From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1iwQ9u-0002V5-GD for barebox@lists.infradead.org; Tue, 28 Jan 2020 12:40:02 +0000 References: <20200128092832.18615-1-o.rempel@pengutronix.de> <20200128145513.aae1244ee8e7faf94d661640@gmail.com> From: Oleksij Rempel Message-ID: Date: Tue, 28 Jan 2020 13:39:55 +0100 MIME-Version: 1.0 In-Reply-To: <20200128145513.aae1244ee8e7faf94d661640@gmail.com> Content-Language: en-US List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: Re: [PATCH v1] MIPS: remove .bss to __rel_start overlay To: Antony Pavlov Cc: barebox@lists.infradead.org, Peter Mamonov On 28.01.20 12:55, Antony Pavlov wrote: > On Tue, 28 Jan 2020 10:28:32 +0100 > Oleksij Rempel wrote: > > Hi! > > Looks like this patch has some undocummented side effects > (or in other words, it makes undocummented fixups). > > I have tested this patch on qemu-malta with current master, > ee8960aec018df2de ("ARM: imx6: properly check for IPU presence"). > It works fine: memtest works, iomem output looks good. > > But the patch fixes several issues and commit message does not contain > any information about it. > > I rebuild current master with qemu-malta_defconfig and MMU enabled. > > I used this qemu cmdline to enable qemu monitor: > > qemu-system-mips -nodefaults -M malta -m 256 -nographic -bios barebox-flash-image > -net user -net nic,model=rtl8139 -serial mon:stdio > > With '-serial mon:stdio' one can invoke qemu monitor with "ctrl-a c" keypress sequence. > > So I tried 'info registers' qemu monitor command after barebox startup: > > Hit any to stop autoboot: 3 > barebox@qemu malta:/ > barebox@qemu malta:/ > barebox@qemu malta:/ iomem > 0x00000000 - 0xffffffff (size 0x00000000) iomem > 0x180003f8 - 0x180003ff (size 0x00000008) 180003f8.serial@180003f8.of > 0x1e000000 - 0x1e3fffff (size 0x00400000) 1e000000.flash@1e000000.of > 0x1f000900 - 0x1f00093f (size 0x00000040) 1f000900.serial@1f000900.of > 0x1f000b00 - 0x1f000b1f (size 0x00000020) 1f000b00.gpio@1f000b00.of > 0x80000000 - 0x8fffffff (size 0x10000000) kseg0_ram0 > barebox@qemu malta:/ QEMU 4.2.0 monitor - type 'help' for more information > (qemu) info registers > pc=0xa081232c HI=0x00000026 LO=0x20000000 ds 0090 a081232c 1 > GPR00: r0 00000000 at 00000000 v0 b80003f8 v1 00000000 > GPR04: a0 a0408668 a1 b80003fd a2 b80003f8 a3 ffffffff > GPR08: t0 00000001 t1 00000000 t2 0000005a t3 00000023 > GPR12: t4 00000000 t5 00010000 t6 00000040 t7 00000010 > GPR16: s0 a0408668 s1 a085cd20 s2 a0860000 s3 a0860000 > GPR20: s4 a0860000 s5 00000400 s6 a08613c0 s7 00000001 > GPR24: t8 00000008 t9 a0812340 k0 00400000 k1 fffffffa > GPR28: gp 00000000 sp 8fb8fd10 s8 ffffffff ra a0812420 > CP0 Status 0x00000000 Cause 0x00000400 EPC 0x00000000 > Config0 0x80008482 Config1 0x9e190c8f LLAddr 0x0000000000000000 > Config2 0x80000000 Config3 0x00000000 > Config4 0x00000000 Config5 0x00000000 > (qemu) quit > > So I see several issues in current master at once: > > * iomem output has no information on sdram regions, so memtest is unusable; > * pc=0xa081232c, relocation does not work, barebox is located with 8M offset > from start of RAM. The board has 256M and relocation routine > should move barebox code much higher; > * pc=0xa081232c, so barebox code works from KSEG1 not from KSEG0 as MMU=y option implies. > > Your patch fixes all these symptoms at ones however the commit message > says nothing about them. OK, thx! I'll update commit message. >> .bss __rel_start (OVERLAY) was used to optimize RAM size used by >> barebox. Since .bss and __rel_start overlap, we should clear bss only >> after __rel_start was used. >> >> There is a choice of moving .bss clear sequence after __rel_start or >> remove this optimization. Since the use of this optimization is minimal >> and danger to trap in to similar issue is still high, i prefer to remove >> this optimization. >> >> Fixes: 1e5aef61fc6a444 ("MIPS: reloc: init bss and cpu") >> Signed-off-by: Oleksij Rempel >> --- >> arch/mips/lib/barebox.lds.S | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/arch/mips/lib/barebox.lds.S b/arch/mips/lib/barebox.lds.S >> index 693a778980..c954df41f3 100644 >> --- a/arch/mips/lib/barebox.lds.S >> +++ b/arch/mips/lib/barebox.lds.S >> @@ -59,7 +59,7 @@ SECTIONS >> >> _end = .; >> >> - .bss __rel_start (OVERLAY) : { >> + .bss : { >> __bss_start = .; >> *(.sbss.*) >> *(.bss.*) >> -- >> 2.25.0 >> > > Kind regards, Oleksij Rempel -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox