2020-08-28 04:53:35 +00:00
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From b92073bdc2225792633135f50dd9122ccdb5e326 Mon Sep 17 00:00:00 2001
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Message-Id: <b92073bdc2225792633135f50dd9122ccdb5e326.1596234184.git.zanussi@kernel.org>
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In-Reply-To: <378ee68279f6a7631221f2670a9298620148690d.1596234183.git.zanussi@kernel.org>
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References: <378ee68279f6a7631221f2670a9298620148690d.1596234183.git.zanussi@kernel.org>
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2018-08-27 14:32:32 +00:00
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From: Thomas Gleixner <tglx@linutronix.de>
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Date: Thu, 1 Nov 2012 10:14:11 +0100
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2020-07-15 20:05:29 +00:00
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Subject: [PATCH 243/329] powerpc: Add support for lazy preemption
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2020-08-28 04:53:35 +00:00
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.135-rt60.tar.xz
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2018-08-27 14:32:32 +00:00
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Implement the powerpc pieces for lazy preempt.
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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---
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2019-04-08 23:49:20 +00:00
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arch/powerpc/Kconfig | 1 +
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arch/powerpc/include/asm/thread_info.h | 9 +++++++--
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arch/powerpc/kernel/asm-offsets.c | 1 +
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arch/powerpc/kernel/entry_32.S | 17 ++++++++++++-----
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arch/powerpc/kernel/entry_64.S | 16 ++++++++++++----
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2018-08-31 15:16:36 +00:00
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5 files changed, 33 insertions(+), 11 deletions(-)
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2018-08-27 14:32:32 +00:00
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2019-04-08 23:49:20 +00:00
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diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
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2020-06-23 13:42:59 +00:00
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index 8455293d1435..dbf8cb62e77b 100644
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2018-08-27 14:32:32 +00:00
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--- a/arch/powerpc/Kconfig
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+++ b/arch/powerpc/Kconfig
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2018-10-30 12:40:05 +00:00
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@@ -216,6 +216,7 @@ config PPC
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2018-08-27 14:32:32 +00:00
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select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI && !HAVE_HARDLOCKUP_DETECTOR_ARCH
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select HAVE_PERF_REGS
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select HAVE_PERF_USER_STACK_DUMP
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+ select HAVE_PREEMPT_LAZY
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select HAVE_RCU_TABLE_FREE if SMP
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select HAVE_REGS_AND_STACK_ACCESS_API
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select HAVE_RELIABLE_STACKTRACE if PPC64 && CPU_LITTLE_ENDIAN
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2019-04-08 23:49:20 +00:00
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diff --git a/arch/powerpc/include/asm/thread_info.h b/arch/powerpc/include/asm/thread_info.h
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index 3c0002044bc9..ce316076bc52 100644
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2018-08-27 14:32:32 +00:00
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--- a/arch/powerpc/include/asm/thread_info.h
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+++ b/arch/powerpc/include/asm/thread_info.h
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2018-10-30 12:40:05 +00:00
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@@ -37,6 +37,8 @@ struct thread_info {
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2018-08-27 14:32:32 +00:00
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int cpu; /* cpu we're on */
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int preempt_count; /* 0 => preemptable,
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<0 => BUG */
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+ int preempt_lazy_count; /* 0 => preemptable,
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+ <0 => BUG */
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unsigned long local_flags; /* private flags for thread */
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#ifdef CONFIG_LIVEPATCH
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unsigned long *livepatch_sp;
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2019-04-08 23:49:20 +00:00
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@@ -81,7 +83,7 @@ extern int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src
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2018-08-31 15:16:36 +00:00
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#define TIF_SIGPENDING 1 /* signal pending */
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#define TIF_NEED_RESCHED 2 /* rescheduling necessary */
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#define TIF_FSCHECK 3 /* Check FS is USER_DS on return */
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-#define TIF_32BIT 4 /* 32 bit binary */
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+#define TIF_NEED_RESCHED_LAZY 4 /* lazy rescheduling necessary */
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#define TIF_RESTORE_TM 5 /* need to restore TM FP/VEC/VSX */
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#define TIF_PATCH_PENDING 6 /* pending live patching update */
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#define TIF_SYSCALL_AUDIT 7 /* syscall auditing active */
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2019-04-08 23:49:20 +00:00
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@@ -100,6 +102,7 @@ extern int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src
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2018-08-27 14:32:32 +00:00
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#define TIF_ELF2ABI 18 /* function descriptors must die! */
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#endif
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#define TIF_POLLING_NRFLAG 19 /* true if poll_idle() is polling TIF_NEED_RESCHED */
