[PATCH 4/4] powerpc/64: system call implement the bulk of the logic in C
Nicholas Piggin
npiggin at gmail.com
Tue Aug 27 13:30:10 AEST 2019
System call entry and particularly exit code is beyond the limit of what
is reasonable to implement in asm.
This conversion moves all conditional branches out of the asm code,
except a relatively simple test to see whether all GPRs should be
restored at exit time.
Null syscall test is about 5% faster after this patch, because the exit
work is handled under local_irq_disable, and the hard mask and pending
interrupt replay is handled after that, which avoids games with MSR.
The asm instruction scheduling has not really been analysed and
optimised yet, as there are higher level features and improvements to
add first.
Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
---
arch/powerpc/include/asm/asm-prototypes.h | 11 -
arch/powerpc/include/asm/ptrace.h | 3 +
arch/powerpc/include/asm/signal.h | 2 +
arch/powerpc/include/asm/switch_to.h | 4 +
arch/powerpc/include/asm/time.h | 3 +
arch/powerpc/kernel/Makefile | 3 +-
arch/powerpc/kernel/entry_64.S | 343 ++++------------------
arch/powerpc/kernel/process.c | 6 +-
arch/powerpc/kernel/signal.h | 2 -
arch/powerpc/kernel/syscall_64.c | 202 +++++++++++++
10 files changed, 271 insertions(+), 308 deletions(-)
create mode 100644 arch/powerpc/kernel/syscall_64.c
diff --git a/arch/powerpc/include/asm/asm-prototypes.h b/arch/powerpc/include/asm/asm-prototypes.h
index ec1c97a8e8cb..f00ef8924a99 100644
--- a/arch/powerpc/include/asm/asm-prototypes.h
+++ b/arch/powerpc/include/asm/asm-prototypes.h
@@ -92,14 +92,6 @@ long sys_switch_endian(void);
notrace unsigned int __check_irq_replay(void);
void notrace restore_interrupts(void);
-/* ptrace */
-long do_syscall_trace_enter(struct pt_regs *regs);
-void do_syscall_trace_leave(struct pt_regs *regs);
-
-/* process */
-void restore_math(struct pt_regs *regs);
-void restore_tm_state(struct pt_regs *regs);
-
/* prom_init (OpenFirmware) */
unsigned long __init prom_init(unsigned long r3, unsigned long r4,
unsigned long pp,
@@ -110,9 +102,6 @@ unsigned long __init prom_init(unsigned long r3, unsigned long r4,
void __init early_setup(unsigned long dt_ptr);
void early_setup_secondary(void);
-/* time */
-void accumulate_stolen_time(void);
-
/* misc runtime */
extern u64 __bswapdi2(u64);
extern s64 __lshrdi3(s64, int);
diff --git a/arch/powerpc/include/asm/ptrace.h b/arch/powerpc/include/asm/ptrace.h
index feee1b21bbd5..af363086403a 100644
--- a/arch/powerpc/include/asm/ptrace.h
+++ b/arch/powerpc/include/asm/ptrace.h
@@ -138,6 +138,9 @@ extern unsigned long profile_pc(struct pt_regs *regs);
#define profile_pc(regs) instruction_pointer(regs)
#endif
+long do_syscall_trace_enter(struct pt_regs *regs);
+void do_syscall_trace_leave(struct pt_regs *regs);
+
#define kernel_stack_pointer(regs) ((regs)->gpr[1])
static inline int is_syscall_success(struct pt_regs *regs)
{
diff --git a/arch/powerpc/include/asm/signal.h b/arch/powerpc/include/asm/signal.h
index 0803ca8b9149..0113be8dcb59 100644
--- a/arch/powerpc/include/asm/signal.h
+++ b/arch/powerpc/include/asm/signal.h
@@ -6,4 +6,6 @@
