[PATCH v3] powerpc/64: system call implement the bulk of the logic in C
Christophe Leroy
christophe.leroy at c-s.fr
Fri Sep 6 01:25:31 AEST 2019
On 09/05/2019 12:35 PM, Nicholas Piggin wrote:
> 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 for the case that all GPRs should be restored at exit.
>
> 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.
>
> Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
Cannot apply it on latest powerpc/merge. On what does that apply ?
# git show --oneline
62d4496a1ecc (HEAD -> int64, hubppc/merge, merge) Automatic merge of
branches 'master', 'next' and 'fixes' into merge
# git am -3
/root/Downloads/v3-powerpc-64-system-call-implement-the-bulk-of-the-logic-in-C.patch
Applying: powerpc/64: system call implement the bulk of the logic in C
Using index info to reconstruct a base tree...
M arch/powerpc/include/asm/asm-prototypes.h
M arch/powerpc/include/asm/ptrace.h
M arch/powerpc/include/asm/time.h
M arch/powerpc/kernel/Makefile
M arch/powerpc/kernel/entry_64.S
Falling back to patching base and 3-way merge...
Auto-merging arch/powerpc/kernel/entry_64.S
CONFLICT (content): Merge conflict in arch/powerpc/kernel/entry_64.S
Auto-merging arch/powerpc/kernel/Makefile
CONFLICT (content): Merge conflict in arch/powerpc/kernel/Makefile
Auto-merging arch/powerpc/include/asm/time.h
Auto-merging arch/powerpc/include/asm/ptrace.h
Auto-merging arch/powerpc/include/asm/asm-prototypes.h
error: Failed to merge in the changes.
Patch failed at 0001 powerpc/64: system call implement the bulk of the
logic in C
The copy of the patch that failed is found in: .git/rebase-apply/patch
When you have resolved this problem, run "git am --continue".
If you prefer to skip this patch, run "git am --skip" instead.
To restore the original branch and stop patching, run "git am --abort".
Christophe
>
> v3:
> - Fix !KUAP build [mpe]
> - Fix BookE build/boot [mpe]
> - Don't trace irqs with MSR[RI]=0
> - Don't allow syscall_exit_prepare to be ftraced, because function
> graph tracing which traces exits barfs after the IRQ state is
> prepared for kernel exit.
> - Fix BE syscall table to use normal function descriptors now that they
> are called from C.
> - Comment syscall_exit_prepare.
> ---
> arch/powerpc/include/asm/asm-prototypes.h | 11 -
> .../powerpc/include/asm/book3s/64/kup-radix.h | 14 +-
> arch/powerpc/include/asm/cputime.h | 24 ++
> arch/powerpc/include/asm/hw_irq.h | 4 +
> arch/powerpc/include/asm/ptrace.h | 3 +
> arch/powerpc/include/asm/signal.h | 3 +
> arch/powerpc/include/asm/switch_to.h | 5 +
> arch/powerpc/include/asm/time.h | 3 +
> arch/powerpc/kernel/Makefile | 3 +-
> arch/powerpc/kernel/entry_64.S | 337 +++---------------
> arch/powerpc/kernel/signal.h | 2 -
> arch/powerpc/kernel/syscall_64.c | 195 ++++++++++
> arch/powerpc/kernel/systbl.S | 9 +-
> 13 files changed, 300 insertions(+), 313 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/book3s/64/kup-radix.h b/arch/powerpc/include/asm/book3s/64/kup-radix.h
> index f254de956d6a..07058edc5970 100644
> --- a/arch/powerpc/include/asm/book3s/64/kup-radix.h
> +++ b/arch/powerpc/include/asm/book3s/64/kup-radix.h
> @@ -3,6 +3,7 @@
> #define _ASM_POWERPC_BOOK3S_64_KUP_RADIX_H
>
> #include <linux/const.h>
> +#include <asm/reg.h>
>
> #define AMR_KUAP_BLOCK_READ UL(0x4000000000000000)
> #define AMR_KUAP_BLOCK_WRITE UL(0x8000000000000000)
> @@ -56,7 +57,14 @@
>
> #ifdef CONFIG_PPC_KUAP
>
> -#include <asm/reg.h>
> +#include <asm/mmu.h>
> +#include <asm/ptrace.h>
> +
> +static inline void kuap_check_amr(void)
