On x86_64 without HAVE_USE_MS_ABI support, uefi_call_wrapper() is a
variadic function. Parameters >=5 are copied to the stack and, when
passed small immediate values (and possibly other parameters), gcc
would emit a movl instruction before calling uefi_call_wrapper(). As a
result, only the lower 32b of these stack values are significant, the
upper 32b potentially contain garbage. Considering that
uefi_call_wrapper() assumes these arguments are clean 64b values
before calling the efi_callX() trampolines, the latter may be passed
garbage. This makes calling functions like
EFI_PCI_IO_PROTOCOL.Mem.Read()/Write() or BS->OpenProtocol() quite
unreliable.
This patch fixes this by turning uefi_call_wrapper() into a macro that
allows to expose the efi_callX() trampoline signatures to the callers,
so that gcc can know upfront that it has to pass all arguments to
efi_callX() as clean 64b values (eg. movq for immediates). The
_cast64_efi_callX macros are just here to avoid a gcc warning, they do
nothing otherwise.
Signed-off-by: David Decotigny <decot@googlers.com>
macros only exist in link.h on Linux. On FreeBSD, the equivalent macro is
__ElfN(). But the macro usage is redundant. You're only going to compile the
ia32 file for IA32 binaries and the x86_64 file for X64 binaries. If you had
just one file built for both cases, then using the macro might make more
sense.
- Removes the "#define foo_t efi_foo_t" macros from reloc_ia32.c and
reloc_x86_64.c.
- Modifies inc/x86_64/efibind.h and inc/ia32/efibind.h to use the new
definitions for uint64_t, int64_t and int8_t. The 64-bit types are now defined
as:
typedef int __attribute__((__mode__(__DI__))) int64_t;
typedef unsigned int __attribute__((__mode__(__DI__))) uint64_t;
This removes the conflict between the host types dragged in by elf.h and the
type definitions in efibind.h that made the #define foo_t efi_foo_t" hack
necessary. Also, int8_t is now defined as signed char instead of just char
(assuming char == signed char is apparently not good enough).
- Also modifies these files to use stdint.h instead of stdint-gcc.h. It's
unclear if this is completely correct, but stdint-gcc.h is not present with
all GCC installs, and if you use -std=c99 or later you will force this case to
be hit. This also can break clang, which doesn't have a stdint-gcc.h at all.
- Removes the #include of <link.h> from reloc_ia32.c and reloc_x86_64.c (since
with the previous changes it's not needed anymore).
- Places the #include of <elf.h> after #include <efi>/#include <efilib.h> so
that we know the types will always be defined properly, in case you build on a
system where <elf.h> doesn't automatically pull in the right header files to
define all the needed types. (This actually happens on VxWorks. It's harmless
elsewhere. If you don't care about VxWorks, you can leave this out.)
- Modifies setjmp_ia32.S and setjmp_x86_64.S so to change "function" to
@function. The clang compiler doesn't like the former. Clang and GCC both like
the latter.
- Modifles Make.defaults so that if ARCH is detected as "amd64," it's changed
to "x86_64." It happens that uname -m on 64-bit FreeBSD reports the former
rather than the latter, which breaks the build. This may also be the case on
some other OSes. There's a way to force uname(1) to return x86_64 as the
machine type, but this way is a little friendlier.
- Creates gnuefi/elf_ia32_fbsd_efi.lds which specifies the object file type as
elf-ia32-freebsd. This is required for building on FreeBSD/i386, not just
FreeBSD/amd64.
- Modifies apps/Makefile to always use
$(TOPDIR)/gnuefi/elf_$(ARCH)_fbsd_efi.lds when building on either 32-bit or
64-bit FreeBSD instead of just for the x86_64 case.
- Changed LDFLAGS in Make.defaults to include --no-undefined. This will cause
linking to fail if there are any unsatisfied symbols when creating foo.so
during any of the app builds, as opposed to just silently succeeding and
producing an unusable binary.
- Changed CFLAGS to include -ffreestanding -fno-stack-protector -fno-stack-
check. This prevents clang from inserting a call to memset() when compiling
the RtZeroMem() and RtSetMem() routines in lib/runtime/efirtlib.c and guards
against the native compiler in some Linux distros from adding in stack
checking code which relies on libc help that isn't present in the EFI runtime
environment.
This does the following:
- Cleans up the ia32 and x86-64 relocation code a bit (tries to break the
dependency between the host ELF headers and the EFI runtime environment)
- Avoids the dependency on stdint-gcc.h which may not always be available
- Allows GNU EFI to build out of the box on both FreeBSD/i386 and
FreeBSD/amd64
- Allows GNU EFI to build out of the box with either GCC or clang on
FreeBSD/i386 and FreeBSD/amd64 9.0 and later.
- Makes things a little easier to port to VxWorks
- Avoids creating un-runable binaries with unresolved symbol definitions
(which can be very confusing to debug)
