d2cdfff63b
The effect of pointer aliasing on writes is that any data on CPU registers that has been resolved from (non-const and non-volatile) memory objects has to be discarded and resolved. In other words, the compiler assumes that a pointer that does not have an absolute value at build-time, and is of type 'void *' or 'char *', may write over any memory object. Using a unique datatype for MMIO writes makes the pointer to _not_ qualify for pointer aliasing with any other objects in memory. This avoid constantly resolving the PCI MMCONF address, which is a derived value from a 'struct device *'. Change-Id: Id112aa5e729ffd8015bb806786bdee38783b7ea9 Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com> Reviewed-on: https://review.coreboot.org/c/coreboot/+/31752 Reviewed-by: Aaron Durbin <adurbin@chromium.org> Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
16 lines
600 B
C
16 lines
600 B
C
/*
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* This file is part of the coreboot project.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <stdint.h>
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u8 *const pci_mmconf = (void *)(uintptr_t)CONFIG_MMCONF_BASE_ADDRESS;
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