From dc7ee00d4771b3218b10e09e1071ee6eb176d381 Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Wed, 24 Apr 2013 10:20:43 +0200 Subject: [PATCH] s390: lowcore stack pointer offsets Store the stack pointers in the lowcore for the kernel stack, the async stack and the panic stack with the offset required for the first user. This avoids an unnecessary add instruction on the system call path. Signed-off-by: Martin Schwidefsky --- arch/s390/kernel/entry.S | 36 ++++++++++++++++-------------------- arch/s390/kernel/entry64.S | 34 ++++++++++++++-------------------- arch/s390/kernel/setup.c | 9 ++++++--- arch/s390/kernel/smp.c | 15 ++++++++++----- 4 files changed, 46 insertions(+), 48 deletions(-) diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S index 94feff7d6132..17d5cc057893 100644 --- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -45,6 +45,7 @@ _TIF_TRACE = (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SECCOMP | \ STACK_SHIFT = PAGE_SHIFT + THREAD_ORDER STACK_SIZE = 1 << STACK_SHIFT +STACK_INIT = STACK_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE #define BASED(name) name-system_call(%r13) @@ -97,10 +98,10 @@ STACK_SIZE = 1 << STACK_SHIFT sra %r14,\shift jnz 1f CHECK_STACK 1<<\shift,\savearea + ahi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE) j 2f 1: l %r15,\stack # load target stack -2: ahi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE) - la %r11,STACK_FRAME_OVERHEAD(%r15) +2: la %r11,STACK_FRAME_OVERHEAD(%r15) .endm .macro ADD64 high,low,timer @@ -150,7 +151,7 @@ ENTRY(__switch_to) l %r4,__THREAD_info(%r2) # get thread_info of prev l %r5,__THREAD_info(%r3) # get thread_info of next lr %r15,%r5 - ahi %r15,STACK_SIZE # end of kernel stack of next + ahi %r15,STACK_INIT # end of kernel stack of next st %r3,__LC_CURRENT # store task struct of next st %r5,__LC_THREAD_INFO # store thread info of next st %r15,__LC_KERNEL_STACK # store end of kernel stack @@ -178,7 +179,6 @@ sysc_stm: l %r13,__LC_SVC_NEW_PSW+4 sysc_per: l %r15,__LC_KERNEL_STACK - ahi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE) la %r11,STACK_FRAME_OVERHEAD(%r15) # pointer to pt_regs sysc_vtime: UPDATE_VTIME %r8,%r9,__LC_SYNC_ENTER_TIMER @@ -359,11 +359,11 @@ ENTRY(pgm_check_handler) tm __LC_PGM_ILC+3,0x80 # check for per exception jnz pgm_svcper # -> single stepped svc 0: CHECK_STACK STACK_SIZE,__LC_SAVE_AREA_SYNC + ahi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE) j 2f 1: UPDATE_VTIME %r14,%r15,__LC_SYNC_ENTER_TIMER l %r15,__LC_KERNEL_STACK -2: ahi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE) - la %r11,STACK_FRAME_OVERHEAD(%r15) +2: la %r11,STACK_FRAME_OVERHEAD(%r15) stm %r0,%r7,__PT_R0(%r11) mvc __PT_R8(32,%r11),__LC_SAVE_AREA_SYNC stm %r8,%r9,__PT_PSW(%r11) @@ -485,7 +485,6 @@ io_work: # io_work_user: l %r1,__LC_KERNEL_STACK - ahi %r1,-(STACK_FRAME_OVERHEAD + __PT_SIZE) mvc STACK_FRAME_OVERHEAD(__PT_SIZE,%r1),0(%r11) xc __SF_BACKCHAIN(4,%r1),__SF_BACKCHAIN(%r1) la %r11,STACK_FRAME_OVERHEAD(%r1) @@ -646,7 +645,6 @@ mcck_skip: tm __PT_PSW+1(%r11),0x01 # returning to user ? jno mcck_return l %r1,__LC_KERNEL_STACK # switch to kernel stack - ahi %r1,-(STACK_FRAME_OVERHEAD + __PT_SIZE) mvc STACK_FRAME_OVERHEAD(__PT_SIZE,%r1),0(%r11) xc __SF_BACKCHAIN(4,%r1),__SF_BACKCHAIN(%r1) la %r11,STACK_FRAME_OVERHEAD(%r15) @@ -674,6 +672,7 @@ mcck_panic: sra %r14,PAGE_SHIFT jz 0f l %r15,__LC_PANIC_STACK + j mcck_skip 0: ahi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE) j mcck_skip @@ -714,12 +713,10 @@ ENTRY(restart_int_handler) */ stack_overflow: l %r15,__LC_PANIC_STACK # change to panic stack - ahi %r15,-__PT_SIZE # create pt_regs - stm %r0,%r7,__PT_R0(%r15) - stm %r8,%r9,__PT_PSW(%r15) + la %r11,STACK_FRAME_OVERHEAD(%r15) + stm %r0,%r7,__PT_R0(%r11) + stm %r8,%r9,__PT_PSW(%r11) mvc __PT_R8(32,%r11),0(%r14) - lr %r15,%r11 - ahi %r15,-STACK_FRAME_OVERHEAD l %r1,BASED(1f) xc __SF_BACKCHAIN(4,%r15),__SF_BACKCHAIN(%r15) lr %r2,%r11 # pass pointer to pt_regs @@ -799,15 +796,14 @@ cleanup_system_call: mvc __LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER # set up saved register 11 l %r15,__LC_KERNEL_STACK - ahi %r15,-__PT_SIZE - st %r15,12(%r11) # r11 pt_regs pointer + la %r9,STACK_FRAME_OVERHEAD(%r15) + st %r9,12(%r11) # r11 pt_regs pointer # fill pt_regs - mvc __PT_R8(32,%r15),__LC_SAVE_AREA_SYNC - stm %r0,%r7,__PT_R0(%r15) - mvc __PT_PSW(8,%r15),__LC_SVC_OLD_PSW - mvc __PT_INT_CODE(4,%r15),__LC_SVC_ILC + mvc __PT_R8(32,%r9),__LC_SAVE_AREA_SYNC + stm %r0,%r7,__PT_R0(%r9) + mvc __PT_PSW(8,%r9),__LC_SVC_OLD_PSW + mvc __PT_INT_CODE(4,%r9),__LC_SVC_ILC # setup saved register 15 - ahi %r15,-STACK_FRAME_OVERHEAD st %r15,28(%r11) # r15 stack pointer # set new psw address and exit l %r9,BASED(cleanup_table+4) # sysc_do_svc + 0x80000000 diff --git a/arch/s390/kernel/entry64.S b/arch/s390/kernel/entry64.S index 2e6d60c55f90..72f230baf5d1 100644 --- a/arch/s390/kernel/entry64.S +++ b/arch/s390/kernel/entry64.S @@ -39,6 +39,7 @@ __PT_R15 = __PT_GPRS + 120 STACK_SHIFT = PAGE_SHIFT + THREAD_ORDER STACK_SIZE = 1 << STACK_SHIFT +STACK_INIT = STACK_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE _TIF_WORK_SVC = (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED | \ _TIF_MCCK_PENDING | _TIF_PER_TRAP ) @@ -124,10 +125,10 @@ _TIF_EXIT_SIE = (_TIF_SIGPENDING | _TIF_NEED_RESCHED | _TIF_MCCK_PENDING) srag %r14,%r14,\shift jnz 1f CHECK_STACK 1<<\shift,\savearea + aghi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE) j 2f 1: lg %r15,\stack # load target stack -2: aghi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE) - la %r11,STACK_FRAME_OVERHEAD(%r15) +2: la %r11,STACK_FRAME_OVERHEAD(%r15) .endm .macro UPDATE_VTIME scratch,enter_timer @@ -177,7 +178,7 @@ ENTRY(__switch_to) lg %r4,__THREAD_info(%r2) # get thread_info of prev lg %r5,__THREAD_info(%r3) # get thread_info of next lgr %r15,%r5 - aghi %r15,STACK_SIZE # end of kernel stack of next + aghi %r15,STACK_INIT # end of kernel stack of next stg %r3,__LC_CURRENT # store task struct of next stg %r5,__LC_THREAD_INFO # store thread info of next stg %r15,__LC_KERNEL_STACK # store end of kernel stack @@ -203,10 +204,8 @@ sysc_stmg: stmg %r8,%r15,__LC_SAVE_AREA_SYNC lg %r10,__LC_LAST_BREAK lg %r12,__LC_THREAD_INFO - larl %r13,system_call sysc_per: lg %r15,__LC_KERNEL_STACK - aghi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE) la %r11,STACK_FRAME_OVERHEAD(%r15) # pointer to pt_regs sysc_vtime: UPDATE_VTIME %r13,__LC_SYNC_ENTER_TIMER @@ -389,6 +388,7 @@ ENTRY(pgm_check_handler) tm __LC_PGM_ILC+3,0x80 # check for per exception jnz pgm_svcper # -> single stepped svc 0: CHECK_STACK STACK_SIZE,__LC_SAVE_AREA_SYNC + aghi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE) j 2f 1: UPDATE_VTIME %r14,__LC_SYNC_ENTER_TIMER LAST_BREAK %r14 @@ -398,8 +398,7 @@ ENTRY(pgm_check_handler) tm __LC_PGM_ILC+2,0x02 # check for transaction abort jz 2f mvc __THREAD_trap_tdb(256,%r14),0(%r13) -2: aghi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE) - la %r11,STACK_FRAME_OVERHEAD(%r15) +2: la %r11,STACK_FRAME_OVERHEAD(%r15) stmg %r0,%r7,__PT_R0(%r11) mvc __PT_R8(64,%r11),__LC_SAVE_AREA_SYNC stmg %r8,%r9,__PT_PSW(%r11) @@ -526,7 +525,6 @@ io_work: # io_work_user: lg %r1,__LC_KERNEL_STACK - aghi %r1,-(STACK_FRAME_OVERHEAD + __PT_SIZE) mvc STACK_FRAME_OVERHEAD(__PT_SIZE,%r1),0(%r11) xc __SF_BACKCHAIN(8,%r1),__SF_BACKCHAIN(%r1) la %r11,STACK_FRAME_OVERHEAD(%r1) @@ -688,7 +686,6 @@ mcck_skip: tm __PT_PSW+1(%r11),0x01 # returning to user ? jno mcck_return lg %r1,__LC_KERNEL_STACK # switch to kernel stack - aghi %r1,-(STACK_FRAME_OVERHEAD + __PT_SIZE) mvc STACK_FRAME_OVERHEAD(__PT_SIZE,%r1),0(%r11) xc __SF_BACKCHAIN(8,%r1),__SF_BACKCHAIN(%r1) la %r11,STACK_FRAME_OVERHEAD(%r1) @@ -755,14 +752,12 @@ ENTRY(restart_int_handler) * Setup a pt_regs so that show_trace can provide a good call trace. */ stack_overflow: - lg %r11,__LC_PANIC_STACK # change to panic stack - aghi %r11,-__PT_SIZE # create pt_regs + lg %r15,__LC_PANIC_STACK # change to panic stack + la %r11,STACK_FRAME_OVERHEAD(%r15) stmg %r0,%r7,__PT_R0(%r11) stmg %r8,%r9,__PT_PSW(%r11) mvc __PT_R8(64,%r11),0(%r14) stg %r10,__PT_ORIG_GPR2(%r11) # store last break to orig_gpr2 - lgr %r15,%r11 - aghi %r15,-STACK_FRAME_OVERHEAD xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15) lgr %r2,%r11 # pass pointer to pt_regs jg kernel_stack_overflow @@ -846,15 +841,14 @@ cleanup_system_call: mvc __TI_last_break(8,%r12),16(%r11) 0: # set up saved register r11 lg %r15,__LC_KERNEL_STACK - aghi %r15,-__PT_SIZE - stg %r15,24(%r11) # r11 pt_regs pointer + la %r9,STACK_FRAME_OVERHEAD(%r15) + stg %r9,24(%r11) # r11 pt_regs pointer # fill pt_regs - mvc __PT_R8(64,%r15),__LC_SAVE_AREA_SYNC - stmg %r0,%r7,__PT_R0(%r15) - mvc __PT_PSW(16,%r15),__LC_SVC_OLD_PSW - mvc __PT_INT_CODE(4,%r15),__LC_SVC_ILC + mvc __PT_R8(64,%r9),__LC_SAVE_AREA_SYNC + stmg %r0,%r7,__PT_R0(%r9) + mvc __PT_PSW(16,%r9),__LC_SVC_OLD_PSW + mvc __PT_INT_CODE(4,%r9),__LC_SVC_ILC # setup saved register r15 - aghi %r15,-STACK_FRAME_OVERHEAD stg %r15,56(%r11) # r15 stack pointer # set new psw address and exit larl %r9,sysc_do_svc diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c