While testing cpu hoptlug (cpu down and up in loops) on kernel 4.4, it was
observed that occasionally check for cpu online will fail in kernel/cpu.c,
_cpu_up:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/tree/kernel/cpu.c?h=v4.4.79#n485
518 /* Arch-specific enabling code. */
519 ret = __cpu_up(cpu, idle);
520
521 if (ret != 0)
522 goto out_notify;
523 BUG_ON(!cpu_online(cpu));
Reason is race between start_secondary and _cpu_up. cpu_callin_map is set
before cpu_online_mask. In __cpu_up, cpu_callin_map is waited for, but cpu
online mask is not, resulting in race in which secondary processor started
and set cpu_callin_map, but not yet set the online mask,resulting in above
BUG being hit.
Upstream differs in the area. cpu_online check is in bringup_wait_for_ap,
which is after cpu reached AP_ONLINE_IDLE,where secondary passed its start
function. Nonetheless, fix makes start_secondary safe and not depending on
other locks throughout the code. It protects as well against cpu_online
checks put in between sometimes in the future.
Fix this by moving completion after all flags are set.
Signed-off-by: Matija Glavinic Pecotic <matija.glavinic-pecotic.ext@nokia.com>
Cc: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16925/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Pull MIPS updates from Ralf Baechle:
"Boston platform support:
- Document DT bindings
- Add CLK driver for board clocks
CM:
- Avoid per-core locking with CM3 & higher
- WARN on attempt to lock invalid VP, not BUG
CPS:
- Select CONFIG_SYS_SUPPORTS_SCHED_SMT for MIPSr6
- Prevent multi-core with dcache aliasing
- Handle cores not powering down more gracefully
- Handle spurious VP starts more gracefully
DSP:
- Add lwx & lhx missaligned access support
eBPF:
- Add MIPS support along with many supporting change to add the
required infrastructure
Generic arch code:
- Misc sysmips MIPS_ATOMIC_SET fixes
- Drop duplicate HAVE_SYSCALL_TRACEPOINTS
- Negate error syscall return in trace
- Correct forced syscall errors
- Traced negative syscalls should return -ENOSYS
- Allow samples/bpf/tracex5 to access syscall arguments for sane
traces
- Cleanup from old Kconfig options in defconfigs
- Fix PREF instruction usage by memcpy for MIPS R6
- Fix various special cases in the FPU eulation
- Fix some special cases in MIPS16e2 support
- Fix MIPS I ISA /proc/cpuinfo reporting
- Sort MIPS Kconfig alphabetically
- Fix minimum alignment requirement of IRQ stack as required by
ABI / GCC
- Fix special cases in the module loader
- Perform post-DMA cache flushes on systems with MAARs
- Probe the I6500 CPU
- Cleanup cmpxchg and add support for 1 and 2 byte operations
- Use queued read/write locks (qrwlock)
- Use queued spinlocks (qspinlock)
- Add CPU shared FTLB feature detection
- Handle tlbex-tlbp race condition
- Allow storing pgd in C0_CONTEXT for MIPSr6
- Use current_cpu_type() in m4kc_tlbp_war()
- Support Boston in the generic kernel
Generic platform:
- yamon-dt: Pull YAMON DT shim code out of SEAD-3 board
- yamon-dt: Support > 256MB of RAM
- yamon-dt: Use serial* rather than uart* aliases
- Abstract FDT fixup application
- Set RTC_ALWAYS_BCD to 0
- Add a MAINTAINERS entry
core kernel:
- qspinlock.c: include linux/prefetch.h
Loongson 3:
- Add support
Perf:
- Add I6500 support
SEAD-3:
- Remove GIC timer from DT
- Set interrupt-parent per-device, not at root node
- Fix GIC interrupt specifiers
SMP:
- Skip IPI setup if we only have a single CPU
VDSO:
- Make comment match reality
- Improvements to time code in VDSO"
* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: (86 commits)
locking/qspinlock: Include linux/prefetch.h
MIPS: Fix MIPS I ISA /proc/cpuinfo reporting
MIPS: Fix minimum alignment requirement of IRQ stack
MIPS: generic: Support MIPS Boston development boards
MIPS: DTS: img: Don't attempt to build-in all .dtb files
clk: boston: Add a driver for MIPS Boston board clocks
dt-bindings: Document img,boston-clock binding
MIPS: Traced negative syscalls should return -ENOSYS
MIPS: Correct forced syscall errors
MIPS: Negate error syscall return in trace
MIPS: Drop duplicate HAVE_SYSCALL_TRACEPOINTS select
MIPS16e2: Provide feature overrides for non-MIPS16 systems
MIPS: MIPS16e2: Report ASE presence in /proc/cpuinfo
MIPS: MIPS16e2: Subdecode extended LWSP/SWSP instructions
MIPS: MIPS16e2: Identify ASE presence
MIPS: VDSO: Fix a mismatch between comment and preprocessor constant
MIPS: VDSO: Add implementation of gettimeofday() fallback
MIPS: VDSO: Add implementation of clock_gettime() fallback
MIPS: VDSO: Fix conversions in do_monotonic()/do_monotonic_coarse()
MIPS: Use current_cpu_type() in m4kc_tlbp_war()
...
