Subject: [PATCH] Revert "ARM: pxa: call debug_ll_io_init for earlyprintk"

From: [email-masked] (Robert Jarzmik)
Date: Tue, 07 Oct 2014 21:33:56 +0200

Arnd Bergmann <[email-masked]> writes:
>
> Can't you just define CONFIG_DEBUG_UART_VIRT outside of the existing
> mappings? It doesn't have to use the same mapping as PERIPH_PHYS.
>
> 	Arnd
Yep, that looks better.
Would something like that be appropriate ? I tested that on pxa27x, but not on
pxa25x, even if there seems to be no reason it wouldn't work for it too ...

And I have not yet thought over if there is any impact on vmalloc memory or if
the double virtual mapping can trigger something bad.

Cheers.

-- 
Robert

---<8---
>>From 93239cf3015997d45fec8fee97059758cac1fab3 Mon Sep 17 00:00:00 2001
From: Robert Jarzmik <[email-masked]>
Date: Tue, 7 Oct 2014 21:18:14 +0200
Subject: [PATCH] ARM: pxa: fix hang on startup with DEBUG_LL

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.

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!

Cc: <[email-masked]>
Reported-by: Dmitry Eremin-Solenikov <[email-masked]>
Signed-off-by: Robert Jarzmik <[email-masked]>
---
 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 b11ad54..2f78e54 100644
--- a/arch/arm/Kconfig.debug
+++ b/arch/arm/Kconfig.debug
@@ -1142,7 +1142,7 @@ config DEBUG_UART_VIRT
 	default 0xf1c28000 if DEBUG_SUNXI_UART0
 	default 0xf1c28400 if DEBUG_SUNXI_UART1
 	default 0xf1f02800 if DEBUG_SUNXI_R_UART
-	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 bbf9df3..d28fe29 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
-- 
2.1.0