linux.git/arch/xtensa/kernel/traps.c, branch v3.17

xtensa: don't allow overflow/underflow on unaligned stack

2014-08-14T07:59:32+00:00

Double exceptions that happen during register window overflow/underflow
are handled in the topmost stack frame, as if it was the only exception
that occured. However unaligned access exception handler is special
because it needs to analyze instruction that caused the exception, but
the userspace instruction that triggered window exception is completely
irrelevant. Unaligned data access is rather normal in the generic
userspace code, but stack pointer manipulation must always be done by
architecture-aware code and thus unaligned stack means a serious problem
anyway.
Use the default unaligned access handler that raises SIGBUS in case
of unaligned access in window overflow/underflow handler.

Signed-off-by: Max Filippov

xtensa: implement CPU hotplug

2014-01-14T18:19:59+00:00

Signed-off-by: Max Filippov 
Signed-off-by: Chris Zankel

xtensa: add SMP support

2014-01-14T18:19:58+00:00

This is largely based on SMP code from the xtensa-2.6.29-smp tree by
Piet Delaney, Marc Gauthier, Joe Taylor, Christian Zankel (and possibly
other Tensilica folks).

Signed-off-by: Max Filippov 
Signed-off-by: Chris Zankel

xtensa: clean up do_interrupt/do_IRQ

2014-01-14T18:19:57+00:00

- set up irq registers and call irq_enter/irq_exit once for each kernel
  entry due to interrupt;
- don't attempt to clear current IRQ in the do_interrupt, IRQ handler
  will take care of it;
- find pending interrupt with highest priority before every ISR
  invocation.

Signed-off-by: Max Filippov 
Signed-off-by: Chris Zankel

Merge tag 'xtensa-next-20130508' of git://github.com/czankel/xtensa-linux

2013-05-09T21:38:16+00:00

Pull xtensa updates from Chris Zankel:
 "Support for the latest MMU architecture that allows for a larger
  accessible memory region, and various bug-fixes"

* tag 'xtensa-next-20130508' of git://github.com/czankel/xtensa-linux:
  xtensa: Switch to asm-generic/linkage.h
  xtensa: fix redboot load address
  xtensa: ISS: fix timer_lock usage in rs_open
  xtensa: disable IRQs while IRQ handler is running
  xtensa: enable lockdep support
  xtensa: fix arch_irqs_disabled_flags implementation
  xtensa: add irq flags trace support
  xtensa: provide custom CALLER_ADDR* implementations
  xtensa: add stacktrace support
  xtensa: clean up stpill_registers
  xtensa: don't use a7 in simcalls
  xtensa: don't attempt to use unconfigured timers
  xtensa: provide default platform_pcibios_init implementation
  xtensa: remove KCORE_ELF again
  xtensa: document MMUv3 setup sequence
  xtensa: add MMU v3 support
  xtensa: fix ibreakenable register update
  xtensa: fix oprofile building as module

xtensa: disable IRQs while IRQ handler is running

2013-05-09T08:07:11+00:00

IRQ handlers are expected to run with IRQs disabled.
See e.g. http://lwn.net/Articles/380931/ for a longer story.

This was overlooked in the commit
  2d1c645 xtensa: dispatch medium-priority interrupts
Revert to old behavior and simplify interrupt entry and exit code.
Interrupt handler still honours IRQ priority.

do_notify_resume/schedule must be called with interrupts enabled, enable
interrupts if we return from user exception.

Signed-off-by: Max Filippov 
Signed-off-by: Chris Zankel

xtensa: add stacktrace support

2013-05-09T08:07:10+00:00

Signed-off-by: Max Filippov 
Signed-off-by: Chris Zankel

dump_stack: unify debug information printed by show_regs()

2013-05-01T00:04:02+00:00

show_regs() is inherently arch-dependent but it does make sense to print
generic debug information and some archs already do albeit in slightly
different forms.  This patch introduces a generic function to print debug
information from show_regs() so that different archs print out the same
information and it's much easier to modify what's printed.

show_regs_print_info() prints out the same debug info as dump_stack()
does plus task and thread_info pointers.

