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linuxkit/kernel/patches-5.4.x-rt/0257-powerpc-preempt-lazy-support.patch
Tiejun Chen 6f40ada81c enable rt for 5.4.x 
Signed-off-by: Tiejun Chen <tiejunc@vmware.com>
2020-04-08 20:18:14 -07:00

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From: Thomas Gleixner <tglx@linutronix.de>
Date: Thu, 1 Nov 2012 10:14:11 +0100
Subject: powerpc: Add support for lazy preemption
Implement the powerpc pieces for lazy preempt.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/powerpc/Kconfig | 1 +
arch/powerpc/include/asm/thread_info.h | 16 ++++++++++++----
arch/powerpc/kernel/asm-offsets.c | 1 +
arch/powerpc/kernel/entry_32.S | 23 ++++++++++++++++-------
arch/powerpc/kernel/entry_64.S | 24 +++++++++++++++++-------
5 files changed, 47 insertions(+), 18 deletions(-)
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -221,6 +221,7 @@ config PPC
select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI && !HAVE_HARDLOCKUP_DETECTOR_ARCH
select HAVE_PERF_REGS
select HAVE_PERF_USER_STACK_DUMP
+ select HAVE_PREEMPT_LAZY
select HAVE_RCU_TABLE_FREE
select HAVE_MMU_GATHER_PAGE_SIZE
select HAVE_REGS_AND_STACK_ACCESS_API
--- a/arch/powerpc/include/asm/thread_info.h
+++ b/arch/powerpc/include/asm/thread_info.h
@@ -30,6 +30,8 @@
struct thread_info {
int preempt_count; /* 0 => preemptable,
<0 => BUG */
+ int preempt_lazy_count; /* 0 => preemptable,
+ <0 => BUG */
unsigned long local_flags; /* private flags for thread */
#ifdef CONFIG_LIVEPATCH
unsigned long *livepatch_sp;
@@ -80,11 +82,12 @@ void arch_setup_new_exec(void);
#define TIF_SINGLESTEP 8 /* singlestepping active */
#define TIF_NOHZ 9 /* in adaptive nohz mode */
#define TIF_SECCOMP 10 /* secure computing */
-#define TIF_RESTOREALL 11 /* Restore all regs (implies NOERROR) */
-#define TIF_NOERROR 12 /* Force successful syscall return */
+
+#define TIF_NEED_RESCHED_LAZY 11 /* lazy rescheduling necessary */
+#define TIF_SYSCALL_TRACEPOINT 12 /* syscall tracepoint instrumentation */
+
#define TIF_NOTIFY_RESUME 13 /* callback before returning to user */
#define TIF_UPROBE 14 /* breakpointed or single-stepping */
-#define TIF_SYSCALL_TRACEPOINT 15 /* syscall tracepoint instrumentation */
#define TIF_EMULATE_STACK_STORE 16 /* Is an instruction emulation
for stack store? */
#define TIF_MEMDIE 17 /* is terminating due to OOM killer */
@@ -93,6 +96,9 @@ void arch_setup_new_exec(void);
#endif
#define TIF_POLLING_NRFLAG 19 /* true if poll_idle() is polling TIF_NEED_RESCHED */
#define TIF_32BIT 20 /* 32 bit binary */
+#define TIF_RESTOREALL 21 /* Restore all regs (implies NOERROR) */
+#define TIF_NOERROR 22 /* Force successful syscall return */
+
/* as above, but as bit values */
#define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE)
