/*
* 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
/*
* kernel_thread(fn, arg, clone_flags)
*/
.align 4
.globl kernel_thread
.ent kernel_thread
kernel_thread:
/* We can be called from a module. */
ldgp $gp, 0($27)
.prologue 1
subq $sp, SP_OFF+6*8, $sp
br $1, 2f /* load start address */
/* We've now "returned" from a fake system call. */
unop
blt $0, 1f /* error? */
ldi $1, 0x3fff
beq $20, 1f /* parent or child? */
bic $sp, $1, $8 /* in child. */
jsr $26, ($27)
ldgp $gp, 0($26)
mov $0, $16
mov $31, $26
jmp $31, sys_exit
1: ret /* in parent. */
.align 4
2: /* Fake a system call stack frame, as we can't do system calls
from kernel space. Note that we store FN and ARG as they
need to be set up in the child for the call. Also store $8
and $26 for use in the parent. */
stq $31, SP_OFF($sp) /* ps */
stq $1, SP_OFF+8($sp) /* pc */
stq $gp, SP_OFF+16($sp) /* gp */
stq $16, 136($sp) /* $27; FN for child */
stq $17, SP_OFF+24($sp) /* $16; ARG for child */
stq $8, 64($sp) /* $8 */
stq $26, 128($sp) /* $26 */
/* Avoid the HAE being gratuitously wrong, to avoid restoring it. */
ldq $2, alpha_mv+HAE_CACHE
stq $2, 152($sp) /* HAE */
/* Shuffle FLAGS to the front; add CLONE_VM. */
ldi $1, CLONE_VM|CLONE_UNTRACED
or $18, $1, $16
bsr $26, sys_clone
/* We don't actually care for a3 success widgetry in the kernel.
Not for positive errno values. */
stq $0, 0($sp) /* $0 */
br ret_to_kernel
.end 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 sys_execve
.ent sys_execve
sys_execve:
.prologue 0
mov $sp, $19
jmp $31, do_sys_execve
.end sys_execve
.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