Correct a commit 515a6393db ("MIPS: kernel: proc: Add MIPS R6 support
to /proc/cpuinfo") regression that caused MIPS I systems to show no ISA
levels supported in /proc/cpuinfo, e.g.:
system type : Digital DECstation 2100/3100
machine : Unknown
processor : 0
cpu model : R3000 V2.0 FPU V2.0
BogoMIPS : 10.69
wait instruction : no
microsecond timers : no
tlb_entries : 64
extra interrupt vector : no
hardware watchpoint : no
isa :
ASEs implemented :
shadow register sets : 1
kscratch registers : 0
package : 0
core : 0
VCED exceptions : not available
VCEI exceptions : not available
and similarly exclude `mips1' from the ISA list for any processors below
MIPSr1. This is because the condition to show `mips1' on has been made
`cpu_has_mips_r1' rather than newly-introduced `cpu_has_mips_1'. Use
the correct condition then.
Fixes: 515a6393db ("MIPS: kernel: proc: Add MIPS R6 support to /proc/cpuinfo")
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: stable@vger.kernel.org # 3.19+
Patchwork: https://patchwork.linux-mips.org/patch/16758/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
If a negative system call number is used when system call tracing is
enabled, syscall_trace_enter() will return that negative system call
number without having written the return value and error flag into the
pt_regs.
The caller then treats it as a cancelled system call and assumes that
the return value and error flag are already written, leaving the
negative system call number in the return register ($v0), and the 4th
system call argument in the error register ($a3).
Add a special case to detect this at the end of syscall_trace_enter(),
to set the return value to error -ENOSYS when this happens.
Fixes: d218af7849 ("MIPS: scall: Always run the seccomp syscall filters")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16653/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The sys_exit trace event takes a single return value for the system
call, which MIPS passes the value of the $v0 (result) register, however
MIPS returns positive error codes in $v0 with $a3 specifying that $v0
contains an error code. As a result erroring system calls are traced
returning positive error numbers that can't always be distinguished from
success.
Use regs_return_value() to negate the error code if $a3 is set.
Fixes: 1d7bf993e0 ("MIPS: ftrace: Add support for syscall tracepoints.")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: <stable@vger.kernel.org> # 3.13+
Patchwork: https://patchwork.linux-mips.org/patch/16651/
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Only now that both feature determination and unaligned emulation is in
place add reporting to /proc/cpuinfo, so that the presence of "mips16e2"
there not only indicates our recognition of the hardware feature, but
correct unaligned emulation as well.
Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16757/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Implement extended LWSP/SWSP instruction subdecoding for the purpose of
unaligned GP-relative memory access emulation.
With the introduction of the MIPS16e2 ASE[1] the previously must-be-zero
3-bit field at bits 7..5 of the extended encodings of the instructions
selected with the LWSP and SWSP major opcodes has become a `sel' field,
acting as an opcode extension for additional operations. In both cases
the `sel' value of 0 has retained the original operation, that is:
LW rx, offset(sp)
and:
SW rx, offset(sp)
for LWSP and SWSP respectively. In hardware predating the MIPS16e2 ASE
other values may or may not have been decoded, architecturally yielding
unpredictable results, and in our unaligned memory access emulation we
have treated the 3-bit field as a don't-care, that is effectively making
all the possible encodings of the field alias to the architecturally
defined encoding of 0.
For the non-zero values of the `sel' field the MIPS16e2 ASE has in
particular defined these GP-relative operations:
LW rx, offset(gp) # sel = 1
LH rx, offset(gp) # sel = 2
LHU rx, offset(gp) # sel = 4
and
SW rx, offset(gp) # sel = 1
SH rx, offset(gp) # sel = 2
for LWSP and SWSP respectively, which will trap with an Address Error
exception if the effective address calculated is not naturally-aligned
for the operation requested. These operations have been selected for
unaligned access emulation, for consistency with the corresponding
regular MIPS and microMIPS operations.
For other non-zero values of the `sel' field the MIPS16e2 ASE has
defined further operations, which however either never trap with an
Address Error exception, such as LWL or GP-relative SB, or are not
supposed to be emulated, such as LL or SC. These operations have been
selected to exclude from unaligned access emulation, should an Address
Error exception ever happen with them.
Subdecode the `sel' field in unaligned access emulation then for the
extended encodings of the instructions selected with the LWSP and SWSP
major opcodes, whenever support for the MIPS16e2 ASE has been detected
in hardware, and either emulate the operation requested or send SIGBUS
to the originating process, according to the selection described above.
For hardware implementing the MIPS16 ASE, however lacking MIPS16e2 ASE
support retain the original interpretation of the `sel' field.
The effects of this change are illustrated with the following user
program:
$ cat mips16e2-test.c
#include <inttypes.h>
#include <stdio.h>
int main(void)
{
int64_t scratch[16] = { 0 };
int32_t *tmp0, *tmp1, *tmp2;
int i;
scratch[0] = 0xc8c7c6c5c4c3c2c1;
scratch[1] = 0xd0cfcecdcccbcac9;
asm volatile(
"move %0, $sp\n\t"
"move %1, $gp\n\t"
"move $sp, %4\n\t"
"addiu %2, %4, 8\n\t"
"move $gp, %2\n\t"
"lw %2, 2($sp)\n\t"
"sw %2, 16(%4)\n\t"
"lw %2, 2($gp)\n\t"
"sw %2, 24(%4)\n\t"
"lw %2, 1($sp)\n\t"
"sw %2, 32(%4)\n\t"
"lh %2, 1($gp)\n\t"
"sw %2, 40(%4)\n\t"
"lw %2, 3($sp)\n\t"
"sw %2, 48(%4)\n\t"
"lhu %2, 3($gp)\n\t"
"sw %2, 56(%4)\n\t"
"lw %2, 0(%4)\n\t"
"sw %2, 66($sp)\n\t"
"lw %2, 8(%4)\n\t"
"sw %2, 82($gp)\n\t"
"lw %2, 0(%4)\n\t"
"sw %2, 97($sp)\n\t"
"lw %2, 8(%4)\n\t"
"sh %2, 113($gp)\n\t"
"move $gp, %1\n\t"
"move $sp, %0"
: "=&d" (tmp0), "=&d" (tmp1), "=&d" (tmp2), "=m" (scratch)
: "d" (scratch));
for (i = 0; i < sizeof(scratch) / sizeof(*scratch); i += 2)
printf("%016" PRIx64 "\t%016" PRIx64 "\n",
scratch[i], scratch[i + 1]);
return 0;
}
$
to be compiled with:
$ gcc -mips16 -mips32r2 -Wa,-mmips16e2 -o mips16e2-test mips16e2-test.c
$
With 74Kf hardware, which does not implement the MIPS16e2 ASE, this
program produces the following output:
$ ./mips16e2-test
c8c7c6c5c4c3c2c1 d0cfcecdcccbcac9
00000000c6c5c4c3 00000000c6c5c4c3
00000000c5c4c3c2 00000000c5c4c3c2
00000000c7c6c5c4 00000000c7c6c5c4
0000c4c3c2c10000 0000000000000000
0000cccbcac90000 0000000000000000
000000c4c3c2c100 0000000000000000
000000cccbcac900 0000000000000000
$
regardless of whether the change has been applied or not.