#include <uapi/asm/signal.h>
#include <uapi/asm/ptrace.h>
+void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags);
+
#endif /* _ASM_POWERPC_SIGNAL_H */
diff --git a/arch/powerpc/include/asm/switch_to.h b/arch/powerpc/include/asm/switch_to.h
index 5b03d8a82409..231fcb2058cf 100644
--- a/arch/powerpc/include/asm/switch_to.h
+++ b/arch/powerpc/include/asm/switch_to.h
@@ -5,6 +5,7 @@
#ifndef _ASM_POWERPC_SWITCH_TO_H
#define _ASM_POWERPC_SWITCH_TO_H
+#include <linux/sched.h>
#include <asm/reg.h>
struct thread_struct;
@@ -22,6 +23,9 @@ extern void switch_booke_debug_regs(struct debug_reg *new_debug);
extern int emulate_altivec(struct pt_regs *);
+void restore_math(struct pt_regs *regs);
+void restore_tm_state(struct pt_regs *regs);
+
extern void flush_all_to_thread(struct task_struct *);
extern void giveup_all(struct task_struct *);
diff --git a/arch/powerpc/include/asm/time.h b/arch/powerpc/include/asm/time.h
index 54f4ec1f9fab..ba97858c9d76 100644
--- a/arch/powerpc/include/asm/time.h
+++ b/arch/powerpc/include/asm/time.h
@@ -199,5 +199,8 @@ DECLARE_PER_CPU(u64, decrementers_next_tb);
/* Convert timebase ticks to nanoseconds */
unsigned long long tb_to_ns(unsigned long long tb_ticks);
+/* SPLPAR */
+void accumulate_stolen_time(void);
+
#endif /* __KERNEL__ */
#endif /* __POWERPC_TIME_H */
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index 56dfa7a2a6f2..7f53cc07f933 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -52,7 +52,8 @@ obj-y := cputable.o ptrace.o syscalls.o \
of_platform.o prom_parse.o
obj-$(CONFIG_PPC64) += setup_64.o sys_ppc32.o \
signal_64.o ptrace32.o \
- paca.o nvram_64.o firmware.o
+ paca.o nvram_64.o firmware.o \
+ syscall_64.o
obj-$(CONFIG_VDSO32) += vdso32/
obj-$(CONFIG_PPC_WATCHDOG) += watchdog.o
obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index 5a3e0b5c9ad1..2ec825a85f5b 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -63,12 +63,6 @@ exception_marker:
.globl system_call_common
system_call_common:
-#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
-BEGIN_FTR_SECTION
- extrdi. r10, r12, 1, (63-MSR_TS_T_LG) /* transaction active? */
- bne .Ltabort_syscall
-END_FTR_SECTION_IFSET(CPU_FTR_TM)
-#endif
mr r10,r1
ld r1,PACAKSAVE(r13)
std r10,0(r1)
@@ -76,350 +70,118 @@ END_FTR_SECTION_IFSET(CPU_FTR_TM)
std r12,_MSR(r1)
std r0,GPR0(r1)
std r10,GPR1(r1)
+ std r2,GPR2(r1)
#ifdef CONFIG_PPC_FSL_BOOK3E
+ andi. r10,r12,MSR_PR
+ beq 1f /* if from kernel mode */
START_BTB_FLUSH_SECTION
BTB_FLUSH(r10)
END_BTB_FLUSH_SECTION
+1:
#endif
- ACCOUNT_CPU_USER_ENTRY(r13, r10, r11)
- std r2,GPR2(r1)
+ ld r2,PACATOC(r13)
+ mfcr r12
+ li r11,0
+ /* Can we avoid saving r3-r8 in common case? */
std r3,GPR3(r1)
- mfcr r2
std r4,GPR4(r1)
std r5,GPR5(r1)
std r6,GPR6(r1)
std r7,GPR7(r1)
std r8,GPR8(r1)
- li r11,0
+ /* Zero r9-r12, this should only be required when restoring all GPRs */
std r11,GPR9(r1)
std r11,GPR10(r1)
std r11,GPR11(r1)
std r11,GPR12(r1)
- std r11,_XER(r1)
- std r11,_CTR(r1)
std r9,GPR13(r1)
SAVE_NVGPRS(r1)
+ std r11,_XER(r1)
+ std r11,_CTR(r1)
mflr r10
+
/*
* This clears CR0.SO (bit 28), which is the error indication on
* return from this system call.
