[U-Boot] [PATCH v3] x86: lib: Implement standalone __udivdi3 etc instead of libgcc ones
This patch removes the inclusion of the libgcc math functions and replaces them by functions coded in C, taken from the coreboot project. This makes U-Boot building more independent from the toolchain installed / available on the build system.
The code taken from coreboot is authored from Vadim Bendebury vbendeb@chromium.org on 2014-11-28 and committed with commit ID e63990ef [libpayload: provide basic 64bit division implementation] (coreboot git repository located here [1]).
I modified the code so that its checkpatch clean without any functional changes.
[1] git://github.com/coreboot/coreboot.git
Signed-off-by: Stefan Roese sr@denx.de Cc: Simon Glass sjg@chromium.org Cc: Bin Meng bmeng.cn@gmail.com --- v3: - Completely get rid of all libgcc references in arch/x86/lib/Makefile, also for the standalone applications
v2: - Added coreboot git repository link to commit message
arch/x86/config.mk | 3 -- arch/x86/lib/Makefile | 8 +--- arch/x86/lib/div64.c | 113 ++++++++++++++++++++++++++++++++++++++++++++++++++ arch/x86/lib/gcc.c | 29 ------------- 4 files changed, 114 insertions(+), 39 deletions(-) create mode 100644 arch/x86/lib/div64.c delete mode 100644 arch/x86/lib/gcc.c
diff --git a/arch/x86/config.mk b/arch/x86/config.mk index 8835dcf36f..472ada5490 100644 --- a/arch/x86/config.mk +++ b/arch/x86/config.mk @@ -34,9 +34,6 @@ PLATFORM_RELFLAGS += -ffunction-sections -fvisibility=hidden PLATFORM_LDFLAGS += -Bsymbolic -Bsymbolic-functions PLATFORM_LDFLAGS += -m $(if $(IS_32BIT),elf_i386,elf_x86_64)
-LDFLAGS_FINAL += --wrap=__divdi3 --wrap=__udivdi3 -LDFLAGS_FINAL += --wrap=__moddi3 --wrap=__umoddi3 - # This is used in the top-level Makefile which does not include # PLATFORM_LDFLAGS LDFLAGS_EFI_PAYLOAD := -Bsymbolic -Bsymbolic-functions -shared --no-undefined diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile index fe00d7573f..7d729ea0f7 100644 --- a/arch/x86/lib/Makefile +++ b/arch/x86/lib/Makefile @@ -18,7 +18,6 @@ obj-$(CONFIG_SEABIOS) += coreboot_table.o obj-y += early_cmos.o obj-$(CONFIG_EFI) += efi/ obj-y += e820.o -obj-y += gcc.o obj-y += init_helpers.o obj-y += interrupts.o obj-y += lpc-uclass.o @@ -49,12 +48,7 @@ endif obj-$(CONFIG_HAVE_FSP) += fsp/ obj-$(CONFIG_SPL_BUILD) += spl.o
-extra-$(CONFIG_USE_PRIVATE_LIBGCC) += lib.a - -NORMAL_LIBGCC = $(shell $(CC) $(PLATFORM_CPPFLAGS) -print-libgcc-file-name) -OBJCOPYFLAGS := --prefix-symbols=__normal_ -$(obj)/lib.a: $(NORMAL_LIBGCC) FORCE - $(call if_changed,objcopy) +lib-$(CONFIG_USE_PRIVATE_LIBGCC) += div64.o
ifeq ($(CONFIG_$(SPL_)X86_64),) obj-$(CONFIG_EFI_APP) += crt0_ia32_efi.o reloc_ia32_efi.o diff --git a/arch/x86/lib/div64.c b/arch/x86/lib/div64.c new file mode 100644 index 0000000000..4efed74037 --- /dev/null +++ b/arch/x86/lib/div64.c @@ -0,0 +1,113 @@ +/* + * This file is copied from the coreboot repository as part of + * the libpayload project: + * + * Copyright 2014 Google Inc. + * + * SPDX-License-Identifier: BSD-3-Clause + */ + +#include <common.h> + +union overlay64 { + u64 longw; + struct { + u32 lower; + u32 higher; + } words; +}; + +u64 __ashldi3(u64 num, unsigned int shift) +{ + union overlay64 output; + + output.longw = num; + if (shift >= 32) { + output.words.higher = output.words.lower << (shift - 32); + output.words.lower = 0; + } else { + if (!shift) + return num; + output.words.higher = (output.words.higher << shift) | + (output.words.lower >> (32 - shift)); + output.words.lower = output.words.lower << shift; + } + return output.longw; +} + +u64 __lshrdi3(u64 num, unsigned int shift) +{ + union overlay64 output; + + output.longw = num; + if (shift >= 32) { + output.words.lower = output.words.higher >> (shift - 32); + output.words.higher = 0; + } else { + if (!shift) + return num; + output.words.lower = output.words.lower >> shift | + (output.words.higher << (32 - shift)); + output.words.higher = output.words.higher >> shift; + } + return output.longw; +} + +#define MAX_32BIT_UINT ((((u64)1) << 32) - 1) + +static u64 _64bit_divide(u64 dividend, u64 divider, u64 *rem_p) +{ + u64 result = 0; + + /* + * If divider is zero - let the rest of the system care about the + * exception. + */ + if (!divider) + return 1 / (u32)divider; + + /* As an optimization, let's not use 64 bit division unless we must. */ + if (dividend <= MAX_32BIT_UINT) { + if (divider > MAX_32BIT_UINT) { + result = 0; + if (rem_p) + *rem_p = divider; + } else { + result = (u32)dividend / (u32)divider; + if (rem_p) + *rem_p = (u32)dividend % (u32)divider; + } + return result; + } + + while (divider <= dividend) { + u64 locald = divider; + u64 limit = __lshrdi3(dividend, 1); + int shifts = 0; + + while (locald <= limit) { + shifts++; + locald = locald + locald; + } + result |= __ashldi3(1, shifts); + dividend -= locald; + } + + if (rem_p) + *rem_p = dividend; + + return result; +} + +u64 __udivdi3(u64 num, u64 den) +{ + return _64bit_divide(num, den, NULL); +} + +u64 __umoddi3(u64 num, u64 den) +{ + u64 v = 0; + + _64bit_divide(num, den, &v); + return v; +} diff --git a/arch/x86/lib/gcc.c b/arch/x86/lib/gcc.c deleted file mode 100644 index 3c70d790d4..0000000000 --- a/arch/x86/lib/gcc.c +++ /dev/null @@ -1,29 +0,0 @@ -/* - * This file is part of the coreboot project. - * - * Copyright (C) 2009 coresystems GmbH - * - * SPDX-License-Identifier: GPL-2.0 - */ - -#ifdef __GNUC__ - -/* - * GCC's libgcc handling is quite broken. While the libgcc functions - * are always regparm(0) the code that calls them uses whatever the - * compiler call specifies. Therefore we need a wrapper around those - * functions. See gcc bug PR41055 for more information. - */ -#define WRAP_LIBGCC_CALL(type, name) \ - type __normal_##name(type a, type b) __attribute__((regparm(0))); \ - type __wrap_##name(type a, type b); \ - type __attribute__((no_instrument_function)) \ - __wrap_##name(type a, type b) \ - { return __normal_##name(a, b); } - -WRAP_LIBGCC_CALL(long long, __divdi3) -WRAP_LIBGCC_CALL(unsigned long long, __udivdi3) -WRAP_LIBGCC_CALL(long long, __moddi3) -WRAP_LIBGCC_CALL(unsigned long long, __umoddi3) - -#endif
On Wed, Nov 29, 2017 at 11:23 PM, Stefan Roese sr@denx.de wrote:
This patch removes the inclusion of the libgcc math functions and replaces them by functions coded in C, taken from the coreboot project. This makes U-Boot building more independent from the toolchain installed / available on the build system.
The code taken from coreboot is authored from Vadim Bendebury vbendeb@chromium.org on 2014-11-28 and committed with commit ID e63990ef [libpayload: provide basic 64bit division implementation] (coreboot git repository located here [1]).
I modified the code so that its checkpatch clean without any functional changes.
[1] git://github.com/coreboot/coreboot.git
Signed-off-by: Stefan Roese sr@denx.de Cc: Simon Glass sjg@chromium.org Cc: Bin Meng bmeng.cn@gmail.com
v3:
- Completely get rid of all libgcc references in arch/x86/lib/Makefile, also for the standalone applications
v2:
- Added coreboot git repository link to commit message
arch/x86/config.mk | 3 -- arch/x86/lib/Makefile | 8 +--- arch/x86/lib/div64.c | 113 ++++++++++++++++++++++++++++++++++++++++++++++++++ arch/x86/lib/gcc.c | 29 ------------- 4 files changed, 114 insertions(+), 39 deletions(-) create mode 100644 arch/x86/lib/div64.c delete mode 100644 arch/x86/lib/gcc.c
Reviewed-by: Bin Meng bmeng.cn@gmail.com Tested-by: Bin Meng bmeng.cn@gmail.com
On Thu, Nov 30, 2017 at 1:31 PM, Bin Meng bmeng.cn@gmail.com wrote:
On Wed, Nov 29, 2017 at 11:23 PM, Stefan Roese sr@denx.de wrote:
This patch removes the inclusion of the libgcc math functions and replaces them by functions coded in C, taken from the coreboot project. This makes U-Boot building more independent from the toolchain installed / available on the build system.
