Date: Wed, 3 Mar 2021 14:37:01 +0000 From: Jessica Clarke <jrtc27@freebsd.org> To: Andrew Turner <andrew@FreeBSD.org> Cc: "src-committers@freebsd.org" <src-committers@FreeBSD.org>, "dev-commits-src-all@freebsd.org" <dev-commits-src-all@FreeBSD.org>, "dev-commits-src-main@freebsd.org" <dev-commits-src-main@FreeBSD.org> Subject: Re: git: 28d945204ea1 - main - Handle functions that use a nop in the arm64 fbt Message-ID: <F46D1F1C-364B-427C-A1AD-059AD2CCF646@freebsd.org> In-Reply-To: <FF6A9C3C-82CB-45E1-83A5-166057192321@freebsd.org> References: <202103031426.123EQoM5082920@gitrepo.freebsd.org> <FF6A9C3C-82CB-45E1-83A5-166057192321@freebsd.org>
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On 3 Mar 2021, at 14:29, Jessica Clarke <jrtc27@freebsd.org> wrote: > On 3 Mar 2021, at 14:26, Andrew Turner <andrew@FreeBSD.org> wrote: >> >> The branch main has been updated by andrew: >> >> URL: https://cgit.FreeBSD.org/src/commit/?id=28d945204ea1014d7de6906af8470ed8b3311335 >> >> commit 28d945204ea1014d7de6906af8470ed8b3311335 >> Author: Andrew Turner <andrew@FreeBSD.org> >> AuthorDate: 2021-01-13 11:08:19 +0000 >> Commit: Andrew Turner <andrew@FreeBSD.org> >> CommitDate: 2021-03-03 14:18:03 +0000 >> >> Handle functions that use a nop in the arm64 fbt >> >> To trace leaf asm functions we can insert a single nop instruction as >> the first instruction in a function and trigger off this. >> >> Reviewed by: gnn >> Sponsored by: Innovate UK >> Differential Revision: https://reviews.freebsd.org/D28132 >> --- >> sys/arm64/include/asm.h | 8 +++- >> .../contrib/opensolaris/uts/common/sys/dtrace.h | 2 + >> sys/cddl/dev/dtrace/aarch64/dtrace_subr.c | 5 +++ >> sys/cddl/dev/fbt/aarch64/fbt_isa.c | 51 ++++++++++++++-------- >> 4 files changed, 46 insertions(+), 20 deletions(-) >> >> diff --git a/sys/arm64/include/asm.h b/sys/arm64/include/asm.h >> index 05e618500e59..32b79d256e80 100644 >> --- a/sys/arm64/include/asm.h >> +++ b/sys/arm64/include/asm.h >> @@ -38,9 +38,15 @@ >> >> #define _C_LABEL(x) x >> >> +#ifdef KDTRACE_HOOKS >> +#define DTRACE_NOP nop >> +#else >> +#define DTRACE_NOP >> +#endif >> + >> #define LENTRY(sym) \ >> .text; .align 2; .type sym,#function; sym: \ >> - .cfi_startproc >> + .cfi_startproc; DTRACE_NOP >> #define ENTRY(sym) \ >> .globl sym; LENTRY(sym) > > Doesn't this mean ENTRY incorrectly also has the nop? Hm, right, the L in LENTRY means local not leaf. Isn't this a problem though? (L)ENTRY are perfectly legal to use for non-leaf assembly functions today. Shouldn't there be separate ones specifically for leaf functions if you want to treat them differently? Jesshelp
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