*/
- rldimi r2,r11,28,(63-28)
+ rldimi r12,r11,28,(63-28)
li r11,0xc00
std r10,_LINK(r1)
std r11,_TRAP(r1)
+ std r12,_CCR(r1)
std r3,ORIG_GPR3(r1)
- std r2,_CCR(r1)
- ld r2,PACATOC(r13)
- addi r9,r1,STACK_FRAME_OVERHEAD
+ addi r10,r1,STACK_FRAME_OVERHEAD
ld r11,exception_marker at toc(r2)
- std r11,-16(r9) /* "regshere" marker */
-
- kuap_check_amr r10, r11
-
-#if defined(CONFIG_VIRT_CPU_ACCOUNTING_NATIVE) && defined(CONFIG_PPC_SPLPAR)
-BEGIN_FW_FTR_SECTION
- /* see if there are any DTL entries to process */
- ld r10,PACALPPACAPTR(r13) /* get ptr to VPA */
- ld r11,PACA_DTL_RIDX(r13) /* get log read index */
- addi r10,r10,LPPACA_DTLIDX
- LDX_BE r10,0,r10 /* get log write index */
- cmpd r11,r10
- beq+ 33f
- bl accumulate_stolen_time
- REST_GPR(0,r1)
- REST_4GPRS(3,r1)
- REST_2GPRS(7,r1)
- addi r9,r1,STACK_FRAME_OVERHEAD
-33:
-END_FW_FTR_SECTION_IFSET(FW_FEATURE_SPLPAR)
-#endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE && CONFIG_PPC_SPLPAR */
-
- /*
- * A syscall should always be called with interrupts enabled
- * so we just unconditionally hard-enable here. When some kind
- * of irq tracing is used, we additionally check that condition
- * is correct
- */
-#if defined(CONFIG_PPC_IRQ_SOFT_MASK_DEBUG) && defined(CONFIG_BUG)
- lbz r10,PACAIRQSOFTMASK(r13)
-1: tdnei r10,IRQS_ENABLED
- EMIT_BUG_ENTRY 1b,__FILE__,__LINE__,BUGFLAG_WARNING
-#endif
-
-#ifdef CONFIG_PPC_BOOK3E
- wrteei 1
-#else
- li r11,MSR_RI
- ori r11,r11,MSR_EE
- mtmsrd r11,1
-#endif /* CONFIG_PPC_BOOK3E */
-
-system_call: /* label this so stack traces look sane */
- /* We do need to set SOFTE in the stack frame or the return
- * from interrupt will be painful
- */
- li r10,IRQS_ENABLED
- std r10,SOFTE(r1)
-
- ld r11, PACA_THREAD_INFO(r13)
- ld r10,TI_FLAGS(r11)
- andi. r11,r10,_TIF_SYSCALL_DOTRACE
- bne .Lsyscall_dotrace /* does not return */
- cmpldi 0,r0,NR_syscalls
- bge- .Lsyscall_enosys
-
-.Lsyscall:
-/*
- * Need to vector to 32 Bit or default sys_call_table here,
- * based on caller's run-mode / personality.