With the change not applied and interAptive MR2 hardware[2], which does
implement the MIPS16e2 ASE, it produces the following output:
$ ./mips16e2-test
c8c7c6c5c4c3c2c1 d0cfcecdcccbcac9
00000000c6c5c4c3 00000000cecdcccb
00000000c5c4c3c2 00000000cdcccbca
00000000c7c6c5c4 00000000cfcecdcc
0000c4c3c2c10000 0000000000000000
0000000000000000 0000cccbcac90000
000000c4c3c2c100 0000000000000000
0000000000000000 000000cccbcac900
$
which shows that for GP-relative operations the correct trapping address
calculated from $gp has been obtained from the CP0 BadVAddr register and
so has data from the source operand, however masking and extension has
not been applied for halfword operations.
With the change applied and interAptive MR2 hardware the program
produces the following output:
$ ./mips16e2-test
c8c7c6c5c4c3c2c1 d0cfcecdcccbcac9
00000000c6c5c4c3 00000000cecdcccb
00000000c5c4c3c2 00000000ffffcbca
00000000c7c6c5c4 000000000000cdcc
0000c4c3c2c10000 0000000000000000
0000000000000000 0000cccbcac90000
000000c4c3c2c100 0000000000000000
0000000000000000 0000000000cac900
$
as expected.
References:
[1] "MIPS32 Architecture for Programmers: MIPS16e2 Application-Specific
Extension Technical Reference Manual", Imagination Technologies
Ltd., Document Number: MD01172, Revision 01.00, April 26, 2016
[2] "MIPS32 interAptiv Multiprocessing System Software User's Manual",
Imagination Technologies Ltd., Document Number: MD00904, Revision
02.01, June 15, 2016, Chapter 24 "MIPS16e Application-Specific
Extension to the MIPS32 Instruction Set", pp. 871-883
Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16095/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Identify the presence of the MIPS16e2 ASE as per the architecture
specification[1], by checking for CP0 Config5.CA2 bit being 1[2].
References:
[1] "MIPS32 Architecture for Programmers: MIPS16e2 Application-Specific
Extension Technical Reference Manual", Imagination Technologies
Ltd., Document Number: MD01172, Revision 01.00, April 26, 2016,
Section 1.2 "Software Detection of the ASE", p. 5
[2] "MIPS32 interAptiv Multiprocessing System Software User's Manual",
Imagination Technologies Ltd., Document Number: MD00904, Revision
02.01, June 15, 2016, Section 2.2.1.6 "Device Configuration 5 --
Config5 (CP0 Register 16, Select 5)", pp. 71-72
Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16094/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Pull SMP hotplug updates from Thomas Gleixner:
"This update is primarily a cleanup of the CPU hotplug locking code.
The hotplug locking mechanism is an open coded RWSEM, which allows
recursive locking. The main problem with that is the recursive nature
as it evades the full lockdep coverage and hides potential deadlocks.
The rework replaces the open coded RWSEM with a percpu RWSEM and
establishes full lockdep coverage that way.
The bulk of the changes fix up recursive locking issues and address
the now fully reported potential deadlocks all over the place. Some of
these deadlocks have been observed in the RT tree, but on mainline the
probability was low enough to hide them away."
* 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (37 commits)
cpu/hotplug: Constify attribute_group structures
powerpc: Only obtain cpu_hotplug_lock if called by rtasd
ARM/hw_breakpoint: Fix possible recursive locking for arch_hw_breakpoint_init
cpu/hotplug: Remove unused check_for_tasks() function
perf/core: Don't release cred_guard_mutex if not taken
cpuhotplug: Link lock stacks for hotplug callbacks
acpi/processor: Prevent cpu hotplug deadlock
sched: Provide is_percpu_thread() helper
cpu/hotplug: Convert hotplug locking to percpu rwsem
s390: Prevent hotplug rwsem recursion
arm: Prevent hotplug rwsem recursion
arm64: Prevent cpu hotplug rwsem recursion
kprobes: Cure hotplug lock ordering issues
jump_label: Reorder hotplug lock and jump_label_lock
perf/tracing/cpuhotplug: Fix locking order
ACPI/processor: Use cpu_hotplug_disable() instead of get_online_cpus()
PCI: Replace the racy recursion prevention
PCI: Use cpu_hotplug_disable() instead of get_online_cpus()
perf/x86/intel: Drop get_online_cpus() in intel_snb_check_microcode()
x86/perf: Drop EXPORT of perf_check_microcode
...