* Archs which didn't print debug info now do.

  alpha, arc, blackfin, c6x, cris, frv, h8300, hexagon, ia64, m32r,
  metag, microblaze, mn10300, openrisc, parisc, score, sh64, sparc,
  um, xtensa

* Already prints debug info.  Replaced with show_regs_print_info().
  The printed information is superset of what used to be there.

  arm, arm64, avr32, mips, powerpc, sh32, tile, unicore32, x86

* s390 is special in that it used to print arch-specific information
  along with generic debug info.  Heiko and Martin think that the
  arch-specific extra isn't worth keeping s390 specfic implementation.
  Converted to use the generic version.

Note that now all archs print the debug info before actual register
dumps.

An example BUG() dump follows.

 kernel BUG at /work/os/work/kernel/workqueue.c:4841!
 invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
 Modules linked in:
 CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.9.0-rc1-work+ #7
 Hardware name: empty empty/S3992, BIOS 080011  10/26/2007
 task: ffff88007c85e040 ti: ffff88007c860000 task.ti: ffff88007c860000
 RIP: 0010:[]  [] init_workqueues+0x4/0x6
 RSP: 0000:ffff88007c861ec8  EFLAGS: 00010246
 RAX: ffff88007c861fd8 RBX: ffffffff824466a8 RCX: 0000000000000001
 RDX: 0000000000000046 RSI: 0000000000000001 RDI: ffffffff8234a07a
 RBP: ffff88007c861ec8 R08: 0000000000000000 R09: 0000000000000000
 R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff8234a07a
 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 FS:  0000000000000000(0000) GS:ffff88007dc00000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
 CR2: ffff88015f7ff000 CR3: 00000000021f1000 CR4: 00000000000007f0
 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
 Stack:
  ffff88007c861ef8 ffffffff81000312 ffffffff824466a8 ffff88007c85e650
  0000000000000003 0000000000000000 ffff88007c861f38 ffffffff82335e5d
  ffff88007c862080 ffffffff8223d8c0 ffff88007c862080 ffffffff81c47760
 Call Trace:
  [] do_one_initcall+0x122/0x170
  [] kernel_init_freeable+0x9b/0x1c8
  [] ? rest_init+0x140/0x140
  [] kernel_init+0xe/0xf0
  [] ret_from_fork+0x7c/0xb0
  [] ? rest_init+0x140/0x140
  ...

v2: Typo fix in x86-32.

v3: CPU number dropped from show_regs_print_info() as
    dump_stack_print_info() has been updated to print it.  s390
    specific implementation dropped as requested by s390 maintainers.

Signed-off-by: Tejun Heo 
Acked-by: David S. Miller 
Acked-by: Jesper Nilsson 
Cc: Heiko Carstens 
Cc: Martin Schwidefsky 
Cc: Bjorn Helgaas 
Cc: Fengguang Wu 
Cc: Mike Frysinger 
Cc: Vineet Gupta 
Cc: Sam Ravnborg 
Acked-by: Chris Metcalf 		[tile bits]
Acked-by: Richard Kuo 		[hexagon bits]
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

dump_stack: consolidate dump_stack() implementations and unify their behaviors

2013-05-01T00:04:02+00:00

Both dump_stack() and show_stack() are currently implemented by each
architecture.  show_stack(NULL, NULL) dumps the backtrace for the
current task as does dump_stack().  On some archs, dump_stack() prints
extra information - pid, utsname and so on - in addition to the
backtrace while the two are identical on other archs.

The usages in arch-independent code of the two functions indicate
show_stack(NULL, NULL) should print out bare backtrace while
dump_stack() is used for debugging purposes when something went wrong,
so it does make sense to print additional information on the task which
triggered dump_stack().

There's no reason to require archs to implement two separate but mostly
identical functions.  It leads to unnecessary subtle information.

This patch expands the dummy fallback dump_stack() implementation in
lib/dump_stack.c such that it prints out debug information (taken from
x86) and invokes show_stack(NULL, NULL) and drops arch-specific
dump_stack() implementations in all archs except blackfin.  Blackfin's
dump_stack() does something wonky that I don't understand.

