This code adds an in_nmi() macro that uses the current tasks preempt count
to track when it is in NMI context. Other parts of the kernel can
use this to determine if the context is in NMI context or not.
This code was inspired by the -rt patch in_nmi version that was
written by Peter Zijlstra, who borrowed that code from
Mathieu Desnoyers.
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: clean up
The in_nmi variable in x86 arch ftrace.c is a misnomer.
Andrew Morton pointed out that the in_nmi variable is incremented
by all CPUS. It can be set when another CPU is running an NMI.
Since this is actually intentional, the fix is to rename it to
what it really is: "nmi_running"
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
tracing_off() is the fastest way to stop recording to the ring buffers.
This may be used in places like panic and die, just before the
ftrace_dump is called.
This patch adds the appropriate CPP conditionals to make it a stub
function when the ring buffer is not configured it.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: prevent deadlock in NMI
The ring buffers are not yet totally lockless with writing to
the buffer. When a writer crosses a page, it grabs a per cpu spinlock
to protect against a reader. The spinlocks taken by a writer are not
to protect against other writers, since a writer can only write to
its own per cpu buffer. The spinlocks protect against readers that
can touch any cpu buffer. The writers are made to be reentrant
with the spinlocks disabling interrupts.
The problem arises when an NMI writes to the buffer, and that write
crosses a page boundary. If it grabs a spinlock, it can be racing
with another writer (since disabling interrupts does not protect
against NMIs) or with a reader on the same CPU. Luckily, most of the
users are not reentrant and protects against this issue. But if a
user of the ring buffer becomes reentrant (which is what the ring
buffers do allow), if the NMI also writes to the ring buffer then
we risk the chance of a deadlock.
This patch moves the ftrace_nmi_enter called by nmi_enter() to the
ring buffer code. It replaces the current ftrace_nmi_enter that is
used by arch specific code to arch_ftrace_nmi_enter and updates
the Kconfig to handle it.
When an NMI is called, it will set a per cpu variable in the ring buffer
code and will clear it when the NMI exits. If a write to the ring buffer
crosses page boundaries inside an NMI, a trylock is used on the spin
lock instead. If the spinlock fails to be acquired, then the entry
is discarded.
This bug appeared in the ftrace work in the RT tree, where event tracing
is reentrant. This workaround solved the deadlocks that appeared there.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: fix to prevent developers from using entry->cpu
With the new ring buffer infrastructure, the cpu for the entry is
implicit with which CPU buffer it is on.
The original code use to record the current cpu into the generic
entry header, which can be retrieved by entry->cpu. When the
ring buffer was introduced, the users were convert to use the
the cpu number of which cpu ring buffer was in use (this was passed
to the tracers by the iterator: iter->cpu).
Unfortunately, the cpu item in the entry structure was never removed.
This allowed for developers to use it instead of the proper iter->cpu,
unknowingly, using an uninitialized variable. This was not the fault
of the developers, since it would seem like the logical place to
retrieve the cpu identifier.
This patch removes the cpu item from the entry structure and fixes
all the users that should have been using iter->cpu.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
As they actually all return these enumerators.
Reported-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: bugfix and cleanup
Some callsites were returning either TRACE_ITER_PARTIAL_LINE if the
trace_seq routines (trace_seq_printf, etc) returned 0 meaning its buffer
was full, or zero otherwise.
But...
/* Return values for print_line callback */
enum print_line_t {
TRACE_TYPE_PARTIAL_LINE = 0, /* Retry after flushing the seq */
TRACE_TYPE_HANDLED = 1,
TRACE_TYPE_UNHANDLED = 2 /* Relay to other output functions */
};
In other cases the return value was not being relayed at all.
Most of the time it didn't hurt because the page wasn't get filled, but
for correctness sake, handle the return values everywhere.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/cooloney/blackfin-2.6: (40 commits)
Blackfin arch: Remove outdated code
Blackfin arch: Fix udelay implementation
Blackfin arch: Update Copyright information
Blackfin arch: Add BF561 PPI POLS, POLC Masks
Blackfin arch: Update CM-BF527 kernel config
Blackfin arch: define bfin_memmap as static since it is only used here
Blackfin arch: cplb mananger: use a do...while loop rather than a for loop
Blackfin arch: fix bug - traps test case 19 for exception 0x2d fails
Blackfin arch: add platform device bfin_mii-bus and KSZ8893M switch driver platform resources to board files
Blackfin arch: build jtag tty driver as a module by default
Blackfin arch: fix 2 bugs related to debug
Blackfin arch: Add ANOMALY_05000380 to BF54x to kill the compile warning
Blackfin arch: Fix bug - 561 SMP kernel can't boot from jffs2
Blackfin arch: base SIC_IWR# programming on whether the MMR exists
Blackfin arch: read SYSCR on newer parts that mirror the bits of SWRST in it
Blackfin arch: fixup board init function name
Blackfin arch: drop CONFIG_I2C_BOARDINFO ifdefs
Blackfin arch: bfin_reset->_bfin_reset redirection no longer needed
Blackfin arch: sync reboot handler with version in u-boot
Blackfin arch: Faster Implementation of csum_tcpudp_nofold()
...