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2018-08-31 15:16:36 +00:00
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+#define TIF_32BIT 20 /* 32 bit binary */
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2018-08-27 14:32:32 +00:00
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/* as above, but as bit values */
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#define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE)
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2019-04-08 23:49:20 +00:00
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@@ -119,6 +122,7 @@ extern int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src
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2018-08-27 14:32:32 +00:00
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#define _TIF_SYSCALL_TRACEPOINT (1<<TIF_SYSCALL_TRACEPOINT)
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#define _TIF_EMULATE_STACK_STORE (1<<TIF_EMULATE_STACK_STORE)
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#define _TIF_NOHZ (1<<TIF_NOHZ)
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+#define _TIF_NEED_RESCHED_LAZY (1<<TIF_NEED_RESCHED_LAZY)
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#define _TIF_FSCHECK (1<<TIF_FSCHECK)
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#define _TIF_SYSCALL_DOTRACE (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
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_TIF_SECCOMP | _TIF_SYSCALL_TRACEPOINT | \
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2019-04-08 23:49:20 +00:00
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@@ -127,8 +131,9 @@ extern int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src
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2018-08-27 14:32:32 +00:00
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#define _TIF_USER_WORK_MASK (_TIF_SIGPENDING | _TIF_NEED_RESCHED | \
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_TIF_NOTIFY_RESUME | _TIF_UPROBE | \
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_TIF_RESTORE_TM | _TIF_PATCH_PENDING | \
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- _TIF_FSCHECK)
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+ _TIF_FSCHECK | _TIF_NEED_RESCHED_LAZY)
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#define _TIF_PERSYSCALL_MASK (_TIF_RESTOREALL|_TIF_NOERROR)
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+#define _TIF_NEED_RESCHED_MASK (_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY)
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/* Bits in local_flags */
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/* Don't move TLF_NAPPING without adjusting the code in entry_32.S */
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2019-04-08 23:49:20 +00:00
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diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
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2020-01-03 23:36:11 +00:00
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index 50400f213bbf..1bb82c5dc1d9 100644
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2018-08-27 14:32:32 +00:00
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--- a/arch/powerpc/kernel/asm-offsets.c
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+++ b/arch/powerpc/kernel/asm-offsets.c
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@@ -156,6 +156,7 @@ int main(void)
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OFFSET(TI_FLAGS, thread_info, flags);
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OFFSET(TI_LOCAL_FLAGS, thread_info, local_flags);
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OFFSET(TI_PREEMPT, thread_info, preempt_count);
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+ OFFSET(TI_PREEMPT_LAZY, thread_info, preempt_lazy_count);
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OFFSET(TI_TASK, thread_info, task);
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OFFSET(TI_CPU, thread_info, cpu);
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2019-04-08 23:49:20 +00:00
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diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
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index 26b3f853cbf6..3783f3ef17a4 100644
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2018-08-27 14:32:32 +00:00
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--- a/arch/powerpc/kernel/entry_32.S
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+++ b/arch/powerpc/kernel/entry_32.S
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2020-01-03 23:36:11 +00:00
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@@ -888,7 +888,14 @@ resume_kernel:
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2018-08-27 14:32:32 +00:00
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cmpwi 0,r0,0 /* if non-zero, just restore regs and return */
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bne restore
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andi. r8,r8,_TIF_NEED_RESCHED
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+ bne+ 1f
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+ lwz r0,TI_PREEMPT_LAZY(r9)
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+ cmpwi 0,r0,0 /* if non-zero, just restore regs and return */
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+ bne restore
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+ lwz r0,TI_FLAGS(r9)
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+ andi. r0,r0,_TIF_NEED_RESCHED_LAZY
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beq+ restore
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+1:
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lwz r3,_MSR(r1)
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andi. r0,r3,MSR_EE /* interrupts off? */
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beq restore /* don't schedule if so */
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2020-01-03 23:36:11 +00:00
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@@ -899,11 +906,11 @@ resume_kernel:
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2018-08-27 14:32:32 +00:00
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*/
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bl trace_hardirqs_off
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#endif
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-1: bl preempt_schedule_irq
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+2: bl preempt_schedule_irq
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CURRENT_THREAD_INFO(r9, r1)
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lwz r3,TI_FLAGS(r9)
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- andi. r0,r3,_TIF_NEED_RESCHED
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- bne- 1b
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+ andi. r0,r3,_TIF_NEED_RESCHED_MASK
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+ bne- 2b
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#ifdef CONFIG_TRACE_IRQFLAGS
