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qemu/Makefile.target
Timothy E Baldwin 4d330cee37 linux-user: Provide safe_syscall for fixing races between signals and syscalls 
If a signal is delivered immediately before a blocking system call the
handler will only be called after the system call returns, which may be a
long time later or never.

This is fixed by using a function (safe_syscall) that checks if a guest
signal is pending prior to making a system call, and if so does not call the
system call and returns -TARGET_ERESTARTSYS. If a signal is received between
the check and the system call host_signal_handler() rewinds execution to
before the check. This rewinding has the effect of closing the race window
so that safe_syscall will reliably either (a) go into the host syscall
with no unprocessed guest signals pending or or (b) return
-TARGET_ERESTARTSYS so that the caller can deal with the signals.
Implementing this requires a per-host-architecture assembly language
fragment.

This will also resolve the mishandling of the SA_RESTART flag where
we would restart a host system call and not call the guest signal handler
until the syscall finally completed -- syscall restarting now always
happens at the guest syscall level so the guest signal handler will run.
(The host syscall will never be restarted because if the host kernel
rewinds the PC to point at the syscall insn for a restart then our
host_signal_handler() will see this and arrange the guest PC rewind.)

This commit contains the infrastructure for implementing safe_syscall
and the assembly language fragment for x86-64, but does not change any
syscalls to use it.

Signed-off-by: Timothy Edward Baldwin <T.E.Baldwin99@members.leeds.ac.uk>
Message-id: 1441497448-32489-14-git-send-email-T.E.Baldwin99@members.leeds.ac.uk
[PMM:
 * Avoid having an architecture if-ladder in configure by putting
   linux-user/host/$(ARCH) on the include path and including
   safe-syscall.inc.S from it
 * Avoid ifdef ladder in signal.c by creating new hostdep.h to hold
   host-architecture-specific things
 * Added copyright/license header to safe-syscall.inc.S
 * Rewrote commit message
 * Added comments to safe-syscall.inc.S
 * Changed calling convention of safe_syscall() to match syscall()
   (returns -1 and host error in errno on failure)
 * Added a long comment in qemu.h about how to use safe_syscall()
   to implement guest syscalls.
]
RV: squashed Peters "fixup! linux-user: compile on non-x86-64 hosts"
patch
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2016-05-27 14:49:51 +03:00

238 lines
7.1 KiB
Makefile
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# -*- Mode: makefile -*-
BUILD_DIR?=$(CURDIR)/..
include ../config-host.mak
include config-target.mak
include config-devices.mak
include $(SRC_PATH)/rules.mak
$(call set-vpath, $(SRC_PATH):$(BUILD_DIR))
ifdef CONFIG_LINUX
QEMU_CFLAGS += -I../linux-headers
endif
QEMU_CFLAGS += -I.. -I$(SRC_PATH)/target-$(TARGET_BASE_ARCH) -DNEED_CPU_H
QEMU_CFLAGS+=-I$(SRC_PATH)/include
ifdef CONFIG_USER_ONLY
# user emulator name
QEMU_PROG=qemu-$(TARGET_NAME)
QEMU_PROG_BUILD = $(QEMU_PROG)
else
# system emulator name
QEMU_PROG=qemu-system-$(TARGET_NAME)$(EXESUF)
ifneq (,$(findstring -mwindows,$(libs_softmmu)))
# Terminate program name with a 'w' because the linker builds a windows executable.
QEMU_PROGW=qemu-system-$(TARGET_NAME)w$(EXESUF)
$(QEMU_PROG): $(QEMU_PROGW)
$(call quiet-command,$(OBJCOPY) --subsystem console $(QEMU_PROGW) $(QEMU_PROG)," GEN $(TARGET_DIR)$(QEMU_PROG)")
QEMU_PROG_BUILD = $(QEMU_PROGW)
else
QEMU_PROG_BUILD = $(QEMU_PROG)
endif
endif
PROGS=$(QEMU_PROG) $(QEMU_PROGW)
STPFILES=
config-target.h: config-target.h-timestamp
config-target.h-timestamp: config-target.mak
ifdef CONFIG_TRACE_SYSTEMTAP
stap: $(QEMU_PROG).stp-installed $(QEMU_PROG).stp $(QEMU_PROG)-simpletrace.stp
ifdef CONFIG_USER_ONLY
TARGET_TYPE=user
else
TARGET_TYPE=system
endif
$(QEMU_PROG).stp-installed: $(SRC_PATH)/trace-events
$(call quiet-command,$(TRACETOOL) \
--format=stap \
--backends=$(TRACE_BACKENDS) \
--binary=$(bindir)/$(QEMU_PROG) \
--target-name=$(TARGET_NAME) \
--target-type=$(TARGET_TYPE) \
< $< > $@," GEN $(TARGET_DIR)$(QEMU_PROG).stp-installed")
$(QEMU_PROG).stp: $(SRC_PATH)/trace-events
$(call quiet-command,$(TRACETOOL) \
--format=stap \
--backends=$(TRACE_BACKENDS) \
--binary=$(realpath .)/$(QEMU_PROG) \
--target-name=$(TARGET_NAME) \
--target-type=$(TARGET_TYPE) \
< $< > $@," GEN $(TARGET_DIR)$(QEMU_PROG).stp")
$(QEMU_PROG)-simpletrace.stp: $(SRC_PATH)/trace-events
$(call quiet-command,$(TRACETOOL) \
--format=simpletrace-stap \
--backends=$(TRACE_BACKENDS) \
--probe-prefix=qemu.$(TARGET_TYPE).$(TARGET_NAME) \
< $< > $@," GEN $(TARGET_DIR)$(QEMU_PROG)-simpletrace.stp")
else
stap:
endif
all: $(PROGS) stap
# Dummy command so that make thinks it has done something
@true
#########################################################
# cpu emulator library
obj-y = exec.o translate-all.o cpu-exec.o
obj-y += translate-common.o
obj-y += cpu-exec-common.o
obj-y += tcg/tcg.o tcg/tcg-op.o tcg/optimize.o
obj-$(CONFIG_TCG_INTERPRETER) += tci.o
obj-y += tcg/tcg-common.o
obj-$(CONFIG_TCG_INTERPRETER) += disas/tci.o
obj-y += fpu/softfloat.o
obj-y += target-$(TARGET_BASE_ARCH)/
obj-y += disas.o
obj-$(call notempty,$(TARGET_XML_FILES)) += gdbstub-xml.o
obj-$(call lnot,$(CONFIG_KVM)) += kvm-stub.o
obj-$(CONFIG_LIBDECNUMBER) += libdecnumber/decContext.o
obj-$(CONFIG_LIBDECNUMBER) += libdecnumber/decNumber.o
obj-$(CONFIG_LIBDECNUMBER) += libdecnumber/dpd/decimal32.o
obj-$(CONFIG_LIBDECNUMBER) += libdecnumber/dpd/decimal64.o
obj-$(CONFIG_LIBDECNUMBER) += libdecnumber/dpd/decimal128.o
#########################################################
# Linux user emulator target
ifdef CONFIG_LINUX_USER
# Note that we only add linux-user/host/$ARCH if it exists, and
# that it must come before linux-user/host/generic in the search path.
QEMU_CFLAGS+=-I$(SRC_PATH)/linux-user/$(TARGET_ABI_DIR) \
$(patsubst %,-I%,$(wildcard $(SRC_PATH)/linux-user/host/$(ARCH))) \
-I$(SRC_PATH)/linux-user/host/generic \
-I$(SRC_PATH)/linux-user
obj-y += linux-user/
obj-y += gdbstub.o thunk.o user-exec.o