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6:
sparc64: Kill bogus TPC/address truncation during 32-bit faults.
sparc: fixup for sparseirq changes
sparc64: Validate kernel generated fault addresses on sparc64.
sparc64: On non-Niagara, need to touch NMI watchdog in NOHZ mode.
sparc64: Implement NMI watchdog on capable cpus.
sparc: Probe PMU type and record in sparc_pmu_type.
sparc64: Move generic PCR support code to seperate file.
The removed version with the loop registers saved on the stack was
originally intended to workaround the missing toolchain support for
LoopReg Clobbers.
Since our toolchain now supports these there is no point in keeping this
workaround. And since we don't touch LoopRegs anymore we're no longer
subject for ANOMALY_05000312.
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Avoid possible overflow during 32*32->32 multiplies.
Reported-by: Marco Reppenhagen <marco.reppenhagen@auerswald.de>
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
use a do...while loop rather than a for loop to get slightly better
optimization and to avoid gcc "may be used uninitialized" warnings ...
we know that the [id]cplb_nr_bounds variables will never be 0, so this
is OK
Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Enable null pointer checking for ICPLBs. The code was there but for
some reason I had commented it out at some stage during development.
Should restrict this to 1K since atomic ops start there.
Signed-off-by: Bernd Schmidt <bernds_cb1@t-online.de>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
- unable to single step over emuexcpt instruction
- gdbproxy goes into infinite loop when doing gdb does "next" over
"emuexcpt"
Don't decrement PC after software breakpoint.
Signed-off-by: Jie Zhang <jie.zhang@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
bss_l2 section is garbage when the data in this section is used by
_bfin_relocate_l1_mem, so move the zero out function ahead.
Signed-off-by: Graf Yang <graf.yang@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
base SIC_IWR# programming on whether the MMR exists
rather than having to maintain another list of processors
Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Drop CONFIG_I2C_BOARDINFO ifdefs as the common i2c header handles this
already by stubbing things out
Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Avoid conditional branch instructions during carry bit additions.
Special thanks to Bernd.
Simplify: Use ((len + proto) << 8) like every other __LITTLE_ENDIAN__ machine
Cc: Bernd Schmidt <bernds_cb1@t-online.de>
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
[Mike Frysinger <vapier.adi@gmail.com>:
- setup P_DEFAULT_BOOT_SPI_CS for every arch based on
the default bootrom behavior and convert all our boards
to it
- revert previous anomaly change ... bf51x is not affected
by anomaly 05000353]
Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
remove subscribers-only marking as the list is
automatically & silently moderated for people
Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
merge more of the bf54x and !bf54x gpio code together to
cut down on #ifdef mess
Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
According to the documentation gpio_free should only be called from task
context only. To make this more explicit add a might sleep to all
implementations.
This patch changes the gpio_free implementations for the blackfin
architecture.
Signed-off-by: Uwe Kleine-Koenig <ukleinek@strlen.de>
Cc: David Brownell <david-b@pacbell.net>
Acked-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Make sure we don't accidently re-enable interrupts if we are being
called in atomic context
Signed-off-by: Robin Getz <rgetz@blackfin.uclinux.org>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
when requesting a GPIO for the first time, the POLAR setting is not
set to a sane state. this can lead to indeterminate behavior that
cannot be resolved without an explicit write to the Blackfin port POLAR
register.
when requesting a GPIO for the first time via gpio_request(), the POLAR
setting for the GPIO in question should be set to sane state. this
should occur if the GPIO has not been allocated in any other way.
some examples:
- when doing something like "request_irq(); gpio_request();" on the
same GPIO, the POLAR setting should not be reset.
- when doing "gpio_request(); gpio_request();" on the same GPIO, the
POLAR setting should be reset only the first time and not the second.
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
On BF561 EBIU_SDGCTL bit 31 controls the SDRAM external data
path width, typically set 0 for a 32-bit bus width. On other
Blackfin derivatives this bit should be set by default.
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Dmacopy failed in BF537-STAMP when copy from SRAM to SDRAM and kernel
will reboot automatically.
Fixing by doing a SSYNC before mucking with DMA registers
Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
