Hi Daniel, looks quite good to me, will re-test it asap, just have a questions:
On 3/31/26 00:01, Daniel Palmer wrote: > Most m68k retro/homebrew machines will have limited flash/RAM > so having LTO working would be nice. > > Not many changes are need really. Most of this is copy/paste > from the ARM32 version. > > The major change is that the direct register usage of d7 for gd > needs to be hidden so that when LTO passes over everything it > doesn't see multiple instances of d7. > > Signed-off-by: Daniel Palmer <[email protected]> > --- > arch/Kconfig | 1 + > arch/m68k/config.mk | 8 ++++++-- > arch/m68k/cpu/m680x0/cpu.c | 2 +- > arch/m68k/include/asm/global_data.h | 19 +++++++++++++++++++ > arch/m68k/lib/ashldi3.c | 6 ++++-- > arch/m68k/lib/lshrdi3.c | 6 ++++-- > arch/m68k/lib/muldi3.c | 4 +++- > common/board_r.c | 4 ++-- > common/init/board_init.c | 4 ++-- > 9 files changed, 42 insertions(+), 12 deletions(-) > > diff --git a/arch/Kconfig b/arch/Kconfig > index 4af0da2485fb..488de442f557 100644 > --- a/arch/Kconfig > +++ b/arch/Kconfig > @@ -112,6 +112,7 @@ config ARM > > config M68K > bool "M68000 architecture" > + select ARCH_SUPPORTS_LTO > select HAVE_PRIVATE_LIBGCC > select USE_PRIVATE_LIBGCC > select SYS_BOOT_GET_CMDLINE > diff --git a/arch/m68k/config.mk b/arch/m68k/config.mk > index 458953f97122..4d8c83b51cdb 100644 > --- a/arch/m68k/config.mk > +++ b/arch/m68k/config.mk > @@ -8,9 +8,13 @@ ifneq ($(CONFIG_M680x0),y) > PLATFORM_CPPFLAGS += -fPIC > endif > KBUILD_LDFLAGS += -n -pie > -PLATFORM_RELFLAGS += -ffunction-sections -fdata-sections > PLATFORM_RELFLAGS += -ffixed-d7 > ifneq ($(CONFIG_M680x0),y) > PLATFORM_RELFLAGS += -msep-data > endif > -LDFLAGS_FINAL += --gc-sections -pie > +LDFLAGS_FINAL += -pie > + > +ifneq ($(LTO_ENABLE),y) > +PLATFORM_RELFLAGS += -ffunction-sections -fdata-sections > +LDFLAGS_FINAL += --gc-sections > +endif > diff --git a/arch/m68k/cpu/m680x0/cpu.c b/arch/m68k/cpu/m680x0/cpu.c > index f60b932c7dd4..3f87076b8c3d 100644 > --- a/arch/m68k/cpu/m680x0/cpu.c > +++ b/arch/m68k/cpu/m680x0/cpu.c > @@ -24,7 +24,7 @@ void m68k_virt_init_reserve(ulong base) > for (i = 0; i < sizeof(*gd_ptr); i++) > p[i] = 0; > > - gd = gd_ptr; > + arch_setup_gd(gd); > > gd->malloc_base = base + sizeof(*gd_ptr); > } > diff --git a/arch/m68k/include/asm/global_data.h > b/arch/m68k/include/asm/global_data.h > index aea2ccabe083..9150ed4ab466 100644 > --- a/arch/m68k/include/asm/global_data.h > +++ b/arch/m68k/include/asm/global_data.h > @@ -32,6 +32,25 @@ struct arch_global_data { > > #include <asm-generic/global_data.h> > > +#if defined(LTO_ENABLE) > +/* If LTO is enabled we have to hide d7 to avoid multiple symbol > declarations */ > +#define DECLARE_GLOBAL_DATA_PTR > +#define gd get_gd() > + > +static inline gd_t *get_gd(void) > +{ > + gd_t *gd_ptr; > + > + __asm__ volatile("move.l %%d7, %0\n" : "=r" (gd_ptr)); > + > + return gd_ptr; > +} > +#else > #define DECLARE_GLOBAL_DATA_PTR register gd_t *gd asm ("d7") > +#endif > +static inline void arch_setup_gd(gd_t *new_gd) > +{ > + __asm__ volatile("move.l %0, %%d7\n" : : "r" (new_gd)); > +} > > #endif /* __ASM_GBL_DATA_H */ > diff --git a/arch/m68k/lib/ashldi3.c b/arch/m68k/lib/ashldi3.c > index 9a4bc676bf4c..9e84bd0d9a07 100644 > --- a/arch/m68k/lib/ashldi3.c > +++ b/arch/m68k/lib/ashldi3.c > @@ -6,6 +6,8 @@ > * Copyright (C) 1989-2015 Free