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/* And now, to properly rebalance the above, we tell lockdep they
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* are being turned back on, which will happen when we return
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2020-01-03 23:36:11 +00:00
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@@ -1232,7 +1239,7 @@ global_dbcr0:
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2018-08-27 14:32:32 +00:00
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#endif /* !(CONFIG_4xx || CONFIG_BOOKE) */
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do_work: /* r10 contains MSR_KERNEL here */
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- andi. r0,r9,_TIF_NEED_RESCHED
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+ andi. r0,r9,_TIF_NEED_RESCHED_MASK
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beq do_user_signal
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do_resched: /* r10 contains MSR_KERNEL here */
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2020-01-03 23:36:11 +00:00
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@@ -1253,7 +1260,7 @@ recheck:
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2018-08-27 14:32:32 +00:00
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MTMSRD(r10) /* disable interrupts */
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CURRENT_THREAD_INFO(r9, r1)
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lwz r9,TI_FLAGS(r9)
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- andi. r0,r9,_TIF_NEED_RESCHED
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+ andi. r0,r9,_TIF_NEED_RESCHED_MASK
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bne- do_resched
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andi. r0,r9,_TIF_USER_WORK_MASK
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beq restore_user
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2019-04-08 23:49:20 +00:00
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diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
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2020-01-03 23:36:11 +00:00
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index 58b50967b3e5..ef02e41d5d96 100644
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2018-08-27 14:32:32 +00:00
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--- a/arch/powerpc/kernel/entry_64.S
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+++ b/arch/powerpc/kernel/entry_64.S
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2019-04-30 12:45:19 +00:00
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@@ -176,7 +176,7 @@ system_call: /* label this so stack traces look sane */
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2018-08-31 15:16:36 +00:00
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* based on caller's run-mode / personality.
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*/
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ld r11,SYS_CALL_TABLE@toc(2)
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- andi. r10,r10,_TIF_32BIT
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+ andis. r10,r10,_TIF_32BIT@h
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beq 15f
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addi r11,r11,8 /* use 32-bit syscall entries */
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clrldi r3,r3,32
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2020-01-03 23:36:11 +00:00
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@@ -774,7 +774,7 @@ _GLOBAL(ret_from_except_lite)
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2018-08-27 14:32:32 +00:00
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bl restore_math
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b restore
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#endif
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-1: andi. r0,r4,_TIF_NEED_RESCHED
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+1: andi. r0,r4,_TIF_NEED_RESCHED_MASK
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beq 2f
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bl restore_interrupts
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SCHEDULE_USER
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2020-01-03 23:36:11 +00:00
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@@ -836,10 +836,18 @@ resume_kernel:
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2018-08-27 14:32:32 +00:00
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#ifdef CONFIG_PREEMPT
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/* Check if we need to preempt */
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+ lwz r8,TI_PREEMPT(r9)
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+ cmpwi 0,r8,0 /* if non-zero, just restore regs and return */
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+ bne restore
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andi. r0,r4,_TIF_NEED_RESCHED
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+ bne+ check_count
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+
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+ andi. r0,r4,_TIF_NEED_RESCHED_LAZY
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beq+ restore
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+ lwz r8,TI_PREEMPT_LAZY(r9)
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+
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/* Check that preempt_count() == 0 and interrupts are enabled */
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- lwz r8,TI_PREEMPT(r9)
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+check_count:
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cmpwi cr0,r8,0
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bne restore
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ld r0,SOFTE(r1)
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2020-01-03 23:36:11 +00:00
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@@ -856,7 +864,7 @@ resume_kernel:
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2018-08-27 14:32:32 +00:00
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/* Re-test flags and eventually loop */
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CURRENT_THREAD_INFO(r9, r1)
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ld r4,TI_FLAGS(r9)
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- andi. r0,r4,_TIF_NEED_RESCHED
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+ andi. r0,r4,_TIF_NEED_RESCHED_MASK
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bne 1b
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/*
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2020-01-03 23:36:11 +00:00
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--
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2020-06-22 13:14:16 +00:00
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2.17.1
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2020-01-03 23:36:11 +00:00
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