linux/arch/alpha/kernel/entry.S
Al Viro cba1ec7e88 alpha: switch to generic kernel_thread()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-09-30 22:53:18 -04:00

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/*
* arch/alpha/kernel/entry.S
*
* Kernel entry-points.
*/
#include <asm/asm-offsets.h>
#include <asm/thread_info.h>
#include <asm/pal.h>
#include <asm/errno.h>
#include <asm/unistd.h>
.text
.set noat
/* Stack offsets. */
#define SP_OFF 184
#define SWITCH_STACK_SIZE 320
/*
* This defines the normal kernel pt-regs layout.
*
* regs 9-15 preserved by C code
* regs 16-18 saved by PAL-code
* regs 29-30 saved and set up by PAL-code
* JRP - Save regs 16-18 in a special area of the stack, so that
* the palcode-provided values are available to the signal handler.
*/
#define SAVE_ALL \
subq $sp, SP_OFF, $sp; \
stq $0, 0($sp); \
stq $1, 8($sp); \
stq $2, 16($sp); \
stq $3, 24($sp); \
stq $4, 32($sp); \
stq $28, 144($sp); \
lda $2, alpha_mv; \
stq $5, 40($sp); \
stq $6, 48($sp); \
stq $7, 56($sp); \
stq $8, 64($sp); \
stq $19, 72($sp); \
stq $20, 80($sp); \
stq $21, 88($sp); \
ldq $2, HAE_CACHE($2); \
stq $22, 96($sp); \
stq $23, 104($sp); \
stq $24, 112($sp); \
stq $25, 120($sp); \
stq $26, 128($sp); \
stq $27, 136($sp); \
stq $2, 152($sp); \
stq $16, 160($sp); \
stq $17, 168($sp); \
stq $18, 176($sp)
#define RESTORE_ALL \
lda $19, alpha_mv; \
ldq $0, 0($sp); \
ldq $1, 8($sp); \
ldq $2, 16($sp); \
ldq $3, 24($sp); \
ldq $21, 152($sp); \
ldq $20, HAE_CACHE($19); \
ldq $4, 32($sp); \
ldq $5, 40($sp); \
ldq $6, 48($sp); \
ldq $7, 56($sp); \
subq $20, $21, $20; \
ldq $8, 64($sp); \
beq $20, 99f; \
ldq $20, HAE_REG($19); \
stq $21, HAE_CACHE($19); \
stq $21, 0($20); \
99:; \
ldq $19, 72($sp); \
ldq $20, 80($sp); \
ldq $21, 88($sp); \
ldq $22, 96($sp); \
ldq $23, 104($sp); \
ldq $24, 112($sp); \
ldq $25, 120($sp); \
ldq $26, 128($sp); \
ldq $27, 136($sp); \
ldq $28, 144($sp); \
addq $sp, SP_OFF, $sp
/*
* Non-syscall kernel entry points.
*/
.align 4
.globl entInt
.ent entInt
entInt:
SAVE_ALL
lda $8, 0x3fff
lda $26, ret_from_sys_call
bic $sp, $8, $8
mov $sp, $19
jsr $31, do_entInt
.end entInt
.align 4
.globl entArith
.ent entArith
entArith:
SAVE_ALL
lda $8, 0x3fff
lda $26, ret_from_sys_call
bic $sp, $8, $8
mov $sp, $18
jsr $31, do_entArith
.end entArith
.align 4
.globl entMM
.ent entMM
entMM:
SAVE_ALL
/* save $9 - $15 so the inline exception code can manipulate them. */
subq $sp, 56, $sp
stq $9, 0($sp)
stq $10, 8($sp)
stq $11, 16($sp)
stq $12, 24($sp)
stq $13, 32($sp)
stq $14, 40($sp)
stq $15, 48($sp)
addq $sp, 56, $19
/* handle the fault */
lda $8, 0x3fff
bic $sp, $8, $8
jsr $26, do_page_fault
/* reload the registers after the exception code played. */