Since commit 81a76d7119 ("MIPS: Avoid using unwind_stack() with
usermode") show_backtrace() invokes the raw backtracer when
cp0_status & ST0_KSU indicates user mode to fix issues on EVA kernels
where user and kernel address spaces overlap.
However this is used by show_stack() which creates its own pt_regs on
the stack and leaves cp0_status uninitialised in most of the code paths.
This results in the non deterministic use of the raw back tracer
depending on the previous stack content.
show_stack() deals exclusively with kernel mode stacks anyway, so
explicitly initialise regs.cp0_status to KSU_KERNEL (i.e. 0) to ensure
we get a useful backtrace.
Fixes: 81a76d7119 ("MIPS: Avoid using unwind_stack() with usermode")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: <stable@vger.kernel.org> # 3.15+
Patchwork: https://patchwork.linux-mips.org/patch/16656/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
When the scheduler sets TIF_NEED_RESCHED & we call into the scheduler
from arch/mips/kernel/entry.S we disable interrupts. This is true
regardless of whether we reach work_resched from syscall_exit_work,
resume_userspace or by looping after calling schedule(). Although we
disable interrupts in these paths we don't call trace_hardirqs_off()
before calling into C code which may acquire locks, and we therefore
leave lockdep with an inconsistent view of whether interrupts are
disabled or not when CONFIG_PROVE_LOCKING & CONFIG_DEBUG_LOCKDEP are
both enabled.
Without tracing this interrupt state lockdep will print warnings such
as the following once a task returns from a syscall via
syscall_exit_partial with TIF_NEED_RESCHED set:
[ 49.927678] ------------[ cut here ]------------
[ 49.934445] WARNING: CPU: 0 PID: 1 at kernel/locking/lockdep.c:3687 check_flags.part.41+0x1dc/0x1e8
[ 49.946031] DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)
[ 49.946355] CPU: 0 PID: 1 Comm: init Not tainted 4.10.0-00439-gc9fd5d362289-dirty #197
[ 49.963505] Stack : 0000000000000000 ffffffff81bb5d6a 0000000000000006 ffffffff801ce9c4
[ 49.974431] 0000000000000000 0000000000000000 0000000000000000 000000000000004a
[ 49.985300] ffffffff80b7e487 ffffffff80a24498 a8000000ff160000 ffffffff80ede8b8
[ 49.996194] 0000000000000001 0000000000000000 0000000000000000 0000000077c8030c
[ 50.007063] 000000007fd8a510 ffffffff801cd45c 0000000000000000 a8000000ff127c88
[ 50.017945] 0000000000000000 ffffffff801cf928 0000000000000001 ffffffff80a24498
[ 50.028827] 0000000000000000 0000000000000001 0000000000000000 0000000000000000
[ 50.039688] 0000000000000000 a8000000ff127bd0 0000000000000000 ffffffff805509bc
[ 50.050575] 00000000140084e0 0000000000000000 0000000000000000 0000000000040a00
[ 50.061448] 0000000000000000 ffffffff8010e1b0 0000000000000000 ffffffff805509bc
[ 50.072327] ...
[ 50.076087] Call Trace:
[ 50.079869] [<ffffffff8010e1b0>] show_stack+0x80/0xa8
[ 50.086577] [<ffffffff805509bc>] dump_stack+0x10c/0x190
[ 50.093498] [<ffffffff8015dde0>] __warn+0xf0/0x108
[ 50.099889] [<ffffffff8015de34>] warn_slowpath_fmt+0x3c/0x48
[ 50.107241] [<ffffffff801c15b4>] check_flags.part.41+0x1dc/0x1e8
[ 50.114961] [<ffffffff801c239c>] lock_is_held_type+0x8c/0xb0
[ 50.122291] [<ffffffff809461b8>] __schedule+0x8c0/0x10f8
[ 50.129221] [<ffffffff80946a60>] schedule+0x30/0x98
[ 50.135659] [<ffffffff80106278>] work_resched+0x8/0x34
[ 50.142397] ---[ end trace 0cb4f6ef5b99fe21 ]---
[ 50.148405] possible reason: unannotated irqs-off.
[ 50.154600] irq event stamp: 400463
[ 50.159566] hardirqs last enabled at (400463): [<ffffffff8094edc8>] _raw_spin_unlock_irqrestore+0x40/0xa8
[ 50.171981] hardirqs last disabled at (400462): [<ffffffff8094eb98>] _raw_spin_lock_irqsave+0x30/0xb0
[ 50.183897] softirqs last enabled at (400450): [<ffffffff8016580c>] __do_softirq+0x4ac/0x6a8
[ 50.195015] softirqs last disabled at (400425): [<ffffffff80165e78>] irq_exit+0x110/0x128
Fix this by using the TRACE_IRQS_OFF macro to call trace_hardirqs_off()
when CONFIG_TRACE_IRQFLAGS is enabled. This is done before invoking
schedule() following the work_resched label because:
1) Interrupts are disabled regardless of the path we take to reach
work_resched() & schedule().
2) Performing the tracing here avoids the need to do it in paths which
disable interrupts but don't call out to C code before hitting a
path which uses the RESTORE_SOME macro that will call
trace_hardirqs_on() or trace_hardirqs_off() as appropriate.
