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| 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/include/device/pci_type.h | |
| parent | bf0970e762a6611cef06af761bc2dec068d439bb (diff) | |
| download | coreboot-d2cdfff63b6e2376fad729252a57acfd2b4418ea.tar.gz coreboot-d2cdfff63b6e2376fad729252a57acfd2b4418ea.tar.bz2 coreboot-d2cdfff63b6e2376fad729252a57acfd2b4418ea.zip | |
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/include/device/pci_type.h')
| -rw-r--r-- | src/include/device/pci_type.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/src/include/device/pci_type.h b/src/include/device/pci_type.h index 27d35589cca5..4d8c2a3d08ec 100644 --- a/src/include/device/pci_type.h +++ b/src/include/device/pci_type.h @@ -18,6 +18,10 @@ typedef u32 pci_devfn_t; +/* Convert pci_devfn_t to offset in MMCONF space. + * As it is one-to-one, nothing needs to be done. */ +#define PCI_DEVFN_OFFSET(x) ((x)) + #define PCI_DEV(SEGBUS, DEV, FN) ( \ (((SEGBUS) & 0xFFF) << 20) | \ (((DEV) & 0x1F) << 15) | \ |