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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /arch/alpha/kernel/entry.S
Initial import
Diffstat (limited to 'arch/alpha/kernel/entry.S')
-rw-r--r--arch/alpha/kernel/entry.S857
1 files changed, 857 insertions, 0 deletions
diff --git a/arch/alpha/kernel/entry.S b/arch/alpha/kernel/entry.S
new file mode 100644
index 000000000..98703d99b
--- /dev/null
+++ b/arch/alpha/kernel/entry.S
@@ -0,0 +1,857 @@
+/*
+ * 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
+#endif
+ bne $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
+ .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, $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, 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 */
+
+ 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)
+ mov $31, $19 /* to disable syscall restarts */
+ 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 or in some way use the pt_regs struct.
+ */
+
+.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
+
+ .align 4
+ .globl sys_sigreturn
+ .ent sys_sigreturn
+sys_sigreturn:
+ .prologue 0
+ lda $9, ret_from_straced
+ cmpult $26, $9, $9
+ lda $sp, -SWITCH_STACK_SIZE($sp)
+ jsr $26, do_sigreturn
+ bne $9, 1f
+ jsr $26, syscall_trace_leave
+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
+ lda $sp, -SWITCH_STACK_SIZE($sp)
+ jsr $26, do_rt_sigreturn
+ bne $9, 1f
+ jsr $26, syscall_trace_leave
+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