We call trace_hardirqs_on() using the TRACE_IRQS_ON macro before calling
syscall_trace_leave() for similar reasons, ensuring that lockdep has a
consistent view of state after we re-enable interrupts.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Cc: linux-mips@linux-mips.org
Cc: stable <stable@vger.kernel.org>
Patchwork: https://patchwork.linux-mips.org/patch/15385/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
We allocate memory for a ready_count variable per-CPU, which is accessed
via a cached non-coherent TLB mapping to perform synchronisation between
threads within the core using LL/SC instructions. In order to ensure
that the variable is contained within its own data cache line we
allocate 2 lines worth of memory & align the resulting pointer to a line
boundary. This is however unnecessary, since kmalloc is guaranteed to
return memory which is at least cache-line aligned (see
ARCH_DMA_MINALIGN). Stop the redundant manual alignment.
Besides cleaning up the code & avoiding needless work, this has the side
effect of avoiding an arithmetic error found by Bryan on 64 bit systems
due to the 32 bit size of the former dlinesz. This led the ready_count
variable to have its upper 32b cleared erroneously for MIPS64 kernels,
causing problems when ready_count was later used on MIPS64 via cpuidle.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Fixes: 3179d37ee1 ("MIPS: pm-cps: add PM state entry code for CPS systems")
Reported-by: Bryan O'Donoghue <bryan.odonoghue@imgtec.com>
Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@imgtec.com>
Tested-by: Bryan O'Donoghue <bryan.odonoghue@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: stable <stable@vger.kernel.org> # v3.16+
Patchwork: https://patchwork.linux-mips.org/patch/15383/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Some systems share FTLB RAMs or entries between sibling CPUs (ie.
hardware threads, or VP(E)s, within a core). These properties require
kernel handling in various places. As a start this patch introduces
cpu_has_shared_ftlb_ram & cpu_has_shared_ftlb_entries feature macros
which we set appropriately for I6400 & I6500 CPUs. Further patches will
make use of these macros as appropriate.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16202/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
On pre-r6 systems with the MT ASE the CPS SMP code included checks to
halt the VPE running mips_cps_boot_vpes() if its bit in the struct
core_boot_config vpe_mask field is clear. This was largely done in order
to allow us to start arbitrary VPEs within a core despite the fact that
hardware is typically configured to run only VPE0 after powering up a
core. VPE0 would start the desired other VPEs, halt itself, and the fact
that VPE0 started would be largely hidden & irrelevant.
In MIPSr6 multithreading we have control over which VPs start executing
when a core powers up via the cores CPC registers accessed remotely
through the redirect block. For this reason the MIPSr6 multithreading
path in mips_cps_boot_vpes() hasn't bothered up until now to handle
halting the VP running it.
However it is possible to power up cores entirely in hardware by using a
pwr_up pin associated with the core. Unfortunately some systems wire
this pin to a logic 1, which means that it is possible for a core to
power up at a point that software doesn't expect. The result is that we
generally go execute the kernel on a CPU that ought not to be running &
the results can be unpredictable.
Handle this case by stopping VPs that we don't expect to be running in
mips_cps_boot_vpes() - with this change even if a core powers up it will
do nothing useful & all VPs within it will stop running before they
proceed to run general kernel code & do any damage. Ideally we would
produce some sort of warning here, but given the stage of core bringup
this happens at that would be non-trivial. We also will only hit this if
a core starts up after being offlined via hotplug, and when that happens
we will already produce a warning that the CPU didn't power down in
cps_cpu_die() which seems sufficient.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16198/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
If we get into a state where a core that ought to power down isn't doing
so then the current result is that another CPU gets stuck inside
cps_cpu_die() waiting for CPU that ought to be powering down to do so.
The best case scenario is that we then trigger RCU stall messages or
lockup messages, but neither makes it particularly clear what's
happening.
Handle this more gracefully by introducing a timeout beyond which we
warn the user that the core didn't power down & stop waiting for it.
This at least allows the CPU running cps_cpu_die() to continue normally,
and hopefully presuming the CPU that powered back up is doing nothing
harmful the system will continue functioning as normal.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16197/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Systems using the MIPS Coherence Manager (CM) cannot support multi-core
SMP with dcache aliasing. This is because CPU caches are VIPT, but
interventions in CM-based systems provide only the physical address to
remote caches. This means that interventions may behave incorrectly in
the presence of an aliasing dcache, since the physical address used
when handling an intervention may lead to operation on an aliased cache
line rather than the correct line.
Prevent us from running into this issue by refusing to boot secondary
cores in systems where dcache aliasing may occur.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16196/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Rather than using BUG_ON in the case of an invalid attempt to lock
access to a non-zero VP on a pre-CM3 system, use WARN_ON so that we have
even the slightest chance of recovery.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16194/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
CM3 provides a GCR_CL_OTHER register per VP, rather than only per core.
This means that we don't need to prevent other VPs within a core from
racing with code that makes use of the core-other register region.
Reduce locking overhead by demoting the per-core spinlock providing
protection for CM2.5 & lower to a per-CPU/per-VP spinlock for CM3 &
higher.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16193/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
If we're running on a system with only 1 possible CPU then it makes no
sense to reserve or initialise IPIs since we'll never use them. Avoid
doing so.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16192/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Reduce the log level for branch emulation error messages issued before
sending SIGILL by `__compute_return_epc_for_insn' as these are triggered
by user software and are not an event that would normally require any
attention. The same signal sent from elsewhere does not actually leave
any trace in the kernel log at all.
Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16402/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This is a user-visible message, so we want it to be spelled correctly.
