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ARM: Implement *context routines.

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* sysdeps/unix/sysv/linux/arm/eabi/getcontext.S: New file.
	* sysdeps/unix/sysv/linux/arm/eabi/makecontext.c: New file.
	* sysdeps/unix/sysv/linux/arm/eabi/setcontext.S: New file.
	* sysdeps/unix/sysv/linux/arm/eabi/swapcontext.S: New file.
	* sysdeps/unix/sysv/linux/arm/ucontext_i.sym: New file.
	* sysdeps/unix/sysv/linux/arm/Makefile (gen-as-const-headers): Add
	ucontext_i.sym.
This commit is contained in:
Michael Hope 2012-03-05 17:58:13 -05:00 committed by Carlos O'Donell
parent 052178e613
commit 402a76b62d
7 changed files with 394 additions and 0 deletions
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10
ChangeLog.arm
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@ -1,3 +1,13 @@
2012-03-05 Michael Hope <michael.hope@linaro.org>
* sysdeps/unix/sysv/linux/arm/eabi/getcontext.S: New file.
* sysdeps/unix/sysv/linux/arm/eabi/makecontext.c: New file.
* sysdeps/unix/sysv/linux/arm/eabi/setcontext.S: New file.
* sysdeps/unix/sysv/linux/arm/eabi/swapcontext.S: New file.
* sysdeps/unix/sysv/linux/arm/ucontext_i.sym: New file.
* sysdeps/unix/sysv/linux/arm/Makefile (gen-as-const-headers): Add
ucontext_i.sym.
2012-02-27 Joseph Myers <joseph@codesourcery.com>
* sysdeps/unix/sysv/linux/arm/nptl/bits/pthreadtypes.h

4
sysdeps/unix/sysv/linux/arm/Makefile
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@ -20,3 +20,7 @@ endif
ifeq ($(subdir),resource)
sysdep_routines += oldgetrlimit64
endif
ifeq ($(subdir),stdlib)
gen-as-const-headers += ucontext_i.sym
endif

113
sysdeps/unix/sysv/linux/arm/eabi/getcontext.S Normal file
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@ -0,0 +1,113 @@
/* Copyright (C) 2012 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <sysdep.h>
#include <rtld-global-offsets.h>
#include "ucontext_i.h"
.syntax unified
.text
/* int getcontext (ucontext_t *ucp) */
ENTRY(__getcontext)
/* No need to save r0-r3, d0-d7, or d16-d31. */
add r1, r0, #MCONTEXT_ARM_R4
stmia r1, {r4-r11}
/* Save R13 separately as Thumb can't STM it. */
str r13, [r0, #MCONTEXT_ARM_SP]
str r14, [r0, #MCONTEXT_ARM_LR]
/* Return to LR */
str r14, [r0, #MCONTEXT_ARM_PC]
/* Return zero */
mov r2, #0
str r2, [r0, #MCONTEXT_ARM_R0]
/* Save ucontext_t * across the next call. */
mov r4, r0
/* __sigprocmask(SIG_BLOCK, NULL, &(ucontext->uc_sigmask)) */
mov r0, #SIG_BLOCK
mov r1, #0
add r2, r4, #UCONTEXT_SIGMASK
bl PLTJMP(__sigprocmask)
/* Store FP regs. Much of the FP code is copied from arm/eabi/setjmp.S. */
#ifdef PIC
ldr r2, 1f
ldr r1, Lrtld_global_ro
0: add r2, pc, r2
ldr r2, [r2, r1]
ldr r2, [r2, #RTLD_GLOBAL_RO_DL_HWCAP_OFFSET]
#else
ldr r2, Lhwcap
ldr r2, [r2, #0]
#endif
add r0, r4, #UCONTEXT_REGSPACE
tst r2, #HWCAP_ARM_VFP
beq Lno_vfp
/* Store the VFP registers.
Don't use VFP instructions directly because this code
is used in non-VFP multilibs. */
/* Following instruction is vstmia r0!, {d8-d15}. */
stc p11, cr8, [r0], #64
/* Store the floating-point status register. */
/* Following instruction is vmrs r1, fpscr. */
mrc p10, 7, r1, cr1, cr0, 0
str r1, [r0], #4
Lno_vfp:
tst r2, #HWCAP_ARM_IWMMXT
beq Lno_iwmmxt
/* Save the call-preserved iWMMXt registers. */
/* Following instructions are wstrd wr10, [r0], #8 (etc.) */
stcl p1, cr10, [r0], #8
stcl p1, cr11, [r0], #8
stcl p1, cr12, [r0], #8
stcl p1, cr13, [r0], #8
stcl p1, cr14, [r0], #8
stcl p1, cr15, [r0], #8
Lno_iwmmxt:
/* Restore the clobbered R4 and LR. */
ldr r14, [r4, #MCONTEXT_ARM_LR]
ldr r4, [r4, #MCONTEXT_ARM_R4]
mov r0, #0
DO_RET(r14)
END(__getcontext)
#ifdef PIC
1: .long _GLOBAL_OFFSET_TABLE_ - 0b - 8
Lrtld_global_ro:
.long C_SYMBOL_NAME(_rtld_global_ro)(GOT)
#else
Lhwcap:
.long C_SYMBOL_NAME(_dl_hwcap)
#endif
weak_alias(__getcontext, getcontext)

