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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 <schwidefsky@de.ibm.com>
This commit is contained in:
Martin Schwidefsky 2013-04-24 10:20:43 +02:00
parent b8668fd0a7
commit dc7ee00d47
4 changed files with 46 additions and 48 deletions
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36
arch/s390/kernel/entry.S
View File

@ -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

34
arch/s390/kernel/entry64.S
View File

@ -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

9
arch/s390/kernel/setup.c
View File

@ -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;

15
arch/s390/kernel/smp.c
View File

@ -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);