Fixes: 5f9f41c474 ("MIPS: kernel: Prepare the JR instruction for emulation on MIPS R6")
Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: stable@vger.kernel.org # 3.19+
Patchwork: https://patchwork.linux-mips.org/patch/16400/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Fix:
* commit 8467ca0122 ("MIPS: Emulate the new MIPS R6 branch compact
(BC) instruction"),
* commit 84fef63012 ("MIPS: Emulate the new MIPS R6 BALC
instruction"),
* commit 69b9a2fd05 ("MIPS: Emulate the new MIPS R6 BEQZC and JIC
instructions"),
* commit 28d6f93d20 ("MIPS: Emulate the new MIPS R6 BNEZC and JIALC
instructions"),
* commit c893ce38b2 ("MIPS: Emulate the new MIPS R6 BOVC, BEQC and
BEQZALC instructions")
and send SIGILL rather than returning -SIGILL for R6 branch and jump
instructions. Returning -SIGILL is never correct as the API defines
this function's result upon error to be -EFAULT and a signal actually
issued.
Fixes: 8467ca0122 ("MIPS: Emulate the new MIPS R6 branch compact (BC) instruction")
Fixes: 84fef63012 ("MIPS: Emulate the new MIPS R6 BALC instruction")
Fixes: 69b9a2fd05 ("MIPS: Emulate the new MIPS R6 BEQZC and JIC instructions")
Fixes: 28d6f93d20 ("MIPS: Emulate the new MIPS R6 BNEZC and JIALC instructions")
Fixes: c893ce38b2 ("MIPS: Emulate the new MIPS R6 BOVC, BEQC and BEQZALC instructions")
Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: stable@vger.kernel.org # 3.19+
Patchwork: https://patchwork.linux-mips.org/patch/16399/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Fix commit 319824eabc ("MIPS: kernel: branch: Do not emulate the
branch likelies on MIPS R6") and also send SIGILL rather than returning
-SIGILL for BLTZAL, BLTZALL, BGEZAL and BGEZALL instruction encodings no
longer supported in R6, except where emulated. Returning -SIGILL is
never correct as the API defines this function's result upon error to be
-EFAULT and a signal actually issued.
Fixes: 319824eabc ("MIPS: kernel: branch: Do not emulate the branch likelies on MIPS R6")
Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: stable@vger.kernel.org # 3.19+
Patchwork: https://patchwork.linux-mips.org/patch/16398/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Use the more accurate `sigill_r2r6' name for the label used in the case
of sending SIGILL in the absence of the instruction emulator for an
earlier ISA level instruction that has been removed as from the R6 ISA,
so that the `sigill_r6' name is freed for the situation where an R6
instruction is not supposed to be interpreted, because the executing
processor does not support the R6 ISA.
Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: stable@vger.kernel.org # 3.19+
Patchwork: https://patchwork.linux-mips.org/patch/16397/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Fix commit e50c0a8fa6 ("Support the MIPS32 / MIPS64 DSP ASE.") and
send SIGILL rather than SIGBUS whenever an unimplemented BPOSGE32 DSP
ASE instruction has been encountered in `__compute_return_epc_for_insn'
as our Reserved Instruction exception handler would in response to an
attempt to actually execute the instruction. Sending SIGBUS only makes
sense for the unaligned PC case, since moved to `__compute_return_epc'.
Adjust function documentation accordingly, correct formatting and use
`pr_info' rather than `printk' as the other exit path already does.
Fixes: e50c0a8fa6 ("Support the MIPS32 / MIPS64 DSP ASE.")
Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: stable@vger.kernel.org # 2.6.14+
Patchwork: https://patchwork.linux-mips.org/patch/16396/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Complement commit fb6883e580 ("MIPS: microMIPS: Support handling of
delay slots.") and actually decode the regular MIPS JALX major
instruction opcode, the handling of which has been added with the said
commit for EPC calculation in `__compute_return_epc_for_insn'.
Fixes: fb6883e580 ("MIPS: microMIPS: Support handling of delay slots.")
Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: stable@vger.kernel.org # 3.9+
Patchwork: https://patchwork.linux-mips.org/patch/16394/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Implement support for 1 & 2 byte cmpxchg() using read-modify-write atop
a 4 byte cmpxchg(). This allows us to support these atomic operations
despite the MIPS ISA only providing 4 & 8 byte atomic operations.
This is required in order to support queued rwlocks (qrwlock) in a later
patch, since these make use of a 1 byte cmpxchg() in their slow path.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16355/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Implement 1 & 2 byte xchg() using read-modify-write atop a 4 byte
cmpxchg(). This allows us to support these atomic operations despite the
MIPS ISA only providing for 4 & 8 byte atomic operations.
This is required in order to support queued spinlocks (qspinlock) in a
later patch, since these make use of a 2 byte xchg() in their slow path.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16354/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Implement support for parsing 'memmap' kernel command line parameter.
This patch covers parsing of the following two formats for 'memmap'
parameter values:
- nn[KMG]@ss[KMG]
- nn[KMG]$ss[KMG]
([KMG] = K M or G (kilo, mega, giga))
These two allowed formats for parameter value are already documented
in file kernel-parameters.txt in Documentation/admin-guide folder.
Some architectures already support them, but Mips did not prior to
this patch.
Excerpt from Documentation/admin-guide/kernel-parameters.txt:
memmap=nn[KMG]@ss[KMG]
[KNL] Force usage of a specific region of memory.
Region of memory to be used is from ss to ss+nn.
memmap=nn[KMG]$ss[KMG]
Mark specific memory as reserved.
Region of memory to be reserved is from ss to ss+nn.
Example: Exclude memory from 0x18690000-0x1869ffff
memmap=64K$0x18690000
or
memmap=0x10000$0x18690000
There is no need to update this documentation file with respect to
this patch.
