Re: [PATCH] parisc:Remove unnecessary FIXMES in init.c

[John David Anglin]

On 24-Sep-14, at 7:42 AM, nick wrote:

> On 14-09-24 01:30 AM, Guenter Roeck wrote:
> > On Tue, Sep 23, 2014 at 09:49:43PM -0400, Nicholas Krause wrote:
> > > This removes the two fixmes in the file, init.c for compiler hints
> > > for comments related to compiler hints in linux_gateway_page_addr
> > > and map_hpux_gateway_page to change from FIXME to HINT in order
> > > for people reading this code to understand that these are compiler
> > > hints.
> >
> > "* const" tells the compiler that a pointer is a constant.
> > It doesn't tell the compiler that the data shall not be treated
> > as DP-relative.
> >
> > FIXME as in: We should find a better way to tell the compiler to
> > not treat this data as DP-relative.
> >
> > Can you please stop this ?
> >
> > Guenter
> >
> > > Signed-off-by: Nicholas Krause <yocto6@xxxxxxxxx>
> > > ---
> > > arch/parisc/mm/init.c | 4 ++--
> > > 1 file changed, 2 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/arch/parisc/mm/init.c b/arch/parisc/mm/init.c
> > > index 0bef864..668102e 100644
> > > --- a/arch/parisc/mm/init.c
> > > +++ b/arch/parisc/mm/init.c
> > > @@ -733,7 +733,7 @@ static void __init pagetable_init(void)
> > > static void __init gateway_init(void)
> > > {
> > > 	unsigned long linux_gateway_page_addr;
> > > -	/* FIXME: This is 'const' in order to trick the compiler
> > > +	/* HINT: This is 'const' in order to trick the compiler
> > > 	   into not treating it as DP-relative data. */
> > > 	extern void * const linux_gateway_page;
> > >
> > > @@ -761,7 +761,7 @@ map_hpux_gateway_page(struct task_struct *tsk,  
> > > struct mm_struct *mm)
> > > 	unsigned long start_pte;
> > > 	unsigned long address;
> > > 	unsigned long hpux_gw_page_addr;
> > > -	/* FIXME: This is 'const' in order to trick the compiler
> > > +	/* HINT: This is 'const' in order to trick the compiler
> > > 	   into not treating it as DP-relative data. */
> > > 	extern void * const hpux_gateway_page;
> > >
> > > --
> > > 1.9.1
> > >
> > > --
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> Guenter,
> I asked the maintainers and I got,
> On 9/23/2014 4:48 PM, Helge Deller wrote:
> > The FIXME: is misleading. It should maybe better read "HINT:" or  
> > something like that.
> > Trivially it's basically just casting the symbol so that the compiler
> > will produce the correct code later on.
> > There is nothing you could try to "fix".
> Why not just remove "FIXME: " from these comments?


The wording of the comment is not good.  You can't "trick" the  
compiler into not
treating a constant as DP-relative data.  Whether or not a constant is  
loaded as an
immediate depends on its value.

Dave
--
John David Anglin	dave.anglin@xxxxxxxx



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