| Message ID | 20200420223418.117186-4-mhorne@FreeBSD.org |
|---|---|
| State | New |
| Headers | show |
| Series | Add support for CONFIG_API on RISC-V | expand |
On Tue, Apr 21, 2020 at 7:28 AM <mhorne at freebsd.org> wrote: > > From: Mitchell Horne <mhorne at FreeBSD.org> > > When compiling the API demo program, the first object file in the linker > arguments is crt0.o, which contains the _start routine. This is done > with the hope that it will appear first in the .text section, but the > linker doesn't guarantee this behaviour. > > Add a simple linker script that ensures this ordering. This fixes > execution of the API demo binary for cases where _start was placed > elsewhere in the .text section. > > Signed-off-by: Mitchell Horne <mhorne at FreeBSD.org> > --- > examples/api/Makefile | 4 +++- > examples/api/crt0.S | 2 ++ > examples/api/demo.lds | 14 ++++++++++++++ > 3 files changed, 19 insertions(+), 1 deletion(-) > create mode 100644 examples/api/demo.lds > > diff --git a/examples/api/Makefile b/examples/api/Makefile > index 9ff793206f..8fa9c04118 100644 > --- a/examples/api/Makefile > +++ b/examples/api/Makefile > @@ -48,10 +48,12 @@ OBJS := $(OBJ-y) $(notdir $(EXT_COBJ-y) $(EXT_SOBJ-y)) > targets += $(OBJS) > OBJS := $(addprefix $(obj)/,$(OBJS)) > > +LDS = $(obj)/demo.lds > ######################################################################### > > quiet_cmd_link_demo = LD $@ > -cmd_link_demo = $(LD) --gc-sections -Ttext $(LOAD_ADDR) -o $@ $(filter-out $(PHONY), $^) $(PLATFORM_LIBS) > +cmd_link_demo = $(LD) --gc-sections -Ttext $(LOAD_ADDR) -T $(LDS) \ > + -o $@ $(filter-out $(PHONY), $^) $(PLATFORM_LIBS) > > $(obj)/demo: $(OBJS) FORCE > $(call if_changed,link_demo) > diff --git a/examples/api/crt0.S b/examples/api/crt0.S > index 2f75f5a036..658bc59a82 100644 > --- a/examples/api/crt0.S > +++ b/examples/api/crt0.S > @@ -62,12 +62,14 @@ syscall: > .end syscall > > return_addr: > + .data I think we need put .data before return_addr: to make it clearer. > .align 8 > .long 0 > #else > #error No support for this arch! > #endif > > + .data And changing these symbols should be a separate patch. > .globl syscall_ptr > syscall_ptr: > .align 8 Regards, Bin
diff --git a/examples/api/Makefile b/examples/api/Makefile index 9ff793206f..8fa9c04118 100644 --- a/examples/api/Makefile +++ b/examples/api/Makefile @@ -48,10 +48,12 @@ OBJS := $(OBJ-y) $(notdir $(EXT_COBJ-y) $(EXT_SOBJ-y)) targets += $(OBJS) OBJS := $(addprefix $(obj)/,$(OBJS)) +LDS = $(obj)/demo.lds ######################################################################### quiet_cmd_link_demo = LD $@ -cmd_link_demo = $(LD) --gc-sections -Ttext $(LOAD_ADDR) -o $@ $(filter-out $(PHONY), $^) $(PLATFORM_LIBS) +cmd_link_demo = $(LD) --gc-sections -Ttext $(LOAD_ADDR) -T $(LDS) \ + -o $@ $(filter-out $(PHONY), $^) $(PLATFORM_LIBS) $(obj)/demo: $(OBJS) FORCE $(call if_changed,link_demo) diff --git a/examples/api/crt0.S b/examples/api/crt0.S index 2f75f5a036..658bc59a82 100644 --- a/examples/api/crt0.S +++ b/examples/api/crt0.S @@ -62,12 +62,14 @@ syscall: .end syscall return_addr: + .data .align 8 .long 0 #else #error No support for this arch! #endif + .data .globl syscall_ptr syscall_ptr: .align 8 diff --git a/examples/api/demo.lds b/examples/api/demo.lds new file mode 100644 index 0000000000..a6b88dedef --- /dev/null +++ b/examples/api/demo.lds @@ -0,0 +1,14 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* + * Copyright (C) 2020 Mitchell Horne <mhorne at FreeBSD.org> + */ + +ENTRY(_start) +SECTIONS +{ + .text : + { + *crt0.S(.text*) + *(.text*) + } +}