diff options
| author | Kyösti Mälkki <kyosti.malkki@gmail.com> | 2019-03-05 07:56:38 +0200 |
|---|---|---|
| committer | Kyösti Mälkki <kyosti.malkki@gmail.com> | 2019-04-07 02:31:36 +0000 |
| commit | d2cdfff63b6e2376fad729252a57acfd2b4418ea (patch) | |
| tree | 01d0ccd1e0826c9449a6c4f1781e7feb813fe537 /src/device/pci_ops.c | |
| parent | bf0970e762a6611cef06af761bc2dec068d439bb (diff) | |
device/pci: Rewrite PCI MMCONF with symbol reference
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>
Diffstat (limited to 'src/device/pci_ops.c')
| -rw-r--r-- | src/device/pci_ops.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/src/device/pci_ops.c b/src/device/pci_ops.c index bdf8ec4584..34f9d1e5b5 100644 --- a/src/device/pci_ops.c +++ b/src/device/pci_ops.c @@ -10,3 +10,7 @@ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ + +#include <stdint.h> + +u8 *const pci_mmconf = (void *)(uintptr_t)CONFIG_MMCONF_BASE_ADDRESS; |