Meelis Roos reported that kernels built with gcc-4.9 do not boot, we
eventually narrowed this down to only impacting machines using
UltraSPARC-III and derivitive cpus.
The crash happens right when the first user process is spawned:
[ 54.451346] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000004
[ 54.451346]
[ 54.571516] CPU: 1 PID: 1 Comm: init Not tainted 3.16.0-rc2-00211-gd7933ab #96
[ 54.666431] Call Trace:
[ 54.698453] [0000000000762f8c] panic+0xb0/0x224
[ 54.759071] [000000000045cf68] do_exit+0x948/0x960
[ 54.823123] [000000000042cbc0] fault_in_user_windows+0xe0/0x100
[ 54.902036] [0000000000404ad0] __handle_user_windows+0x0/0x10
[ 54.978662] Press Stop-A (L1-A) to return to the boot prom
[ 55.050713] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000004
Further investigation showed that compiling only per_cpu_patch() with
an older compiler fixes the boot.
Detailed analysis showed that the function is not being miscompiled by
gcc-4.9, but it is using a different register allocation ordering.
With the gcc-4.9 compiled function, something during the code patching
causes some of the %i* input registers to get corrupted. Perhaps
we have a TLB miss path into the firmware that is deep enough to
cause a register window spill and subsequent restore when we get
back from the TLB miss trap.
Let's plug this up by doing two things:
1) Stop using the firmware stack for client interface calls into
the firmware. Just use the kernel's stack.
2) As soon as we can, call into a new function "start_early_boot()"
to put a one-register-window buffer between the firmware's
deepest stack frame and the top-most initial kernel one.
Reported-by: Meelis Roos <mroos@linux.ee>
Tested-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: David S. Miller <davem@davemloft.net>
* 'next-devicetree' of git://git.secretlab.ca/git/linux-2.6: (29 commits)
of/flattree: forward declare struct device_node in of_fdt.h
ipmi: explicitly include of_address.h and of_irq.h
sparc: explicitly cast negative phandle checks to s32
powerpc/405: Fix missing #{address,size}-cells in i2c node
powerpc/5200: dts: refactor dts files
powerpc/5200: dts: Change combatible strings on localbus
powerpc/5200: dts: remove unused properties
powerpc/5200: dts: rename nodes to prepare for refactoring dts files
of/flattree: Update dtc to current mainline.
of/device: Don't register disabled devices
powerpc/dts: fix syntax bugs in bluestone.dts
of: Fixes for OF probing on little endian systems
of: make drivers depend on CONFIG_OF instead of CONFIG_PPC_OF
of/flattree: Add of_flat_dt_match() helper function
of_serial: explicitly include of_irq.h
of/flattree: Refactor unflatten_device_tree and add fdt_unflatten_tree
of/flattree: Reorder unflatten_dt_node
of/flattree: Refactor unflatten_dt_node
of/flattree: Add non-boottime device tree functions
of/flattree: Add Kconfig for EARLY_FLATTREE
...
Fix up trivial conflict in arch/sparc/prom/tree_32.c as per Grant.
When we switched sparc from using 'int's to 'phandle's (which is a u32), we
neglected to do anything with the various checks for -1. For those tests,
explicitly cast the phandles to s32.
Signed-off-by: Andres Salomon <dilinger@queued.net>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Rather than passing around ints everywhere, use the
phandle type where appropriate for the various functions
that talk to the PROM.
Signed-off-by: Andres Salomon <dilinger@queued.net>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
- all files with identical names copied and renamed to *_64.c
- the remaning files copied as is
- added sparc64 specific files to sparc/prom/Makefile
- teach sparc64 Makefile to look into sparc/prom/
- delete unused Makefile from sparc64/prom/
linking order was not kept for sparc64 with this change.
It was not possible to keep linking order for both sparc and sparc64
and as sparc64 see more testing than sparc it was natural to
break linking order on sparc64. Should it have any effect it
would be detected sooner this way.
printf_32.c and printf_64.c are obvious candidates to be merged
but they are not 100% equal so that was left for later
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
David S. Miller
Geert Uytterhoeven
Linus Torvalds
Andres Salomon
Sam Ravnborg