From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Jiri Slaby <jslaby@suse.cz>
Cc: mingo@redhat.com, tglx@linutronix.de, hpa@zytor.com,
x86@kernel.org, linux-kernel@vger.kernel.org,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Juergen Gross <jgross@suse.com>,
xen-devel@lists.xenproject.org
Subject: Re: [PATCH v3 04/29] x86: assembly, use ENDPROC for functions
Date: Fri, 19 May 2017 14:50:08 -0500 [thread overview]
Message-ID: <20170519195008.ls6ynaoxcxilip4x@treble> (raw)
In-Reply-To: <a78d080c-1d32-c47c-b5b5-b5f809faacb5@suse.cz>
On Fri, May 19, 2017 at 11:17:24AM +0200, Jiri Slaby wrote:
> On 05/17/2017, 03:23 PM, Jiri Slaby wrote:
> >> So the initial CFI state is different between the two types of
> >> "functions". And there are a lot of other differences. C-type
> >> functions have to follow frame pointer conventions, for example. So
> >> your FUNC_START macro (and objtool) would have to somehow figure out a
> >> way to make a distinction between the two. So it would probably work
> >> out better if we kept the distinction between C-type functions and other
> >> code.
> >
> > Ok, that makes a lot of sense.
>
> A quick question:
> Do you consider these to be C-type functions?
>
> ENTRY(function_hook)
> ret
> END(function_hook)
>
> or this?
>
> ENTRY(native_load_gs_index)
> pushfq
> DISABLE_INTERRUPTS(CLBR_ANY & ~CLBR_RDI)
> SWAPGS
> movl %edi, %gs
> SWAPGS
> popfq
> ret
> END(native_load_gs_index)
>
> Both are called from C, but they do not setup frame pointer etc.
Yeah, those are valid C-type functions. Setting up the frame pointer is
optional for leaf functions (i.e. functions which don't call other
functions).
--
Josh
next prev parent reply other threads:[~2017-05-19 19:50 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-21 14:12 [PATCH v3 01/29] x86: boot/copy, remove unused functions Jiri Slaby
2017-04-21 14:12 ` [PATCH v3 02/29] x86_32: boot, extract efi_pe_entry from startup_32 Jiri Slaby
2017-04-21 14:12 ` [PATCH v3 03/29] x86_64: boot, extract efi_pe_entry from startup_64 Jiri Slaby
2017-04-21 14:12 ` [PATCH v3 04/29] x86: assembly, use ENDPROC for functions Jiri Slaby
2017-04-26 1:42 ` Josh Poimboeuf
2017-05-12 7:53 ` Jiri Slaby
2017-05-12 22:15 ` Josh Poimboeuf
2017-05-17 13:23 ` Jiri Slaby
2017-05-19 9:17 ` Jiri Slaby
2017-05-19 19:50 ` Josh Poimboeuf [this message]
2017-04-21 14:12 ` [PATCH v3 05/29] x86: assembly, add ENDPROC to functions Jiri Slaby
2017-04-21 14:12 ` [PATCH v3 06/29] x86: assembly, annotate functions by ENTRY, not GLOBAL Jiri Slaby
2017-04-21 14:12 ` [PATCH v3 07/29] x86: bpf_jit, use ENTRY+ENDPROC Jiri Slaby
2017-04-21 19:32 ` Alexei Starovoitov
2017-04-24 6:45 ` Jiri Slaby
2017-04-24 14:41 ` David Miller
2017-04-24 14:52 ` Jiri Slaby
2017-04-24 15:08 ` David Miller
2017-04-24 15:41 ` Jiri Slaby
2017-04-24 15:51 ` David Miller
2017-04-24 15:53 ` Jiri Slaby
2017-04-24 15:55 ` Ingo Molnar
2017-04-24 16:02 ` Jiri Slaby
2017-04-24 16:40 ` Ingo Molnar
2017-04-24 16:47 ` Alexei Starovoitov
2017-04-24 17:51 ` Jiri Slaby
2017-04-24 18:24 ` David Miller
2017-04-25 14:41 ` Jiri Slaby
2017-04-21 14:12 ` [PATCH v3 08/29] linkage: new macros for assembler symbols Jiri Slaby
2017-04-21 14:12 ` [PATCH v3 09/29] x86: assembly, use DATA_SIMPLE for data Jiri Slaby
2017-04-27 11:53 ` Pavel Machek
2017-04-27 12:30 ` Jiri Slaby
2017-04-27 12:43 ` Pavel Machek
2017-04-21 14:12 ` [PATCH v3 10/29] x86: assembly, annotate relocate_kernel Jiri Slaby
2017-04-21 14:12 ` [PATCH v3 11/29] x86: entry, annotate THUNKs Jiri Slaby
2017-04-21 14:12 ` [PATCH v3 12/29] x86: assembly, annotate local functions Jiri Slaby
2017-04-21 14:12 ` [PATCH v3 13/29] x86: crypto, " Jiri Slaby
2017-04-21 14:12 ` [PATCH v3 14/29] x86: boot, " Jiri Slaby
2017-04-21 14:12 ` [PATCH v3 15/29] x86: assembly, annotate aliases Jiri Slaby
2017-04-21 14:12 ` [PATCH v3 16/29] x86: entry, annotate interrupt symbols properly Jiri Slaby
2017-04-21 14:12 ` [PATCH v3 17/29] x86: head, annotate data appropriatelly Jiri Slaby
2017-04-21 14:12 ` [PATCH v3 18/29] x86: boot, " Jiri Slaby
2017-04-21 14:12 ` [PATCH v3 19/29] x86: um, " Jiri Slaby
2017-04-21 14:12 ` [PATCH v3 20/29] x86: xen-pvh, " Jiri Slaby
2017-04-21 14:12 ` [PATCH v3 21/29] x86: purgatory, start using annotations Jiri Slaby
2017-04-21 14:12 ` [PATCH v3 22/29] x86: assembly, use SYM_FUNC_INNER_LABEL instead of GLOBAL Jiri Slaby
2017-04-21 14:12 ` [PATCH v3 23/29] x86: realmode, use SYM_DATA_* " Jiri Slaby
2017-04-21 14:13 ` [PATCH v3 24/29] x86: assembly, remove GLOBAL macro Jiri Slaby
2017-04-21 14:13 ` [PATCH v3 25/29] x86: assembly, make some functions local Jiri Slaby
2017-04-21 14:13 ` [PATCH v3 26/29] x86_64: assembly, change all ENTRY to SYM_FUNC_START Jiri Slaby
2017-04-21 14:13 ` [PATCH v3 27/29] x86_32: " Jiri Slaby
2017-04-21 14:13 ` [PATCH v3 28/29] x86_32: lguest, use SYM_ENTRY Jiri Slaby
2017-04-21 14:13 ` [PATCH v3 29/29] x86: assembly, replace WEAK uses Jiri Slaby
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