> +{
> + if (IS_ENABLED(CONFIG_PPC_KUAP_DEBUG) && mmu_has_feature(MMU_FTR_RADIX_KUAP))
> + WARN_ON_ONCE(mfspr(SPRN_AMR) != AMR_KUAP_BLOCKED);
> +}
>
> /*
> * We support individually allowing read or write, but we don't support nesting
> @@ -101,6 +109,10 @@ static inline bool bad_kuap_fault(struct pt_regs *regs, bool is_write)
> (regs->kuap & (is_write ? AMR_KUAP_BLOCK_WRITE : AMR_KUAP_BLOCK_READ)),
> "Bug: %s fault blocked by AMR!", is_write ? "Write" : "Read");
> }
> +#else /* CONFIG_PPC_KUAP */
> +static inline void kuap_check_amr(void)
> +{
> +}
> #endif /* CONFIG_PPC_KUAP */
>
> #endif /* __ASSEMBLY__ */
> diff --git a/arch/powerpc/include/asm/cputime.h b/arch/powerpc/include/asm/cputime.h
> index 2431b4ada2fa..c43614cffaac 100644
> --- a/arch/powerpc/include/asm/cputime.h
> +++ b/arch/powerpc/include/asm/cputime.h
> @@ -60,6 +60,30 @@ static inline void arch_vtime_task_switch(struct task_struct *prev)
> }
> #endif
>
> +static inline void account_cpu_user_entry(void)
> +{
> + unsigned long tb = mftb();
> + struct cpu_accounting_data *acct = get_accounting(current);
> +
> + acct->utime += (tb - acct->starttime_user);
> + acct->starttime = tb;
> +}
> +static inline void account_cpu_user_exit(void)
> +{
> + unsigned long tb = mftb();
> + struct cpu_accounting_data *acct = get_accounting(current);
> +
> + acct->stime += (tb - acct->starttime);
> + acct->starttime_user = tb;
> +}
> +
> #endif /* __KERNEL__ */
> +#else /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
> +static inline void account_cpu_user_entry(void)
> +{
> +}
> +static inline void account_cpu_user_exit(void)
> +{
> +}
> #endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
> #endif /* __POWERPC_CPUTIME_H */
> diff --git a/arch/powerpc/include/asm/hw_irq.h b/arch/powerpc/include/asm/hw_irq.h
> index 32a18f2f49bc..7e1c7f5873a8 100644
> --- a/arch/powerpc/include/asm/hw_irq.h
> +++ b/arch/powerpc/include/asm/hw_irq.h
> @@ -228,9 +228,13 @@ static inline bool arch_irqs_disabled(void)
> #ifdef CONFIG_PPC_BOOK3E
> #define __hard_irq_enable() asm volatile("wrteei 1" : : : "memory")
> #define __hard_irq_disable() asm volatile("wrteei 0" : : : "memory")
> +#define __hard_EE_RI_disable() asm volatile("wrteei 0" : : : "memory")
> +#define __hard_RI_enable() do { } while (0)
> #else
> #define __hard_irq_enable() __mtmsrd(MSR_EE|MSR_RI, 1)
> #define __hard_irq_disable() __mtmsrd(MSR_RI, 1)
> +#define __hard_EE_RI_disable() __mtmsrd(0, 1)
> +#define __hard_RI_enable() __mtmsrd(MSR_RI, 1)
> #endif
>
> #define hard_irq_disable() do { \
> 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..99e1c6de27bc 100644
> --- a/arch/powerpc/include/asm/signal.h
> +++ b/arch/powerpc/include/asm/signal.h
> @@ -6,4 +6,7 @@
> #include <uapi/asm/signal.h>
> #include <uapi/asm/ptrace.h>
>
> +struct pt_regs;
> +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..476008bc3d08 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 +23,10 @@ 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..15bc2a872a76 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 +70,111 @@ 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
> START_BTB_FLUSH_SECTION
> BTB_FLUSH(r10)
> END_BTB_FLUSH_SECTION
> #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)
> + std r11,-16(r10) /* "regshere" marker */
>
> - 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
> + /* Calling convention has r9 = orig r0, r10 = regs */
> + mr r9,r0
> + bl system_call_exception
>
> -.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.