The code taken from coreboot is authored from Vadim Bendebury vbendeb@chromium.org on 2014-11-28 and committed with commit ID e63990ef [libpayload: provide basic 64bit division implementation] (coreboot git repository located here [1]).
I modified the code so that its checkpatch clean without any functional changes.
[1] git://github.com/coreboot/coreboot.git
Signed-off-by: Stefan Roese sr@denx.de Cc: Simon Glass sjg@chromium.org Cc: Bin Meng bmeng.cn@gmail.com
v3:
- Completely get rid of all libgcc references in arch/x86/lib/Makefile, also for the standalone applications
v2:
- Added coreboot git repository link to commit message
arch/x86/config.mk | 3 -- arch/x86/lib/Makefile | 8 +--- arch/x86/lib/div64.c | 113 ++++++++++++++++++++++++++++++++++++++++++++++++++ arch/x86/lib/gcc.c | 29 ------------- 4 files changed, 114 insertions(+), 39 deletions(-) create mode 100644 arch/x86/lib/div64.c delete mode 100644 arch/x86/lib/gcc.c
Reviewed-by: Bin Meng bmeng.cn@gmail.com Tested-by: Bin Meng bmeng.cn@gmail.com
applied to u-boot-x86, thanks!
Op Wed, 29 Nov 2017 16:23:31 +0100, schreef Stefan Roese:
This patch removes the inclusion of the libgcc math functions and replaces them by functions coded in C, taken from the coreboot project. This makes U-Boot building more independent from the toolchain installed / available on the build system.
Thanks Stefan,
Great work, I'll try to test that soon.
BTW I eventually have been able to work around the problem in Yocto. The work around involved creating a seperate .conf file for u-boot which includes multilib support. I couldn't add multilib support to my rootfs .conf file because that broke building the sdk. Of course the effect is to build a complete seperate target infrastructure (x86_64 + ml) just to build one binary.
This patch will save people a lot of grief I'm sure.
The code taken from coreboot is authored from Vadim Bendebury vbendeb@chromium.org on 2014-11-28 and committed with commit ID e63990ef [libpayload: provide basic 64bit division implementation] (coreboot git repository located here [1]).
I modified the code so that its checkpatch clean without any functional changes.
[1] git://github.com/coreboot/coreboot.git
Signed-off-by: Stefan Roese sr@denx.de Cc: Simon Glass sjg@chromium.org Cc: Bin Meng bmeng.cn@gmail.com
v3:
- Completely get rid of all libgcc references in arch/x86/lib/Makefile, also for the standalone applications
v2:
- Added coreboot git repository link to commit message
arch/x86/config.mk | 3 -- arch/x86/lib/Makefile | 8 +--- arch/x86/lib/div64.c | 113 ++++++++++++++++++++++++++++++++++++++++++++++++++ arch/x86/lib/gcc.c | 29 ------------- 4 files changed, 114 insertions(+), 39 deletions(-) create mode 100644 arch/x86/lib/div64.c delete mode 100644 arch/x86/lib/gcc.c
diff --git a/arch/x86/config.mk b/arch/x86/config.mk index 8835dcf36f..472ada5490 100644 --- a/arch/x86/config.mk +++ b/arch/x86/config.mk @@ -34,9 +34,6 @@ PLATFORM_RELFLAGS += -ffunction-sections -fvisibility=hidden PLATFORM_LDFLAGS += -Bsymbolic -Bsymbolic-functions PLATFORM_LDFLAGS += -m $(if $(IS_32BIT),elf_i386,elf_x86_64)
-LDFLAGS_FINAL += --wrap=__divdi3 --wrap=__udivdi3 -LDFLAGS_FINAL += --wrap=__moddi3 --wrap=__umoddi3 - # This is used in the top-level Makefile which does not include # PLATFORM_LDFLAGS LDFLAGS_EFI_PAYLOAD := -Bsymbolic -Bsymbolic-functions -shared --no-undefined diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile index fe00d7573f..7d729ea0f7 100644 --- a/arch/x86/lib/Makefile +++ b/arch/x86/lib/Makefile @@ -18,7 +18,6 @@ obj-$(CONFIG_SEABIOS) += coreboot_table.o obj-y += early_cmos.o obj-$(CONFIG_EFI) += efi/ obj-y += e820.o -obj-y += gcc.o obj-y += init_helpers.o obj-y += interrupts.o obj-y += lpc-
uclass.o
@@ -49,12 +48,7 @@ endif obj-$(CONFIG_HAVE_FSP) += fsp/ obj-$(CONFIG_SPL_BUILD) += spl.o
-extra-$(CONFIG_USE_PRIVATE_LIBGCC) += lib.a - -NORMAL_LIBGCC = $(shell $(CC) $(PLATFORM_CPPFLAGS) -print-libgcc-file-name) -OBJCOPYFLAGS := --prefix-symbols=__normal_ -$(obj)/lib.a: $(NORMAL_LIBGCC) FORCE - $(call if_changed,objcopy) +lib-$(CONFIG_USE_PRIVATE_LIBGCC) += div64.o
ifeq ($(CONFIG_$(SPL_)X86_64),) obj-$(CONFIG_EFI_APP) += crt0_ia32_efi.o reloc_ia32_efi.o diff --git a/arch/x86/lib/div64.c b/arch/x86/lib/div64.c new file mode 100644 index 0000000000..4efed74037 --- /dev/null +++ b/arch/x86/lib/div64.c @@ -0,0 +1,113 @@ +/*
- This file is copied from the coreboot repository as part of + * the
libpayload project:
- Copyright 2014 Google Inc.