index 29268859d8ee..0f419c5765c8 100644 --- a/arch/s390/kernel/setup.c +++ b/arch/s390/kernel/setup.c @@ -377,11 +377,14 @@ static void __init setup_lowcore(void) PSW_MASK_DAT | PSW_MASK_MCHECK; lc->io_new_psw.addr = PSW_ADDR_AMODE | (unsigned long) io_int_handler; lc->clock_comparator = -1ULL; - lc->kernel_stack = ((unsigned long) &init_thread_union) + THREAD_SIZE; + lc->kernel_stack = ((unsigned long) &init_thread_union) + + THREAD_SIZE - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs); lc->async_stack = (unsigned long) - __alloc_bootmem(ASYNC_SIZE, ASYNC_SIZE, 0) + ASYNC_SIZE; + __alloc_bootmem(ASYNC_SIZE, ASYNC_SIZE, 0) + + ASYNC_SIZE - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs); lc->panic_stack = (unsigned long) - __alloc_bootmem(PAGE_SIZE, PAGE_SIZE, 0) + PAGE_SIZE; + __alloc_bootmem(PAGE_SIZE, PAGE_SIZE, 0) + + PAGE_SIZE - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs); lc->current_task = (unsigned long) init_thread_union.thread_info.task; lc->thread_info = (unsigned long) &init_thread_union; lc->machine_flags = S390_lowcore.machine_flags; diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c index 549c9d173c0f..8bde89eafd88 100644 --- a/arch/s390/kernel/smp.c +++ b/arch/s390/kernel/smp.c @@ -181,8 +181,10 @@ static int __cpuinit pcpu_alloc_lowcore(struct pcpu *pcpu, int cpu) lc = pcpu->lowcore; memcpy(lc, &S390_lowcore, 512); memset((char *) lc + 512, 0, sizeof(*lc) - 512); - lc->async_stack = pcpu->async_stack + ASYNC_SIZE; - lc->panic_stack = pcpu->panic_stack + PAGE_SIZE; + lc->async_stack = pcpu->async_stack + ASYNC_SIZE + - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs); + lc->panic_stack = pcpu->panic_stack + PAGE_SIZE + - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs); lc->cpu_nr = cpu; #ifndef CONFIG_64BIT if (MACHINE_HAS_IEEE) { @@ -253,7 +255,8 @@ static void pcpu_attach_task(struct pcpu *pcpu, struct task_struct *tsk) struct _lowcore *lc = pcpu->lowcore; struct thread_info *ti = task_thread_info(tsk); - lc->kernel_stack = (unsigned long) task_stack_page(tsk) + THREAD_SIZE; + lc->kernel_stack = (unsigned long) task_stack_page(tsk) + + THREAD_SIZE - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs); lc->thread_info = (unsigned long) task_thread_info(tsk); lc->current_task = (unsigned long) tsk; lc->user_timer = ti->user_timer; @@ -810,8 +813,10 @@ void __init smp_prepare_boot_cpu(void) pcpu->state = CPU_STATE_CONFIGURED; pcpu->address = boot_cpu_address; pcpu->lowcore = (struct _lowcore *)(unsigned long) store_prefix(); - pcpu->async_stack = S390_lowcore.async_stack - ASYNC_SIZE; - pcpu->panic_stack = S390_lowcore.panic_stack - PAGE_SIZE; + pcpu->async_stack = S390_lowcore.async_stack - ASYNC_SIZE + + STACK_FRAME_OVERHEAD + sizeof(struct pt_regs); + pcpu->panic_stack = S390_lowcore.panic_stack - PAGE_SIZE + + STACK_FRAME_OVERHEAD + sizeof(struct pt_regs); S390_lowcore.percpu_offset = __per_cpu_offset[0]; smp_cpu_set_polarization(0, POLARIZATION_UNKNOWN); set_cpu_present(0, true); -- 2.20.1