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On each sample, Monitor Mode Control Register A (MMCRA) content is
saved in pt_regs. MMCRA does not have a entry as-is in the pt_regs but
instead, MMCRA content is saved in the "dsisr" register of pt_regs.
Patch adds another entry to the perf_regs structure to include the
"MMCRA" printing which internally maps to the "dsisr" of pt_regs.
It also check for the MMCRA availability in the platform and present
value accordingly
mpe: This was the 2nd patch in a series with commit 333804dc3b7a
("powerpc/perf: Update perf_regs structure to include SIER") but I
accidentally only merged the 1st patch, so merge this one now.
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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On each sample, Sample Instruction Event Register (SIER) content
is saved in pt_regs. SIER does not have a entry as-is in the pt_regs
but instead, SIER content is saved in the "dar" register of pt_regs.
Patch adds another entry to the perf_regs structure to include the "SIER"
printing which internally maps to the "dar" of pt_regs.
It also check for the SIER availability in the platform and present
value accordingly
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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When a kthread calls call_usermodehelper() the steps are:
1. allocate current->mm
2. load_elf_binary()
3. populate current->thread.regs
While doing this, interrupts are not disabled. If there is a perf
interrupt in the middle of this process (i.e. step 1 has completed
but not yet reached to step 3) and if perf tries to read userspace
regs, kernel oops with following log:
Unable to handle kernel paging request for data at address 0x00000000
Faulting instruction address: 0xc0000000000da0fc
...
Call Trace:
perf_output_sample_regs+0x6c/0xd0
perf_output_sample+0x4e4/0x830
perf_event_output_forward+0x64/0x90
__perf_event_overflow+0x8c/0x1e0
record_and_restart+0x220/0x5c0
perf_event_interrupt+0x2d8/0x4d0
performance_monitor_exception+0x54/0x70
performance_monitor_common+0x158/0x160
--- interrupt: f01 at avtab_search_node+0x150/0x1a0
LR = avtab_search_node+0x100/0x1a0
...
load_elf_binary+0x6e8/0x15a0
search_binary_handler+0xe8/0x290
do_execveat_common.isra.14+0x5f4/0x840
call_usermodehelper_exec_async+0x170/0x210
ret_from_kernel_thread+0x5c/0x7c
Fix it by setting abi to PERF_SAMPLE_REGS_ABI_NONE when userspace
pt_regs are not set.
Fixes: ed4a4ef85cf5 ("powerpc/perf: Add support for sampling interrupt register state")
Cc: stable@vger.kernel.org # v4.7+
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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We are going to split <linux/sched/task_stack.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.
Create a trivial placeholder <linux/sched/task_stack.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.
Include the new header in the files that are going to need it.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The perf infrastructure uses a bit mask to find out valid registers to
display. Define a register mask for supported registers defined in
uapi/asm/perf_regs.h. The bit positions also correspond to register IDs
which is used by perf infrastructure to fetch the register values.
CONFIG_HAVE_PERF_REGS enables sampling of the interrupted machine state.
Signed-off-by: Anju T <anju@linux.vnet.ibm.com>
[mpe: Add license, use CONFIG_PPC64, fix 32-bit build]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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Madhavan Srinivasan
Ravi Bangoria
Ingo Molnar
Anju T