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|
/**************************************************************************/
/* */
/* OCaml */
/* */
/* Xavier Leroy, projet Gallium, INRIA Rocquencourt */
/* Tom Kelly, OCaml Labs Consultancy, UK */
/* */
/* Copyright 2013 Institut National de Recherche en Informatique et */
/* en Automatique. */
/* Copyright 2022 OCaml Labs Consultancy Ltd. */
/* */
/* All rights reserved. This file is distributed under the terms of */
/* the GNU Lesser General Public License version 2.1, with the */
/* special exception on linking described in the file LICENSE. */
/* */
/**************************************************************************/
/* Asm part of the runtime system, ARM processor, 64-bit mode */
/* Must be preprocessed by cpp */
#include "caml/m.h"
#include "caml/asm.h"
/* Special registers */
#define DOMAIN_STATE_PTR x28
#define TRAP_PTR x26
#define ALLOC_PTR x27
#define ADDITIONAL_ARG x8
#define STACK_ARG_BEGIN x20
#define STACK_ARG_END x21
#define TMP x16
#define TMP2 x17
#define C_ARG_1 x0
#define C_ARG_2 x1
#define C_ARG_3 x2
#define C_ARG_4 x3
/* DWARF
These ARM64 specific register numbers are coming from
Table 4 ("Mapping from DWARF register numbers to Arm
64-bit architecture registers") of:
https://developer.arm.com/documentation/ihi0057/latest
*/
#define DW_REG_x21 21
#define DW_REG_x29 29
#define DW_REG_sp 31
.set domain_curr_field, 0
#if defined(SYS_macosx)
#define DOMAIN_STATE(c_type, name) DOMAIN_STATE c_type, name
.macro DOMAIN_STATE c_type, name
.equ domain_field_caml_\name, domain_curr_field
.set domain_curr_field, domain_curr_field + 1
.endm
#else
#define DOMAIN_STATE(c_type, name) \
.equ domain_field_caml_##name, domain_curr_field ; \
.set domain_curr_field, domain_curr_field + 1
#endif
#include "../runtime/caml/domain_state.tbl"
#undef DOMAIN_STATE
#define Caml_state(var) [DOMAIN_STATE_PTR, 8*domain_field_caml_##var]
/* Globals and labels */
#if defined(SYS_macosx)
#define CAMLSEP(x,y) caml_##x##$##y
#define G(sym) _##sym
#define L(lbl) L##lbl
#else
#define CAMLSEP(x,y) caml_##x##.##y
#define G(sym) sym
#define L(lbl) .L##lbl
#endif
#if defined(SYS_macosx)
#define ADDRGLOBAL(reg,symb) ADDRGLOBAL reg, symb
.macro ADDRGLOBAL reg, symb
adrp TMP2, G(\symb)@GOTPAGE
ldr \reg, [TMP2, G(\symb)@GOTPAGEOFF]
.endm
#elif defined(__PIC__)
#define ADDRGLOBAL(reg,symb) \
adrp TMP2, :got:G(symb); \
ldr reg, [TMP2, #:got_lo12:G(symb)]
#else
#define ADDRGLOBAL(reg,symb) \
adrp reg, G(symb); \
add reg, reg, #:lo12:G(symb)
#endif
#if defined(FUNCTION_SECTIONS)
#define TEXT_SECTION(name) .section .text.caml.##name,"ax",%progbits
#else
#define TEXT_SECTION(name)
#endif
#if defined(FUNCTION_SECTIONS)
TEXT_SECTION(CAMLSEP(hot,code_begin))
.globl G(CAMLSEP(hot,code_begin))
G(CAMLSEP(hot,code_begin)):
TEXT_SECTION(CAMLSEP(hot,code_end))
.globl G(CAMLSEP(hot,code_end))
G(CAMLSEP(hot,code_end)):
#endif
#if defined(SYS_macosx)
#define FUNCTION(name) FUNCTION name
.macro FUNCTION name
TEXT_SECTION(G(\name))
.align 2
.globl G(\name)
G(\name):
.endm
#define END_FUNCTION(name)
#define OBJECT(name) OBJECT name
.macro OBJECT name
.data
.align 3
.globl G(\name)
G(\name):
.endm
#define END_OBJECT(name)
#else
#define FUNCTION(name) \
TEXT_SECTION(name); \
.align 2; \
.globl G(name); \
TYPE_DIRECTIVE(G(name),%function) \
G(name):
#define END_FUNCTION(name) \
SIZE_DIRECTIVE(G(name))
#define OBJECT(name) \
.data; \
.align 3; \
.globl G(name); \
TYPE_DIRECTIVE(G(name),%object) \
G(name):
#define END_OBJECT(name) \
SIZE_DIRECTIVE(G(name))
#endif
/* Function prologue and epilogue */
.macro ENTER_FUNCTION
CFI_OFFSET(29, -16)
CFI_OFFSET(30, -8)
stp x29, x30, [sp, -16]!
CFI_ADJUST(16)
add x29, sp, #0
.endm
.macro LEAVE_FUNCTION
ldp x29, x30, [sp], 16
CFI_ADJUST(-16)
.endm
/* Stack switching operations */
/* struct stack_info */
#define Stack_sp(reg) [reg]
#define Stack_sp_offset 0
#define Stack_exception(reg) [reg, #8]
#define Stack_handler(reg) [reg, #16]
#define Stack_handler_from_cont(reg) [reg, #15]
/* struct c_stack_link */
#define Cstack_stack(reg) [reg]
#define Cstack_sp(reg) [reg, #8]
#define Cstack_sp_offset 8
#define Cstack_prev(reg) [reg, #16]
/* struct stack_handler */
#define Handler_value(reg) [reg]
#define Handler_exception(reg) [reg, #8]
#define Handler_effect(reg) [reg, #16]
#define Handler_parent(reg) [reg, #24]
#define Handler_parent_offset 24
/* Switch from OCaml to C stack.
