From: Segher Boessenkool <segher@kernel.crashing.org>
To: Nicholas Piggin <npiggin@gmail.com>
Cc: "linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
Nicholas Miehlbradt <nicholas@linux.ibm.com>
Subject: Re: [PATCH] powerpc/64: Implement arch_within_stack_frames
Date: Wed, 14 Dec 2022 18:17:25 -0600 [thread overview]
Message-ID: <20221215001725.GS25951@gate.crashing.org> (raw)
In-Reply-To: <CP1IFJNCTTZ4.33ROBE5VAFAKM@bobo>
On Wed, Dec 14, 2022 at 09:39:25PM +1000, Nicholas Piggin wrote:
> What about just copying x86's implementation including using
> __builtin_frame_address(1/2)? Are those builtins reliable for all
> our targets and compiler versions?
__builtin_frame_address(n) with n > 0 is specifically not supported, not
on any architecture; it does not work in all situations on *any* arch,
and not in *any* situation on some archs.
This is clearly documented:
Calling this function with a nonzero argument can have
unpredictable effects, including crashing the calling program. As
a result, calls that are considered unsafe are diagnosed when the
'-Wframe-address' option is in effect. Such calls should only be
made in debugging situations.
(and that warning is enabled by -Wall).
Segher
next prev parent reply other threads:[~2022-12-15 0:20 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-14 4:42 [PATCH] powerpc/64: Implement arch_within_stack_frames Nicholas Miehlbradt
2022-12-14 8:39 ` Christophe Leroy
2022-12-14 11:39 ` Nicholas Piggin
2022-12-14 11:48 ` Christophe Leroy
2022-12-14 11:54 ` Christophe Leroy
2022-12-15 0:17 ` Segher Boessenkool [this message]
2022-12-15 0:52 ` Nicholas Piggin
2022-12-15 16:29 ` Segher Boessenkool
2022-12-15 17:16 ` Segher Boessenkool
2022-12-19 6:32 ` Nicholas Miehlbradt
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