From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnout Vandecappelle Date: Sat, 19 Mar 2016 16:46:04 +0100 Subject: [Buildroot] [PATCH v2 04/17] uclibc: add patches to simplify Thumb handling In-Reply-To: <1458335299-27409-5-git-send-email-thomas.petazzoni@free-electrons.com> References: <1458335299-27409-1-git-send-email-thomas.petazzoni@free-electrons.com> <1458335299-27409-5-git-send-email-thomas.petazzoni@free-electrons.com> Message-ID: <56ED743C.9070500@mind.be> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: buildroot@busybox.net On 03/18/16 22:08, Thomas Petazzoni wrote: > This commit adds a number of patches to uClibc that radically > simplifies the Thumb handling. uClibc currently has three options that > you need to toggle on Thumb configurations depending on the specific > ARM CPU being targeted. > > However, it turns out that none of those options are necessary: > > - USE_BX can simply be guessed by looking at the ARM core being > used. The bx instruction is available for all ARM cores >= > ARMv4T. This is exactly what glibc is doing. > > - USE_LDREXSTREX can also be guessed by looking at the ARM core being > used: whenever you have Thumb2, ldrex/strex is available. > > - COMPILE_IN_THUMB becomes useless, since all it does is passing > -mthumb. But just like the uClibc config options to set > --march= have been removed a long time ago, there's no need to > -have an option to pass -mthumb. > > Signed-off-by: Thomas Petazzoni Reviewed-by: Arnout Vandecappelle (Essensium/Mind) Upstream status? Knowing Waldemar's lightning reflexes, we will probably just bump the uClibc version rather than having these patches in Buildroot :-) Regards, Arnout > --- > .../0001-arm-remove-use-of-USE_BX-option.patch | 53 ++++++++++++++++++++++ > package/uclibc/0002-arm-remove-USE_BX-option.patch | 40 ++++++++++++++++ > .../0003-arm-remove-use-of-USE_LDREXSTREX.patch | 49 ++++++++++++++++++++ > .../uclibc/0004-arm-remove-USE_LDREXSTREX.patch | 34 ++++++++++++++ > .../uclibc/0005-arm-remove-COMPILE_IN_THUMB.patch | 43 ++++++++++++++++++ > 5 files changed, 219 insertions(+) > create mode 100644 package/uclibc/0001-arm-remove-use-of-USE_BX-option.patch > create mode 100644 package/uclibc/0002-arm-remove-USE_BX-option.patch > create mode 100644 package/uclibc/0003-arm-remove-use-of-USE_LDREXSTREX.patch > create mode 100644 package/uclibc/0004-arm-remove-USE_LDREXSTREX.patch > create mode 100644 package/uclibc/0005-arm-remove-COMPILE_IN_THUMB.patch -- Arnout Vandecappelle arnout at mind be Senior Embedded Software Architect +32-16-286500 Essensium/Mind http://www.mind.be G.Geenslaan 9, 3001 Leuven, Belgium BE 872 984 063 RPR Leuven LinkedIn profile: http://www.linkedin.com/in/arnoutvandecappelle GPG fingerprint: 7493 020B C7E3 8618 8DEC 222C 82EB F404 F9AC 0DDF