If a C function is called which might call back into OCaml,
then nothing may be pushed to the C stack between SWITCH_OCAML_TO_C
and the next C call. (This is to ensure frame pointers are correctly
maintained if the stack is reallocated) */
.macro SWITCH_OCAML_TO_C
/* Fill in Caml_state->current_stack->sp */
ldr TMP, Caml_state(current_stack)
mov TMP2, sp
str TMP2, Stack_sp(TMP)
/* Fill in Caml_state->c_stack */
ldr TMP2, Caml_state(c_stack)
str TMP, Cstack_stack(TMP2)
mov TMP, sp
str TMP, Cstack_sp(TMP2)
/* Switch to C stack */
mov sp, TMP2
#ifdef ASM_CFI_SUPPORTED
CFI_REMEMBER_STATE
/* sp points to the c_stack_link. */
.cfi_escape DW_CFA_def_cfa_expression, 5, \
DW_OP_breg + DW_REG_sp, Cstack_sp_offset, DW_OP_deref, \
DW_OP_plus_uconst, 16 /* fp + retaddr */
#endif
.endm
/* Switch from C to OCaml stack. */
.macro SWITCH_C_TO_OCAML
ldr TMP, Cstack_sp(sp)
mov sp, TMP
CFI_RESTORE_STATE
.endm
/* Save all of the registers that may be in use to a free gc_regs bucket
and store ALLOC_PTR and TRAP_PTR back to Caml_state
At the end the saved registers are placed in Caml_state(gc_regs)
*/
.macro SAVE_ALL_REGS
/* First, save the young_ptr & exn_handler */
str ALLOC_PTR, Caml_state(young_ptr)
str TRAP_PTR, Caml_state(exn_handler)
/* Now, use TMP to point to the gc_regs bucket */
ldr TMP, Caml_state(gc_regs_buckets)
ldr TMP2, [TMP, 0] /* next ptr */
str TMP2, Caml_state(gc_regs_buckets)
/* Save allocatable registers */
stp x0, x1, [TMP, 16]
stp x2, x3, [TMP, 32]
stp x4, x5, [TMP, 48]
stp x6, x7, [TMP, 64]
stp x8, x9, [TMP, 80]
stp x10, x11, [TMP, 96]
stp x12, x13, [TMP, 112]
stp x14, x15, [TMP, 128]
stp x19, x20, [TMP, 144]
stp x21, x22, [TMP, 160]
stp x23, x24, [TMP, 176]
str x25, [TMP, 192]
/* Save caller-save floating-point registers
(callee-saves are preserved by C functions) */
stp d0, d1, [TMP, 208]
stp d2, d3, [TMP, 224]
stp d4, d5, [TMP, 240]
stp d6, d7, [TMP, 256]
stp d16, d17, [TMP, 272]
stp d18, d19, [TMP, 288]
stp d20, d21, [TMP, 304]
stp d22, d23, [TMP, 320]
stp d24, d25, [TMP, 336]
stp d26, d27, [TMP, 352]
stp d28, d29, [TMP, 368]
stp d30, d31, [TMP, 384]
add TMP, TMP, #16
str TMP, Caml_state(gc_regs)
.endm
/* Undo SAVE_ALL_REGS by loading the registers saved in Caml_state(gc_regs)
and refreshing ALLOC_PTR & TRAP_PTR from Caml_state */
.macro RESTORE_ALL_REGS
/* Restore x0, x1, freeing up the next ptr slot */
ldr TMP, Caml_state(gc_regs)
sub TMP, TMP, #16
/* Restore registers */
ldp x0, x1, [TMP, 16]
ldp x2, x3, [TMP, 32]
ldp x4, x5, [TMP, 48]
ldp x6, x7, [TMP, 64]
ldp x8, x9, [TMP, 80]
ldp x10, x11, [TMP, 96]
ldp x12, x13, [TMP, 112]
ldp x14, x15, [TMP, 128]
ldp x19, x20, [TMP, 144]
ldp x21, x22, [TMP, 160]
ldp x23, x24, [TMP, 176]
ldr x25, [TMP, 192]
ldp d0, d1, [TMP, 208]
ldp d2, d3, [TMP, 224]
ldp d4, d5, [TMP, 240]
ldp d6, d7, [TMP, 256]
ldp d16, d17, [TMP, 272]
ldp d18, d19, [TMP, 288]
ldp d20, d21, [TMP, 304]
ldp d22, d23, [TMP, 320]
ldp d24, d25, [TMP, 336]
ldp d26, d27, [TMP, 352]
ldp d28, d29, [TMP, 368]
ldp d30, d31, [TMP, 384]
/* Put gc_regs struct back in bucket linked list */
ldr TMP2, Caml_state(gc_regs_buckets)
str TMP2, [TMP, 0] /* next ptr */
str TMP, Caml_state(gc_regs_buckets)
/* Reload new allocation pointer & exn handler */
ldr ALLOC_PTR, Caml_state(young_ptr)
ldr TRAP_PTR, Caml_state(exn_handler)
.endm
/* Updates the oldest saved frame pointer in the target fiber.
A fiber stack may need to grow, causing the reallocation of the entire fiber,
including stack_info and stack_handler structures.
caml_try_realloc_stack will not be able to update the linked list of
frame-pointers if it has been split (i.e., in a continuation).
caml_resume and caml_reperform use this macro to update the oldest saved x29
(highest one in the stack) in case the fiber was reallocated to reattach the
frame-pointer linked list.
REG: Stack_handler(target_fiber)
The frame pointer will be pushed into the stack immediately after these
instructions. The offset of the oldest saved x29 in a fiber from the stack
handler is 48 = 4 words (caml_runstack) + 2 words (x30 and x29).
*/
#ifdef WITH_FRAME_POINTERS
.macro UPDATE_BASE_POINTER reg
sub TMP2, sp, 16
str TMP2, [\reg, -48]
.endm
#else
.macro UPDATE_BASE_POINTER reg
.endm
#endif
#if defined(WITH_THREAD_SANITIZER) /* { */
/* Push the current value of the link register to the stack. */
.macro TSAN_SETUP_C_CALL
CFI_OFFSET(30, -16)
str x30, [sp, -16]!