Debug information can be printed separately by calling
dump_stack_print_info() so that arch-specific dump_stack()
implementation can still emit the same debug information.  This is used
in blackfin.

This patch brings the following behavior changes.

* On some archs, an extra level in backtrace for show_stack() could be
  printed.  This is because the top frame was determined in
  dump_stack() on those archs while generic dump_stack() can't do that
  reliably.  It can be compensated by inlining dump_stack() but not
  sure whether that'd be necessary.

* Most archs didn't use to print debug info on dump_stack().  They do
  now.

An example WARN dump follows.

 WARNING: at kernel/workqueue.c:4841 init_workqueues+0x35/0x505()
 Hardware name: empty
 Modules linked in:
 CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.9.0-rc1-work+ #9
  0000000000000009 ffff88007c861e08 ffffffff81c614dc ffff88007c861e48
  ffffffff8108f50f ffffffff82228240 0000000000000040 ffffffff8234a03c
  0000000000000000 0000000000000000 0000000000000000 ffff88007c861e58
 Call Trace:
  [] dump_stack+0x19/0x1b
  [] warn_slowpath_common+0x7f/0xc0
  [] warn_slowpath_null+0x1a/0x20
  [] init_workqueues+0x35/0x505
  ...

v2: CPU number added to the generic debug info as requested by s390
    folks and dropped the s390 specific dump_stack().  This loses %ksp
    from the debug message which the maintainers think isn't important
    enough to keep the s390-specific dump_stack() implementation.

    dump_stack_print_info() is moved to kernel/printk.c from
    lib/dump_stack.c.  Because linkage is per objecct file,
    dump_stack_print_info() living in the same lib file as generic
    dump_stack() means that archs which implement custom dump_stack()
    - at this point, only blackfin - can't use dump_stack_print_info()
    as that will bring in the generic version of dump_stack() too.  v1
    The v1 patch broke build on blackfin due to this issue.  The build
    breakage was reported by Fengguang Wu.

Signed-off-by: Tejun Heo 
Acked-by: David S. Miller 
Acked-by: Vineet Gupta 
Acked-by: Jesper Nilsson 
Acked-by: Vineet Gupta 
Acked-by: Martin Schwidefsky 	[s390 bits]
Cc: Heiko Carstens 
Cc: Mike Frysinger 
Cc: Fengguang Wu 
Cc: Bjorn Helgaas 
Cc: Sam Ravnborg 
Acked-by: Richard Kuo 		[hexagon bits]
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge tag 'xtensa-next-20130225' of git://github.com/czankel/xtensa-linux

2013-02-27T03:53:12+00:00

Pull xtensa update from Chris Zankel:
 "Added features:
   - add support for thread local storage (TLS)

   - add accept4 and finit_module syscalls

   - support medium-priority interrupts

   - add support for dc232c processor variant

   - support file-base simulated disk for ISS simulator

  Bug fixes:

   - fix return values returned by the str[n]cmp functions

   - avoid mmap cache aliasing

   - fix handling of 'windowed registers' in ptrace"

* tag 'xtensa-next-20130225' of git://github.com/czankel/xtensa-linux:
  xtensa: add accept4 syscall
  xtensa: add support for TLS
  xtensa: add missing include asm/uaccess.h to checksum.h
  xtensa: do not enable GENERIC_GPIO by default
  xtensa: complete ptrace handling of register windows
  xtensa: add support for oprofile
  xtensa: move spill_registers to traps.h
  xtensa: ISS: add host file-based simulated disk
  xtensa: fix str[n]cmp return value
  xtensa: avoid mmap cache aliasing
  xtensa: add finit_module syscall
  xtensa: pull signal definitions from signal-defs.h
  xtensa: fix ipc_parse_version selection
  xtensa: dispatch medium-priority interrupts
  xtensa: Add config files for Diamond 233L - Rev C processor variant
  xtensa: use new common dtc rule
  xtensa: rename prom_update_property to of_update_property