Re: [PATCH 3.16.y-ckt 053/168] ARM: pxa: fix hang on startup with DEBUG_LL

[Luis Henriques <luis.henriques@canonical.com>]

On Sun, Jan 11, 2015 at 10:39:08PM +0000, Ben Hutchings wrote:
> On Mon, 2014-12-15 at 14:25 +0000, Luis Henriques wrote:
> > 3.16.7-ckt3 -stable review patch.  If anyone has any objections, please let me know.
> > 
> > ------------------
> > 
> > From: Robert Jarzmik <robert.jarzmik@free.fr>
> > 
> > commit cde7fc879969f933614b1256df2625d6ff637bab upstream.
> > 
> > The commit 2111667b4677 ("ARM: pxa: call debug_ll_io_init for
> > earlyprintk") triggers in the current kernel the attached backtrace on
> > PXA/tosa early in the boot time when DEBUG_LL is enabled.
> 
> That was in 3.17-rc1, so I don't think this fix was needed for 3.16.  I
> don't know whether it causes any harm to apply it here.
> 

Thanks Ben.

Robert, do you think this is a problem?  I can revert this patch as
it has already been released in 3.16.7-ckt3.

Cheers,
--
Luís

> Ben.
> 
> > It is due to overlap between uart virtual memory defined in
> > DEBUG_UART_VIRT and mapped by debug_ll_io_init() and peripheral bus
> > mapped by pxa_map_io at the same address, 0xf2100000.
> > 
> > As hinted by Arnd, map early virtual memory for low level debug on
> > address 0xf6200000, even if that means 2 virtual mappings will give
> > access to the pxa internal UARTs (FFUART, BTUART, STUART, ...).
> > 
> > ------------[ cut here ]------------
> > kernel BUG at /home/lumag/linux/mm/vmalloc.c:1143!
> > Internal error: Oops - BUG: 0 [#1] PREEMPT ARM
> > Modules linked in:
> > CPU: 0 PID: 0 Comm: swapper Not tainted 3.17.0-00032-g8e0d202-dirty #23
> > task: c062a5a8 ti: c0620000 task.ti: c0620000
> > PC is at vm_area_add_early+0x54/0x84
> > LR is at add_static_vm_early+0xc/0x60
> > pc : [<c03e1100>]    lr : [<c03d9ef4>]    psr: 800001d3
> > sp : c0621f04  ip : c03efa74  fp : c03edf84
> > r10: c0637e98  r9 : 40000001  r8 : c03da57c
> > r7 : c3ffcfb0  r6 : 00000000  r5 : c3ffcfb0  r4 : 02000000
> > r3 : c3ffcfd8  r2 : f2100000  r1 : f4000000  r0 : c3ffcfb0
> > Flags: Nzcv  IRQs off  FIQs off  Mode SVC_32  ISA ARM  Segment kernel
> > Control: 00007977  Table: a0004000  DAC: 00000017
> > Process swapper (pid: 0, stack limit = 0xc06201c8)
> > Stack: (0xc0621f04 to 0xc0622000)
> > 1f00:          c3ffcfd8 40000001 c3ffcfd8 c03ee08c c03da570 c03db90c c0637d24
> > 1f20: 00000000 c03ec7cc c066e654 a0700000 000a0700 c03db914 c03db90c c03daf84
> > 1f40: 00000000 000a0000 c0000000 c03ec7cc 000a0700 c0700000 ffff1000 000a3fff
> > 1f60: 00001000 00000007 00000000 c03ec7cc c0008000 c03ed748 c0621fd4 c03d5d18
> > 1f80: 69052d00 a03ec48c 00000000 c03d8ad0 0000006c 00007977 c036c6e8 00000001
> > 1fa0: c0621fd4 c03ed744 c0628000 a0004000 69052d00 a03ec48c 00000000 c03d68d4
> > 1fc0: 00000000 00000000 00000000 00000000 00000000 c03ed748 c0649894 c062801c
> > 1fe0: c03ed744 c062b2f0 a0004000 69052d00 a03ec48c a0008040 00000000 00000000
> > [<c03e1100>] (vm_area_add_early) from [<c03d9ef4>] (add_static_vm_early+0xc/0x60)
> > [<c03d9ef4>] (add_static_vm_early) from [<c03da570>] (iotable_init.part.6+0xa8/0xb4)
> > [<c03da570>] (iotable_init.part.6) from [<c03db914>] (pxa25x_map_io+0x8/0x24)
> > [<c03db914>] (pxa25x_map_io) from [<c03daf84>] (paging_init+0x744/0x8d8)
> > [<c03daf84>] (paging_init) from [<c03d8ad0>] (setup_arch+0x354/0x608)
> > [<c03d8ad0>] (setup_arch) from [<c03d68d4>] (start_kernel+0xa8/0x3dc)
> > [<c03d68d4>] (start_kernel) from [<a0008040>] (0xa0008040)
> > Code: e5904008 e0811004 e1520001 2a000005 (e7f001f2)
> > ---[ end trace f24b6c88ae00fa9a ]---
> > Kernel panic - not syncing: Attempted to kill the idle task!
> > ---[ end Kernel panic - not syncing: Attempted to kill the idle task!
> > 
> > Reported-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
> > Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
> > Acked-by: Arnd Bergmann <arnd@arndb.de>
> > [ luis: backported to 3.16: adjusted context ]
> > Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
> > ---
> >  arch/arm/Kconfig.debug                    | 2 +-
> >  arch/arm/mach-pxa/include/mach/addr-map.h | 5 +++++
> >  2 files changed, 6 insertions(+), 1 deletion(-)
> > 
> > diff --git a/arch/arm/Kconfig.debug b/arch/arm/Kconfig.debug
> > index 8f90595069a1..1fdb08427db7 100644
> > --- a/arch/arm/Kconfig.debug
> > +++ b/arch/arm/Kconfig.debug
> > @@ -1118,7 +1118,7 @@ config DEBUG_UART_VIRT
> >  	default 0xf1600000 if ARCH_INTEGRATOR
> >  	default 0xf1c28000 if DEBUG_SUNXI_UART0
> >  	default 0xf1c28400 if DEBUG_SUNXI_UART1
> > -	default 0xf2100000 if DEBUG_PXA_UART1
> > +	default 0xf6200000 if DEBUG_PXA_UART1
> >  	default 0xf4090000 if ARCH_LPC32XX
> >  	default 0xf4200000 if ARCH_GEMINI
> >  	default 0xf7000000 if DEBUG_S3C24XX_UART && (DEBUG_S3C_UART0 || \
> > diff --git a/arch/arm/mach-pxa/include/mach/addr-map.h b/arch/arm/mach-pxa/include/mach/addr-map.h
> > index bbf9df37ad4b..d28fe291233a 100644
> > --- a/arch/arm/mach-pxa/include/mach/addr-map.h
> > +++ b/arch/arm/mach-pxa/include/mach/addr-map.h
> > @@ -39,6 +39,11 @@
> >  #define DMEMC_SIZE		0x00100000
> >  
> >  /*
> > + * Reserved space for low level debug virtual addresses within
> > + * 0xf6200000..0xf6201000
> > + */
> > +
> > +/*
> >   * Internal Memory Controller (PXA27x and later)
> >   */
> >  #define IMEMC_PHYS		0x58000000
> 
> -- 
> Ben Hutchings
> One of the nice things about standards is that there are so many of them.