CFI_ADJUST(16)
.endm
/* Restore the value of the link register from the stack. */
.macro TSAN_CLEANUP_AFTER_C_CALL
ldr x30, [sp], 16
CFI_ADJUST(-16)
.endm
/* Invoke a C function, switching back and forth the OCaml and C stacks. */
.macro TSAN_C_CALL fun
SWITCH_OCAML_TO_C
TSAN_SETUP_C_CALL
bl \fun
TSAN_CLEANUP_AFTER_C_CALL
SWITCH_C_TO_OCAML
.endm
/* Invoke __tsan_func_entry(return address in the caller) */
.macro TSAN_ENTER_FUNCTION
mov x0, x30 /* arg1: return address in caller */
TSAN_C_CALL G(__tsan_func_entry)
.endm
/* Invoke __tsan_func_exit(0) */
.macro TSAN_EXIT_FUNCTION
mov x0, xzr
TSAN_C_CALL G(__tsan_func_exit)
.endm
/* This is similar to SAVE_ALL_REGS, but only saving the caller-saved
registers. */
.macro TSAN_SAVE_CALLER_REGS
/* First, save the young_ptr & exn_handler */
str ALLOC_PTR, Caml_state(young_ptr)
str TRAP_PTR, Caml_state(exn_handler)
/* Now, use TMP to point to the gc_regs bucket */
ldr TMP, Caml_state(gc_regs_buckets)
ldr TMP2, [TMP, 0] /* next ptr */
str TMP2, Caml_state(gc_regs_buckets)
/* Save caller-saved registers */
stp x0, x1, [TMP, 16]
stp x2, x3, [TMP, 32]
stp x4, x5, [TMP, 48]
stp x6, x7, [TMP, 64]
stp x8, x9, [TMP, 80]
stp x10, x11, [TMP, 96]
stp x12, x13, [TMP, 112]
stp x14, x15, [TMP, 128]
/* Save caller-save floating-point registers */
stp d0, d1, [TMP, 208]
stp d2, d3, [TMP, 224]
stp d4, d5, [TMP, 240]
stp d6, d7, [TMP, 256]
stp d16, d17, [TMP, 272]
stp d18, d19, [TMP, 288]
stp d20, d21, [TMP, 304]
stp d22, d23, [TMP, 320]
stp d24, d25, [TMP, 336]
stp d26, d27, [TMP, 352]
stp d28, d29, [TMP, 368]
stp d30, d31, [TMP, 384]
add TMP, TMP, #16
str TMP, Caml_state(gc_regs)
.endm
/* This is similar to RESTORE_ALL_REGS, but only restoring the caller-saved
registers. */
.macro TSAN_RESTORE_CALLER_REGS
/* Restore x0, x1, freeing up the next ptr slot */
ldr TMP, Caml_state(gc_regs)
sub TMP, TMP, #16
/* Restore registers */
ldp x0, x1, [TMP, 16]
ldp x2, x3, [TMP, 32]
ldp x4, x5, [TMP, 48]
ldp x6, x7, [TMP, 64]
ldp x8, x9, [TMP, 80]
ldp x10, x11, [TMP, 96]
ldp x12, x13, [TMP, 112]
ldp x14, x15, [TMP, 128]
ldp d0, d1, [TMP, 208]
ldp d2, d3, [TMP, 224]
ldp d4, d5, [TMP, 240]
ldp d6, d7, [TMP, 256]
ldp d16, d17, [TMP, 272]
ldp d18, d19, [TMP, 288]
ldp d20, d21, [TMP, 304]
ldp d22, d23, [TMP, 320]
ldp d24, d25, [TMP, 336]
ldp d26, d27, [TMP, 352]
ldp d28, d29, [TMP, 368]
ldp d30, d31, [TMP, 384]
/* Put gc_regs struct back in bucket linked list */
ldr TMP2, Caml_state(gc_regs_buckets)
str TMP2, [TMP, 0] /* next ptr */
str TMP, Caml_state(gc_regs_buckets)
/* Reload new allocation pointer & exn handler */
ldr ALLOC_PTR, Caml_state(young_ptr)
ldr TRAP_PTR, Caml_state(exn_handler)
.endm
#else /* } { */
.macro TSAN_ENTER_FUNCTION
.endm
.macro TSAN_EXIT_FUNCTION
.endm
.macro TSAN_SAVE_CALLER_REGS
.endm
.macro TSAN_RESTORE_CALLER_REGS
.endm
#endif /* } WITH_THREAD_SANITIZER */
/* Allocation functions and GC interface.
Referenced from C code in runtime/startup_nat.c
*/
TEXT_SECTION(caml_system__code_begin)
.globl G(caml_system__code_begin)
G(caml_system__code_begin):
FUNCTION(caml_call_realloc_stack)
CFI_STARTPROC
CFI_SIGNAL_FRAME
/* Save return address and frame pointer */
ENTER_FUNCTION
/* Save all registers (including ALLOC_PTR & TRAP_PTR) */
SAVE_ALL_REGS
ldr C_ARG_1, [sp, 16] /* argument */
SWITCH_OCAML_TO_C
bl G(caml_try_realloc_stack)
SWITCH_C_TO_OCAML
cbz x0, 1f
RESTORE_ALL_REGS
/* Free stack space and return to caller */
LEAVE_FUNCTION
ret
1: RESTORE_ALL_REGS
/* Raise the Stack_overflow exception */
LEAVE_FUNCTION
add sp, sp, 16 /* pop argument */
ADDRGLOBAL(x0, caml_exn_Stack_overflow)
b G(caml_raise_exn)
CFI_ENDPROC
END_FUNCTION(caml_call_realloc_stack)
FUNCTION(caml_call_gc)
CFI_STARTPROC
L(caml_call_gc):
CFI_SIGNAL_FRAME
/* Save return address and frame pointer */
ENTER_FUNCTION
/* Store all registers (including ALLOC_PTR & TRAP_PTR) */
SAVE_ALL_REGS
TSAN_ENTER_FUNCTION
SWITCH_OCAML_TO_C
/* Call the garbage collector */
bl G(caml_garbage_collection)
SWITCH_C_TO_OCAML
TSAN_EXIT_FUNCTION
RESTORE_ALL_REGS
/* Free stack space and return to caller */
LEAVE_FUNCTION
ret
CFI_ENDPROC
END_FUNCTION(caml_call_gc)
FUNCTION(caml_alloc1)
CFI_STARTPROC
ldr TMP, Caml_state(young_limit)
sub ALLOC_PTR, ALLOC_PTR, #16
cmp ALLOC_PTR, TMP
b.lo L(caml_call_gc)
ret
CFI_ENDPROC
