Re: runtime check for omap-aes bus access permission (was: Re: 3.13-rc3 (commit 7ce93f3) breaks Nokia N900 DT boot)

["Pali Rohár" <pali.rohar@gmail.com>]

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On Saturday 17 January 2015 18:41:26 Tony Lindgren wrote:
> * Pali Rohár <pali.rohar@gmail.com> [150117 09:32]:
> > On Saturday 17 January 2015 18:04:11 Tony Lindgren wrote:
> > > * Pali Rohár <pali.rohar@gmail.com> [150117 01:21]:
> > > > Hello, after playing with aes and non-aes version of
> > > > bootloaders I found out that code which configure L3
> > > > firewall must be in signed X-Loader part. So probably we
> > > > cannot change configuration at runtime...
> > > > 
> > > > Tony,
> > > > any idea how to dump L3_PM_ADDR_MATCH_* registers from
> > > > userspace or from kernel? Now I have configured one N900
> > > > with original Nokia X-Loader (where loading omap aes
> > > > driver cause kernel crash) and one N900 with aes
> > > > X-Loader (where loading omap aes driver is working).
> > > 
> > > Hmm maybe give the omapconf too a try? It's at:
> > > 
> > > https://github.com/omapconf/omapconf
> > > 
> > > That uses /dev/mem from userspace, then you can just
> > > ioremap them in the kernel code if you need to do
> > > something during runtime. Probably best to access them
> > > with a syscon mapping from the aes driver.
> > > 
> > > Regards,
> > > 
> > > Tony
> > 
> > https://github.com/omapconf/omapconf/wiki
> > 
> > Legacy TI OMAP platforms (OMAP[1-2-3]) are not supported.
> 
> Oh OK. Well at least you can look at the code if you want to
> do it from the user space :)
> 
> Regards,
> 
> Tony

I played with devmem2.c program, but trying to read any of those register caused probably L3 violation 
error...

registers:
L3_PM_ERROR_LOG
L3_PM_CONTROL
L3_PM_REQ_INFO_PERMISSION_i
L3_PM_READ_PERMISSION_i
L3_PM_WRITE_PERMISSION_i
L3_PM_ADDR_MATCH_k

protection mechanisms:
PM_RT
PM_GPMC
PM_OCM_RAM
PM_OCM_ROM
PM_IVA2.2

Here is example output for address 0x68010028 (PM_RT L3_PM_CONTROL):

$ devmem2 0x68010028 w
/dev/mem opened.
Memory mapped at address 0xb6f87000.
Bus error

dmesg output:
[  172.923553] Unhandled fault: external abort on non-linefetch (0x1018) at 0xb6f87028
[  172.930664] In-band Error seen by MPU  at address 0
[  172.937408] ------------[ cut here ]------------
[  172.944061] WARNING: CPU: 0 PID: 612 at drivers/bus/omap_l3_smx.c:166 omap3_l3_app_irq+0xd4/0x118()
[  172.957733] Modules linked in: wl1251_spi wl1251 crc7 mac80211 cfg80211 isp1704_charger 
lis3lv02d_i2c lis3lv02d input_polldev bq2415x_charger si4713 bq27x00_battery v4l2_common videodev 
media leds_lp5523 omap_ssi hsi leds_lp55xx_common tsl2563 rtc_twl rx51_battery twl4030_vibra 
ff_memless tsc2005 twl4030_wdt omap_wdt
[  172.987762] CPU: 0 PID: 612 Comm: devmem2 Tainted: G        W      3.19.0-rc5+ #297
[  172.995483] Hardware name: Nokia RX-51 board
[  173.002960] [<c0012678>] (unwind_backtrace) from [<c0010d44>] (show_stack+0x10/0x14)
[  173.010589] [<c0010d44>] (show_stack) from [<c0032194>] (warn_slowpath_common+0x84/0xac)
[  173.018280] [<c0032194>] (warn_slowpath_common) from [<c00321d4>] (warn_slowpath_null+0x18/0x1c)
[  173.026123] [<c00321d4>] (warn_slowpath_null) from [<c01f30e0>] (omap3_l3_app_irq+0xd4/0x118)
[  173.034057] [<c01f30e0>] (omap3_l3_app_irq) from [<c0061fd0>] (handle_irq_event_percpu+0xcc/0x294)
[  173.049987] [<c0061fd0>] (handle_irq_event_percpu) from [<c00621fc>] (handle_irq_event+0x64/0x8c)
[  173.058441] [<c00621fc>] (handle_irq_event) from [<c0064b9c>] (handle_level_irq+0xcc/0x130)
[  173.066925] [<c0064b9c>] (handle_level_irq) from [<c0061850>] (generic_handle_irq+0x20/0x30)
[  173.075592] [<c0061850>] (generic_handle_irq) from [<c0061a38>] (__handle_domain_irq+0x80/0xa4)
[  173.084411] [<c0061a38>] (__handle_domain_irq) from [<c0008520>] (omap_intc_handle_irq+0x78/0xa4)
[  173.093383] [<c0008520>] (omap_intc_handle_irq) from [<c0409380>] (__irq_svc+0x40/0x74)
[  173.102508] Exception stack(0xc6f2ff58 to 0xc6f2ffa0)
[  173.111755] ff40:                                                       00000000 00000001
[  173.121154] ff60: 60000010 00000001 c6f2ffb0 00000000 ffffffff 10c5387d 00000000 c6f2e000
[  173.130554] ff80: 00000000 bea65b44 00000000 c6f2ffa0 c000dc20 c00104a0 20000113 ffffffff
[  173.140136] [<c0409380>] (__irq_svc) from [<c00104a0>] (do_work_pending+0x34/0xb4)
[  173.149902] [<c00104a0>] (do_work_pending) from [<c000dc20>] (work_pending+0xc/0x20)
[  173.159759] ---[ end trace 124b6fccc1bf5a71 ]---

-- 
Pali Rohár
pali.rohar@gmail.com

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