linux-stable.git/arch/csky/kernel/entry.S, branch v5.8

csky: Fixup CONFIG_DEBUG_RSEQ

2020-05-28T00:18:36+00:00

Put the rseq_syscall check point at the prologue of the syscall
will break the a0 ... a7. This will casue system call bug when
DEBUG_RSEQ is enabled.

So move it to the epilogue of syscall, but before syscall_trace.

Signed-off-by: Guo Ren

csky: Coding convention in entry.S

2020-05-28T00:18:36+00:00

There is no fixup or feature in the patch, we only cleanup with:

 - Remove unnecessary reg used (r11, r12), just use r9 & r10 &
   syscallid regs as temp useage.
 - Add _TIF_SYSCALL_WORK and _TIF_WORK_MASK to gather macros.

Signed-off-by: Guo Ren

csky: Fixup abiv2 syscall_trace break a4 & a5

2020-05-28T00:18:36+00:00

Current implementation could destory a4 & a5 when strace, so we need to get them
from pt_regs by SAVE_ALL.

Signed-off-by: Guo Ren

csky: Fixup CONFIG_PREEMPT panic

2020-05-28T00:18:36+00:00

log:
[    0.13373200] Calibrating delay loop...
[    0.14077600] ------------[ cut here ]------------
[    0.14116700] WARNING: CPU: 0 PID: 0 at kernel/sched/core.c:3790 preempt_count_add+0xc8/0x11c
[    0.14348000] DEBUG_LOCKS_WARN_ON((preempt_count() < 0))Modules linked in:
[    0.14395100] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.6.0 #7
[    0.14410800]
[    0.14427400] Call Trace:
[    0.14450700] [<807cd226>] dump_stack+0x8a/0xe4
[    0.14473500] [<80072792>] __warn+0x10e/0x15c
[    0.14495900] [<80072852>] warn_slowpath_fmt+0x72/0xc0
[    0.14518600] [<800a5240>] preempt_count_add+0xc8/0x11c
[    0.14544900] [<807ef918>] _raw_spin_lock+0x28/0x68
[    0.14572600] [<800e0eb8>] vprintk_emit+0x84/0x2d8
[    0.14599000] [<800e113a>] vprintk_default+0x2e/0x44
[    0.14625100] [<800e2042>] vprintk_func+0x12a/0x1d0
[    0.14651300] [<800e1804>] printk+0x30/0x48
[    0.14677600] [<80008052>] lockdep_init+0x12/0xb0
[    0.14703800] [<80002080>] start_kernel+0x558/0x7f8
[    0.14730000] [<800052bc>] csky_start+0x58/0x94
[    0.14756600] irq event stamp: 34
[    0.14775100] hardirqs last  enabled at (33): [<80067370>] ret_from_exception+0x2c/0x72
[    0.14793700] hardirqs last disabled at (34): [<800e0eae>] vprintk_emit+0x7a/0x2d8
[    0.14812300] softirqs last  enabled at (32): [<800655b0>] __do_softirq+0x578/0x6d8
[    0.14830800] softirqs last disabled at (25): [<8007b3b8>] irq_exit+0xec/0x128

The preempt_count of reg could be destroyed after csky_do_IRQ without reload
from memory.

After reference to other architectures (arm64, riscv), we move preempt entry
into ret_from_exception and disable irq at the beginning of
ret_from_exception instead of RESTORE_ALL.

Signed-off-by: Guo Ren 
Reported-by: Lu Baoquan

csky: Fixup remove unnecessary save/restore PSR code

2020-05-13T09:55:06+00:00

All processes' PSR could success from SETUP_MMU, so need set it
in INIT_THREAD again.

And use a3 instead of r7 in __switch_to for code convention.

Signed-off-by: Guo Ren

csky: Fixup remove duplicate irq_disable

2020-05-13T09:55:06+00:00

Interrupt has been disabled in __schedule() with local_irq_disable()
and enabled in finish_task_switch->finish_lock_switch() with
local_irq_enabled(), So needn't to disable irq here.

Signed-off-by: Liu Yibin 
Signed-off-by: Guo Ren

csky: Add uprobes support

2020-04-03T03:37:51+00:00

This patch adds support for uprobes on csky architecture.

Just like kprobe, it support single-step and simulate instructions.

Signed-off-by: Guo Ren 
Cc: Arnd Bergmann 
Cc: Steven Rostedt (VMware)

csky: Enable LOCKDEP_SUPPORT

2020-04-02T11:39:42+00:00

Lockdep is needed by proving the spinlocks and rwlocks. Currently,
we only put trace_hardirqs_on/off with csky_irq and
ret_from_exception.

Signed-off-by: Guo Ren

csky: Add support for restartable sequence

2020-03-08T12:55:14+00:00

Copied and adapted from vincent's patch, but modified for csky.

ref:
https://lore.kernel.org/linux-riscv/1572919114-3886-3-git-send-email-vincent.chen@sifive.com/raw

Add calls to rseq_signal_deliver(), rseq_handle_notify_resume() and
rseq_syscall() to introduce RSEQ support.

1. Call the rseq_handle_notify_resume() function on return to userspace
   if TIF_NOTIFY_RESUME thread flag is set.

2. Call the rseq_signal_deliver() function to fixup on the pre-signal
   frame when a signal is delivered on top of a restartable sequence
   critical section.

3. Check that system calls are not invoked from within rseq critical
   sections by invoking rseq_signal() from ret_from_syscall(). With
   CONFIG_DEBUG_RSEQ, such behavior results in termination of the
   process with SIGSEGV.

Signed-off-by: Guo Ren

sched/rt, csky: Use CONFIG_PREEMPTION

2019-12-08T13:37:33+00:00

CONFIG_PREEMPTION is selected by CONFIG_PREEMPT and by CONFIG_PREEMPT_RT.
Both PREEMPT and PREEMPT_RT require the same functionality which today
depends on CONFIG_PREEMPT.

Switch the entry code over to use CONFIG_PREEMPTION.

Signed-off-by: Thomas Gleixner 
Signed-off-by: Sebastian Andrzej Siewior 
Signed-off-by: Thomas Gleixner 
Acked-by: Guo Ren 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Link: https://lore.kernel.org/r/20191015191821.11479-7-bigeasy@linutronix.de
Signed-off-by: Ingo Molnar