END_FUNCTION(caml_alloc1)
FUNCTION(caml_alloc2)
CFI_STARTPROC
ldr TMP, Caml_state(young_limit)
sub ALLOC_PTR, ALLOC_PTR, #24
cmp ALLOC_PTR, TMP
b.lo L(caml_call_gc)
ret
CFI_ENDPROC
END_FUNCTION(caml_alloc2)
FUNCTION(caml_alloc3)
CFI_STARTPROC
ldr TMP, Caml_state(young_limit)
sub ALLOC_PTR, ALLOC_PTR, #32
cmp ALLOC_PTR, TMP
b.lo L(caml_call_gc)
ret
CFI_ENDPROC
END_FUNCTION(caml_alloc3)
FUNCTION(caml_allocN)
CFI_STARTPROC
ldr TMP, Caml_state(young_limit)
sub ALLOC_PTR, ALLOC_PTR, ADDITIONAL_ARG
cmp ALLOC_PTR, TMP
b.lo L(caml_call_gc)
ret
CFI_ENDPROC
END_FUNCTION(caml_allocN)
/* Call a C function from OCaml */
/* Function to call is in ADDITIONAL_ARG */
.macro RET_FROM_C_CALL
ldr TMP, Caml_state(action_pending)
cbnz TMP, 1f
ret
1: mov TMP, #-1
str TMP, Caml_state(young_limit)
ret
.endm
FUNCTION(caml_c_call)
CFI_STARTPROC
CFI_SIGNAL_FRAME
ENTER_FUNCTION
TSAN_SAVE_CALLER_REGS
TSAN_ENTER_FUNCTION
TSAN_RESTORE_CALLER_REGS
/* Switch from OCaml to C */
SWITCH_OCAML_TO_C
/* Make the exception handler alloc ptr available to the C code */
str ALLOC_PTR, Caml_state(young_ptr)
str TRAP_PTR, Caml_state(exn_handler)
/* Call the function */
blr ADDITIONAL_ARG
/* Reload new allocation pointer & exn handler */
ldr ALLOC_PTR, Caml_state(young_ptr)
ldr TRAP_PTR, Caml_state(exn_handler)
/* Load ocaml stack */
SWITCH_C_TO_OCAML
#if defined(WITH_THREAD_SANITIZER)
/* Save return value registers. Since the called function could be
anything, it may have returned its result (if any) either in x0
or d0:d1. */
stp x0, x1, [sp, -16]!
CFI_ADJUST(16)
stp d0, d1, [sp, -16]!
CFI_ADJUST(16)
TSAN_EXIT_FUNCTION
/* Restore return value registers */
ldp d0, d1, [sp], 16
CFI_ADJUST(-16)
ldp x0, x1, [sp], 16
CFI_ADJUST(-16)
#endif
/* Return */
LEAVE_FUNCTION
RET_FROM_C_CALL
CFI_ENDPROC
END_FUNCTION(caml_c_call)
FUNCTION(caml_c_call_stack_args)
CFI_STARTPROC
CFI_SIGNAL_FRAME
/* Arguments:
C arguments : x0 to x7, d0 to d7
C function : ADDITIONAL_ARG
C stack args : begin=STACK_ARG_BEGIN
end=STACK_ARG_END */
ENTER_FUNCTION
/* Switch from OCaml to C */
SWITCH_OCAML_TO_C
/* Make the exception handler alloc ptr available to the C code */
str ALLOC_PTR, Caml_state(young_ptr)
str TRAP_PTR, Caml_state(exn_handler)
/* Copy the arguments and call */
bl G(caml_c_call_copy_stack_args)
/* Reload new allocation pointer & exn handler */
ldr ALLOC_PTR, Caml_state(young_ptr)
ldr TRAP_PTR, Caml_state(exn_handler)
/* Switch from C to OCaml */
SWITCH_C_TO_OCAML
/* Return */
LEAVE_FUNCTION
RET_FROM_C_CALL
CFI_ENDPROC
END_FUNCTION(caml_c_call_stack_args)
/* To correctly maintain frame pointers during stack reallocation,
the runtime assumes that the caml_c_call stub does not push
anything to the stack before the first frame pointer on the C stack.
To guarantee this when stack arguments are used, the actual pushing
of arguments is done by this separate function */
FUNCTION(caml_c_call_copy_stack_args)
CFI_STARTPROC
ENTER_FUNCTION
CFI_DEF_CFA_REGISTER(DW_REG_x29)
/* Copy arguments from OCaml to C stack
NB: STACK_ARG_{BEGIN,END} are 16-byte aligned */
1: sub STACK_ARG_END, STACK_ARG_END, 16
cmp STACK_ARG_END, STACK_ARG_BEGIN
b.lo 2f
ldp TMP, TMP2, [STACK_ARG_END]
stp TMP, TMP2, [sp, -16]!
b 1b
2: /* Call the function */
blr ADDITIONAL_ARG
/* Restore stack */
mov sp, x29
CFI_DEF_CFA_REGISTER(DW_REG_sp)
LEAVE_FUNCTION
ret
CFI_ENDPROC
END_FUNCTION(caml_c_call_copy_stack_args)
/* Start the OCaml program */
FUNCTION(caml_start_program)
CFI_STARTPROC
CFI_SIGNAL_FRAME
#if defined(WITH_THREAD_SANITIZER)
str x0, [sp, -16]!
CFI_ADJUST(16)
/* We can't use the TSAN_ENTER_FUNCTION macro, as it assumes to run on an
OCaml stack, and we are still on a C stack at this point. */
mov x0, x30 /* arg1: return address in caller */
TSAN_SETUP_C_CALL
bl G(__tsan_func_entry)
TSAN_CLEANUP_AFTER_C_CALL
ldr x0, [sp], 16
CFI_ADJUST(-16)
#endif
/* domain state is passed as arg from C */
mov TMP, C_ARG_1
/* Initial entry point is caml_program */
ADDRGLOBAL(TMP2, caml_program)
/* Code shared with caml_callback* */
/* Address of domain state is in TMP */
/* Address of OCaml code to call is in TMP2 */
/* Arguments to the OCaml code are in x0...x7 */
L(jump_to_caml):
/* Set up stack frame and save callee-save registers */
CFI_OFFSET(29, -160)
CFI_OFFSET(30, -152)
stp x29, x30, [sp, -160]!
