Thread (3 messages) 3 messages, 3 authors, 2010-09-16

Re: [PATCH 01/15] ppc: fix return type of BUID_{HI,LO} macros

From: Linas Vepstas <linasvepstas@gmail.com>
Date: 2010-09-16 22:55:09

Acked-by: Linas Vepstas <linasvepstas@gmail.com>

I'm guessing this worked up til now because the rtas_call function prototyp=
e
was telling compiler to cast these to 32-bit before passing them as args.
(and since these would still get passed as one arg per 64-bit reg, it
still wouldn't go wrong.)

What I'm wondering about is why there was no compiler warning about an
implicit cast of a 64-bit int to a 32-bit int?  Surely, this is something t=
hat
should be warned about!

-- Linas

On 15 September 2010 13:13, Nishanth Aravamudan [off-list ref] wrote:
quoted hunk ↗ jump to hunk
BUID_HI and BUID_LO are used to pass data to call_rtas, which expects
ints or u32s. But the macro doesn't cast the return, so the result is
still u64. Use the upper_32_bits and lower_32_bits macros that have been
added to kernel.h.

Found by getting printf format errors trying to debug print the args, no
actual code change for 64 bit kernels where the macros are actually
used.

Signed-off-by: Milton Miller <redacted>
Signed-off-by: Nishanth Aravamudan <redacted>
---
=C2=A0arch/powerpc/include/asm/ppc-pci.h | =C2=A0 =C2=A04 ++--
=C2=A01 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/include/asm/ppc-pci.h b/arch/powerpc/include/as=
m/ppc-pci.h
quoted hunk ↗ jump to hunk
index 42fdff0..43268f1 100644
--- a/arch/powerpc/include/asm/ppc-pci.h
+++ b/arch/powerpc/include/asm/ppc-pci.h
@@ -28,8 +28,8 @@ extern void find_and_init_phbs(void);
=C2=A0extern struct pci_dev *isa_bridge_pcidev; =C2=A0 =C2=A0 =C2=A0/* ma=
y be NULL if no ISA bus */
=C2=A0/** Bus Unit ID macros; get low and hi 32-bits of the 64-bit BUID *=
/
-#define BUID_HI(buid) ((buid) >> 32)
-#define BUID_LO(buid) ((buid) & 0xffffffff)
+#define BUID_HI(buid) upper_32_bits(buid)
+#define BUID_LO(buid) lower_32_bits(buid)

=C2=A0/* PCI device_node operations */
=C2=A0struct device_node;
--
1.7.0.4
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