ldq $9, 0($sp)
ldq $10, 8($sp)
ldq $11, 16($sp)
ldq $12, 24($sp)
ldq $13, 32($sp)
ldq $14, 40($sp)
ldq $15, 48($sp)
addq $sp, 56, $sp
/* finish up the syscall as normal. */
br ret_from_sys_call
.end entMM
.align 4
.globl entIF
.ent entIF
entIF:
SAVE_ALL
lda $8, 0x3fff
lda $26, ret_from_sys_call
bic $sp, $8, $8
mov $sp, $17
jsr $31, do_entIF
.end entIF
.align 4
.globl entUna
.ent entUna
entUna:
lda $sp, -256($sp)
stq $0, 0($sp)
ldq $0, 256($sp) /* get PS */
stq $1, 8($sp)
stq $2, 16($sp)
stq $3, 24($sp)
and $0, 8, $0 /* user mode? */
stq $4, 32($sp)
bne $0, entUnaUser /* yup -> do user-level unaligned fault */
stq $5, 40($sp)
stq $6, 48($sp)
stq $7, 56($sp)
stq $8, 64($sp)
stq $9, 72($sp)
stq $10, 80($sp)
stq $11, 88($sp)
stq $12, 96($sp)
stq $13, 104($sp)
stq $14, 112($sp)
stq $15, 120($sp)
/* 16-18 PAL-saved */
stq $19, 152($sp)
stq $20, 160($sp)
stq $21, 168($sp)
stq $22, 176($sp)
stq $23, 184($sp)
stq $24, 192($sp)
stq $25, 200($sp)
stq $26, 208($sp)
stq $27, 216($sp)
stq $28, 224($sp)
mov $sp, $19
stq $gp, 232($sp)
lda $8, 0x3fff
stq $31, 248($sp)
bic $sp, $8, $8
jsr $26, do_entUna
ldq $0, 0($sp)
ldq $1, 8($sp)
ldq $2, 16($sp)
ldq $3, 24($sp)
ldq $4, 32($sp)
ldq $5, 40($sp)
ldq $6, 48($sp)
ldq $7, 56($sp)
ldq $8, 64($sp)
ldq $9, 72($sp)
ldq $10, 80($sp)
ldq $11, 88($sp)
ldq $12, 96($sp)
ldq $13, 104($sp)
ldq $14, 112($sp)
ldq $15, 120($sp)
/* 16-18 PAL-saved */
ldq $19, 152($sp)
ldq $20, 160($sp)
ldq $21, 168($sp)
ldq $22, 176($sp)
ldq $23, 184($sp)
ldq $24, 192($sp)
ldq $25, 200($sp)
ldq $26, 208($sp)
ldq $27, 216($sp)
ldq $28, 224($sp)
ldq $gp, 232($sp)
lda $sp, 256($sp)
call_pal PAL_rti
.end entUna
.align 4
.ent entUnaUser
entUnaUser:
ldq $0, 0($sp) /* restore original $0 */
lda $sp, 256($sp) /* pop entUna's stack frame */
SAVE_ALL /* setup normal kernel stack */
lda $sp, -56($sp)
stq $9, 0($sp)
stq $10, 8($sp)
stq $11, 16($sp)
stq $12, 24($sp)
stq $13, 32($sp)
stq $14, 40($sp)
stq $15, 48($sp)
lda $8, 0x3fff
addq $sp, 56, $19
bic $sp, $8, $8
jsr $26, do_entUnaUser
ldq $9, 0($sp)
ldq $10, 8($sp)
ldq $11, 16($sp)
ldq $12, 24($sp)
ldq $13, 32($sp)
ldq $14, 40($sp)
ldq $15, 48($sp)
lda $sp, 56($sp)
br ret_from_sys_call
.end entUnaUser
.align 4
.globl entDbg
.ent entDbg
entDbg:
SAVE_ALL
lda $8, 0x3fff
lda $26, ret_from_sys_call
bic $sp, $8, $8
mov $sp, $16
jsr $31, do_entDbg
.end entDbg
/*
* The system call entry point is special. Most importantly, it looks
* like a function call to userspace as far as clobbered registers. We
* do preserve the argument registers (for syscall restarts) and $26
* (for leaf syscall functions).
*
* So much for theory. We don't take advantage of this yet.
*
* Note that a0-a2 are not saved by PALcode as with the other entry points.