> - */
> -
> - ldx r12,r11,r0 /* Fetch system call handler [ptr] */
> - mtctr r12
> - bctrl /* Call handler */
> -
> - /* syscall_exit can exit to kernel mode, via ret_from_kernel_thread */
> .Lsyscall_exit:
> - std r3,RESULT(r1)
> + addi r4,r1,STACK_FRAME_OVERHEAD
> + bl syscall_exit_prepare
>
> -#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 */
> -
> - 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
> + mtspr SPRN_SRR0,r4
> + mtspr SPRN_SRR1,r5
> + mtlr r6
>
> -#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
> -#endif
> -
> - 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:
> +_GLOBAL(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)
> @@ -438,8 +193,6 @@ 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
> 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..3787ec54c727
> --- /dev/null
> +++ b/arch/powerpc/kernel/syscall_64.c
> @@ -0,0 +1,195 @@
> +#include <linux/err.h>
> +#include <asm/book3s/64/kup-radix.h>
> +#include <asm/cputime.h>
> +#include <asm/hw_irq.h>
> +#include <asm/kprobes.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);
> +
> +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));
> +
> + if (IS_ENABLED(CONFIG_PPC_TRANSACTIONAL_MEM) &&
> + unlikely(regs->msr & MSR_TS_T))
> + tabort_syscall();
> +
> + account_cpu_user_entry();
> +
> +#ifdef CONFIG_PPC_SPLPAR
> + if (IS_ENABLED(CONFIG_VIRT_CPU_ACCOUNTING_NATIVE) &&
> + firmware_has_feature(FW_FEATURE_SPLPAR)) {
> + struct lppaca *lp = get_lppaca();
> +
> + if (unlikely(local_paca->dtl_ridx != lp->dtl_idx))
> + accumulate_stolen_time();
> + }
> +#endif
> +
> + kuap_check_amr();
> +
> + /*
> + * 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 (IS_ENABLED(CONFIG_PPC_IRQ_SOFT_MASK_DEBUG)) {
> + WARN_ON(irq_soft_mask_return() != IRQS_ENABLED);
> + WARN_ON(local_paca->irq_happened);
> + }
> + /*
> + * This is not required for the syscall exit path, but makes the
> + * stack frame look nicer. If this was initialised in the first stack
> + * frame, or if the unwinder was taught the first stack frame always
> + * returns to user with IRQS_ENABLED, this store could be avoided!
> + */
> + regs->softe = IRQS_ENABLED;
> +
> + __hard_irq_enable();
> +
> + 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);
> +}
> +
> +/*
> + * This should be called after a syscall returns, with r3 the return value
> + * from the syscall. If this function returns non-zero, the system call
> + * exit assembly should additionally load all GPR registers and CTR and XER
> + * from the interrupt frame.
> + *
> + * The function graph tracer can not trace the return side of this function,
> + * because RI=0 and soft mask state is "unreconciled", so it is marked notrace.
> + */
> +notrace 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(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;
> + }
> +
> + if (unlikely(ti_flags & _TIF_SYSCALL_DOTRACE))
> + do_syscall_trace_leave(regs);
> +
> +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);
> + }
> +
> + if (IS_ENABLED(CONFIG_PPC_FPU)) {
> + unsigned long mathflags = MSR_FP;
> +
> + if (IS_ENABLED(CONFIG_ALTIVEC))
> + mathflags |= MSR_VEC;
> +
> + if ((regs->msr & mathflags) != mathflags)
> + restore_math(regs);
> + }
> +
> + /* This must be done with RI=1 because tracing may touch vmaps */
> + trace_hardirqs_on();
> +
> + /* This pattern matches prep_irq_for_idle */
> + __hard_EE_RI_disable();
> + if (unlikely(lazy_irq_pending())) {
> + __hard_RI_enable();
> + trace_hardirqs_off();
> + local_paca->irq_happened |= PACA_IRQ_HARD_DIS;
> + local_irq_enable();
> + /* Took an interrupt which may have more exit work to do. */
> + goto again;
> + }
> + local_paca->irq_happened &= ~PACA_IRQ_HARD_DIS;
> + irq_soft_mask_set(IRQS_ENABLED);
> +
> +#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
> + local_paca->tm_scratch = regs->msr;
> +#endif
> +
> + kuap_check_amr();
> +
> + account_cpu_user_exit();
> +
> + return ret;
> +}
> diff --git a/arch/powerpc/kernel/systbl.S b/arch/powerpc/kernel/systbl.S
> index 5b905a2f4e4d..d34276f3c495 100644
> --- a/arch/powerpc/kernel/systbl.S
> +++ b/arch/powerpc/kernel/systbl.S
> @@ -16,25 +16,22 @@
>
> #ifdef CONFIG_PPC64
> .p2align 3
> +#define __SYSCALL(nr, entry) .8byte entry
> +#else
> +#define __SYSCALL(nr, entry) .long entry
> #endif
>
> .globl sys_call_table
> sys_call_table:
> #ifdef CONFIG_PPC64
> -#define __SYSCALL(nr, entry) .8byte DOTSYM(entry)
> #include <asm/syscall_table_64.h>
> -#undef __SYSCALL
> #else
> -#define __SYSCALL(nr, entry) .long entry
> #include <asm/syscall_table_32.h>
> -#undef __SYSCALL
> #endif
>
> #ifdef CONFIG_COMPAT
> .globl compat_sys_call_table
> compat_sys_call_table:
> #define compat_sys_sigsuspend sys_sigsuspend
> -#define __SYSCALL(nr, entry) .8byte DOTSYM(entry)
> #include <asm/syscall_table_c32.h>
> -#undef __SYSCALL
> #endif
>
More information about the Linuxppc-dev
mailing list