Signed-off-by: Miodrag Dinic <miodrag.dinic@imgtec.com>
Signed-off-by: Goran Ferenc <goran.ferenc@imgtec.com>
Signed-off-by: Aleksandar Markovic <aleksandar.markovic@imgtec.com>
Cc: James.Hogan@imgtec.com
Cc: Paul.Burton@imgtec.com
Cc: Raghu.Gandham@imgtec.com
Cc: Leonid.Yegoshin@imgtec.com
Cc: Douglas.Leung@imgtec.com
Cc: Petar.Jovanovic@imgtec.com
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16508/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Adjust the atomic loop in the MIPS_ATOMIC_SET operation of the sysmips
system call to branch straight back to the linked load rather than
jumping via a different subsection (whose purpose remains a mystery to
me).
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16150/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
EVA linked loads (LLE) and conditional stores (SCE) should be used on
EVA kernels for the MIPS_ATOMIC_SET operation of the sysmips system
call, or else the atomic set will apply to the kernel view of the
virtual address space (potentially unmapped on EVA kernels) rather than
the user view (TLB mapped).
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: <stable@vger.kernel.org> # 3.15.x-
Patchwork: https://patchwork.linux-mips.org/patch/16151/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The MIPS sysmips system call handler may return directly from the
MIPS_ATOMIC_SET case (mips_atomic_set()) to syscall_exit. This path
restores the static (callee saved) registers, however they won't have
been saved on entry to the system call.
Use the save_static_function() macro to create a __sys_sysmips wrapper
function which saves the static registers before calling sys_sysmips, so
that the correct static register state is restored by syscall_exit.
Fixes: f1e39a4a61 ("MIPS: Rewrite sysmips(MIPS_ATOMIC_SET, ...) in C with inline assembler")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: stable@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/16149/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The inline asm retry check in the MIPS_ATOMIC_SET operation of the
sysmips system call has been backwards since commit f1e39a4a61 ("MIPS:
Rewrite sysmips(MIPS_ATOMIC_SET, ...) in C with inline assembler")
merged in v2.6.32, resulting in the non R10000_LLSC_WAR case retrying
until the operation was inatomic, before returning the new value that
was probably just written multiple times instead of the old value.
Invert the branch condition to fix that particular issue.
Fixes: f1e39a4a61 ("MIPS: Rewrite sysmips(MIPS_ATOMIC_SET, ...) in C with inline assembler")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: stable@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/16148/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Add a definition of the perf registers for the new I6500 core.
Since I6500 has the same event definitions as I6400, re-use the existing
i6400 map structures by renaming them to a slightly more generic
'i6x00_***_map'.
Signed-off-by: Marcin Nowakowski <marcin.nowakowski@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16362/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Introduce the I6500 PRID & probe it just the same way as I6400. The MIPS
I6500 is the latest in Imagination Technologies' I-Class range of CPUs,
with a focus on scalability & heterogeneity. It introduces the notion of
multiple clusters to the MIPS Coherent Processing System, allowing for a
far higher total number of cores & threads in a system when compared
with its predecessors. Clusters don't need to be identical, and may
contain differing numbers of cores & IOCUs, or cores with differing
properties.
This patch alone adds the basic support for booting Linux on an I6500
CPU without support for any of its new functionality, for which support
will be introduced in further patches.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16190/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
KProbes of __seccomp_filter() are not very useful without access to
the syscall arguments.
Do what x86 does, and populate a struct seccomp_data to be passed to
__secure_computing(). This allows samples/bpf/tracex5 to extract a
sensible trace.
Signed-off-by: David Daney <david.daney@cavium.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Matt Redfearn <matt.redfearn@imgtec.com>
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16368/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The module load code has previously had entirely separate
implementations for rel & rela style relocs, which unnecessarily
duplicates a whole lot of code. Unify the implementations of both types
of reloc, sharing the bulk of the code.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/15832/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
If we hit an error whilst processing a reloc then we would return early
from apply_relocate & potentially not free entries in r_mips_hi16_list,
thereby leaking memory. Fix this by ensuring that we always run the code
to free r_mipps_hi16_list when errors occur.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Fixes: 861667dc82 ("MIPS: Fix race condition in module relocation code.")
Fixes: 04211a5746 ("MIPS: Bail on unsupported module relocs")
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/15831/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
In this sequence the 'move' is assumed in the delay slot of the 'beq',
but head.S is in reorder mode and the former gets pushed one 'nop'
farther by the assembler.
The corrected behavior made booting with an UHI supplied dtb erratic.
Fixes: 15f37e1588 ("MIPS: store the appended dtb address in a variable")
Signed-off-by: Karl Beldan <karl.beldan+oss@gmail.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: Jonas Gorski <jogo@openwrt.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/16614/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The code handling the pop76 opcode (ie. bnezc & jialc instructions) in
__compute_return_epc_for_insn() needs to set the value of $31 in the
jialc case, which is encoded with rs = 0. However its check to
differentiate bnezc (rs != 0) from jialc (rs = 0) was unfortunately
backwards, meaning that if we emulate a bnezc instruction we clobber $31
& if we emulate a jialc instruction it actually behaves like a jic
instruction.
Fix this by inverting the check of rs to match the way the instructions
are actually encoded.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Fixes: 28d6f93d20 ("MIPS: Emulate the new MIPS R6 BNEZC and JIALC instructions")
Cc: stable <stable@vger.kernel.org> # v4.0+
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16178/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Since introduction of tracing for init functions the in_kernel_space()
check is no longer correct, as it ignores the init sections. As a
result, when probes are inserted (and disabled) in the init functions,
a branch instruction is inserted instead of a nop, which is likely to
result in random crashes during boot.
Remove the MIPS-specific in_kernel_space() method and replace it with a
generic core_kernel_text() that also checks for init sections during
system boot stage.
