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C strict aliasing rules state that it is undefined behaviour to access
any pointer using another pointer of a different type (with several small
exceptions). Eg.
uint64_t x = 3;
uint16_t y = *((uint16_t *)&x); // undefined behaviour
From an architectural point of view there is often nothing wrong with
pointer aliasing - the problem is that since it is undefined behaviour,
the compiler will often use this as a cop-out to perform unintended or
unsafe optimizations. The "safe" way to perfom the above assignment is
to cast the pointers to a uint8_t * first (which is allowed to alias
anything), and then work on a byte level:
*((uint8_t *)&y) = *((uint8_t *)&x);
*((uint8_t *)&y + 1) = *((uint8_t *)&x + 1);
Horribly ugly, but there you go. Anyway, in an attempt to follow these
strict aliasing rules, the ReadMEM() function in SB800 does the above
operation when reading a uint16_t. While perfectly fine, however, it
doesn't have to - all calls to ReadMEM() that read a uint16_t are passed
a uint16_t pointer, so there are no strict aliasing violations to worry
about (the WriteMEM() function is exactly similar). The problem is that
using this unnecessary workaround generates almost 50 false positive
warnings in Coverity. Rather than manually ignore them one-by-one, let's
just remove the workaround entirely. As a side note, this change makes
ReadMEM() and WriteMEM() now match their definitions in the SB900 code.
Change-Id: Ia7e3a1eff88b855a05b33c7dafba16ed23784e43
Signed-off-by: Jacob Garber <jgarber1@ualberta.ca>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/34783
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
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Change-Id: I485f79ece481210f31b0b6d3c62d7269131e29ab
Signed-off-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-on: http://review.coreboot.org/6184
Tested-by: build bot (Jenkins)
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
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This code currently generates many warnings that are functionally benign. These are being addressed, but the wheels of bureaucracy turn slowly. This drop supports AMD cpu families 10h and 14h. Only Family 14h is used as an example in this set of patches. Other cpu families are supported by the infrastructure, but their specific support is not included herein. This patch is functionally independent of the other patches in this set.
Signed-off-by: Frank Vibrans <frank.vibrans@amd.com>
Acked-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Acked-by: Marc Jones <marcj303@gmail.com>
git-svn-id: svn://svn.coreboot.org/coreboot/trunk@6344 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1
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Signed-off-by: Zheng Bao <zheng.bao@amd.com>
Acked-by: Zheng Bao <zheng.bao@amd.com>
git-svn-id: svn://svn.coreboot.org/coreboot/trunk@6261 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1
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The main CIMx code is in a src/vendorcode directory and should not be
changed with regard to coding style etc. in order to remain easily syncable
with the "upstream" AMD code.
Signed-off-by: Kerry She <Kerry.she@amd.com>
Acked-by: Stefan Reinauer <stepan@coreboot.org>
git-svn-id: svn://svn.coreboot.org/coreboot/trunk@6229 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1
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