Re: [PATCH] riscv: Drop setup_initrd

From: Guenter Roeck <linux@roeck-us.net>
To: Andreas Schwab <schwab@linux-m68k.org>
Cc: Palmer Dabbelt <palmer@sifive.com>,
	aou@eecs.berkeley.edu, linux-riscv@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] riscv: Drop setup_initrd
Date: Tue, 28 Aug 2018 14:59:59 -0700	[thread overview]
Message-ID: <20180828215959.GA6279@roeck-us.net> (raw)
In-Reply-To: <87mut6b1we.fsf@igel.home>

On Tue, Aug 28, 2018 at 11:46:09PM +0200, Andreas Schwab wrote:
> On Aug 28 2018, Guenter Roeck <linux@roeck-us.net> wrote:
> 
> > On Tue, Aug 28, 2018 at 01:10:20PM -0700, Palmer Dabbelt wrote:
> >> On Thu, 09 Aug 2018 21:11:40 PDT (-0700), linux@roeck-us.net wrote:
> >> >setup_initrd() does not appear to serve a practical purpose other than
> >> >preventing qemu boots with "-initrd" parameter, so let's drop it.
> >> >
> >> >Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> >> >---
> >> > arch/riscv/kernel/setup.c | 39 ---------------------------------------
> >> > 1 file changed, 39 deletions(-)
> >> >
> >> >diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
> >> >index 2e56af3281f8..579f58a42974 100644
> >> >--- a/arch/riscv/kernel/setup.c
> >> >+++ b/arch/riscv/kernel/setup.c
> >> >@@ -82,41 +82,6 @@ EXPORT_SYMBOL(empty_zero_page);
> >> > /* The lucky hart to first increment this variable will boot the other cores */
> >> > atomic_t hart_lottery;
> >> >
> >> >-#ifdef CONFIG_BLK_DEV_INITRD
> >> >-static void __init setup_initrd(void)
> >> >-{
> >> >-	extern char __initramfs_start[];
> >> >-	extern unsigned long __initramfs_size;
> >> >-	unsigned long size;
> >> >-
> >> >-	if (__initramfs_size > 0) {
> >> >-		initrd_start = (unsigned long)(&__initramfs_start);
> >> >-		initrd_end = initrd_start + __initramfs_size;
> >> >-	}
> >
> > The underlying problem is probably that __initramfs_size == 512 even
> > if there is no embedded initrd. Result is that initrd_start and initrd_end
> > are always overwritten, even if provided and even if there is no embedded
> > initrd. Result is that initrd_start and initrd_end are always overwritten,
> > and -initrd from the qemu command line is always ignored.
> >
> > A less invasive fix than mine would be
> >
> > -	if (__initramfs_size > 0) {
> > +	if (__initramfs_size > 0 && !initrd_start) {
> >
> > Any chance you can test that with your setup ?
> 
> You should just delete the last four lines above.  They serve no purpose.
> 

You mean the entire if() statement plus the variable declarations ?

That works for me, for both embedded initrd and initrd specified with
-initrd option, but we still need someone to test if it works for 
Palmer's use case, ie with vmlinux (and possibly initrd) embedded in
bbl.

Thanks,
Guenter

> Andreas.
> 
> -- 
> Andreas Schwab, schwab@linux-m68k.org
> GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510  2552 DF73 E780 A9DA AEC1
> "And now for something completely different."