- */
- ld r11,SYS_CALL_TABLE at toc(2)
- andis. r10,r10,_TIF_32BIT at h
- beq 15f
- ld r11,COMPAT_SYS_CALL_TABLE at toc(2)
- clrldi r3,r3,32
- clrldi r4,r4,32
- clrldi r5,r5,32
- clrldi r6,r6,32
- clrldi r7,r7,32
- clrldi r8,r8,32
-15:
- slwi r0,r0,3
-
- barrier_nospec_asm
- /*
- * Prevent the load of the handler below (based on the user-passed
- * system call number) being speculatively executed until the test
- * against NR_syscalls and branch to .Lsyscall_enosys above has
- * committed.
- */
+ std r11,-16(r10) /* "regshere" marker */
- ldx r12,r11,r0 /* Fetch system call handler [ptr] */
- mtctr r12
- bctrl /* Call handler */
+ /* Calling convention has r9 = orig r0, r10 = regs */
+ mr r9,r0
+ bl system_call_exception
- /* syscall_exit can exit to kernel mode, via ret_from_kernel_thread */
.Lsyscall_exit:
- std r3,RESULT(r1)
-
-#ifdef CONFIG_DEBUG_RSEQ
- /* Check whether the syscall is issued inside a restartable sequence */
- addi r3,r1,STACK_FRAME_OVERHEAD
- bl rseq_syscall
- ld r3,RESULT(r1)
-#endif
-
- ld r12, PACA_THREAD_INFO(r13)
-
- ld r8,_MSR(r1)
-
-/*
- * This is a few instructions into the actual syscall exit path (which actually
- * starts at .Lsyscall_exit) to cater to kprobe blacklisting and to reduce the
- * number of visible symbols for profiling purposes.
- *
- * We can probe from system_call until this point as MSR_RI is set. But once it
- * is cleared below, we won't be able to take a trap.
- *
- * This is blacklisted from kprobes further below with _ASM_NOKPROBE_SYMBOL().
- */
-system_call_exit:
- /*
- * Disable interrupts so current_thread_info()->flags can't change,
- * and so that we don't get interrupted after loading SRR0/1.
- *
- * Leave MSR_RI enabled for now, because with THREAD_INFO_IN_TASK we
- * could fault on the load of the TI_FLAGS below.
- */
-#ifdef CONFIG_PPC_BOOK3E
- wrteei 0
-#else
- li r11,MSR_RI
- mtmsrd r11,1
-#endif /* CONFIG_PPC_BOOK3E */
+ addi r4,r1,STACK_FRAME_OVERHEAD
+ bl syscall_exit_prepare
- ld r9,TI_FLAGS(r12)
- li r11,-MAX_ERRNO
- andi. r0,r9,(_TIF_SYSCALL_DOTRACE|_TIF_SINGLESTEP|_TIF_USER_WORK_MASK|_TIF_PERSYSCALL_MASK)
- bne- .Lsyscall_exit_work
+ ld r2,_CCR(r1)
+ ld r4,_NIP(r1)
+ ld r5,_MSR(r1)
+ ld r6,_LINK(r1)
- andi. r0,r8,MSR_FP
- beq 2f
-#ifdef CONFIG_ALTIVEC
- andis. r0,r8,MSR_VEC at h
- bne 3f
-#endif
-2: addi r3,r1,STACK_FRAME_OVERHEAD
- bl restore_math
- ld r8,_MSR(r1)
- ld r3,RESULT(r1)
- li r11,-MAX_ERRNO
-
-3: cmpld r3,r11
- ld r5,_CCR(r1)
- bge- .Lsyscall_error
-.Lsyscall_error_cont:
- ld r7,_NIP(r1)
BEGIN_FTR_SECTION
stdcx. r0,0,r1 /* to clear the reservation */
END_FTR_SECTION_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS)
- andi. r6,r8,MSR_PR
- ld r4,_LINK(r1)
- kuap_check_amr r10, r11
-
-#ifdef CONFIG_PPC_BOOK3S
- /*
- * Clear MSR_RI, MSR_EE is already and remains disabled. We could do
- * this later, but testing shows that doing it here causes less slow
- * down than doing it closer to the rfid.