Fixes: 42c269c88d ("ftrace: Allow for function tracing to record init functions on boot up")
Signed-off-by: Marcin Nowakowski <marcin.nowakowski@imgtec.com>
Tested-by: Matt Redfearn <matt.redfearn@imgtec.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16092/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
All performance counters on I6400 (odd and even) are capable of counting
any of the available events, so drop current logic of using the extra
bit to determine which counter to use.
Signed-off-by: Marcin Nowakowski <marcin.nowakowski@imgtec.com>
Fixes: 4e88a86213 ("MIPS: Add cases for CPU_I6400")
Fixes: fd716fca10 ("MIPS: perf: Fix I6400 event numbers")
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/15991/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This fixes a regression in commit 4d6501dce0 where I didn't notice
that MIPS and OpenRISC were reinitialising p->{set,clear}_child_tid to
NULL after our initialisation in copy_process().
We can simply get rid of the arch-specific initialisation here since it
is now always done in copy_process() before hitting copy_thread{,_tls}().
Review notes:
- As far as I can tell, copy_process() is the only user of
copy_thread_tls(), which is the only caller of copy_thread() for
architectures that don't implement copy_thread_tls().
- After this patch, there is no arch-specific code touching
p->set_child_tid or p->clear_child_tid whatsoever.
- It may look like MIPS/OpenRISC wanted to always have these fields be
NULL, but that's not true, as copy_process() would unconditionally
set them again _after_ calling copy_thread_tls() before commit
4d6501dce0.
Fixes: 4d6501dce0 ("kthread: Fix use-after-free if kthread fork fails")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net> # MIPS only
Acked-by: Stafford Horne <shorne@gmail.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: openrisc@lists.librecores.org
Cc: Jamie Iles <jamie.iles@oracle.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The conversion of the hotplug locking to a percpu rwsem unearthed lock
ordering issues all over the place.
The jump_label code has two issues:
1) Nested get_online_cpus() invocations
2) Ordering problems vs. the cpus rwsem and the jump_label_mutex
To cure these, the following lock order has been established;
cpus_rwsem -> jump_label_lock -> text_mutex
Even if not all architectures need protection against CPU hotplug, taking
cpus_rwsem before jump_label_lock is now mandatory in code pathes which
actually modify code and therefor need text_mutex protection.
Move the get_online_cpus() invocations into the core jump label code and
establish the proper lock order where required.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: "David S. Miller" <davem@davemloft.net>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jason Baron <jbaron@akamai.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Link: http://lkml.kernel.org/r/20170524081549.025830817@linutronix.de
Merge more updates from Andrew Morton:
- the rest of MM
- various misc things
- procfs updates
- lib/ updates
- checkpatch updates
- kdump/kexec updates
- add kvmalloc helpers, use them
- time helper updates for Y2038 issues. We're almost ready to remove
current_fs_time() but that awaits a btrfs merge.
- add tracepoints to DAX
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (114 commits)
drivers/staging/ccree/ssi_hash.c: fix build with gcc-4.4.4
selftests/vm: add a test for virtual address range mapping
dax: add tracepoint to dax_insert_mapping()
dax: add tracepoint to dax_writeback_one()
dax: add tracepoints to dax_writeback_mapping_range()
dax: add tracepoints to dax_load_hole()
dax: add tracepoints to dax_pfn_mkwrite()
dax: add tracepoints to dax_iomap_pte_fault()
mtd: nand: nandsim: convert to memalloc_noreclaim_*()
treewide: convert PF_MEMALLOC manipulations to new helpers
mm: introduce memalloc_noreclaim_{save,restore}
mm: prevent potential recursive reclaim due to clearing PF_MEMALLOC
mm/huge_memory.c: deposit a pgtable for DAX PMD faults when required
mm/huge_memory.c: use zap_deposited_table() more
time: delete CURRENT_TIME_SEC and CURRENT_TIME
gfs2: replace CURRENT_TIME with current_time
apparmorfs: replace CURRENT_TIME with current_time()
lustre: replace CURRENT_TIME macro
fs: ubifs: replace CURRENT_TIME_SEC with current_time
fs: ufs: use ktime_get_real_ts64() for birthtime
...
While examining output from trial builds with -Wformat-security enabled,
many strings were found that should be defined as "const", or as a char
array instead of char pointer. This makes some static analysis easier,
by producing fewer false positives.
As these are all trivial changes, it seemed best to put them all in a
single patch rather than chopping them up per maintainer.
Link: http://lkml.kernel.org/r/20170405214711.GA5711@beast
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Jes Sorensen <jes@trained-monkey.org> [runner.c]
Cc: Tony Lindgren <tony@atomide.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: "Maciej W. Rozycki" <macro@linux-mips.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: David Airlie <airlied@linux.ie>
Cc: Yisen Zhuang <yisen.zhuang@huawei.com>
Cc: Salil Mehta <salil.mehta@huawei.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Patrice Chotard <patrice.chotard@st.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Matt Redfearn <matt.redfearn@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Mugunthan V N <mugunthanvnm@ti.com>
Cc: Felipe Balbi <felipe.balbi@linux.intel.com>
Cc: Jarod Wilson <jarod@redhat.com>
Cc: Florian Westphal <fw@strlen.de>
Cc: Antonio Quartulli <a@unstable.cc>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Kejian Yan <yankejian@huawei.com>
Cc: Daode Huang <huangdaode@hisilicon.com>
Cc: Qianqian Xie <xieqianqian@huawei.com>
Cc: Philippe Reynes <tremyfr@gmail.com>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Christian Gromm <christian.gromm@microchip.com>
Cc: Andrey Shvetsov <andrey.shvetsov@k2l.de>
Cc: Jason Litzinger <jlitzingerdev@gmail.com>
Cc: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Matija Glavinic Pecotic