Andy Shevchenko 63dcc70901 device property: Get rid of union aliasing ... Commit 318a197182 (device property: refactor built-in properties support) went way too far and brought a union aliasing. Partially revert it here to get rid of union aliasing. Note, all Apple properties are considered as u8 arrays. To get a value of any of them the caller must use device_property_read_u8_array(). What's union aliasing? ~~~~~~~~~~~~~~~~~~~~~~ The C99 standard in section 6.2.5 paragraph 20 defines union type as "an overlapping nonempty set of member objects". It also states in section 6.7.2.1 paragraph 14 that "the value of at most one of the members can be stored in a union object at any time'. Union aliasing is a type punning mechanism using union members to store as one type and read back as another. Why it's not good? ~~~~~~~~~~~~~~~~~~ Section 6.2.6.1 paragraph 6 says that a union object may not be a trap representation, although its member objects may be. Meanwhile annex J.1 says that "the value of a union member other than the last one stored into" is unspecified [removed in C11]. In TC3, a footnote is added which specifies that accessing a member of a union other than the last one stored causes "the object representation" to be re-interpreted in the new type and specifically refers to this as "type punning". This conflicts to some degree with Annex J.1. While it's working in Linux with GCC, the use of union members to do type punning is not clear area in the C standard and might lead to unspecified behaviour. More information is available in this [1] blog post. [1]: https://davmac.wordpress.com/2010/02/26/c99-revisited/ Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>		2018-05-17 12:47:21 +02:00
..
acpi	xen: fixes for 4.17-rc1	2018-04-12 11:04:35 -07:00
asm-generic	earlycon: Use a pointer table to fix __earlycon_table stride	2018-04-23 10:06:59 +02:00
clocksource	ARM: SoC platform updates for 4.17	2018-04-05 21:21:08 -07:00
crypto	crypto: api - Remove unused crypto_type lookup function	2018-03-31 01:32:57 +08:00
drm	drm: Fix HDCP downstream dev count read	2018-04-16 12:10:48 -04:00
dt-bindings	Merge branch 'clk-stm32mp1' into clk-fixes	2018-04-16 08:58:39 -07:00
keys
kvm	KVM: arm/arm64: vgic: Fix source vcpu issues for GICv2 SGI	2018-04-27 12:39:09 +01:00
linux	device property: Get rid of union aliasing	2018-05-17 12:47:21 +02:00
math-emu
media	MAINTAINERS & files: Canonize the e-mails I use at files	2018-05-04 06:21:06 -04:00
memory
misc
net	bonding: send learning packets for vlans on slave	2018-05-11 11:50:41 -04:00
pcmcia
ras
rdma	Merge candidates for 4.17 merge window	2018-04-06 17:35:43 -07:00
scsi	scsi: core: remove reference to scsi_show_extd_sense()	2018-04-18 23:37:39 -04:00
soc	soc: bcm2835: Make !RASPBERRYPI_FIRMWARE dummies return failure	2018-04-16 15:15:23 -07:00
sound	ALSA: control: Hardening for potential Spectre v1	2018-04-25 10:37:46 +02:00
target
trace	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2018-05-11 14:14:46 -07:00
uapi	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2018-05-11 14:14:46 -07:00
video
xen	xen/sndif: Sync up with the canonical definition in Xen	2018-04-17 08:26:33 -04:00