CFI_ADJUST(160)
mov x29, sp
stp x19, x20, [sp, 16]
stp x21, x22, [sp, 32]
stp x23, x24, [sp, 48]
stp x25, x26, [sp, 64]
stp x27, x28, [sp, 80]
stp d8, d9, [sp, 96]
stp d10, d11, [sp, 112]
stp d12, d13, [sp, 128]
stp d14, d15, [sp, 144]
/* Load domain state pointer from argument */
mov DOMAIN_STATE_PTR, TMP
/* Reload allocation pointer */
ldr ALLOC_PTR, Caml_state(young_ptr)
/* Build (16-byte aligned) struct c_stack_link on the C stack */
ldr x8, Caml_state(c_stack)
stp x8, xzr, [sp, -16]! /* C_stack_prev, pad */
CFI_ADJUST(16)
stp xzr, xzr, [sp, -16]! /* C_stack_stack, C_stack_sp */
CFI_ADJUST(16)
mov x8, sp
str x8, Caml_state(c_stack)
/* Load the OCaml stack */
ldr x8, Caml_state(current_stack)
ldr x8, Stack_sp(x8)
/* Store the gc_regs for callbacks during a GC */
ldr x9, Caml_state(gc_regs)
str x9, [x8, -8]!
/* Store the stack pointer to allow DWARF unwind */
mov x9, sp
str x9, [x8, -8]! /* C_stack_sp */
/* Setup a trap frame to catch exceptions escaping the OCaml code */
ldr x9, Caml_state(exn_handler)
adr x10, L(trap_handler)
stp x9, x10, [x8, -16]!
mov TRAP_PTR, x8
/* Switch stacks and call the OCaml code */
mov sp, x8
#ifdef ASM_CFI_SUPPORTED
CFI_REMEMBER_STATE
.cfi_escape DW_CFA_def_cfa_expression, 3 + 2 + 2, \
/* sp points to the exn handler on the OCaml stack */ \
/* sp + 16 contains the C_STACK_SP */ \
DW_OP_breg + DW_REG_sp, 16 /* exn handler */, DW_OP_deref, \
/* 32 struct c_stack_link + pad */ \
/* 18*8 callee save regs */ \
/* 16 fp + ret addr */ \
/* need to split to get under 127 limit */ \
DW_OP_plus_uconst, 96, DW_OP_plus_uconst, 96
#endif
/* Call the OCaml code */
blr TMP2
L(caml_retaddr):
/* Pop the trap frame, restoring Caml_state->exn_handler */
ldr x8, [sp], 16
CFI_ADJUST(-16)
str x8, Caml_state(exn_handler)
L(return_result):
/* restore GC regs */
ldp x8, x9, [sp], 16
CFI_ADJUST(-16)
str x9, Caml_state(gc_regs)
/* Update allocation pointer */
str ALLOC_PTR, Caml_state(young_ptr)
/* Return to C stack */
ldr x8, Caml_state(current_stack)
mov x9, sp
str x9, Stack_sp(x8)
ldr x9, Caml_state(c_stack)
mov sp, x9
CFI_RESTORE_STATE
/* Pop the struct c_stack_link */
ldr x8, Cstack_prev(sp)
add sp, sp, 32
CFI_ADJUST(-32)
str x8, Caml_state(c_stack)
#if defined(WITH_THREAD_SANITIZER)
/* We can't use the TSAN_EXIT_FUNCTION macro, as it assumes to run on an
OCaml stack, and we are back to a C stack at this point. */
str x0, [sp, -16]!
CFI_ADJUST(16)
mov x0, xzr
TSAN_SETUP_C_CALL
bl G(__tsan_func_exit)
TSAN_CLEANUP_AFTER_C_CALL
ldr x0, [sp], 16
CFI_ADJUST(-16)
#endif
/* Reload callee-save registers and return address */
ldp x19, x20, [sp, 16]
ldp x21, x22, [sp, 32]
ldp x23, x24, [sp, 48]
ldp x25, x26, [sp, 64]
ldp x27, x28, [sp, 80]
ldp d8, d9, [sp, 96]
ldp d10, d11, [sp, 112]
ldp d12, d13, [sp, 128]
ldp d14, d15, [sp, 144]
ldp x29, x30, [sp], 160
CFI_ADJUST(-160)
/* Return to C caller */
ret
CFI_ENDPROC
END_FUNCTION(caml_start_program)
/* The trap handler */
.align 2
L(trap_handler):
CFI_STARTPROC
/* Save exception pointer */
str TRAP_PTR, Caml_state(exn_handler)
/* Encode exception bucket as an exception result */
orr x0, x0, #2
/* Return it */
b L(return_result)
CFI_ENDPROC
/* Exceptions */
.macro JUMP_TO_TRAP_PTR
/* Cut stack at current trap handler */
mov sp, TRAP_PTR
/* Pop previous handler and jump to it */
ldp TRAP_PTR, TMP, [sp], 16
br TMP
.endm
/* Raise an exception from OCaml */
FUNCTION(caml_raise_exn)
CFI_STARTPROC
/* Test if backtrace is active */
ldr TMP, Caml_state(backtrace_active)
cbnz TMP, 2f
1:
JUMP_TO_TRAP_PTR
2: /* Zero backtrace_pos */
str xzr, Caml_state(backtrace_pos)
L(caml_reraise_exn_stash):
/* Preserve exception bucket in callee-save register x19 */
mov x19, x0
/* Stash the backtrace */
/* arg1: exn bucket, already in x0 */
mov x1, x30 /* arg2: pc of raise */
mov x2, sp /* arg3: sp of raise */
mov x3, TRAP_PTR /* arg4: sp of handler */
/* Switch to C stack */
ldr TMP, Caml_state(c_stack)
mov sp, TMP
bl G(caml_stash_backtrace)
/* Restore exception bucket and raise */
mov x0, x19
b 1b
CFI_ENDPROC
END_FUNCTION(caml_raise_exn)
FUNCTION(caml_reraise_exn)
CFI_STARTPROC
ldr TMP, Caml_state(backtrace_active)
cbnz TMP, L(caml_reraise_exn_stash)
JUMP_TO_TRAP_PTR
CFI_ENDPROC
END_FUNCTION(caml_reraise_exn)
#if defined(WITH_THREAD_SANITIZER)
/* When TSan support is enabled, this routine should be called just before
raising an exception. It calls __tsan_func_exit for every OCaml frame about
to be exited due to the exception.