@@ -112,6 +118,7 @@ void arch_setup_new_exec(void);
#define _TIF_SYSCALL_TRACEPOINT (1<<TIF_SYSCALL_TRACEPOINT)
#define _TIF_EMULATE_STACK_STORE (1<<TIF_EMULATE_STACK_STORE)
#define _TIF_NOHZ (1<<TIF_NOHZ)
+#define _TIF_NEED_RESCHED_LAZY (1<<TIF_NEED_RESCHED_LAZY)
#define _TIF_FSCHECK (1<<TIF_FSCHECK)
#define _TIF_SYSCALL_EMU (1<<TIF_SYSCALL_EMU)
#define _TIF_SYSCALL_DOTRACE (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
@@ -121,8 +128,9 @@ void arch_setup_new_exec(void);
#define _TIF_USER_WORK_MASK (_TIF_SIGPENDING | _TIF_NEED_RESCHED | \
_TIF_NOTIFY_RESUME | _TIF_UPROBE | \
_TIF_RESTORE_TM | _TIF_PATCH_PENDING | \
- _TIF_FSCHECK)
+ _TIF_FSCHECK | _TIF_NEED_RESCHED_LAZY)
#define _TIF_PERSYSCALL_MASK (_TIF_RESTOREALL|_TIF_NOERROR)
+#define _TIF_NEED_RESCHED_MASK (_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY)
/* Bits in local_flags */
/* Don't move TLF_NAPPING without adjusting the code in entry_32.S */
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -167,6 +167,7 @@ int main(void)
OFFSET(TI_FLAGS, thread_info, flags);
OFFSET(TI_LOCAL_FLAGS, thread_info, local_flags);
OFFSET(TI_PREEMPT, thread_info, preempt_count);
+ OFFSET(TI_PREEMPT_LAZY, thread_info, preempt_lazy_count);
#ifdef CONFIG_PPC64
OFFSET(DCACHEL1BLOCKSIZE, ppc64_caches, l1d.block_size);
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -401,7 +401,9 @@
MTMSRD(r10)
lwz r9,TI_FLAGS(r2)
li r8,-MAX_ERRNO
- andi. r0,r9,(_TIF_SYSCALL_DOTRACE|_TIF_SINGLESTEP|_TIF_USER_WORK_MASK|_TIF_PERSYSCALL_MASK)
+ lis r0,(_TIF_SYSCALL_DOTRACE|_TIF_SINGLESTEP|_TIF_USER_WORK_MASK|_TIF_PERSYSCALL_MASK)@h
+ ori r0,r0, (_TIF_SYSCALL_DOTRACE|_TIF_SINGLESTEP|_TIF_USER_WORK_MASK|_TIF_PERSYSCALL_MASK)@l
+ and. r0,r9,r0
bne- syscall_exit_work
cmplw 0,r3,r8
blt+ syscall_exit_cont
@@ -516,13 +518,13 @@ END_FTR_SECTION_IFSET(CPU_FTR_NEED_PAIRE
b syscall_dotrace_cont
syscall_exit_work:
- andi. r0,r9,_TIF_RESTOREALL
+ andis. r0,r9,_TIF_RESTOREALL@h
beq+ 0f
REST_NVGPRS(r1)
b 2f
0: cmplw 0,r3,r8
blt+ 1f
- andi. r0,r9,_TIF_NOERROR
+ andis. r0,r9,_TIF_NOERROR@h
bne- 1f
lwz r11,_CCR(r1) /* Load CR */
neg r3,r3
@@ -531,12 +533,12 @@ END_FTR_SECTION_IFSET(CPU_FTR_NEED_PAIRE
1: stw r6,RESULT(r1) /* Save result */
stw r3,GPR3(r1) /* Update return value */
-2: andi. r0,r9,(_TIF_PERSYSCALL_MASK)
+2: andi. r0,r9,(_TIF_PERSYSCALL_MASK)@h
beq 4f
/* Clear per-syscall TIF flags if any are set. */
- li r11,_TIF_PERSYSCALL_MASK
+ li r11,_TIF_PERSYSCALL_MASK@h
addi r12,r2,TI_FLAGS
3: lwarx r8,0,r12
andc r8,r8,r11
@@ -904,7 +906,14 @@ user_exc_return: /* r10 contains MSR_KE
cmpwi 0,r0,0 /* if non-zero, just restore regs and return */
bne restore_kuap
andi. r8,r8,_TIF_NEED_RESCHED
+ bne+ 1f
+ lwz r0,TI_PREEMPT_LAZY(r2)
+ cmpwi 0,r0,0 /* if non-zero, just restore regs and return */
+ bne restore_kuap
