From: afzal mohammed <afzal.mohd.ma@gmail.com>
To: Vladimir Murzin <vladimir.murzin@arm.com>,
Russell King <linux@armlinux.org.uk>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>,
linux-arm-kernel@lists.infradead.org,
Alexandre Torgue <alexandre.torgue@st.com>
Subject: Regression: Cortex-M w/ XIP not booting
Date: Wed, 2 Oct 2019 11:46:37 +0530 [thread overview]
Message-ID: <20191002061637.GA7743@afzalpc> (raw)
Hi Vladimir,
After,
72cd4064fcca "NOMMU: Toggle only bits in EXC_RETURN we are really care of",
the no-MMU Vybrid Cortex-M4 is not booting, relevant logs at the end.
Looks like any Cortex-M with XIP enabled Kernel would have this issue,
i.e. all STM32 Cortex-M baords (STM32 maintainers CC'ed) as well as.
In the above commit, lr value is saved in data section in __v7m_setup,
but the data section is setup only later in __mmap_switched on an XIP
kernel, where it will overwrite the saved value of lr. This causes
reserved EXC_RETURN value resulting in the below.
Reverting the above change fixes the issue.
Regards
afzal
[ 0.801928] Run /init as init process
[ 0.829364]
[ 0.829364] Unhandled exception: IPSR = 00000006 LR = fffffff1
[ 0.836750] CPU: 0 PID: 1 Comm: init Not tainted 5.2.0-00002-gb5fa138a4b0d-dirty #41
[ 0.844523] Hardware name: Freescale Vybrid VF5xx/VF6xx (Device Tree)
[ 0.851001] PC is at 0x0
[ 0.853559] LR is at 0x0
[ 0.856127] pc : [<00000000>] lr : [<00000000>] psr: 4000000b
[ 0.862434] sp : 8e82dff8 ip : 8e82dfe0 fp : 00000000
[ 0.867697] r10: 8eb4ae40 r9 : 00000000 r8 : 00000000
[ 0.872958] r7 : 00000000 r6 : 00000000 r5 : 00000000 r4 : 00000000
[ 0.879523] r3 : 00000000 r2 : 00000000 r1 : 00000000 r0 : 00000000
[ 0.886076] xPSR: 4000000b
[ 0.888836] CPU: 0 PID: 1 Comm: init Not tainted 5.2.0-00002-gb5fa138a4b0d-dirty #41
[ 0.896612] Hardware name: Freescale Vybrid VF5xx/VF6xx (Device Tree)
[ 0.903177] [<0f0042d5>] (unwind_backtrace) from [<0f00354f>] (show_stack+0xb/0xc)
[ 0.910851] [<0f00354f>] (show_stack) from [<0f003d0f>] (__invalid_entry+0x4b/0x4c)
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next reply other threads:[~2019-10-02 6:16 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-02 6:16 afzal mohammed [this message]
2019-10-02 11:55 ` Regression: Cortex-M w/ XIP not booting Vladimir Murzin
2019-10-03 0:04 ` afzal mohammed
2019-10-03 11:43 ` Vladimir Murzin
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