ACK: [Utopic/Trusty][SRU][PATCH] powerpc/pseries: Fix endiannes issue in RTAS call from xmon
Seth Forshee
seth.forshee at canonical.com
Mon Dec 8 17:35:26 UTC 2014
On Mon, Dec 08, 2014 at 10:53:50AM -0600, Chris J Arges wrote:
> From: Laurent Dufour <ldufour at linux.vnet.ibm.com>
>
> BugLink: http://bugs.launchpad.net/bugs/1396235
>
> On pseries system (LPAR) xmon failed to enter when running in LE mode,
> system is hunging. Inititating xmon will lead to such an output on the
> console:
>
> SysRq : Entering xmon
> cpu 0x15: Vector: 0 at [c0000003f39ffb10]
> pc: c00000000007ed7c: sysrq_handle_xmon+0x5c/0x70
> lr: c00000000007ed7c: sysrq_handle_xmon+0x5c/0x70
> sp: c0000003f39ffc70
> msr: 8000000000009033
> current = 0xc0000003fafa7180
> paca = 0xc000000007d75e80 softe: 0 irq_happened: 0x01
> pid = 14617, comm = bash
> Bad kernel stack pointer fafb4b0 at eca7cc4
> cpu 0x15: Vector: 300 (Data Access) at [c000000007f07d40]
> pc: 000000000eca7cc4
> lr: 000000000eca7c44
> sp: fafb4b0
> msr: 8000000000001000
> dar: 10000000
> dsisr: 42000000
> current = 0xc0000003fafa7180
> paca = 0xc000000007d75e80 softe: 0 irq_happened: 0x01
> pid = 14617, comm = bash
> cpu 0x15: Exception 300 (Data Access) in xmon, returning to main loop
> xmon: WARNING: bad recursive fault on cpu 0x15
>
> The root cause is that xmon is calling RTAS to turn off the surveillance
> when entering xmon, and RTAS is requiring big endian parameters.
>
> This patch is byte swapping the RTAS arguments when running in LE mode.
>
> Cc: stable at vger.kernel.org
> Signed-off-by: Laurent Dufour <ldufour at linux.vnet.ibm.com>
> Signed-off-by: Michael Ellerman <mpe at ellerman.id.au>
> (cherry picked from commit 3b8a3c01096925a824ed3272601082289d9c23a5)
> Signed-off-by: Chris J Arges <chris.j.arges at canonical.com>
Straightforward and an upstrem cherry pick, and no regression potential
for any other arches.
Acked-by: Seth Forshee <seth.forshee at canonical.com>
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