73
sysdeps/unix/sysv/linux/arm/eabi/makecontext.c Normal file
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@ -0,0 +1,73 @@
/* Copyright (C) 2012 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <stdarg.h>
#include <ucontext.h>
/* Number of arguments that go in registers. */
#define NREG_ARGS 4
/* Take a context previously prepared via getcontext() and set to
call func() with the given int only args. */
void
__makecontext (ucontext_t *ucp, void (*func) (void), int argc, ...)
{
extern void __startcontext (void);
unsigned long *funcstack;
va_list vl;
unsigned long *regptr;
unsigned int reg;
int misaligned;
/* Start at the top of stack. */
funcstack = (unsigned long *) (ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
/* Ensure the stack stays eight byte aligned. */
misaligned = ((unsigned long) funcstack & 4) != 0;
if ((argc > NREG_ARGS) && (argc & 1) != 0)
misaligned = !misaligned;
if (misaligned)
funcstack -= 1;
va_start (vl, argc);
/* Reserve space for the on-stack arguments. */
if (argc > NREG_ARGS)
funcstack -= (argc - NREG_ARGS);
ucp->uc_mcontext.arm_sp = (unsigned long) funcstack;
ucp->uc_mcontext.arm_pc = (unsigned long) func;
/* Exit to startcontext() with the next context in R4 */
ucp->uc_mcontext.arm_r4 = (unsigned long) ucp->uc_link;
ucp->uc_mcontext.arm_lr = (unsigned long) __startcontext;
/* The first four arguments go into registers. */
regptr = &(ucp->uc_mcontext.arm_r0);
for (reg = 0; (reg < argc) && (reg < NREG_ARGS); reg++)
*regptr++ = va_arg (vl, unsigned long);
/* And the remainder on the stack. */
for (; reg < argc; reg++)
*funcstack++ = va_arg (vl, unsigned long);
va_end (vl);
}
weak_alias (__makecontext, makecontext)

101
sysdeps/unix/sysv/linux/arm/eabi/setcontext.S Normal file
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@ -0,0 +1,101 @@
/* Copyright (C) 2012 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <sysdep.h>
#include <rtld-global-offsets.h>
#include "ucontext_i.h"
.syntax unified
.text
/* int setcontext (const ucontext_t *ucp) */
ENTRY(__setcontext)
mov r4, r0
add r0, r0, #UCONTEXT_REGSPACE
/* Restore the VFP registers. Copied from arm/eabi/__longjmp.S. */
#ifdef PIC
ldr r2, 1f
ldr r1, Lrtld_global_ro
0: add r2, pc, r2
ldr r2, [r2, r1]
ldr r2, [r2, #RTLD_GLOBAL_RO_DL_HWCAP_OFFSET]
#else
ldr r2, Lhwcap
ldr r2, [r2, #0]
#endif
tst r2, #HWCAP_ARM_VFP
beq Lno_vfp_sc
/* Following instruction is vldmia r0!, {d8-d15}. */
ldc p11, cr8, [r0], #64
/* Restore the floating-point status register. */
ldr r1, [r0], #4
/* Following instruction is fmxr fpscr, r1. */
mcr p10, 7, r1, cr1, cr0, 0
Lno_vfp_sc:
tst r2, #HWCAP_ARM_IWMMXT
beq Lno_iwmmxt_sc
/* Restore the call-preserved iWMMXt registers. */
/* Following instructions are wldrd wr10, [r0], #8 (etc.) */
ldcl p1, cr10, [r0], #8
ldcl p1, cr11, [r0], #8
ldcl p1, cr12, [r0], #8
ldcl p1, cr13, [r0], #8
ldcl p1, cr14, [r0], #8
ldcl p1, cr15, [r0], #8
Lno_iwmmxt_sc:
/* Now bring back the signal status. */
mov r0, #SIG_SETMASK
add r1, r4, #UCONTEXT_SIGMASK
mov r2, #0
bl PLTJMP(__sigprocmask)
/* Loading r0-r3 makes makecontext easier. */
add r14, r4, #MCONTEXT_ARM_R0
ldmia r14, {r0-r12}
ldr r13, [r14, #(MCONTEXT_ARM_SP - MCONTEXT_ARM_R0)]
add r14, r14, #(MCONTEXT_ARM_LR - MCONTEXT_ARM_R0)
ldmia r14, {r14, pc}
END(setcontext)
weak_alias(__setcontext, setcontext)
/* Called when a makecontext() context returns. Start the
context in R4 or fall through to exit(). */
ENTRY(__startcontext)
movs r0, r4
bne PLTJMP(__setcontext)
@ New context was 0 - exit
b PLTJMP(_exit)
END(__startcontext)
#ifdef PIC
1: .long _GLOBAL_OFFSET_TABLE_ - 0b - 8
Lrtld_global_ro:
.long C_SYMBOL_NAME(_rtld_global_ro)(GOT)
#else
Lhwcap:
.long C_SYMBOL_NAME(_dl_hwcap)
#endif

