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| author | Marshall Dawson <marshalldawson3rd@gmail.com> | 2017-07-07 16:09:56 -0600 |
|---|---|---|
| committer | Martin Roth <martinroth@google.com> | 2017-07-13 16:48:22 +0000 |
| commit | ce9c88348cb1380199b8f57a435a51a7edb470a0 (patch) | |
| tree | f484a1f3a6c7cfbf5b78817c486d2a8fd793fed1 /Documentation | |
| parent | c35a1e888729b060229b4a326b1b42d09cb7c278 (diff) | |
| download | coreboot-ce9c88348cb1380199b8f57a435a51a7edb470a0.tar.xz | |
arch/x86/assembly_entry: Align stack for car_stage_entry
At process _start, the stack is expected to be aligned to a
16-byte boundary. Upon entry to any function the stack frame
must have the end of any arguments also aligned. In other words
the value of %esp+4 or %rsp+8 is always a multiple of 16 (1).
Align the stack down and change the method for executing
car_stage_entry from jmp to call which should preserve proper
alignment regardless of a 32- or 64-bit build.
Although 4-byte alignment is the minimum requirement for i386,
some AMD platforms use SSE instructions which expect 16-byte.
1) http://wiki.osdev.org/System_V_ABI
See "Initial Stack and Register State" and "The Stack Frame"
in the supplements.
BUG=chrome-os-partner:62841664
Change-Id: I8a15514f551a8e17e9fe77b8402fe0d2b106972e
Signed-off-by: Marshall Dawson <marshalldawson3rd@gmail.com>
Reviewed-on: https://review.coreboot.org/20528
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Diffstat (limited to 'Documentation')
0 files changed, 0 insertions, 0 deletions