- */
- li r11,0
- mtmsrd r11,1
+ mtspr SPRN_SRR0,r4
+ mtspr SPRN_SRR1,r5
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+ std r5,PACATMSCRATCH(r13)
#endif
+ mtlr r6
- beq- 1f
- ACCOUNT_CPU_USER_EXIT(r13, r11, r12)
+ cmpdi r3,0
+ bne syscall_restore_regs
+.Lsyscall_restore_regs_cont:
BEGIN_FTR_SECTION
HMT_MEDIUM_LOW
END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
-#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
- std r8, PACATMSCRATCH(r13)
-#endif
-
/*
* We don't need to restore AMR on the way back to userspace for KUAP.
* The value of AMR only matters while we're in the kernel.
*/
- ld r13,GPR13(r1) /* only restore r13 if returning to usermode */
+ mtcr r2
ld r2,GPR2(r1)
+ ld r3,GPR3(r1)
+ ld r13,GPR13(r1)
ld r1,GPR1(r1)
- mtlr r4
- mtcr r5
- mtspr SPRN_SRR0,r7
- mtspr SPRN_SRR1,r8
RFI_TO_USER
b . /* prevent speculative execution */
+_ASM_NOKPROBE_SYMBOL(system_call_common);
-1: /* exit to kernel */
- kuap_restore_amr r2
-
- ld r2,GPR2(r1)
- ld r1,GPR1(r1)
- mtlr r4
- mtcr r5
- mtspr SPRN_SRR0,r7
- mtspr SPRN_SRR1,r8
- RFI_TO_KERNEL
- b . /* prevent speculative execution */
-
-.Lsyscall_error:
- oris r5,r5,0x1000 /* Set SO bit in CR */
- neg r3,r3
- std r5,_CCR(r1)
- b .Lsyscall_error_cont
-
-/* Traced system call support */
-.Lsyscall_dotrace:
- addi r3,r1,STACK_FRAME_OVERHEAD
- bl do_syscall_trace_enter
-
- /*
- * We use the return value of do_syscall_trace_enter() as the syscall
- * number. If the syscall was rejected for any reason do_syscall_trace_enter()
- * returns an invalid syscall number and the test below against
- * NR_syscalls will fail.
- */
- mr r0,r3
-
- /* Restore argument registers just clobbered and/or possibly changed. */
- ld r3,GPR3(r1)
- ld r4,GPR4(r1)
- ld r5,GPR5(r1)
- ld r6,GPR6(r1)
- ld r7,GPR7(r1)
- ld r8,GPR8(r1)
-
- /* Repopulate r9 and r10 for the syscall path */
- addi r9,r1,STACK_FRAME_OVERHEAD
- ld r10, PACA_THREAD_INFO(r13)
- ld r10,TI_FLAGS(r10)
-
- cmpldi r0,NR_syscalls
- blt+ .Lsyscall
-
- /* Return code is already in r3 thanks to do_syscall_trace_enter() */
- b .Lsyscall_exit
-
-
-.Lsyscall_enosys:
- li r3,-ENOSYS
- b .Lsyscall_exit
-
-.Lsyscall_exit_work:
- /* 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
- beq+ 0f
+syscall_restore_regs:
+ ld r3,_CTR(r1)
+ ld r4,_XER(r1)
REST_NVGPRS(r1)
- b 2f
-0: cmpld r3,r11 /* r11 is -MAX_ERRNO */
- blt+ 1f
- andi. r0,r9,_TIF_NOERROR
- 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)
- beq 4f
-
- /* Clear per-syscall TIF flags if any are set. */
-
- li r11,_TIF_PERSYSCALL_MASK
- addi r12,r12,TI_FLAGS
-3: ldarx r10,0,r12
- andc r10,r10,r11
- stdcx. r10,0,r12
- bne- 3b
- subi r12,r12,TI_FLAGS
-
-4: /* Anything else left to do? */
-BEGIN_FTR_SECTION
- lis r3,DEFAULT_PPR at highest /* Set default PPR */
- sldi r3,r3,32 /* bits 11-13 are used for ppr */
