The modification of code is performed either by kstop_machine, before
SMP starts, or on module code before the module is executed. There is
no reason to do the modifications from assembly. The copy to and from
user functions are sufficient and produces cleaner and easier to read
code.

Thanks to Benjamin Herrenschmidt for suggesting the idea.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Mathieu Desnoyers revealed a bug in the original code. The nop that is
used to relpace the mcount caller can be a two part nop. This runs the
risk where a process can be preempted after executing the first nop, but
before the second part of the nop.

The ftrace code calls kstop_machine to keep multiple CPUs from executing
code that is being modified, but it does not protect against a task preempting
in the middle of a two part nop.

If the above preemption happens and the tracer is enabled, after the
kstop_machine runs, all those nops will be calls to the trace function.
If the preempted process that was preempted between the two nops is executed
again, it will execute half of the call to the trace function, and this
might crash the system.

This patch instead uses what both the latest Intel and AMD spec suggests.
That is the P6_NOP5 sequence of "0x0f 0x1f 0x44 0x00 0x00".

Note, some older CPUs and QEMU might fault on this nop, so this nop
is executed with fault handling first. If it detects a fault, it will then
use the code "0x66 0x66 0x66 0x66 0x90". If that faults, it will then
default to a simple "jmp 1f; .byte 0x00 0x00 0x00; 1:". The jmp is
not optimal but will do if the first two can not be executed.

TODO: Examine the cpuid to determine the nop to use.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

x86 now sets up the mcount locations through the build and no longer
needs to record the ip when the function is executed. This patch changes
the initial mcount to simply return. There's no need to do any other work.
If the ftrace start up test fails, the original mcount will be what everything
will use, so having this as fast as possible is a good thing.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Enable the use of the __mcount_loc infrastructure on x86_64 and i386.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

it can be called in the NMI path:

[    0.645999] calling  ftrace_dynamic_init+0x0/0xd6
[    0.647521] ------------[ cut here ]------------
[    0.647521] WARNING: at kernel/trace/ftrace.c:348 ftrace_record_ip+0x4e/0x252()
[    0.647521] Modules linked in:
[    0.647521] Pid: 15, comm: kstop1 Not tainted 2.6.27-rc1-tip #22686
[    0.647521]
[    0.647521] Call Trace:
[    0.647521]  <NMI>  [<ffffffff8024593f>] warn_on_slowpath+0x5d/0x84
[    0.647521]  [<ffffffff80220b99>] ? lapic_wd_event+0xb/0x5c
[    0.647521]  [<ffffffff80287b3b>] ftrace_record_ip+0x4e/0x252
[    0.647521]  [<ffffffff80211274>] mcount_call+0x5/0x31
[    0.647521]  [<ffffffff80220b9e>] ? lapic_wd_event+0x10/0x5c
[    0.647521]  [<ffffffff8083f3ec>] nmi_watchdog_tick+0x19d/0x1ad
[    0.647521]  [<ffffffff8083e875>] default_do_nmi+0x75/0x1e3
[    0.647521]  [<ffffffff8083f0b3>] do_nmi+0x5d/0x94
[    0.647521]  [<ffffffff8083e2d2>] nmi+0xa2/0xc2
[    0.647521]  [<ffffffff802b48c3>] ? check_bytes_and_report+0x11/0xcc
[    0.647521]  <<EOE>>  [<ffffffff80211274>] ? mcount_call+0x5/0x31
[    0.647521]  [<ffffffff802b49df>] check_object+0x61/0x1b0
[    0.647521]  [<ffffffff802b502a>] __slab_free+0x169/0x2ae
[    0.647521]  [<ffffffff80242dbf>] ? __cleanup_sighand+0x25/0x27
[    0.647521]  [<ffffffff80242dbf>] ? __cleanup_sighand+0x25/0x27
[    0.647521]  [<ffffffff802b60cd>] kmem_cache_free+0x85/0xb9
[    0.647521]  [<ffffffff80242dbf>] __cleanup_sighand+0x25/0x27
[    0.647521]  [<ffffffff80247b3d>] release_task+0x256/0x339
[    0.647521]  [<ffffffff802490b4>] do_exit+0x764/0x7ef
[    0.647521]  [<ffffffff8027624c>] __xchg+0x0/0x38
[    0.647521]  [<ffffffff8027619a>] ? stop_cpu+0x0/0xb2
[    0.647521]  [<ffffffff8027619a>] ? stop_cpu+0x0/0xb2
[    0.647521]  [<ffffffff8025922f>] kthread+0x4e/0x7b
[    0.647521]  [<ffffffff80212979>] child_rip+0xa/0x11
[    0.647521]  [<ffffffff80211c17>] ? restore_args+0x0/0x30
[    0.647521]  [<ffffffff802283a5>] ? native_load_tls+0x14/0x2e
[    0.647521]  [<ffffffff802591e1>] ? kthread+0x0/0x7b
[    0.647521]  [<ffffffff8021296f>] ? child_rip+0x0/0x11
[    0.647521]
[    0.647521] ---[ end trace 4eaa2a86a8e2da22 ]---
[    0.672032] initcall ftrace_dynamic_init+0x0/0xd6 returned 0 after 19 msecs

