diff options
Diffstat (limited to 'arch/alpha/kernel/entry.S')
| -rw-r--r-- | arch/alpha/kernel/entry.S | 854 |
1 files changed, 854 insertions, 0 deletions
diff --git a/arch/alpha/kernel/entry.S b/arch/alpha/kernel/entry.S new file mode 100644 index 000000000..c41a5a9c3 --- /dev/null +++ b/arch/alpha/kernel/entry.S @@ -0,0 +1,854 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * 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 + .cfi_sections .debug_frame + +/* Stack offsets. */ +#define SP_OFF 184 +#define SWITCH_STACK_SIZE 320 + +.macro CFI_START_OSF_FRAME func + .align 4 + .globl \func + .type \func,@function +\func: + .cfi_startproc simple + .cfi_return_column 64 + .cfi_def_cfa $sp, 48 + .cfi_rel_offset 64, 8 + .cfi_rel_offset $gp, 16 + .cfi_rel_offset $16, 24 + .cfi_rel_offset $17, 32 + .cfi_rel_offset $18, 40 +.endm + +.macro CFI_END_OSF_FRAME func + .cfi_endproc + .size \func, . - \func +.endm + +/* + * 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. + */ + +.macro SAVE_ALL + subq $sp, SP_OFF, $sp + .cfi_adjust_cfa_offset SP_OFF + stq $0, 0($sp) + stq $1, 8($sp) + stq $2, 16($sp) + stq $3, 24($sp) + stq $4, 32($sp) + stq $28, 144($sp) + .cfi_rel_offset $0, 0 + .cfi_rel_offset $1, 8 + .cfi_rel_offset $2, 16 + .cfi_rel_offset $3, 24 + .cfi_rel_offset $4, 32 + .cfi_rel_offset $28, 144 + 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) + .cfi_rel_offset $5, 40 + .cfi_rel_offset $6, 48 + .cfi_rel_offset $7, 56 + .cfi_rel_offset $8, 64 + .cfi_rel_offset $19, 72 + .cfi_rel_offset $20, 80 + .cfi_rel_offset $21, 88 + .cfi_rel_offset $22, 96 + .cfi_rel_offset $23, 104 + .cfi_rel_offset $24, 112 + .cfi_rel_offset $25, 120 + .cfi_rel_offset $26, 128 + .cfi_rel_offset $27, 136 +.endm + +.macro 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 + .cfi_restore $0 + .cfi_restore $1 + .cfi_restore $2 + .cfi_restore $3 + .cfi_restore $4 + .cfi_restore $5 + .cfi_restore $6 + .cfi_restore $7 + .cfi_restore $8 + .cfi_restore $19 + .cfi_restore $20 + .cfi_restore $21 + .cfi_restore $22 + .cfi_restore $23 + .cfi_restore $24 + .cfi_restore $25 + .cfi_restore $26 + .cfi_restore $27 + .cfi_restore $28 + .cfi_adjust_cfa_offset -SP_OFF +.endm + +.macro DO_SWITCH_STACK + bsr $1, do_switch_stack + .cfi_adjust_cfa_offset SWITCH_STACK_SIZE + .cfi_rel_offset $9, 0 + .cfi_rel_offset $10, 8 + .cfi_rel_offset $11, 16 + .cfi_rel_offset $12, 24 + .cfi_rel_offset $13, 32 + .cfi_rel_offset $14, 40 + .cfi_rel_offset $15, 48 + /* We don't really care about the FP registers for debugging. */ +.endm + +.macro UNDO_SWITCH_STACK + bsr $1, undo_switch_stack + .cfi_restore $9 + .cfi_restore $10 + .cfi_restore $11 + .cfi_restore $12 + .cfi_restore $13 + .cfi_restore $14 + .cfi_restore $15 + .cfi_adjust_cfa_offset -SWITCH_STACK_SIZE +.endm + +/* + * Non-syscall kernel entry points. + */ + +CFI_START_OSF_FRAME entInt + SAVE_ALL + lda $8, 0x3fff + lda $26, ret_from_sys_call + bic $sp, $8, $8 + mov $sp, $19 + jsr $31, do_entInt +CFI_END_OSF_FRAME entInt + +CFI_START_OSF_FRAME entArith + SAVE_ALL + lda $8, 0x3fff + lda $26, ret_from_sys_call + bic $sp, $8, $8 + mov $sp, $18 + jsr $31, do_entArith +CFI_END_OSF_FRAME entArith + +CFI_START_OSF_FRAME entMM + SAVE_ALL +/* save $9 - $15 so the inline exception code can manipulate them. */ + subq $sp, 56, $sp + .cfi_adjust_cfa_offset 56 + 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) + .cfi_rel_offset $9, 0 + .cfi_rel_offset $10, 8 + .cfi_rel_offset $11, 16 + .cfi_rel_offset $12, 24 + .cfi_rel_offset $13, 32 + .cfi_rel_offset $14, 40 + .cfi_rel_offset $15, 48 + 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 + .cfi_restore $9 + .cfi_restore $10 + .cfi_restore $11 + .cfi_restore $12 + .cfi_restore $13 + .cfi_restore $14 + .cfi_restore $15 + .cfi_adjust_cfa_offset -56 +/* finish up the syscall as normal. */ + br ret_from_sys_call +CFI_END_OSF_FRAME entMM + +CFI_START_OSF_FRAME entIF + SAVE_ALL + lda $8, 0x3fff + lda $26, ret_from_sys_call + bic $sp, $8, $8 + mov $sp, $17 + jsr $31, do_entIF +CFI_END_OSF_FRAME entIF + +CFI_START_OSF_FRAME entUna + lda $sp, -256($sp) + .cfi_adjust_cfa_offset 256 + stq $0, 0($sp) + .cfi_rel_offset $0, 0 + .cfi_remember_state + 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) + .cfi_rel_offset $1, 1*8 + .cfi_rel_offset $2, 2*8 + .cfi_rel_offset $3, 3*8 + .cfi_rel_offset $4, 4*8 + .cfi_rel_offset $5, 5*8 + .cfi_rel_offset $6, 6*8 + .cfi_rel_offset $7, 7*8 + .cfi_rel_offset $8, 8*8 + .cfi_rel_offset $9, 9*8 + .cfi_rel_offset $10, 10*8 + .cfi_rel_offset $11, 11*8 + .cfi_rel_offset $12, 12*8 + .cfi_rel_offset $13, 13*8 + .cfi_rel_offset $14, 14*8 + .cfi_rel_offset $15, 15*8 + .cfi_rel_offset $19, 19*8 + .cfi_rel_offset $20, 20*8 + .cfi_rel_offset $21, 21*8 + .cfi_rel_offset $22, 22*8 + .cfi_rel_offset $23, 23*8 + .cfi_rel_offset $24, 24*8 + .cfi_rel_offset $25, 25*8 + .cfi_rel_offset $26, 26*8 + .cfi_rel_offset $27, 27*8 + .cfi_rel_offset $28, 28*8 + .cfi_rel_offset $29, 29*8 + 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) + .cfi_restore $1 + .cfi_restore $2 + .cfi_restore $3 + .cfi_restore $4 + .cfi_restore $5 + .cfi_restore $6 + .cfi_restore $7 + .cfi_restore $8 + .cfi_restore $9 + .cfi_restore $10 + .cfi_restore $11 + .cfi_restore $12 + .cfi_restore $13 + .cfi_restore $14 + .cfi_restore $15 + .cfi_restore $19 + .cfi_restore $20 + .cfi_restore $21 + .cfi_restore $22 + .cfi_restore $23 + .cfi_restore $24 + .cfi_restore $25 + .cfi_restore $26 + .cfi_restore $27 + .cfi_restore $28 + .cfi_restore $29 + .cfi_adjust_cfa_offset -256 + call_pal PAL_rti + + .align 4 +entUnaUser: + .cfi_restore_state + ldq $0, 0($sp) /* restore original $0 */ + lda $sp, 256($sp) /* pop entUna's stack frame */ + .cfi_restore $0 + .cfi_adjust_cfa_offset -256 + SAVE_ALL /* setup normal kernel stack */ + lda $sp, -56($sp) + .cfi_adjust_cfa_offset 56 + 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) + .cfi_rel_offset $9, 0 + .cfi_rel_offset $10, 8 + .cfi_rel_offset $11, 16 + .cfi_rel_offset $12, 24 + .cfi_rel_offset $13, 32 + .cfi_rel_offset $14, 40 + .cfi_rel_offset $15, 48 + 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) + .cfi_restore $9 + .cfi_restore $10 + .cfi_restore $11 + .cfi_restore $12 + .cfi_restore $13 + .cfi_restore $14 + .cfi_restore $15 + .cfi_adjust_cfa_offset -56 + br ret_from_sys_call +CFI_END_OSF_FRAME entUna + +CFI_START_OSF_FRAME entDbg + SAVE_ALL + lda $8, 0x3fff + lda $26, ret_from_sys_call + bic $sp, $8, $8 + mov $sp, $16 + jsr $31, do_entDbg +CFI_END_OSF_FRAME 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 + .type entSys, @function + .cfi_startproc simple + .cfi_return_column 64 + .cfi_def_cfa $sp, 48 + .cfi_rel_offset 64, 8 + .cfi_rel_offset $gp, 16 +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) + .cfi_rel_offset $16, SP_OFF+24 + .cfi_rel_offset $17, SP_OFF+32 + .cfi_rel_offset $18, SP_OFF+40 +#ifdef CONFIG_AUDITSYSCALL + lda $6, _TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT + and $3, $6, $3 + bne $3, strace +#else + blbs $3, strace /* check for SYSCALL_TRACE in disguise */ +#endif + beq $4, 1f + ldq $27, 0($5) +1: jsr $26, ($27), sys_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 + .globl ret_from_sys_call +ret_from_sys_call: + cmovne $26, 0, $18 /* $18 = 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 $17, TI_FLAGS($8) + and $17, _TIF_WORK_MASK, $2 + bne $2, work_pending +restore_all: + .cfi_remember_state + RESTORE_ALL + call_pal PAL_rti + +ret_to_kernel: + .cfi_restore_state + 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 $18, 0($sp) /* old syscall nr (zero if success) */ + beq $18, $ret_success + + ldq $19, 72($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 + +/* + * Do all cleanup when returning from all interrupts and system calls. + * + * Arguments: + * $8: current. + * $17: TI_FLAGS. + * $18: The old syscall number, or zero if this is not a return + * from a syscall that errored and is possibly restartable. + * $19: The old a3 value + */ + + .align 4 + .type work_pending, @function +work_pending: + and $17, _TIF_NOTIFY_RESUME | _TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL, $2 + bne $2, $work_notifysig + +$work_resched: + /* + * We can get here only if we returned from syscall without SIGPENDING + * or got through work_notifysig already. Either case means no syscall + * restarts for us, so let $18 and $19 burn. + */ + jsr $26, schedule + mov 0, $18 + br ret_to_user + +$work_notifysig: + mov $sp, $16 + DO_SWITCH_STACK + jsr $26, do_work_pending + UNDO_SWITCH_STACK + br restore_all + +/* + * PTRACE syscall handler + */ + + .align 4 + .type strace, @function +strace: + /* set up signal stack, call syscall_trace */ + DO_SWITCH_STACK + jsr $26, syscall_trace_enter /* returns the syscall number */ + UNDO_SWITCH_STACK + + /* get the arguments back.. */ + 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, sys_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 */ + + DO_SWITCH_STACK + jsr $26, syscall_trace_leave + UNDO_SWITCH_STACK + br $31, ret_from_sys_call + + .align 3 +$strace_error: + ldq $18, 0($sp) /* old syscall nr (zero if success) */ + beq $18, $strace_success + ldq $19, 72($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 */ + + DO_SWITCH_STACK + mov $18, $9 /* save old syscall number */ + mov $19, $10 /* save old a3 */ + jsr $26, syscall_trace_leave + mov $9, $18 + mov $10, $19 + UNDO_SWITCH_STACK + + mov $31, $26 /* tell "ret_from_sys_call" we can restart */ + br ret_from_sys_call +CFI_END_OSF_FRAME entSys + +/* + * Save and restore the switch stack -- aka the balance of the user context. + */ + + .align 4 + .type do_switch_stack, @function + .cfi_startproc simple + .cfi_return_column 64 + .cfi_def_cfa $sp, 0 + .cfi_register 64, $1 +do_switch_stack: + lda $sp, -SWITCH_STACK_SIZE($sp) + .cfi_adjust_cfa_offset SWITCH_STACK_SIZE + 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 + .cfi_endproc + .size do_switch_stack, .-do_switch_stack + + .align 4 + .type undo_switch_stack, @function + .cfi_startproc simple + .cfi_def_cfa $sp, 0 + .cfi_register 64, $1 +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 + .cfi_endproc + .size undo_switch_stack, .-undo_switch_stack + +/* + * The meat of the context switch code. + */ + + .align 4 + .globl alpha_switch_to + .type alpha_switch_to, @function + .cfi_startproc +alpha_switch_to: + DO_SWITCH_STACK + call_pal PAL_swpctx + lda $8, 0x3fff + UNDO_SWITCH_STACK + bic $sp, $8, $8 + mov $17, $0 + ret + .cfi_endproc + .size alpha_switch_to, .-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) + br $31, ret_to_user +.end ret_from_kernel_thread + + +/* + * Special system calls. Most of these are special in that they either + * have to play switch_stack games. + */ + +.macro fork_like name + .align 4 + .globl alpha_\name + .ent alpha_\name +alpha_\name: + .prologue 0 + bsr $1, do_switch_stack + jsr $26, sys_\name + ldq $26, 56($sp) + lda $sp, SWITCH_STACK_SIZE($sp) + ret +.end alpha_\name +.endm + +fork_like fork +fork_like vfork +fork_like clone + +.macro sigreturn_like name + .align 4 + .globl sys_\name + .ent sys_\name +sys_\name: + .prologue 0 + lda $9, ret_from_straced + cmpult $26, $9, $9 + lda $sp, -SWITCH_STACK_SIZE($sp) + jsr $26, do_\name + bne $9, 1f + jsr $26, syscall_trace_leave +1: br $1, undo_switch_stack + br ret_from_sys_call +.end sys_\name +.endm + +sigreturn_like sigreturn +sigreturn_like rt_sigreturn + + .align 4 + .globl alpha_syscall_zero + .ent alpha_syscall_zero +alpha_syscall_zero: + .prologue 0 + /* Special because it needs to do something opposite to + force_successful_syscall_return(). We use the saved + syscall number for that, zero meaning "not an error". + That works nicely, but for real syscall 0 we need to + make sure that this logics doesn't get confused. + Store a non-zero there - -ENOSYS we need in register + for our return value will do just fine. + */ + lda $0, -ENOSYS + unop + stq $0, 0($sp) + ret +.end alpha_syscall_zero |