[coreboot-gerrit] Patch merged into coreboot/master: arm, arm64, mips: Add rough static stack size checks with -Wstack-usage

[gerrit at coreboot.org]

the following patch was just integrated into master:
commit 8d8799a33aac86c2acdf94e0f0af3ef291748536
Author: Julius Werner <jwerner at chromium.org>
Date:   Fri Dec 19 16:11:14 2014 -0800

    arm, arm64, mips: Add rough static stack size checks with -Wstack-usage
    
    We've seen an increasing need to reduce stack sizes more and more for
    space reasons, and it's always guesswork because no one has a good idea
    how little is too litte. We now have boards with 3K and 2K stacks, and
    old pieces of common code often allocate large temporary buffers that
    would lead to very dangerous and hard to detect bugs when someone
    eventually tries to use them on one of those.
    
    This patch tries improve this situation at least a bit by declaring 2K
    as the minimum stack size all of coreboot code should work with. It
    checks all function frames with -Wstack-usage=1536 to make sure we don't
    allocate more than 1.5K in a single buffer. This is of course not a
    perfect test, but it should catch the most common situation of declaring
    a single, large buffer in some close-to-leaf function (with the
    assumption that 0.5K is hopefully enough for all the "normal" functions
    above that).
    
    Change one example where we were a bit overzealous and put a 1K buffer
    into BSS back to stack allocation, since it actually conforms to this
    new assumption and frees up another kilobyte of that highly sought-after
    verstage space. Not touching x86 with any of this since it's lack of
    __PRE_RAM__ BSS often requires it to allocate way more on the stack than
    would usually be considered sane.
    
    BRANCH=veyron
    BUG=None
    TEST=Compiled Cosmos, Daisy, Falco, Blaze, Pit, Storm, Urara and Pinky,
    made sure they still build as well as before and don't show any stack
    usage warnings.
    
    Change-Id: Idc53d33bd8487bbef49d3ecd751914b0308006ec
    Signed-off-by: Patrick Georgi <pgeorgi at chromium.org>
    Original-Commit-Id: 8e5931066575e256dfc2295c3dab7f0e1b65417f
    Original-Change-Id: I30bd9c2c77e0e0623df89b9e5bb43ed29506be98
    Original-Signed-off-by: Julius Werner <jwerner at chromium.org>
    Original-Reviewed-on: https://chromium-review.googlesource.com/236978
    Original-Reviewed-by: David Hendricks <dhendrix at chromium.org>
    Original-Reviewed-by: Aaron Durbin <adurbin at chromium.org>
    Reviewed-on: http://review.coreboot.org/9729
    Tested-by: build bot (Jenkins)
    Reviewed-by: Stefan Reinauer <stefan.reinauer at coreboot.org>


See http://review.coreboot.org/9729 for details.

-gerrit