also mark it no-kprobes while at it.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

When SIL, DIL, BPL or SPL registers were used in MMIO, the datum
was extracted from AH, BH, CH, or DH, which are incorrect.
Signed-off-by: NPekka Paalanen <pq@iki.fi>
Cc: "Vegard Nossum" <vegard.nossum@gmail.com>
Cc: "Steven Rostedt" <srostedt@redhat.com>
Cc: proski@gnu.org
Cc: "Pekka Enberg"
	<penberg@cs.helsinki.fi>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This requires three changes:

1) Remove !SPARC restriction in Kconfig.

2) Move Sparc specific serial drivers before 8250, so that serial
   console devices don't change names on us, even if 8250 finds
   devices.

3) Since the Sparc specific serial drivers try to use the
   same major/minor device namespace as 8250, some coordination
   is necessary.  Use the sunserial_*() layer routines to allocate
   minor number space within TTY_MAJOR when CONFIG_SPARC.

   This has no effect on other platforms.

Thanks to Josip Rodin for bringing up this issue and testing
plus debugging various revisions of this patch.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NSonic Zhang <sonic.zhang@analog.com>
Signed-off-by: NBryan Wu <cooloney@kernel.org>
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We now use the sir_dev/irtty_sir/uart/bfin_serial drivers framework
to monitor the TX status.
Signed-off-by: NGraf Yang <graf.yang@analog.com>
Signed-off-by: NBryan Wu <cooloney@kernel.org>
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

move common variables out of serial headers and into the serial driver and
rename "nr_ports" to "nr_active_ports" so as to easily differentiate
between BFIN_UART_NR_PORTS (the # of available) and nr_ports (the # of enabled)
Signed-off-by: NMike Frysinger <vapier.adi@gmail.com>
Signed-off-by: NBryan Wu <cooloney@kernel.org>
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

so we could remove the requirement that one needs to call
early_iounmap() in exactly reverse order of early_ioremap().
Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NJan Beulich <jbeulich@novell.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

After "dumpstack: x86: various small unification steps", the
assembler gives the following compile error. The error is in
dumpstack_64.c.

{standard input}: Assembler messages:
{standard input}:720: Error: Incorrect register `%rbx' used with `l' suffix
{standard input}:1340: Error: Incorrect register `%r12' used with `l' suffix

Indeed the suffix in get_bp() was wrong.
Signed-off-by: NAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

remove remainder of additional_cpus logic. We now just listen to the
disabled_cpus value like we did for years. disabled_cpus is always >=
0 so no need for an extra check.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

additional_cpus=<x> parameter is dangerous and broken: for example
if we boot additional_cpus=-2 on a stock dual-core system it will
crash the box on bootup.

So reduce the maze of code a bit by removingthe user-configurability
angle.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

num_possible_cpus() can be > 1 when disabled CPUs have been accounted.

Disabled CPUs are not in the cpu_present_map, so we can use
num_present_cpus() as a safe indicator to switch to UP alternatives.
Reported-by: NChuck Ebbert <cebbert@redhat.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: <stable@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

- define STACKSLOTS_PER_LINE and use it
 - define get_bp macro to hide the %%ebp/%%rbp difference
 - i386: check task==NULL in dump_trace, like x86_64
 - i386: show_trace(NULL, ...) uses current automatically
 - x86_64: use [#%d] for die_counter, like i386
 - whitespace and comments
Signed-off-by: NAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

- make kstack= and early_param
 - add oops=panic, setting panic_on_oops
Signed-off-by: NAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

