Linux powerpc new system call instruction and ABI

Nicholas Piggin npiggin at
Wed May 19 17:55:35 AEST 2021

Excerpts from Joakim Tjernlund's message of May 19, 2021 5:33 pm:
> On Wed, 2021-05-19 at 02:13 +0300, Dmitry V. Levin wrote:
>> Hi,
>> On Thu, Jun 11, 2020 at 06:12:01PM +1000, Nicholas Piggin wrote:
>> [...]
>> > - Error handling: The consensus among kernel, glibc, and musl is to move to
>> >   using negative return values in r3 rather than CR0[SO]=1 to indicate error,
>> >   which matches most other architectures, and is closer to a function call.
> What about syscalls like times(2) which can return -1 without it being an error?

They do become errors / indistinguishable and have to be dealt with by 
libc or userspace. Which does follow what most architectures do (all 
except ia64, mips, sparc, and powerpc actually).

Interesting question though, it should have been noted.


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