| Message ID | CAEG7qUyQPNG1EtSwWSC77vUm+PZXUpDBtm5obab+Y5aa9Vv4-A@mail.gmail.com |
|---|---|
| State | New |
| Headers | show |
On Fri, Nov 21, 2014 at 10:44 AM, Sterling Augustine <saugustine@google.com> wrote: > Hello, > > sysdeps/x86_64/start.S doesn't have a .size elf directive for _start. > This tripped up some analysis I was doing. > > This patch is the straightforward fix. Would you be interested in a > similar fix for the ~150 assembly files inside x86_64 with similar > issues? > > Sterling > > ChangeLog > > 2014-11-21 Sterling Augustine <saugustine@google.com> > > * sysdeps/x86_64/start.S: Add .size directive. > > > diff --git a/sysdeps/x86_64/start.S b/sysdeps/x86_64/start.S > index e3d4ff8..5106bd0 100644 > --- a/sysdeps/x86_64/start.S > +++ b/sysdeps/x86_64/start.S > @@ -124,6 +124,7 @@ _start: > > hlt /* Crash if somehow `exit' does return. */ > cfi_endproc > + .size _start, .-_start > > /* Define a symbol for the first piece of initialized data. */ > .data Why not use ENTRY/END macros?
On Fri, Nov 21, 2014 at 10:52 AM, H.J. Lu <hjl.tools@gmail.com> wrote: > On Fri, Nov 21, 2014 at 10:44 AM, Sterling Augustine > <saugustine@google.com> wrote: >> Hello, >> >> sysdeps/x86_64/start.S doesn't have a .size elf directive for _start. >> This tripped up some analysis I was doing. >> >> This patch is the straightforward fix. Would you be interested in a >> similar fix for the ~150 assembly files inside x86_64 with similar >> issues? >> >> Sterling >> >> ChangeLog >> >> 2014-11-21 Sterling Augustine <saugustine@google.com> >> >> * sysdeps/x86_64/start.S: Add .size directive. >> >> >> diff --git a/sysdeps/x86_64/start.S b/sysdeps/x86_64/start.S >> index e3d4ff8..5106bd0 100644 >> --- a/sysdeps/x86_64/start.S >> +++ b/sysdeps/x86_64/start.S >> @@ -124,6 +124,7 @@ _start: >> >> hlt /* Crash if somehow `exit' does return. */ >> cfi_endproc >> + .size _start, .-_start >> >> /* Define a symbol for the first piece of initialized data. */ >> .data > > Why not use ENTRY/END macros? I'm hazy here, but I don't think things are sufficiently initialized by _start to call mcount, which ENTRY does. You are right though, in that most of the other files do use END, and so the cleanup isn't as big as I thought. It probably doesn't make sense to use an END without a corresponding ENTRY in start.S, but I'm fine with whatever.
On Fri, Nov 21, 2014 at 11:02 AM, Sterling Augustine <saugustine@google.com> wrote: > On Fri, Nov 21, 2014 at 10:52 AM, H.J. Lu <hjl.tools@gmail.com> wrote: >> On Fri, Nov 21, 2014 at 10:44 AM, Sterling Augustine >> <saugustine@google.com> wrote: >>> Hello, >>> >>> sysdeps/x86_64/start.S doesn't have a .size elf directive for _start. >>> This tripped up some analysis I was doing. >>> >>> This patch is the straightforward fix. Would you be interested in a >>> similar fix for the ~150 assembly files inside x86_64 with similar >>> issues? >>> >>> Sterling >>> >>> ChangeLog >>> >>> 2014-11-21 Sterling Augustine <saugustine@google.com> >>> >>> * sysdeps/x86_64/start.S: Add .size directive. >>> >>> >>> diff --git a/sysdeps/x86_64/start.S b/sysdeps/x86_64/start.S >>> index e3d4ff8..5106bd0 100644 >>> --- a/sysdeps/x86_64/start.S >>> +++ b/sysdeps/x86_64/start.S >>> @@ -124,6 +124,7 @@ _start: >>> >>> hlt /* Crash if somehow `exit' does return. */ >>> cfi_endproc >>> + .size _start, .-_start >>> >>> /* Define a symbol for the first piece of initialized data. */ >>> .data >> >> Why not use ENTRY/END macros? > > I'm hazy here, but I don't think things are sufficiently initialized > by _start to call mcount, which ENTRY does. You are right though, in > that most of the other files do use END, and so the cleanup isn't as > big as I thought. > > It probably doesn't make sense to use an END without a corresponding > ENTRY in start.S, but I'm fine with whatever. We can add # define ENTRY_NO_MCOUNT ... #define ENRTY ... ENTRY_NO_MCOUNT CALL_MCOUNT Then we can use ENTRY_NO_MCOUNT if needed. H.J.
Sterling Augustine <saugustine@google.com> writes: > I'm hazy here, but I don't think things are sufficiently initialized > by _start to call mcount, which ENTRY does. start doesn't have a .po variant, so it doesn't matter. Andreas.
On Fri, Nov 21, 2014 at 11:57 AM, Andreas Schwab <schwab@linux-m68k.org> wrote: > Sterling Augustine <saugustine@google.com> writes: > >> I'm hazy here, but I don't think things are sufficiently initialized >> by _start to call mcount, which ENTRY does. > > start doesn't have a .po variant, so it doesn't matter. So should I follow HJ's approach, or just use an plain ENTRY macro?
On Mon, Nov 24, 2014 at 10:43 AM, Sterling Augustine <saugustine@google.com> wrote: > On Fri, Nov 21, 2014 at 11:57 AM, Andreas Schwab <schwab@linux-m68k.org> wrote: >> Sterling Augustine <saugustine@google.com> writes: >> >>> I'm hazy here, but I don't think things are sufficiently initialized >>> by _start to call mcount, which ENTRY does. >> >> start doesn't have a .po variant, so it doesn't matter. > > So should I follow HJ's approach, or just use an plain ENTRY macro? Plain ENTRY is preferred if it works. Thanks.
diff --git a/sysdeps/x86_64/start.S b/sysdeps/x86_64/start.S index e3d4ff8..5106bd0 100644 --- a/sysdeps/x86_64/start.S +++ b/sysdeps/x86_64/start.S @@ -124,6 +124,7 @@ _start: hlt /* Crash if somehow `exit' does return. */ cfi_endproc + .size _start, .-_start /* Define a symbol for the first piece of initialized data. */ .data