- x86: Write log_lvl strings if available
 - start raw stack dumps on new line
 - i386: Remove extra indentation for raw stack dumps
Signed-off-by: NAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

- i386 and x86_64: always printk the 'data' parameter
 - i386: announce stack switch (irq -> normal)
 - i386: check if there is a stack switch before announcing it

There is a warning that 'context' might come out corrupt in early
boot. If this is true it should be fixed, not worked around.
Signed-off-by: NAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

- Add "end" parameter to valid_stack_ptr and print_context_stack
 - use sizeof(long) as the size of a word on the stack
Signed-off-by: NAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

- x86_64: use %p to print an address
 - make i386-version the same as the above

The result should be the same on x86_64; on i386 the
output only changes if CONFIG_KALLSYMS is turned off,
in which case the address is printed twice.
Signed-off-by: NAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

For some reason die_nmi is still defined in traps.c for
i386, but is found in dumpstack_64.c for x86_64. Move it
to dumpstack_32.c
Signed-off-by: NAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

traps_32.c and traps_64.c are now equal. Move one to traps.c,
delete the other one and change the Makefile
Signed-off-by: NAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Use CONFIG_X86_64/CONFIG_X86_32 to condtionally compile the
parts needed for x86_64 or i386 only.

Runs a small userspace for a number of minimal configurations
and boots the defconfigs.
Signed-off-by: NAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

- reordering include files
 - whitespace changes
 - comment changes
 - removed unused bad_intr()
 - make default_do_nmi static
Signed-off-by: NAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Use task_pid_nr(tsk) instead of tsk->pid in do_general_protection.
Signed-off-by: NAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

This is the last user of clear_mem_error, which is defined
only on i386. Expand the inline function and remove it from
include/asm-x86/mach-default/mach_traps.h
Signed-off-by: NAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Make io_check_error equal to the one on i386.
Signed-off-by: NAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Use preempt_conditional_sti/cli in do_int3, like on x86_64.
Signed-off-by: NAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

- rename variable me -> tsk
 - get thread and tsk like i386
 - expand used_math()
 - copy comment
Signed-off-by: NAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

- set_system_gate on i386 is really set_system_trap_gate
 - set_system_gate on x86_64 is really set_system_intr_gate
 - ist=0 means no special stack switch is done:
	- introduce STACKFAULT_STACK, DOUBLEFAULT_STACK, NMI_STACK,
		DEBUG_STACK and MCE_STACK as on x86_64.
	- use the _ist variants with XXX_STACK set to zero
 - remove set_system_gate
Signed-off-by: NAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

traps: x86: correct copy/paste bug: a trap is a GATE_TRAP

Fix copy/paste/forgot-to-edit bug in desc.h.
Signed-off-by: NAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Make the x86_64-version and the i386-version of do_debug
more similar.

 - introduce preempt_conditional_sti/cli to i386. The preempt-count
	is now elevated during the trap handler, like on x86_64. It
	does not run on a separate stack, however.
 - replace an open-coded "send_sigtrap"
 - copy some comments
Signed-off-by: NAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Mark the exception handlers with "dotraplinkage" to hide the
calling convention differences between i386 and x86_64.
Signed-off-by: NAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

x86_64 does not do the lazy io-bitmap dance. Putting it in
its own function makes i386's do_general_protection look
much more like x86_64's.
Signed-off-by: NAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Split out math_error from do_coprocessor_error and simd_math_error
from do_simd_coprocessor_error, like on i386. While at it, add the
"error_code" parameter to do_coprocessor_error, do_simd_coprocessor_error
and do_spurious_interrupt_bug.

This does not change the generated code, but brings the declarations in
line with all the other trap handlers.
Signed-off-by: NAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The dumpstack code is logically quite independent from the
hardware traps. Split it out into its own file.
Signed-off-by: NAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The dumpstack code is logically quite independent from the
hardware traps. Split it out into its own file.
Signed-off-by: NAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

virt_addr_valid() calls __pa(), which calls __phys_addr(). With
CONFIG_DEBUG_VIRTUAL=y, __phys_addr() will kill the kernel if the
address *isn't* valid. That's clearly wrong for virt_addr_valid().

We also incorporate the debugging checks into virt_addr_valid().
Signed-off-by: NVegard Nossum <vegardno@ben.ifi.uio.no>
Acked-by: NJiri Slaby <jirislaby@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>