- std r3,_PPR(r1)
-END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
-
- andi. r0,r9,(_TIF_SYSCALL_DOTRACE|_TIF_SINGLESTEP)
- beq ret_from_except_lite
-
- /* Re-enable interrupts */
-#ifdef CONFIG_PPC_BOOK3E
- wrteei 1
-#else
- li r10,MSR_RI
- ori r10,r10,MSR_EE
- mtmsrd r10,1
-#endif /* CONFIG_PPC_BOOK3E */
-
- addi r3,r1,STACK_FRAME_OVERHEAD
- bl do_syscall_trace_leave
- b ret_from_except
+ mtctr r3
+ mtspr SPRN_XER,r4
+ ld r0,GPR0(r1)
+ REST_8GPRS(4, r1)
+ ld r12,GPR12(r1)
+ b .Lsyscall_restore_regs_cont
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
-.Ltabort_syscall:
+ .globl tabort_syscall
+tabort_syscall:
/* Firstly we need to enable TM in the kernel */
mfmsr r10
li r9, 1
rldimi r10, r9, MSR_TM_LG, 63-MSR_TM_LG
mtmsrd r10, 0
+ ld r11,_NIP(r13)
+ ld r12,_MSR(r13)
+
/* tabort, this dooms the transaction, nothing else */
li r9, (TM_CAUSE_SYSCALL|TM_CAUSE_PERSISTENT)
TABORT(R9)
@@ -438,9 +200,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
RFI_TO_USER
b . /* prevent speculative execution */
#endif
-_ASM_NOKPROBE_SYMBOL(system_call_common);
-_ASM_NOKPROBE_SYMBOL(system_call_exit);
-
_GLOBAL(ret_from_fork)
bl schedule_tail
REST_NVGPRS(r1)
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 24621e7e5033..f444525da9ce 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1609,7 +1609,6 @@ int copy_thread_tls(unsigned long clone_flags, unsigned long usp,
extern void ret_from_kernel_thread(void);
void (*f)(void);
unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
- struct thread_info *ti = task_thread_info(p);
klp_init_thread_info(p);
@@ -1617,6 +1616,8 @@ int copy_thread_tls(unsigned long clone_flags, unsigned long usp,
sp -= sizeof(struct pt_regs);
childregs = (struct pt_regs *) sp;
if (unlikely(p->flags & PF_KTHREAD)) {
+ struct thread_info *ti = task_thread_info(p);
+
/* kernel thread */
memset(childregs, 0, sizeof(struct pt_regs));
childregs->gpr[1] = sp + sizeof(struct pt_regs);
@@ -1634,12 +1635,13 @@ int copy_thread_tls(unsigned long clone_flags, unsigned long usp,
} else {
/* user thread */
struct pt_regs *regs = current_pt_regs();
+
CHECK_FULL_REGS(regs);
*childregs = *regs;
if (usp)
childregs->gpr[1] = usp;
p->thread.regs = childregs;
- childregs->gpr[3] = 0; /* Result from fork() */
+ /* ret_from_fork sets fork() result to 0 */
if (clone_flags & CLONE_SETTLS) {
#ifdef CONFIG_PPC64
if (!is_32bit_task())
diff --git a/arch/powerpc/kernel/signal.h b/arch/powerpc/kernel/signal.h
index 800433685888..d396efca4068 100644
--- a/arch/powerpc/kernel/signal.h
+++ b/arch/powerpc/kernel/signal.h
@@ -10,8 +10,6 @@
#ifndef _POWERPC_ARCH_SIGNAL_H
#define _POWERPC_ARCH_SIGNAL_H
-extern void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags);
-
extern void __user *get_sigframe(struct ksignal *ksig, unsigned long sp,