63
sysdeps/unix/sysv/linux/arm/eabi/swapcontext.S Normal file
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@ -0,0 +1,63 @@
/* Copyright (C) 2012 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <sysdep.h>
#include "ucontext_i.h"
.syntax unified
.text
/* int swapcontext (ucontext_t *oucp, const ucontext_t *ucp) */
ENTRY(swapcontext)
/* Have getcontext() do most of the work then fix up
LR afterwards. Save R3 to keep the stack aligned. */
push {r0,r1,r3,r14}
cfi_adjust_cfa_offset (16)
cfi_rel_offset (r0,0)
cfi_rel_offset (r1,4)
cfi_rel_offset (r3,8)
cfi_rel_offset (r14,12)
bl __getcontext
mov r4, r0
pop {r0,r1,r3,r14}
cfi_adjust_cfa_offset (-16)
cfi_restore (r0)
cfi_restore (r1)
cfi_restore (r3)
cfi_restore (r14)
/* Exit if getcontext() failed. */
cmp r4, #0
itt ne
movne r0, r4
RETINSTR(ne, r14)
/* Fix up LR and the PC. */
str r13,[r0, #MCONTEXT_ARM_SP]
str r14,[r0, #MCONTEXT_ARM_LR]
str r14,[r0, #MCONTEXT_ARM_PC]
/* And swap using swapcontext(). */
mov r0, r1
b __setcontext
END(swapcontext)

30
sysdeps/unix/sysv/linux/arm/ucontext_i.sym Normal file
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@ -0,0 +1,30 @@
#include <inttypes.h>
#include <signal.h>
#include <stddef.h>
#include <sys/ucontext.h>
SIG_BLOCK
SIG_SETMASK
-- Offsets of the fields in the ucontext_t structure.
#define ucontext(member) offsetof (ucontext_t, member)
#define mcontext(member) ucontext (uc_mcontext.member)
UCONTEXT_FLAGS ucontext (uc_flags)
UCONTEXT_LINK ucontext (uc_link)
UCONTEXT_STACK ucontext (uc_stack)
UCONTEXT_MCONTEXT ucontext (uc_mcontext)
UCONTEXT_SIGMASK ucontext (uc_sigmask)
UCONTEXT_REGSPACE ucontext (uc_regspace)
MCONTEXT_TRAP_NO mcontext (trap_no)
MCONTEXT_ERROR_CODE mcontext (error_code)
MCONTEXT_OLDMASK mcontext (oldmask)
MCONTEXT_ARM_R0 mcontext (arm_r0)
MCONTEXT_ARM_R4 mcontext (arm_r4)
MCONTEXT_ARM_SP mcontext (arm_sp)
MCONTEXT_ARM_LR mcontext (arm_lr)
MCONTEXT_ARM_PC mcontext (arm_pc)
MCONTEXT_ARM_CPSR mcontext (arm_cpsr)
MCONTEXT_FAULT_ADDRESS mcontext (fault_address)