Software Foundation, Inc. > */ > > +#include <linux/compiler_attributes.h> > + > #define BITS_PER_UNIT 8 > > typedef int SItype __attribute__ ((mode (SI))); > @@ -21,7 +23,7 @@ typedef union > DItype ll; > } DIunion; > > -DItype __ashldi3 (DItype u, word_type b) > +__used DItype __ashldi3 (DItype u, word_type b) Why the above __used is needed ? This impacts all the coldfire builds. > { > DIunion w; > word_type bm; > @@ -46,4 +48,4 @@ DItype __ashldi3 (DItype u, word_type b) > } > > return w.ll; > -} > \ No newline at end of file > +} > diff --git a/arch/m68k/lib/lshrdi3.c b/arch/m68k/lib/lshrdi3.c > index e639e676a269..53163bc5f83f 100644 > --- a/arch/m68k/lib/lshrdi3.c > +++ b/arch/m68k/lib/lshrdi3.c > @@ -6,6 +6,8 @@ > * Copyright (C) 1989-2015 Free Software Foundation, Inc. > */ > > +#include <linux/compiler_attributes.h> > + > #define BITS_PER_UNIT 8 > > typedef int SItype __attribute__ ((mode (SI))); > @@ -21,7 +23,7 @@ typedef union > DItype ll; > } DIunion; > > -DItype __lshrdi3 (DItype u, word_type b) > +__used DItype __lshrdi3 (DItype u, word_type b) > { > DIunion w; > word_type bm; > @@ -46,4 +48,4 @@ DItype __lshrdi3 (DItype u, word_type b) > } > > return w.ll; > -} > \ No newline at end of file > +} > diff --git a/arch/m68k/lib/muldi3.c b/arch/m68k/lib/muldi3.c > index c42ca1d753e5..06af5533fde3 100644 > --- a/arch/m68k/lib/muldi3.c > +++ b/arch/m68k/lib/muldi3.c > @@ -6,6 +6,8 @@ > * Copyright (C) 1989, 1992, 1993, 1994, 1995 Free Software Foundation, Inc. > */ > > +#include <linux/compiler_attributes.h> > + > #define SI_TYPE_SIZE 32 > #define __BITS4 (SI_TYPE_SIZE / 4) > #define __ll_B (1L << (SI_TYPE_SIZE / 2)) > @@ -54,7 +56,7 @@ typedef union > DItype ll; > } DIunion; > > -DItype __muldi3 (DItype u, DItype v) > +__used DItype __muldi3 (DItype u, DItype v) > { > DIunion w; > DIunion uu, vv; > diff --git a/common/board_r.c b/common/board_r.c > index 76f9fc090fbe..58eb69005468 100644 > --- a/common/board_r.c > +++ b/common/board_r.c > @@ -800,12 +800,12 @@ void board_init_r(gd_t *new_gd, ulong dest_addr) > * TODO([email protected]): Consider doing this for all archs, or > * dropping the new_gd parameter. > */ > - if (CONFIG_IS_ENABLED(X86_64) && !IS_ENABLED(CONFIG_EFI_APP)) > + if ((CONFIG_IS_ENABLED(X86_64) && !IS_ENABLED(CONFIG_EFI_APP)) || > CONFIG_IS_ENABLED(M68K)) > arch_setup_gd(new_gd); > > #if defined(CONFIG_RISCV) > set_gd(new_gd); > -#elif !defined(CONFIG_X86) && !defined(CONFIG_ARM) && !defined(CONFIG_ARM64) > +#elif !defined(CONFIG_X86) && !defined(CONFIG_ARM) && !defined(CONFIG_ARM64) > && !defined(CONFIG_M68K) > gd = new_gd; > #endif > gd->flags &= ~GD_FLG_LOG_READY; > diff --git a/common/init/board_init.c b/common/init/board_init.c > index 2a6f39f51adb..31b499ebad9c 100644 > --- a/common/init/board_init.c > +++ b/common/init/board_init.c > @@ -14,10 +14,10 @@ > DECLARE_GLOBAL_DATA_PTR; > > /* > - * Unfortunately x86, ARM and RISC-V can't compile this code as gd is defined > + * Unfortunately x86, ARM, RISC-V, M68K can't compile this code as gd is > defined > * as macro and cannot be assigned. > */ > -#if !defined(CONFIG_X86) && !defined(CONFIG_ARM) && !defined(CONFIG_RISCV) > +#if !defined(CONFIG_X86) && !defined(CONFIG_ARM) && !defined(CONFIG_RISCV) > && !defined(CONFIG_M68K) > __weak void arch_setup_gd(struct global_data *gd_ptr) > { > gd = gd_ptr; Regards, -- Angelo
