150 lines
5 KiB
Diff
150 lines
5 KiB
Diff
From 61cb343b4ac20d2d957811cd492fec770646dda8 Mon Sep 17 00:00:00 2001
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From: Gabor Juhos <juhosg@openwrt.org>
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Date: Wed, 3 Apr 2013 19:47:50 +0200
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Subject: [PATCH 1/2] pci/of: remove weak annotation of
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pcibios_get_phb_of_node
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Due to the __weak annotation in the forward declaration
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of the 'pcibios_get_phb_of_node' function GCC will emit
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a weak symbol for this functions even if the actual
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implementation does not use the weak attribute.
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If an architecture tries to override the function
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by providing its own implementation there will be
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multiple weak symbols with the same name in the
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object files. When the kernel is linked from the
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object files the linking order determines which
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implementation will be used in the final image.
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On x86 and on powerpc the architecture specific
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version gets used:
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$ readelf -s arch/x86/kernel/built-in.o drivers/pci/built-in.o \
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vmlinux.o | grep pcibios_get_phb_of_node
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3338: 00029b80 86 FUNC WEAK DEFAULT 1 pcibios_get_phb_of_node
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1701: 00012710 77 FUNC WEAK DEFAULT 1 pcibios_get_phb_of_node
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52072: 0002a170 86 FUNC WEAK DEFAULT 1 pcibios_get_phb_of_node
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$
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$ powerpc-openwrt-linux-uclibc-readelf -s arch/powerpc/kernel/built-in.o \
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drivers/pci/built-in.o vmlinux.o | grep pcibios_get_phb_of_node
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1001: 0000cbb8 12 FUNC WEAK DEFAULT 1 pcibios_get_phb_of_node
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1484: 0001471c 88 FUNC WEAK DEFAULT 1 pcibios_get_phb_of_node
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28652: 0000d6f8 12 FUNC WEAK DEFAULT 1 pcibios_get_phb_of_node
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$
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However on MIPS, the linker puts the default
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implementation into the final image:
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$ mipsel-openwrt-linux-readelf -s arch/mips/pci/built-in.o \
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drivers/pci/built-in.o vmlinux.o | grep pcibios_get_phb_of_node
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86: 0000046c 12 FUNC WEAK DEFAULT 2 pcibios_get_phb_of_node
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1430: 00012e2c 104 FUNC WEAK DEFAULT 2 pcibios_get_phb_of_node
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31898: 0017e4ec 104 FUNC WEAK DEFAULT 2 pcibios_get_phb_of_node
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$
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Rename the default implementation and remove the
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__weak annotation of that. This ensures that there
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will be no multiple weak symbols with the same name
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in the object files. In order to keep the expected
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behaviour, call the architecture specific function
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if the weak symbol is resolved.
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Also move the renamed function to the top instead
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of adding a new forward declaration for that.
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Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
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---
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Notes:
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Unfortunately I'm not a binutils/gcc expert, so
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I don't know if this is the expected behaviour
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of those or not.
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Removing the __weak annotation from the forward
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declaration of 'pcibios_get_phb_of_node' in
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'include/linux/pci.h' also fixes the problem.
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The microblaze architecture also provides its own
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implementation. The behaviour of that is not tested
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but I assume that the linker chooses the arch specific
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implementation on that as well similarly to the
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x86/powerpc.
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The MIPS version is implemented in the followup
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patch.
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Removing the __weak annotation from the forward
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declaration of 'pcibios_get_phb_of_node' in
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'include/linux/pci.h' also fixes the problem.
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-Gabor
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---
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drivers/pci/of.c | 41 +++++++++++++++++++++++------------------
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1 file changed, 23 insertions(+), 18 deletions(-)
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--- a/drivers/pci/of.c
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+++ b/drivers/pci/of.c
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@@ -15,10 +15,32 @@
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#include <linux/of_pci.h>
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#include "pci.h"
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+static struct device_node *__pcibios_get_phb_of_node(struct pci_bus *bus)
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+{
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+ /* This should only be called for PHBs */
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+ if (WARN_ON(bus->self || bus->parent))
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+ return NULL;
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+
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+ if (pcibios_get_phb_of_node)
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+ return pcibios_get_phb_of_node(bus);
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+
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+ /* Look for a node pointer in either the intermediary device we
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+ * create above the root bus or it's own parent. Normally only
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+ * the later is populated.
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+ */
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+ if (bus->bridge->of_node)
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+ return of_node_get(bus->bridge->of_node);
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+ if (bus->bridge->parent && bus->bridge->parent->of_node)
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+ return of_node_get(bus->bridge->parent->of_node);
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+
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+ return NULL;
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+}
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+
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void pci_set_of_node(struct pci_dev *dev)
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{
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if (!dev->bus->dev.of_node)
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return;
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+
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dev->dev.of_node = of_pci_find_child_device(dev->bus->dev.of_node,
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dev->devfn);
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}
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@@ -32,7 +54,7 @@ void pci_release_of_node(struct pci_dev
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void pci_set_bus_of_node(struct pci_bus *bus)
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{
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if (bus->self == NULL)
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- bus->dev.of_node = pcibios_get_phb_of_node(bus);
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+ bus->dev.of_node = __pcibios_get_phb_of_node(bus);
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else
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bus->dev.of_node = of_node_get(bus->self->dev.of_node);
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}
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@@ -42,20 +64,3 @@ void pci_release_bus_of_node(struct pci_
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of_node_put(bus->dev.of_node);
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bus->dev.of_node = NULL;
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}
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-
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-struct device_node * __weak pcibios_get_phb_of_node(struct pci_bus *bus)
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-{
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- /* This should only be called for PHBs */
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- if (WARN_ON(bus->self || bus->parent))
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- return NULL;
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-
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- /* Look for a node pointer in either the intermediary device we
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- * create above the root bus or it's own parent. Normally only
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- * the later is populated.
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- */
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- if (bus->bridge->of_node)
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- return of_node_get(bus->bridge->of_node);
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- if (bus->bridge->parent && bus->bridge->parent->of_node)
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- return of_node_get(bus->bridge->parent->of_node);
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- return NULL;
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-}
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