On 19 June 2018 at 20:17, Ard Biesheuvel <ard.biesheu...@linaro.org> wrote: > On 19 June 2018 at 19:24, Guenter Roeck <li...@roeck-us.net> wrote: >> On Tue, Jun 19, 2018 at 03:35:07PM +0200, Ard Biesheuvel wrote: >>> >> >>> >> + /* this needs to be a separate macro or \@ does not work >>> >> correctly >>> >> */ >>> >> + .macro __badr, c, rd, sym >>> >> + .eqv .Lsym\@, \sym >>> >> + adr\c \rd, .Lsym\@ + 1 >>> > >>> > >>> > Wild shot, but the following works for me. >>> > >>> > .eqv .Lsym\@, \sym + 1 >>> > adr\c \rd, .Lsym\@ >>> > >>> > Does it make sense ? >>> > >>> >>> Interesting. Do you mean this works with your 2.30 binutils that >>> triggers the original issue? >>> >> >> Yes, it does. It is also the solution used for some graphics libraries, >> though of course now I don't find the link anymore. >> >> Guess this is going nowhere given Russell's response, so I'll just >> live with it, like obviously everyone else does already. I built >> a toolchain using gcc 7.3.0 and binutils 2.28.1 which "solves" >> the problem for me. >> > > If we can live with using a wide encoding unconditionally, we could > consider something like below. That forces the symbol references to be > resolved at link time, which means we completely sidestep the new GAS > code. > > -----------8<---------------- > From: Ard Biesheuvel <ard.biesheu...@linaro.org> > Date: Tue, 16 Jan 2018 12:12:45 +0000 > Subject: [PATCH] ARM: assembler: prevent ADR from setting the Thumb bit twice > > To work around recent issues where ADR references to Thumb function > symbols may or may not have the Thumb bit set already when they are > resolved by GAS, reference the symbol indirectly via a global symbol > typed as 'function', and emit a relocation that lets the linker fix > up the reference. > > Signed-off-by: Ard Biesheuvel <ard.biesheu...@linaro.org> > > diff --git a/arch/arm/include/asm/assembler.h > b/arch/arm/include/asm/assembler.h > index 6ae42ad29518..1a55ce4b245c 100644 > --- a/arch/arm/include/asm/assembler.h > +++ b/arch/arm/include/asm/assembler.h > @@ -195,13 +195,22 @@ > .irp c,,eq,ne,cs,cc,mi,pl,vs,vc,hi,ls,ge,lt,gt,le,hs,lo > .macro badr\c, rd, sym > #ifdef CONFIG_THUMB2_KERNEL > - adr\c \rd, \sym + 1 > + __badr \c, \rd, \sym > #else > adr\c \rd, \sym > #endif > .endm > .endr > > + /* this needs to be a separate macro or \@ does not work correctly */ > + .macro __badr, c, rd, sym > + .globl .Lsym_\sym\()_\@ > + .type .Lsym_\sym\()_\@, %function > + .set .Lsym_\sym\()_\@, \sym > + .reloc ., R_ARM_THM_ALU_PREL_11_0, .Lsym_\sym\()_\@ > + adr\c\().w \rd, . > + .endm > + > /* > * Get current thread_info. > */
It seems we can drop the .globl btw