+ lwz r0,TI_FLAGS(r2)
+ andi. r0,r0,_TIF_NEED_RESCHED_LAZY
beq+ restore_kuap
+1:
lwz r3,_MSR(r1)
andi. r0,r3,MSR_EE /* interrupts off? */
beq restore_kuap /* don't schedule if so */
@@ -1225,7 +1234,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_NEED_PAIRE
#endif /* !(CONFIG_4xx || CONFIG_BOOKE) */
do_work: /* r10 contains MSR_KERNEL here */
- andi. r0,r9,_TIF_NEED_RESCHED
+ andi. r0,r9,_TIF_NEED_RESCHED_MASK
beq do_user_signal
do_resched: /* r10 contains MSR_KERNEL here */
@@ -1246,7 +1255,7 @@ do_resched: /* r10 contains MSR_KERNEL
SYNC
MTMSRD(r10) /* disable interrupts */
lwz r9,TI_FLAGS(r2)
- andi. r0,r9,_TIF_NEED_RESCHED
+ andi. r0,r9,_TIF_NEED_RESCHED_MASK
bne- do_resched
andi. r0,r9,_TIF_USER_WORK_MASK
beq restore_user
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -240,7 +240,9 @@ system_call: /* label this so stack tr
ld r9,TI_FLAGS(r12)
li r11,-MAX_ERRNO
- andi. r0,r9,(_TIF_SYSCALL_DOTRACE|_TIF_SINGLESTEP|_TIF_USER_WORK_MASK|_TIF_PERSYSCALL_MASK)
+ lis r0,(_TIF_SYSCALL_DOTRACE|_TIF_SINGLESTEP|_TIF_USER_WORK_MASK|_TIF_PERSYSCALL_MASK)@h
+ ori r0,r0,(_TIF_SYSCALL_DOTRACE|_TIF_SINGLESTEP|_TIF_USER_WORK_MASK|_TIF_PERSYSCALL_MASK)@l
+ and. r0,r9,r0
bne- .Lsyscall_exit_work
andi. r0,r8,MSR_FP
@@ -363,25 +365,25 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
/* If TIF_RESTOREALL is set, don't scribble on either r3 or ccr.
If TIF_NOERROR is set, just save r3 as it is. */
- andi. r0,r9,_TIF_RESTOREALL
+ andis. r0,r9,_TIF_RESTOREALL@h
beq+ 0f
REST_NVGPRS(r1)
b 2f
0: cmpld r3,r11 /* r11 is -MAX_ERRNO */
blt+ 1f
- andi. r0,r9,_TIF_NOERROR
+ andis. r0,r9,_TIF_NOERROR@h
bne- 1f
ld r5,_CCR(r1)
neg r3,r3
oris r5,r5,0x1000 /* Set SO bit in CR */
std r5,_CCR(r1)
1: std r3,GPR3(r1)
-2: andi. r0,r9,(_TIF_PERSYSCALL_MASK)
+2: andis. r0,r9,(_TIF_PERSYSCALL_MASK)@h
beq 4f
/* Clear per-syscall TIF flags if any are set. */
- li r11,_TIF_PERSYSCALL_MASK
+ lis r11,(_TIF_PERSYSCALL_MASK)@h
addi r12,r12,TI_FLAGS
3: ldarx r10,0,r12
andc r10,r10,r11
@@ -786,7 +788,7 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_207S)
bl restore_math
b restore
#endif
-1: andi. r0,r4,_TIF_NEED_RESCHED
+1: andi. r0,r4,_TIF_NEED_RESCHED_MASK
beq 2f
bl restore_interrupts
SCHEDULE_USER
@@ -848,10 +850,18 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_207S)
#ifdef CONFIG_PREEMPTION
/* Check if we need to preempt */
+ lwz r8,TI_PREEMPT(r9)
+ cmpwi 0,r8,0 /* if non-zero, just restore regs and return */
+ bne restore
andi. r0,r4,_TIF_NEED_RESCHED
+ bne+ check_count
+
+ andi. r0,r4,_TIF_NEED_RESCHED_LAZY
beq+ restore
+ lwz r8,TI_PREEMPT_LAZY(r9)
+
/* Check that preempt_count() == 0 and interrupts are enabled */
- lwz r8,TI_PREEMPT(r9)
+check_count:
cmpwi cr0,r8,0
bne restore
ld r0,SOFTE(r1)
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