- SPDX-License-Identifier: BSD-3-Clause + */
+#include <common.h>
+union overlay64 {
- u64 longw;
- struct {
u32 lower;u32 higher;- } words;
+};
+u64 __ashldi3(u64 num, unsigned int shift) +{
- union overlay64 output;
- output.longw = num;
- if (shift >= 32) {
output.words.higher = output.words.lower << (shift - 32);
+
output.words.lower = 0;
- } else {
if (!shift)return num;output.words.higher = (output.words.higher << shift) |
+
(output.words.lower >> (32 - shift));
output.words.lower = output.words.lower << shift;- }
- return output.longw;
+}
+u64 __lshrdi3(u64 num, unsigned int shift) +{
- union overlay64 output;
- output.longw = num;
- if (shift >= 32) {
output.words.lower = output.words.higher >> (shift - 32);
+
output.words.higher = 0;
- } else {
if (!shift)return num;output.words.lower = output.words.lower >> shift |
+
(output.words.higher << (32 - shift));
output.words.higher = output.words.higher >> shift;- }
- return output.longw;
+}
+#define MAX_32BIT_UINT ((((u64)1) << 32) - 1)
+static u64 _64bit_divide(u64 dividend, u64 divider, u64 *rem_p) +{
- u64 result = 0;
- /*
* If divider is zero - let the rest of the system care about the
+ *
exception.
*/- if (!divider)
return 1 / (u32)divider;- /* As an optimization, let's not use 64 bit division unless we
must.
*/ + if (dividend <= MAX_32BIT_UINT) {
if (divider > MAX_32BIT_UINT) {result = 0;if (rem_p)*rem_p = divider;} else {result = (u32)dividend / (u32)divider;if (rem_p)*rem_p = (u32)dividend % (u32)divider;}return result;- }
- while (divider <= dividend) {
u64 locald = divider;u64 limit = __lshrdi3(dividend, 1);int shifts = 0;while (locald <= limit) {shifts++;locald = locald + locald;}result |= __ashldi3(1, shifts);dividend -= locald;- }
- if (rem_p)
*rem_p = dividend;- return result;
+}
+u64 __udivdi3(u64 num, u64 den) +{
- return _64bit_divide(num, den, NULL);
+}
+u64 __umoddi3(u64 num, u64 den) +{
- u64 v = 0;
- _64bit_divide(num, den, &v);
- return v;
+} diff --git a/arch/x86/lib/gcc.c b/arch/x86/lib/gcc.c deleted file mode 100644 index 3c70d790d4..0000000000 --- a/arch/x86/lib/gcc.c +++ /dev/null @@ -1,29 +0,0 @@ -/*
- This file is part of the coreboot project.
- Copyright (C) 2009 coresystems GmbH - *
- SPDX-License-Identifier: GPL-2.0 - */
-#ifdef __GNUC__
-/*
- GCC's libgcc handling is quite broken. While the libgcc functions -
- are always regparm(0) the code that calls them uses whatever the - *
compiler call specifies. Therefore we need a wrapper around those - * functions. See gcc bug PR41055 for more information.
- */
-#define WRAP_LIBGCC_CALL(type, name) \
- type __normal_##name(type a, type b) __attribute__((regparm(0)));
\
- type __wrap_##name(type a, type b); \
- type __attribute__((no_instrument_function)) \
__wrap_##name(type a, type b) \{ return __normal_##name(a, b); }-WRAP_LIBGCC_CALL(long long, __divdi3) -WRAP_LIBGCC_CALL(unsigned long long, __udivdi3) -WRAP_LIBGCC_CALL(long long, __moddi3) -WRAP_LIBGCC_CALL(unsigned long long, __umoddi3)
-#endif
participants (3)
-
Bin Meng -
Ferry Toth -
Stefan Roese