is_32)
+{
+ unsigned long sp;
+
+ if (is_32)
+ sp = regs->gpr[1] & 0x0ffffffffUL;
+ else
+ sp = regs->gpr[1];
+
+ return sp;
+}
+#else
+static inline unsigned long get_clean_sp(struct pt_regs *regs, int is_32)
+{
+ return regs->gpr[1];
+}
+#endif
+
#endif /* __KERNEL__ */
#endif /* __ASSEMBLY__ */
#endif /* _ASM_POWERPC_PROCESSOR_H */