c-UEFI-malloc调用不返回

Question

我会尽量缩短。

我创建了一个UEFI应用程序，它只使用一个简单的malloc，但从不从调用中返回：

main.c:

#include <efi.h>
#include <efilib.h>
#include <stdlib.h>
EFI_STATUS
EFIAPI
efi_main (EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable) 
{
InitializeLib(ImageHandle, SystemTable);
Print(L"trying to allocate memoryn");
malloc(16);
Print(L"allocated successfullyn");
return EFI_SUCCESS;
}

输出：

trying to allocate memory

该系统是linux下的QEMU虚拟机ubuntu:

"qemu-system-x86_64 -cpu qemu64 -bios Bios/bios.bin -drive file=Bios/app.disk,format=raw -global isa-debugcon.iobase=0x402 -debugcon file:app.ovmf.log"

bios.bin是UEFI固件https://wiki.ubuntu.com/UEFI/OVMF.

main.efi通过写入app.disk

dd if=/dev/zero of=Bios/app.disk bs=1 count=1 seek=$(( (128 * 1024) - 1))
sudo mkfs.vfat Bios/app.disk
mkdir Bios/mnt_app
cp Bios/app.disk Bios/mnt_app
sudo mount Bios/app.disk Bios/mnt_app
sudo cp kernel/main.efi Bios/mnt_app

main.c的构建过程几乎完全是从https://www.rodsbooks.com/efi-programming/hello.html:

ARCH            = $(shell uname -m | sed s,i[3456789]86,ia32,)
OBJS            = main.o
TARGET          = main.efi
EFIINC          = /usr/include/efi
EFIINCS         = -I$(EFIINC) -I$(EFIINC)/$(ARCH) -I$(EFIINC)/protocol
EFILIB          = /usr/lib
EFI_CRT_OBJS    = $(EFILIB)/crt0-efi-$(ARCH).o
EFI_LDS         = $(EFILIB)/elf_$(ARCH)_efi.lds
CFLAGS          = $(EFIINCS) -fno-stack-protector -fpic 
-fshort-wchar -mno-red-zone -Wall 
ifeq ($(ARCH),x86_64)
CFLAGS += -DEFI_FUNCTION_WRAPPER
endif
LDFLAGS         = -nostdlib -znocombreloc -T $(EFI_LDS) -shared 
-Bsymbolic -L $(EFILIB) $(EFI_CRT_OBJS) 
all: $(TARGET)
main.so: $(OBJS)
ld $(LDFLAGS) $(OBJS) -o $@ -lefi -lgnuefi
%.efi: %.so
objcopy -j .text -j .sdata -j .data -j .dynamic 
-j .dynsym  -j .rel -j .rela -j .reloc 
--target=efi-app-$(ARCH) $^ $@
@echo   done building target

Answer 1

由于我不知道的原因，malloc只是不起作用，而且可能不打算使用——至少看起来是这样。如果您需要动态内存分配，请使用内存池创建自己的malloc:

void * malloc(UINTN poolSize)
{
EFI_STATUS status;
void * handle;
Print(L"allocating memory pooln");
status = uefi_call_wrapper(BS->AllocatePool, 3, EfiLoaderData, poolSize, &handle);
if(status == EFI_OUT_OF_RESOURCES)
{
Print(L"out of resources for pooln");
return 0;
}
else if(status == EFI_INVALID_PARAMETER)
{
Print(L"invalid pool typen");
return 0;
}
else
{
Print(L"memory pool successfully allocatedn");
return handle;
}
}

免费等价物：

void free(void * pool)
{
EFI_STATUS status;
Print(L"freeing memory pooln");
status = uefi_call_wrapper(BS->FreePool, 1, pool);
if(status == EFI_INVALID_PARAMETER)
{
Print(L"invalid pool pointern");
}
else
{
Print(L"memory pool successfully freedn");
}
}

像通常使用malloc和免费一样使用它：

EFI_STATUS
EFIAPI
efi_main (EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable) 
{
InitializeLib(ImageHandle, SystemTable);
void * memoryPointer = malloc(1024);
free(memoryPointer);
return EFI_SUCCESS;
}

输出：

allocating memory pool
memory pool successfully allocated
freeing memory pool
memory pool successfully freed