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authorMarshall Dawson <marshalldawson3rd@gmail.com>2017-07-07 16:09:56 -0600
committerMartin Roth <martinroth@google.com>2017-07-13 16:48:22 +0000
commitce9c88348cb1380199b8f57a435a51a7edb470a0 (patch)
treef484a1f3a6c7cfbf5b78817c486d2a8fd793fed1 /configs/config.intel_galileo_gen2.vboot
parentc35a1e888729b060229b4a326b1b42d09cb7c278 (diff)
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 'configs/config.intel_galileo_gen2.vboot')
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