size_t frame_size, int is_32);
diff --git a/arch/powerpc/kernel/syscall_64.c b/arch/powerpc/kernel/syscall_64.c
new file mode 100644
index 000000000000..98ed970796d5
--- /dev/null
+++ b/arch/powerpc/kernel/syscall_64.c
@@ -0,0 +1,202 @@
+#include <linux/err.h>
+#include <asm/hw_irq.h>
+#include <asm/paca.h>
+#include <asm/ptrace.h>
+#include <asm/reg.h>
+#include <asm/signal.h>
+#include <asm/switch_to.h>
+#include <asm/syscall.h>
+#include <asm/time.h>
+
+extern void __noreturn tabort_syscall(void);
+
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
+static inline void account_cpu_user_entry(void)
+{
+ unsigned long tb = mftb();
+
+ local_paca->accounting.utime += (tb - local_paca->accounting.starttime_user);
+ local_paca->accounting.starttime = tb;
+}
+static inline void account_cpu_user_exit(void)
+{
+ unsigned long tb = mftb();
+
+ local_paca->accounting.stime += (tb - local_paca->accounting.starttime);
+ local_paca->accounting.starttime_user = tb;
+}
+#else
+static inline void account_cpu_user_entry(void)
+{
+}
+static inline void account_cpu_user_exit(void)
+{
+}
+#endif
+
+typedef long (*syscall_fn)(long, long, long, long, long, long);
+
+long system_call_exception(long r3, long r4, long r5, long r6, long r7, long r8, unsigned long r0, struct pt_regs *regs)
+{
+ unsigned long ti_flags;
+ syscall_fn f;
+
+ BUG_ON(!(regs->msr & MSR_PR));
+
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+ if (unlikely(regs->msr & MSR_TS_T))
+ tabort_syscall();
+#endif
+
+ account_cpu_user_entry();
+
+#if defined(CONFIG_VIRT_CPU_ACCOUNTING_NATIVE) && defined(CONFIG_PPC_SPLPAR)
+ if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
+ struct lppaca *lp = get_lppaca();
+
+ if (unlikely(local_paca->dtl_ridx != lp->dtl_idx))
+ accumulate_stolen_time();
+ }
+#endif
+
+#ifdef CONFIG_PPC_KUAP_DEBUG
+ if (mmu_has_feature(MMU_FTR_RADIX_KUAP))
+ WARN_ON_ONCE(mfspr(SPRN_AMR) != AMR_KUAP_BLOCKED);
+#endif
+
+ /*
+ * A syscall should always be called with interrupts enabled
+ * so we just unconditionally hard-enable here. When some kind
+ * of irq tracing is used, we additionally check that condition
+ * is correct
+ */
+#if defined(CONFIG_PPC_IRQ_SOFT_MASK_DEBUG)
+ WARN_ON(irq_soft_mask_return() != IRQS_ENABLED);
+ WARN_ON(local_paca->irq_happened);
+#endif
+
+ __hard_irq_enable();
+
+ /*
+ * We do need to set SOFTE in the stack frame or the return
+ * from interrupt will be painful
+ */
+ regs->softe = IRQS_ENABLED;
+
+ ti_flags = current_thread_info()->flags;
+ if (unlikely(ti_flags & _TIF_SYSCALL_DOTRACE)) {
+ /*
+ * We use the return value of do_syscall_trace_enter() as the
+ * syscall number. If the syscall was rejected for any reason
+ * do_syscall_trace_enter() returns an invalid syscall number
+ * and the test below against NR_syscalls will fail.