*/
.align 4
.globl entSys
.globl ret_from_sys_call
.ent entSys
entSys:
SAVE_ALL
lda $8, 0x3fff
bic $sp, $8, $8
lda $4, NR_SYSCALLS($31)
stq $16, SP_OFF+24($sp)
lda $5, sys_call_table
lda $27, sys_ni_syscall
cmpult $0, $4, $4
ldl $3, TI_FLAGS($8)
stq $17, SP_OFF+32($sp)
s8addq $0, $5, $5
stq $18, SP_OFF+40($sp)
blbs $3, strace
beq $4, 1f
ldq $27, 0($5)
1: jsr $26, ($27), alpha_ni_syscall
ldgp $gp, 0($26)
blt $0, $syscall_error /* the call failed */
stq $0, 0($sp)
stq $31, 72($sp) /* a3=0 => no error */
.align 4
ret_from_sys_call:
cmovne $26, 0, $19 /* $19 = 0 => non-restartable */
ldq $0, SP_OFF($sp)
and $0, 8, $0
beq $0, ret_to_kernel
ret_to_user:
/* Make sure need_resched and sigpending don't change between
sampling and the rti. */
lda $16, 7
call_pal PAL_swpipl
ldl $5, TI_FLAGS($8)
and $5, _TIF_WORK_MASK, $2
bne $2, work_pending
restore_all:
RESTORE_ALL
call_pal PAL_rti
ret_to_kernel:
lda $16, 7
call_pal PAL_swpipl
br restore_all
.align 3
$syscall_error:
/*
* Some system calls (e.g., ptrace) can return arbitrary
* values which might normally be mistaken as error numbers.
* Those functions must zero $0 (v0) directly in the stack
* frame to indicate that a negative return value wasn't an
* error number..
*/
ldq $19, 0($sp) /* old syscall nr (zero if success) */
beq $19, $ret_success
ldq $20, 72($sp) /* .. and this a3 */
subq $31, $0, $0 /* with error in v0 */
addq $31, 1, $1 /* set a3 for errno return */
stq $0, 0($sp)
mov $31, $26 /* tell "ret_from_sys_call" we can restart */
stq $1, 72($sp) /* a3 for return */
br ret_from_sys_call
$ret_success:
stq $0, 0($sp)
stq $31, 72($sp) /* a3=0 => no error */
br ret_from_sys_call
.end entSys
/*
* Do all cleanup when returning from all interrupts and system calls.
*
* Arguments:
* $5: TI_FLAGS.
* $8: current.
* $19: The old syscall number, or zero if this is not a return
* from a syscall that errored and is possibly restartable.
* $20: The old a3 value
*/
.align 4
.ent work_pending
work_pending:
and $5, _TIF_NEED_RESCHED, $2
beq $2, $work_notifysig
$work_resched:
subq $sp, 16, $sp
stq $19, 0($sp) /* save syscall nr */
stq $20, 8($sp) /* and error indication (a3) */
jsr $26, schedule
ldq $19, 0($sp)
ldq $20, 8($sp)
addq $sp, 16, $sp
/* Make sure need_resched and sigpending don't change between
sampling and the rti. */
lda $16, 7
call_pal PAL_swpipl
ldl $5, TI_FLAGS($8)
and $5, _TIF_WORK_MASK, $2
beq $2, restore_all
and $5, _TIF_NEED_RESCHED, $2
bne $2, $work_resched
$work_notifysig:
mov $sp, $16
bsr $1, do_switch_stack
mov $sp, $17
mov $5, $18
mov $19, $9 /* save old syscall number */
mov $20, $10 /* save old a3 */
and $5, _TIF_SIGPENDING, $2
cmovne $2, 0, $9 /* we don't want double syscall restarts */
jsr $26, do_notify_resume
mov $9, $19
mov $10, $20
bsr $1, undo_switch_stack
br ret_to_user
.end work_pending
/*
* PTRACE syscall handler
*/
.align 4
.ent strace
strace:
/* set up signal stack, call syscall_trace */
bsr $1, do_switch_stack
jsr $26, syscall_trace
bsr $1, undo_switch_stack
/* get the system call number and the arguments back.. */
ldq $0, 0($sp)
ldq $16, SP_OFF+24($sp)
ldq $17, SP_OFF+32($sp)