endif #CONFIG_LINUX_USER
#########################################################
# BSD user emulator target
ifdef CONFIG_BSD_USER
QEMU_CFLAGS+=-I$(SRC_PATH)/bsd-user -I$(SRC_PATH)/bsd-user/$(TARGET_ABI_DIR) \
-I$(SRC_PATH)/bsd-user/$(HOST_VARIANT_DIR)
obj-y += bsd-user/
obj-y += gdbstub.o user-exec.o
endif #CONFIG_BSD_USER
#########################################################
# System emulator target
ifdef CONFIG_SOFTMMU
obj-y += arch_init.o cpus.o monitor.o gdbstub.o balloon.o ioport.o numa.o
obj-y += qtest.o bootdevice.o
obj-y += hw/
obj-$(CONFIG_KVM) += kvm-all.o
obj-y += memory.o cputlb.o
obj-y += memory_mapping.o
obj-y += dump.o
obj-y += migration/ram.o migration/savevm.o
LIBS := $(libs_softmmu) $(LIBS)
# xen support
obj-$(CONFIG_XEN) += xen-common.o
obj-$(CONFIG_XEN_I386) += xen-hvm.o xen-mapcache.o
obj-$(call lnot,$(CONFIG_XEN)) += xen-common-stub.o
obj-$(call lnot,$(CONFIG_XEN_I386)) += xen-hvm-stub.o
# Hardware support
ifeq ($(TARGET_NAME), sparc64)
obj-y += hw/sparc64/
else
obj-y += hw/$(TARGET_BASE_ARCH)/
endif
GENERATED_HEADERS += hmp-commands.h hmp-commands-info.h qmp-commands-old.h
endif # CONFIG_SOFTMMU
# Workaround for http://gcc.gnu.org/PR55489, see configure.
%/translate.o: QEMU_CFLAGS += $(TRANSLATE_OPT_CFLAGS)
dummy := $(call unnest-vars,,obj-y)
all-obj-y := $(obj-y)
target-obj-y :=
block-obj-y :=
common-obj-y :=
include $(SRC_PATH)/Makefile.objs
dummy := $(call unnest-vars,,target-obj-y)
target-obj-y-save := $(target-obj-y)
dummy := $(call unnest-vars,.., \
block-obj-y \
block-obj-m \
crypto-obj-y \
crypto-aes-obj-y \
qom-obj-y \
io-obj-y \
common-obj-y \
common-obj-m)
target-obj-y := $(target-obj-y-save)
all-obj-y += $(common-obj-y)
all-obj-y += $(target-obj-y)
all-obj-y += $(qom-obj-y)
all-obj-$(CONFIG_SOFTMMU) += $(block-obj-y)
all-obj-$(CONFIG_USER_ONLY) += $(crypto-aes-obj-y)
all-obj-$(CONFIG_SOFTMMU) += $(crypto-obj-y)
all-obj-$(CONFIG_SOFTMMU) += $(io-obj-y)
$(QEMU_PROG_BUILD): config-devices.mak
# build either PROG or PROGW
$(QEMU_PROG_BUILD): $(all-obj-y) ../libqemuutil.a ../libqemustub.a
$(call LINK, $(filter-out %.mak, $^))
ifdef CONFIG_DARWIN
$(call quiet-command,Rez -append $(SRC_PATH)/pc-bios/qemu.rsrc -o $@," REZ $(TARGET_DIR)$@")
$(call quiet-command,SetFile -a C $@," SETFILE $(TARGET_DIR)$@")
endif
gdbstub-xml.c: $(TARGET_XML_FILES) $(SRC_PATH)/scripts/feature_to_c.sh
$(call quiet-command,rm -f $@ && $(SHELL) $(SRC_PATH)/scripts/feature_to_c.sh $@ $(TARGET_XML_FILES)," GEN $(TARGET_DIR)$@")
hmp-commands.h: $(SRC_PATH)/hmp-commands.hx
$(call quiet-command,sh $(SRC_PATH)/scripts/hxtool -h < $< > $@," GEN $(TARGET_DIR)$@")
hmp-commands-info.h: $(SRC_PATH)/hmp-commands-info.hx
$(call quiet-command,sh $(SRC_PATH)/scripts/hxtool -h < $< > $@," GEN $(TARGET_DIR)$@")
qmp-commands-old.h: $(SRC_PATH)/qmp-commands.hx
$(call quiet-command,sh $(SRC_PATH)/scripts/hxtool -h < $< > $@," GEN $(TARGET_DIR)$@")
clean:
rm -f *.a *~ $(PROGS)
rm -f $(shell find . -name '*.[od]')
rm -f hmp-commands.h qmp-commands-old.h gdbstub-xml.c
ifdef CONFIG_TRACE_SYSTEMTAP
rm -f *.stp
endif
install: all
ifneq ($(PROGS),)
$(call install-prog,$(PROGS),$(DESTDIR)$(bindir))
endif
ifdef CONFIG_TRACE_SYSTEMTAP
$(INSTALL_DIR) "$(DESTDIR)$(qemu_datadir)/../systemtap/tapset"
$(INSTALL_DATA) $(QEMU_PROG).stp-installed "$(DESTDIR)$(qemu_datadir)/../systemtap/tapset/$(QEMU_PROG).stp"
$(INSTALL_DATA) $(QEMU_PROG)-simpletrace.stp "$(DESTDIR)$(qemu_datadir)/../systemtap/tapset/$(QEMU_PROG)-simpletrace.stp"
endif
GENERATED_HEADERS += config-target.h
Makefile: $(GENERATED_HEADERS)
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