Takes no arguments, clobbers x0, x1, x2 and potentially all
caller-saved registers of the C calling convention. */
FUNCTION(caml_tsan_exit_on_raise_asm)
CFI_STARTPROC
mov x0, x30 /* arg1: pc of raise */
mov x1, sp /* arg2: sp of raise */
mov x2, TRAP_PTR /* arg3: sp of handler */
TSAN_C_CALL G(caml_tsan_exit_on_raise)
ret
CFI_ENDPROC
END_FUNCTION(caml_tsan_exit_on_raise_asm)
#endif
/* Raise an exception from C */
FUNCTION(caml_raise_exception)
CFI_STARTPROC
/* Load the domain state ptr */
mov DOMAIN_STATE_PTR, C_ARG_1
/* Load the exception bucket */
mov x0, C_ARG_2
/* Reload trap ptr and alloc ptr */
ldr TRAP_PTR, Caml_state(exn_handler)
ldr ALLOC_PTR, Caml_state(young_ptr)
/* Discard the C stack pointer and reset to ocaml stack */
ldr TMP, Caml_state(current_stack)
ldr TMP, Stack_sp(TMP)
mov sp, TMP
#if defined(WITH_THREAD_SANITIZER)
str x0, [sp, -16]! /* preserve exception bucket */
CFI_ADJUST(16)
/* Call __tsan_func_exit for every OCaml stack frame exited due to the
exception */
mov x1, TMP
ldr x0, [x1, 8] /* arg1: pc of raise */
/* This stack address adjustment is required to compensate the
saving of x29 and x30 in SWITCH_OCAML_STACKS, which causes
Stack_sp() to be 16 bytes lower than expected. */
add x1, x1, 16 /* arg2: sp of raise */
mov x2, TRAP_PTR /* arg3: sp of handler */
TSAN_C_CALL G(caml_tsan_exit_on_raise)
ldr x0, [sp], 16
CFI_ADJUST(-16)
#endif
/* Restore frame and link on return to OCaml */
LEAVE_FUNCTION
b G(caml_raise_exn)
CFI_ENDPROC
END_FUNCTION(caml_raise_exception)
/* Callback from C to OCaml */
FUNCTION(caml_callback_asm)
CFI_STARTPROC
#if defined(WITH_THREAD_SANITIZER)
/* Save non-callee-saved registers x0, x1, x2 and x30 before C call */
stp x0, x1, [sp, -16]!
CFI_ADJUST(16)
stp x2, x30, [sp, -16]!
CFI_ADJUST(16)
mov x0, x30 /* return address */
bl G(__tsan_func_entry)
ldp x2, x30, [sp], 16
CFI_ADJUST(-16)
ldp x0, x1, [sp], 16
CFI_ADJUST(-16)
#endif
/* Initial shuffling of arguments */
/* (x0 = Caml_state, x1 = closure, [x2] = first arg) */
mov TMP, x0
ldr x0, [x2] /* x0 = first arg */
/* x1 = closure environment */
ldr TMP2, [x1] /* code pointer */
b L(jump_to_caml)
CFI_ENDPROC
END_FUNCTION(caml_callback_asm)
FUNCTION(caml_callback2_asm)
CFI_STARTPROC
#if defined(WITH_THREAD_SANITIZER)
/* Save non-callee-saved registers x0, x1, x2 and x30 before C call */
stp x0, x1, [sp, -16]!
CFI_ADJUST(16)
stp x2, x30, [sp, -16]!
CFI_ADJUST(16)
mov x0, x30 /* return address */
bl G(__tsan_func_entry)
ldp x2, x30, [sp], 16
CFI_ADJUST(-16)
ldp x0, x1, [sp], 16
CFI_ADJUST(-16)
#endif
/* Initial shuffling of arguments */
/* (x0 = Caml_state, x1 = closure, [x2] = arg1, [x2,8] = arg2) */
mov TMP, x0
mov TMP2, x1
ldp x0, x1, [x2, 0] /* x0 = first arg, x1 = second arg */
mov x2, TMP2 /* x2 = closure environment */
ADDRGLOBAL(TMP2, caml_apply2)
b L(jump_to_caml)
CFI_ENDPROC
END_FUNCTION(caml_callback2_asm)
FUNCTION(caml_callback3_asm)
CFI_STARTPROC
#if defined(WITH_THREAD_SANITIZER)
/* Save non-callee-saved registers x0, x1, x2 and x30 before C call */
stp x0, x1, [sp, -16]!
CFI_ADJUST(16)
stp x2, x30, [sp, -16]!
CFI_ADJUST(16)
mov x0, x30 /* return address */
bl G(__tsan_func_entry)
ldp x2, x30, [sp], 16
CFI_ADJUST(-16)
ldp x0, x1, [sp], 16
CFI_ADJUST(-16)
#endif
/* Initial shuffling of arguments */
/* (x0 = Caml_state, x1 = closure, [x2] = arg1, [x2,8] = arg2,
[x2,16] = arg3) */
mov TMP, x0
mov x3, x1 /* x3 = closure environment */
ldp x0, x1, [x2, 0] /* x0 = first arg, x1 = second arg */
ldr x2, [x2, 16] /* x2 = third arg */
ADDRGLOBAL(TMP2, caml_apply3)
b L(jump_to_caml)
CFI_ENDPROC
END_FUNCTION(caml_callback3_asm)
/* Fibers */
/* Switch between OCaml stacks. Clobbers TMP and switches TRAP_PTR
Preserves old_stack and new_stack registers */
.macro SWITCH_OCAML_STACKS old_stack, new_stack
/* Save frame pointer and return address for old_stack */
ENTER_FUNCTION
/* Save OCaml SP and exn_handler in the stack info */
mov TMP, sp
str TMP, Stack_sp(\old_stack)
str TRAP_PTR, Stack_exception(\old_stack)
/* switch stacks */
str \new_stack, Caml_state(current_stack)
ldr TMP, Stack_sp(\new_stack)
mov sp, TMP
/* restore exn_handler for new stack */
ldr TRAP_PTR, Stack_exception(\new_stack)
/* Restore frame pointer and return address for new_stack */
LEAVE_FUNCTION
.endm
/*
* A continuation is a one word object that points to a fiber. A fiber [f] will
* point to its parent at Handler_parent(Stack_handler(f)). In the following,
* the [last_fiber] refers to the last fiber in the linked-list formed by the
* parent pointer.