ldq $18, SP_OFF+40($sp)
ldq $19, 72($sp)
ldq $20, 80($sp)
ldq $21, 88($sp)
/* get the system call pointer.. */
lda $1, NR_SYSCALLS($31)
lda $2, sys_call_table
lda $27, alpha_ni_syscall
cmpult $0, $1, $1
s8addq $0, $2, $2
beq $1, 1f
ldq $27, 0($2)
1: jsr $26, ($27), sys_gettimeofday
ret_from_straced:
ldgp $gp, 0($26)
/* check return.. */
blt $0, $strace_error /* the call failed */
stq $31, 72($sp) /* a3=0 => no error */
$strace_success:
stq $0, 0($sp) /* save return value */
bsr $1, do_switch_stack
jsr $26, syscall_trace
bsr $1, undo_switch_stack
br $31, ret_from_sys_call
.align 3
$strace_error:
ldq $19, 0($sp) /* old syscall nr (zero if success) */
beq $19, $strace_success
ldq $20, 72($sp) /* .. and this a3 */
subq $31, $0, $0 /* with error in v0 */
addq $31, 1, $1 /* set a3 for errno return */
stq $0, 0($sp)
stq $1, 72($sp) /* a3 for return */
bsr $1, do_switch_stack
mov $19, $9 /* save old syscall number */
mov $20, $10 /* save old a3 */
jsr $26, syscall_trace
mov $9, $19
mov $10, $20
bsr $1, undo_switch_stack
mov $31, $26 /* tell "ret_from_sys_call" we can restart */
br ret_from_sys_call
.end strace
/*
* Save and restore the switch stack -- aka the balance of the user context.
*/
.align 4
.ent do_switch_stack
do_switch_stack:
lda $sp, -SWITCH_STACK_SIZE($sp)
stq $9, 0($sp)
stq $10, 8($sp)
stq $11, 16($sp)
stq $12, 24($sp)
stq $13, 32($sp)
stq $14, 40($sp)
stq $15, 48($sp)
stq $26, 56($sp)
stt $f0, 64($sp)
stt $f1, 72($sp)
stt $f2, 80($sp)
stt $f3, 88($sp)
stt $f4, 96($sp)
stt $f5, 104($sp)
stt $f6, 112($sp)
stt $f7, 120($sp)
stt $f8, 128($sp)
stt $f9, 136($sp)
stt $f10, 144($sp)
stt $f11, 152($sp)
stt $f12, 160($sp)
stt $f13, 168($sp)
stt $f14, 176($sp)
stt $f15, 184($sp)
stt $f16, 192($sp)
stt $f17, 200($sp)
stt $f18, 208($sp)
stt $f19, 216($sp)
stt $f20, 224($sp)
stt $f21, 232($sp)
stt $f22, 240($sp)
stt $f23, 248($sp)
stt $f24, 256($sp)
stt $f25, 264($sp)
stt $f26, 272($sp)
stt $f27, 280($sp)
mf_fpcr $f0 # get fpcr
stt $f28, 288($sp)
stt $f29, 296($sp)
stt $f30, 304($sp)
stt $f0, 312($sp) # save fpcr in slot of $f31
ldt $f0, 64($sp) # dont let "do_switch_stack" change fp state.
ret $31, ($1), 1
.end do_switch_stack
.align 4
.ent undo_switch_stack
undo_switch_stack:
ldq $9, 0($sp)
ldq $10, 8($sp)
ldq $11, 16($sp)
ldq $12, 24($sp)
ldq $13, 32($sp)
ldq $14, 40($sp)
ldq $15, 48($sp)
ldq $26, 56($sp)
ldt $f30, 312($sp) # get saved fpcr
ldt $f0, 64($sp)
ldt $f1, 72($sp)
ldt $f2, 80($sp)
ldt $f3, 88($sp)
mt_fpcr $f30 # install saved fpcr
ldt $f4, 96($sp)
ldt $f5, 104($sp)
ldt $f6, 112($sp)
ldt $f7, 120($sp)
ldt $f8, 128($sp)
ldt $f9, 136($sp)
ldt $f10, 144($sp)
ldt $f11, 152($sp)
ldt $f12, 160($sp)
ldt $f13, 168($sp)
ldt $f14, 176($sp)
ldt $f15, 184($sp)
ldt $f16, 192($sp)
ldt $f17, 200($sp)
ldt $f18, 208($sp)
ldt $f19, 216($sp)
ldt $f20, 224($sp)
ldt $f21, 232($sp)
ldt $f22, 240($sp)
ldt $f23, 248($sp)
ldt $f24, 256($sp)
ldt $f25, 264($sp)
ldt $f26, 272($sp)
ldt $f27, 280($sp)
ldt $f28, 288($sp)
ldt $f29, 296($sp)
ldt $f30, 304($sp)
lda $sp, SWITCH_STACK_SIZE($sp)
ret $31, ($1), 1
.end undo_switch_stack
/*
* The meat of the context switch code.
