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Thomas Gleixner 8101b5a153 ARM: futex: Address build warning ... Stephen reported the following build warning on a ARM multi_v7_defconfig build with GCC 9.2.1: kernel/futex.c: In function 'do_futex': kernel/futex.c:1676:17: warning: 'oldval' may be used uninitialized in this function [-Wmaybe-uninitialized] 1676 | return oldval == cmparg; | ~~~~~~~^~~~~~~~~ kernel/futex.c:1652:6: note: 'oldval' was declared here 1652 | int oldval, ret; | ^~~~~~ introduced by commit a08971e948 ("futex: arch_futex_atomic_op_inuser() calling conventions change"). While that change should not make any difference it confuses GCC which fails to work out that oldval is not referenced when the return value is not zero. GCC fails to properly analyze arch_futex_atomic_op_inuser(). It's not the early return, the issue is with the assembly macros. GCC fails to detect that those either set 'ret' to 0 and set oldval or set 'ret' to -EFAULT which makes oldval uninteresting. The store to the callsite supplied oldval pointer is conditional on ret == 0. The straight forward way to solve this is to make the store unconditional. Aside of addressing the build warning this makes sense anyway because it removes the conditional from the fastpath. In the error case the stored value is uninteresting and the extra store does not matter at all. Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/87pncao2ph.fsf@nanos.tec.linutronix.de		History 2020-05-07 00:41:47 +02:00
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asm	ARM: futex: Address build warning	2020-05-07 00:41:47 +02:00
debug	ARM: debug: stm32: add UART early console support for STM32MP1	2020-03-13 17:05:07 +01:00
uapi/asm	arm: Remove 32bit KVM host support	2020-03-24 10:56:04 +00:00