*/
FUNCTION(caml_perform)
CFI_STARTPROC
/* x0: effect to perform
x1: freshly allocated continuation */
ldr x2, Caml_state(current_stack) /* x2 := old stack */
add x3, x2, 1 /* x3 := Val_ptr(old stack) */
str x3, [x1] /* Initialize continuation */
L(do_perform):
/* x0: effect to perform
x1: continuation
x2: old_stack
x3: last_fiber */
#if defined(WITH_THREAD_SANITIZER)
/* Signal to TSan all stack frames exited by the perform. */
TSAN_SAVE_CALLER_REGS
mov x0, x30 /* arg 1: pc of perform */
mov x1, sp /* arg 2: sp of perform */
TSAN_C_CALL G(caml_tsan_exit_on_perform)
TSAN_RESTORE_CALLER_REGS
#endif
str x3, [x1, 8] /* Set the last_fiber field in the continuation */
ldr x9, Stack_handler(x2) /* x9 := old stack -> handler */
ldr x10, Handler_parent(x9) /* x10 := parent stack */
cbz x10, 1f
#if defined(WITH_THREAD_SANITIZER)
/* Save non-callee-saved registers x0, x1, x2, x3, x9 and x10 */
stp x0, x1, [sp, -16]!
CFI_ADJUST(16)
stp x2, x3, [sp, -16]!
CFI_ADJUST(16)
stp x9, x10, [sp, -16]!
CFI_ADJUST(16)
/* Match the TSan-enter made from caml_runstack */
TSAN_EXIT_FUNCTION
ldp x9, x10, [sp], 16
CFI_ADJUST(-16)
ldp x2, x3, [sp], 16
CFI_ADJUST(-16)
ldp x0, x1, [sp], 16
CFI_ADJUST(-16)
#endif
SWITCH_OCAML_STACKS x2, x10
/* we have to null the Handler_parent after the switch because
the Handler_parent is needed to unwind the stack for backtraces */
str xzr, Handler_parent(x9) /* Set parent of performer to NULL */
ldr TMP, Handler_effect(x9)
mov x2, x3 /* x2 := last_fiber */
mov x3, TMP /* x3 := effect handler */
b G(caml_apply3)
1:
/* switch back to original performer before raising Effect.Unhandled
(no-op unless this is a reperform) */
ldr x10, [x1] /* load performer stack from continuation */
sub x10, x10, 1 /* x10 := Ptr_val(x10) */
ldr x9, Caml_state(current_stack)
SWITCH_OCAML_STACKS x9, x10
/* No parent stack. Raise Effect.Unhandled. */
#if defined(WITH_THREAD_SANITIZER)
/* We must let the TSan runtime know that we switched back to the
original performer stack. For that, we perform the necessary calls
to __tsan_func_entry via caml_tsan_entry_on_resume.
Note that from TSan's point of view, we just exited all stack
frames, including those of the main fiber. This is ok, because we
re-enter them immediately via caml_tsan_entry_on_resume below. */
TSAN_SAVE_CALLER_REGS
mov x0, x30 /* arg 1: pc of perform */
mov x1, sp /* arg 2: sp of perform */
mov x2, x10 /* arg 3: performer stack */
TSAN_C_CALL G(caml_tsan_entry_on_resume)
TSAN_RESTORE_CALLER_REGS
#endif
ADDRGLOBAL(ADDITIONAL_ARG, caml_raise_unhandled_effect)
b G(caml_c_call)
CFI_ENDPROC
END_FUNCTION(caml_perform)
FUNCTION(caml_reperform)
CFI_STARTPROC
/* x0: effect to reperform
x1: continuation
x2: last_fiber */
ldr TMP, Stack_handler_from_cont(x2)
ldr x2, Caml_state(current_stack) /* x2 := old stack */
str x2, Handler_parent(TMP) /* Append to last_fiber */
add x3, x2, 1 /* x3 (last_fiber) := Val_ptr(old stack) */
/* Need to update the oldest saved frame pointer here as the execution of
the handler may have caused the current fiber stack to reallocate. */
UPDATE_BASE_POINTER TMP
b L(do_perform)
CFI_ENDPROC
END_FUNCTION(caml_reperform)
FUNCTION(caml_resume)
CFI_STARTPROC
/* x0: new fiber
x1: fun
x2: arg
x3: last_fiber */
sub x0, x0, 1 /* x0 = Ptr_val(x0) */
ldr x4, [x1] /* code pointer */
/* Check if stack null, then already used */
cbz x0, 1f
#if defined(WITH_THREAD_SANITIZER)
/* Save non-callee-saved registers x0, x1, x2, x3 and x4 */
stp x0, x1, [sp, -16]!
CFI_ADJUST(16)
stp x2, x3, [sp, -16]!
CFI_ADJUST(16)
str x4, [sp, -16]!
