On Wed, Jul 05, 2017 at 01:02:42AM +0000, Peng Fan wrote: > > > > -----Original Message----- > > From: Tom Rini [mailto:tr...@konsulko.com] > > Sent: Tuesday, July 04, 2017 9:35 PM > > To: Peng Fan <peng....@nxp.com> > > Cc: Simon Glass <s...@chromium.org>; Philipp Tomsich > > <philipp.toms...@theobroma-systems.com>; albert.u.b...@aribaud.net; u- > > b...@lists.denx.de > > Subject: Re: [U-Boot] [PATCH 2/2] arm: config: enforce -fno-pic for SPL and > > normal U-Boot > > > > On Tue, Jul 04, 2017 at 03:12:54AM +0000, Peng Fan wrote: > > > > > > > > > > -----Original Message----- > > > > From: Tom Rini [mailto:tr...@konsulko.com] > > > > Sent: Tuesday, July 04, 2017 10:47 AM > > > > To: Peng Fan <peng....@nxp.com> > > > > Cc: Simon Glass <s...@chromium.org>; Philipp Tomsich > > > > <philipp.toms...@theobroma-systems.com>; albert.u.b...@aribaud.net; > > > > u- b...@lists.denx.de > > > > Subject: Re: [U-Boot] [PATCH 2/2] arm: config: enforce -fno-pic for > > > > SPL and normal U-Boot > > > > > > > > On Tue, Jul 04, 2017 at 01:09:36AM +0000, Peng Fan wrote: > > > > > Hi Tom, > > > > > > > > > > > -----Original Message----- > > > > > > From: Tom Rini [mailto:tr...@konsulko.com] > > > > > > Sent: Tuesday, July 04, 2017 12:17 AM > > > > > > To: Peng Fan <peng....@nxp.com>; Simon Glass <s...@chromium.org>; > > > > > > Philipp Tomsich <philipp.toms...@theobroma-systems.com> > > > > > > Cc: albert.u.b...@aribaud.net; u-boot@lists.denx.de > > > > > > Subject: Re: [U-Boot] [PATCH 2/2] arm: config: enforce -fno-pic > > > > > > for SPL and normal U-Boot > > > > > > > > > > > > On Mon, Jul 03, 2017 at 09:14:08PM +0800, Peng Fan wrote: > > > > > > > > > > > > > If not pass -fno-pic to toolchains, some toolchains may > > > > > > > generate .got and .got.plt sections, but when generate > > > > > > > binaries, we did not take .got and .got.plt into > > > > > > > consideration, then SPL or normal U-Boot boot failure because > > > > > > > image > > corrupted. > > > > > > > > > > > > > > Need to pass -fno-pic to disable generating .got and .got.plt > > > > > > > sections. > > > > > > > > > > > > > > Signed-off-by: Peng Fan <peng....@nxp.com> > > > > > > > Cc: Albert Aribaud <albert.u.b...@aribaud.net> > > > > > > > Cc: Tom Rini <tr...@konsulko.com> > > > > > > > --- > > > > > > > arch/arm/config.mk | 3 ++- > > > > > > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > > > > > > > > > > > diff --git a/arch/arm/config.mk b/arch/arm/config.mk index > > > > > > > 1a77779..66ae403 100644 > > > > > > > --- a/arch/arm/config.mk > > > > > > > +++ b/arch/arm/config.mk > > > > > > > @@ -130,9 +130,10 @@ ALL-y += checkarmreloc # instruction. > > > > > > > Relocation is not supported for that case, so disable # such > > > > > > > usage by requiring word relocations. > > > > > > > PLATFORM_CPPFLAGS += $(call cc-option, -mword-relocations) > > > > > > > -PLATFORM_CPPFLAGS += $(call cc-option, -fno-pic) endif > > > > > > > > > > > > > > +PLATFORM_CPPFLAGS += $(call cc-option, -fno-pic) > > > > > > > + > > > > > > > # limit ourselves to the sections we want in the .bin. > > > > > > > ifdef CONFIG_ARM64 > > > > > > > OBJCOPYFLAGS += -j .text -j .secure_text -j .secure_data -j > > > > > > > .rodata -j .data \ > > > > > > > > > > > > Something is "up" here and I need you to dig harder and perhaps > > > > > > see if we're missing something in the linker scripts? The very > > > > > > next line of > > > > context here is: > > > > > > -j .u_boot_list -j .rela.dyn -j .got -j .got.plt > > > > > > > > > > > > Meaning that we intentionally copy .got / .got.plt into the > > > > > > resulting binary. And I see that we took in 397d7d5a1be1 from > > > > > > you back in 2016 saying that we needed this in SPL. But > > > > > > 5a942a152776 put the got/got.plt sections (for 32bit > > > > > > ARM) in intentionally as some relocations do need it. And in > > > > > > 4b0d506ed3b4 Philipp seems to have seen the same problem you > > > > > > have, but fixed it with adding got/got.plt to the sections list > > > > > > we copy in (the above > > > > hunk of context). > > > > > > > > > > If pass -fno-pic to compiler, there will be no .got and .got.plt > > > > > sections. > > > > > The .got and .got.plt is usually used for dynamic link, such as linux > > > > > "*.so" > > file. > > > > > We need to pass -fno-pic to compiler to remove .got and .got.plt > > > > > sections. > > > > > > > > "Usually" isn't the same as "always" or "only". And this reminded > > > > me that we > > > > > > From > > > https://gcc.gnu.org/onlinedocs/gcc/Code-Gen-Options.html#Code-Gen-Opti > > > ons, when -fpic is used for ARM, there will be GOT. The dynamic loader > > > resolves the GOT entries when the program starts (the dynamic loader > > > is not part of GCC; it is part of the operating system). > > > > > > > had to deal with e391b1e64b0b because yes, we're not making a shared > > > > library but we do have position independent code. So, in the case > > > > of SPL, since we > > > > > > For position independent code, but not making a shared library, we could > > > use > > -fpie. > > > > Note that "just" a switch to -fno-pic -fpie results in non-booting > > platforms for > > me, so there'd be more work to be done there. > > > > > > can get away with -fno-pic (and get some space > > > > savings) that's just not true of U-Boot itself. We're enforcing > > > > -fpic on other architectures, so what exactly is going on with what > > > > you're seeing? Where > > > > > > If not passing -fno-pic to gcc, the android toolchain will generate > > > .got and .got.plt section. I think these sections are for dynamic > > > link, not for static link. > > > > Right, but that's why we include these sections in the images now. Have you > > confirmed that top of tree doesn't work with that android toolchain, without > > your second patch here? > > I am using 2017.03 release. Without the second patch, gcc will > generate instructions like "str q0, [x2]", and uboot runs into sync > abort when booting .
So you're missing the patch I mentioned that added .got/.got.plt then :) -- Tom
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