+ */
+ r0 = do_syscall_trace_enter(regs);
+ }
+
+ if (unlikely(r0 >= NR_syscalls))
+ return -ENOSYS;
+
+ /* May be faster to do array_index_nospec? */
+ barrier_nospec();
+
+ if (unlikely(ti_flags & _TIF_32BIT)) {
+ f = (void *)compat_sys_call_table[r0];
+
+ r3 &= 0x00000000ffffffffULL;
+ r4 &= 0x00000000ffffffffULL;
+ r5 &= 0x00000000ffffffffULL;
+ r6 &= 0x00000000ffffffffULL;
+ r7 &= 0x00000000ffffffffULL;
+ r8 &= 0x00000000ffffffffULL;
+
+ } else {
+ f = (void *)sys_call_table[r0];
+ }
+
+ return f(r3, r4, r5, r6, r7, r8);
+}
+
+unsigned long syscall_exit_prepare(unsigned long r3, struct pt_regs *regs)
+{
+ unsigned long *ti_flagsp = ¤t_thread_info()->flags;
+ unsigned long ti_flags;
+ unsigned long ret = 0;
+
+ regs->result = r3;
+
+ /* Check whether the syscall is issued inside a restartable sequence */
+ rseq_syscall(regs);
+
+ ti_flags = *ti_flagsp;
+ if (unlikely(ti_flags & _TIF_SYSCALL_DOTRACE))
+ do_syscall_trace_leave(regs);
+
+ if (unlikely(r3 >= (unsigned long)-MAX_ERRNO)) {
+ if (likely(!(ti_flags & (_TIF_NOERROR | _TIF_RESTOREALL)))) {
+ r3 = -r3;
+ regs->ccr |= 0x10000000; /* Set SO bit in CR */
+ }
+ }
+
+ if (unlikely(ti_flags & _TIF_PERSYSCALL_MASK)) {
+ if (ti_flags & _TIF_RESTOREALL)
+ ret = _TIF_RESTOREALL;
+ else
+ regs->gpr[3] = r3;
+ clear_bits(_TIF_PERSYSCALL_MASK, ti_flagsp);
+ } else {
+ regs->gpr[3] = r3;
+ }
+
+again:
+ local_irq_disable();
+ ti_flags = READ_ONCE(*ti_flagsp);
+ while (unlikely(ti_flags & _TIF_USER_WORK_MASK)) {
+ local_irq_enable();
+ if (ti_flags & _TIF_NEED_RESCHED) {
+ schedule();
+ } else {
+ /*
+ * SIGPENDING must restore signal handler function
+ * argument GPRs, and some non-volatiles (e.g., r1).
+ * Restore all for now. This could be made lighter.
+ */
+ if (ti_flags & _TIF_SIGPENDING)
+ ret |= _TIF_RESTOREALL;
+ do_notify_resume(regs, ti_flags);
+ }
+ local_irq_disable();
+ ti_flags = READ_ONCE(*ti_flagsp);
+ }
+
+#ifdef CONFIG_ALTIVEC
+ if ((regs->msr & (MSR_FP|MSR_VEC)) != (MSR_FP|MSR_VEC))
+#else
+ if ((regs->msr & MSR_FP) != MSR_FP)
+#endif
+ restore_math(regs);
+
+ /* This pattern matches prep_irq_for_idle */
+ __mtmsrd(0, 1); /* Disable MSR_EE and MSR_RI */
+ if (unlikely(lazy_irq_pending())) {
+ __mtmsrd(MSR_RI, 1);
+ local_paca->irq_happened |= PACA_IRQ_HARD_DIS;
+ local_irq_enable();
+ /* Took an interrupt which may have more exit work to do. */
+ goto again;
+ }
+ trace_hardirqs_on();
+ local_paca->irq_happened &= ~PACA_IRQ_HARD_DIS;
+ irq_soft_mask_set(IRQS_ENABLED);
+
+ account_cpu_user_exit();
+
+#ifdef CONFIG_PPC_KUAP_DEBUG
+ if (mmu_has_feature(MMU_FTR_RADIX_KUAP))
+ WARN_ON_ONCE(mfspr(SPRN_AMR) != AMR_KUAP_BLOCKED);
+#endif
+
+ return ret;
+}
+
--
2.22.0
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