CFI_ADJUST(16)
/* Necessary to include the caller of caml_resume in the TSan backtrace */
TSAN_ENTER_FUNCTION
ldr x4, [sp], 16
CFI_ADJUST(-16)
ldp x2, x3, [sp], 16
CFI_ADJUST(-16)
ldp x0, x1, [sp], 16
CFI_ADJUST(-16)
TSAN_SAVE_CALLER_REGS
/* Signal to TSan all stack frames exited by the perform. */
mov x2, x0 /* arg 3: fiber */
ldr x1, Stack_sp(x0)
ldr x0, [x1, 8] /* arg 1: pc of perform */
/* This stack address adjustment is required to compensate the
saving of x29 and x30 in SWITCH_OCAML_STACKS, which causes
Stack_sp() to be 16 bytes lower than expected. */
add x1, x1, 16 /* arg 2: sp at perform */
TSAN_C_CALL G(caml_tsan_entry_on_resume)
TSAN_RESTORE_CALLER_REGS
#endif
/* Add current stack to the end */
sub x3, x3, 1 /* x3 = Ptr_val(x3) */
ldr x8, Stack_handler(x3)
ldr x9, Caml_state(current_stack)
str x9, Handler_parent(x8)
/* Need to update the oldest saved frame pointer here as the current fiber
stack may have been reallocated or we may be resuming a computation
that was not originally run here. */
UPDATE_BASE_POINTER x8
SWITCH_OCAML_STACKS x9, x0
mov x0, x2
br x4
1: ADDRGLOBAL(ADDITIONAL_ARG, caml_raise_continuation_already_resumed)
b G(caml_c_call)
CFI_ENDPROC
END_FUNCTION(caml_resume)
/* Run a function on a new stack, then either
return the value or invoke exception handler */
FUNCTION(caml_runstack)
CFI_STARTPROC
#if defined(WITH_THREAD_SANITIZER)
/* Save non-callee-saved registers x0, x1 and x2 */
stp x0, x1, [sp, -16]!
CFI_ADJUST(16)
str x2, [sp, -16]!
CFI_ADJUST(16)
/* Necessary to include the caller of caml_runstack in the TSan backtrace */
TSAN_ENTER_FUNCTION
ldr x2, [sp], 16
CFI_ADJUST(-16)
ldp x0, x1, [sp], 16
CFI_ADJUST(-16)
#endif
CFI_SIGNAL_FRAME
/* x0: fiber
x1: fun
x2: arg */
ENTER_FUNCTION
sub x0, x0, 1 /* x0 := Ptr_val(x0) */
ldr x3, [x1] /* code pointer */
/* save old stack pointer and exception handler */
ldr x8, Caml_state(current_stack) /* x8 := old stack */
mov TMP, sp
str TMP, Stack_sp(x8)
str TRAP_PTR, Stack_exception(x8)
/* Load new stack pointer and set parent */
ldr TMP, Stack_handler(x0)
str x8, Handler_parent(TMP)
str x0, Caml_state(current_stack)
ldr x9, Stack_sp(x0) /* x9 := sp of new stack */
/* Create an exception handler on the target stack
after 16byte DWARF & gc_regs block (which is unused here) */
sub x9, x9, 32
adr TMP, L(fiber_exn_handler)
str TMP, [x9, 8]
/* link the previous exn_handler so that copying stacks works */
ldr TMP, Stack_exception(x0)
str TMP, [x9]
mov TRAP_PTR, x9
/* Switch to the new stack */
mov sp, x9
#ifdef ASM_CFI_SUPPORTED
CFI_REMEMBER_STATE
.cfi_escape DW_CFA_def_cfa_expression, 3+3+2, \
DW_OP_breg + DW_REG_sp, \
16 /* exn */ + \
8 /* gc_regs slot (unused) */ + \
8 /* C_STACK_SP for DWARF (unused) */ \
+ Handler_parent_offset, DW_OP_deref, \
DW_OP_plus_uconst, Stack_sp_offset, DW_OP_deref, \
DW_OP_plus_uconst, 16 /* fp + ret addr */
#endif
/* Call the function on the new stack */
mov x0, x2
blr x3
L(frame_runstack):
add x8, sp, 32 /* x8 := stack_handler */
ldr x19, Handler_value(x8) /* saved across C call */
1:
mov x20, x0 /* save return across C call */
ldr x0, Caml_state(current_stack) /* arg to caml_free_stack */
/* restore parent stack and exn_handler into Caml_state */
ldr TMP, Handler_parent(x8)
str TMP, Caml_state(current_stack)
ldr TRAP_PTR, Stack_exception(TMP)
str TRAP_PTR, Caml_state(exn_handler)
/* free old stack by switching directly to c_stack;
is a no-alloc call */
ldr x21, Stack_sp(TMP) /* saved across C call */
CFI_RESTORE_STATE
CFI_REMEMBER_STATE
CFI_DEF_CFA_REGISTER(DW_REG_x21)
ldr TMP, Caml_state(c_stack)
mov sp, TMP
bl G(caml_free_stack)
/* switch directly to parent stack */
mov sp, x21
CFI_RESTORE_STATE
/* Signal to TSan that we exit caml_runstack (no registers to save here) */
TSAN_EXIT_FUNCTION
/* pick correct return value */
mov x0, x20
mov x1, x19
ldr TMP, [x19] /* code pointer */
/* Invoke handle_value (or handle_exn) */
LEAVE_FUNCTION
br TMP
L(fiber_exn_handler):
add x8, sp, 16 /* x8 := stack_handler */
ldr x19, Handler_exception(x8)
b 1b
CFI_ENDPROC
END_FUNCTION(caml_runstack)
FUNCTION(caml_ml_array_bound_error)
CFI_STARTPROC
/* Load address of [caml_array_bound_error_asm] in ADDITIONAL_ARG */
ADDRGLOBAL(ADDITIONAL_ARG, caml_array_bound_error_asm)
/* Call that function */
b G(caml_c_call)
CFI_ENDPROC
END_FUNCTION(caml_ml_array_bound_error)
TEXT_SECTION(caml_system__code_end)
.globl G(caml_system__code_end)
G(caml_system__code_end):
/* Frametable - GC roots for callback */
/* Uses the same naming convention as ocamlopt generated modules. */
OBJECT(CAMLSEP(system,frametable))
.quad 2 /* two descriptors */
.quad L(caml_retaddr) /* return address into callback */
.short -1 /* negative frame size => use callback link */
.short 0 /* no roots */
.align 3
.quad L(frame_runstack) /* return address into fiber handler */
.short -1 /* negative frame size => use callback link */
.short 0 /* no roots here */
.align 3
END_OBJECT(CAMLSEP(system,frametable))
NONEXECSTACK_NOTE
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