mailing list of musl libc
 help / color / mirror / code / Atom feed
* [musl] New powerpc vdso calling convention
@ 2020-04-25  5:22 Nicholas Piggin
  2020-04-25  5:40 ` Rich Felker
  2020-04-25  7:47 ` [musl] " Christophe Leroy
  0 siblings, 2 replies; 15+ messages in thread
From: Nicholas Piggin @ 2020-04-25  5:22 UTC (permalink / raw)
  To: linuxppc-dev, binutils
  Cc: libc-alpha, libc-dev, musl, Adhemerval Zanella, Rich Felker

As noted in the 'scv' thread, powerpc's vdso calling convention does not 
match the C ELF ABI calling convention (or the proposed scv convention).
I think we could implement a new ABI by basically duplicating function
entry points with different names.

The ELF v2 ABI convention would suit it well, because the caller already
requires the function address for ctr, so having it in r12 will 
eliminate the need for address calculation, which suits the vdso data 
page access.

Is there a need for ELF v1 specific calls as well, or could those just be 
deprecated and remain on existing functions or required to use the ELF 
v2 calls using asm wrappers?

Is there a good reason for the system call fallback to go in the vdso 
function rather than have the caller handle it?

Thanks,
Nick

^ permalink raw reply	[flat|nested] 15+ messages in thread

end of thread, other threads:[~2020-05-06  9:39 UTC | newest]

Thread overview: 15+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-04-25  5:22 [musl] New powerpc vdso calling convention Nicholas Piggin
2020-04-25  5:40 ` Rich Felker
2020-04-25  7:47 ` [musl] " Christophe Leroy
2020-04-25 10:56   ` Nicholas Piggin
2020-04-25 12:20     ` Christophe Leroy
2020-04-25 22:58       ` Nicholas Piggin
2020-04-25 23:11         ` Rich Felker
2020-04-26  3:41           ` Nicholas Piggin
2020-04-27 13:09             ` Adhemerval Zanella
2020-04-29  2:39               ` Nicholas Piggin
2020-04-29 12:15                 ` Adhemerval Zanella
2020-05-05 21:56                 ` Segher Boessenkool
2020-04-25 16:22     ` Rich Felker
2020-04-25 23:07       ` Nicholas Piggin
2020-04-30  2:51       ` Michael Ellerman

Code repositories for project(s) associated with this public inbox

	https://git.vuxu.org/mirror/musl/

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).