*/
.align 4
.globl alpha_switch_to
.ent alpha_switch_to
alpha_switch_to:
.prologue 0
bsr $1, do_switch_stack
call_pal PAL_swpctx
lda $8, 0x3fff
bsr $1, undo_switch_stack
bic $sp, $8, $8
mov $17, $0
ret
.end alpha_switch_to
/*
* New processes begin life here.
*/
.globl ret_from_fork
.align 4
.ent ret_from_fork
ret_from_fork:
lda $26, ret_from_sys_call
mov $17, $16
jmp $31, schedule_tail
.end ret_from_fork
/*
* ... and new kernel threads - here
*/
.align 4
.globl ret_from_kernel_thread
.ent ret_from_kernel_thread
ret_from_kernel_thread:
mov $17, $16
jsr $26, schedule_tail
mov $9, $27
mov $10, $16
jsr $26, ($9)
ldgp $gp, 0($26)
mov $0, $16
mov $31, $26
jmp $31, sys_exit
.end ret_from_kernel_thread
/*
* Special system calls. Most of these are special in that they either
* have to play switch_stack games or in some way use the pt_regs struct.
*/
.align 4
.globl sys_fork
.ent sys_fork
sys_fork:
.prologue 0
mov $sp, $21
bsr $1, do_switch_stack
bis $31, SIGCHLD, $16
mov $31, $17
mov $31, $18
mov $31, $19
mov $31, $20
jsr $26, alpha_clone
bsr $1, undo_switch_stack
ret
.end sys_fork
.align 4
.globl sys_clone
.ent sys_clone
sys_clone:
.prologue 0
mov $sp, $21
bsr $1, do_switch_stack
/* $16, $17, $18, $19, $20 come from the user. */
jsr $26, alpha_clone
bsr $1, undo_switch_stack
ret
.end sys_clone
.align 4
.globl sys_vfork
.ent sys_vfork
sys_vfork:
.prologue 0
mov $sp, $16
bsr $1, do_switch_stack
jsr $26, alpha_vfork
bsr $1, undo_switch_stack
ret
.end sys_vfork
.align 4
.globl sys_sigreturn
.ent sys_sigreturn
sys_sigreturn:
.prologue 0
lda $9, ret_from_straced
cmpult $26, $9, $9
mov $sp, $17
lda $18, -SWITCH_STACK_SIZE($sp)
lda $sp, -SWITCH_STACK_SIZE($sp)
jsr $26, do_sigreturn
bne $9, 1f
jsr $26, syscall_trace
1: br $1, undo_switch_stack
br ret_from_sys_call
.end sys_sigreturn
.align 4
.globl sys_rt_sigreturn
.ent sys_rt_sigreturn
sys_rt_sigreturn:
.prologue 0
lda $9, ret_from_straced
cmpult $26, $9, $9
mov $sp, $17
lda $18, -SWITCH_STACK_SIZE($sp)
lda $sp, -SWITCH_STACK_SIZE($sp)
jsr $26, do_rt_sigreturn
bne $9, 1f
jsr $26, syscall_trace
1: br $1, undo_switch_stack
br ret_from_sys_call
.end sys_rt_sigreturn
.align 4
.globl alpha_ni_syscall
.ent alpha_ni_syscall
alpha_ni_syscall:
.prologue 0
/* Special because it also implements overflow handling via
syscall number 0. And if you recall, zero is a special
trigger for "not an error". Store large non-zero there. */
lda $0, -ENOSYS
unop
stq $0, 0($sp)
ret
.end alpha_ni_syscall