| Message ID | CAKv+Gu8Byj7G3Awnq4Y90Wot=GJTx0gO5A7-960au9ZkBBL2=A@mail.gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
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On 19 June 2018 at 09:48, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote: > On 19 June 2018 at 07:07, Guenter Roeck <linux@roeck-us.net> wrote: >> Modern assemblers may take the ISA into account when resolving local >> symbols. This can result in bad address calculations when using badr >> in the wrong location since the offset + 1 may be added twice, resulting >> in an even address target for THUMB instructions. This in turn results >> in an exception at (destination address + 2). >> >> Unhandled exception: IPSR = 00000006 LR = fffffff1 >> CPU: 0 PID: 1 Comm: init Not tainted 4.18.0-rc1-00026-gf773e5bdf0c9 #15 >> Hardware name: MPS2 (Device Tree Support) >> PC is at ret_fast_syscall+0x2/0x58 >> LR is at tty_ioctl+0x2a5/0x528 >> pc : [<21009002>] lr : [<210d1535>] psr: 4000000b >> sp : 21825fa8 ip : 0000001c fp : 21a95892 >> r10: 00000000 r9 : 21824000 r8 : 210091c0 >> r7 : 00000036 r6 : 21ae1ee0 r5 : 00000000 r4 : 21ae1f3c >> r3 : 00000000 r2 : 3d9adc25 r1 : 00000000 r0 : 00000000 >> xPSR: 4000000b >> CPU: 0 PID: 1 Comm: init Not tainted 4.18.0-rc1-00026-gf773e5bdf0c9 #15 >> Hardware name: MPS2 (Device Tree Support) >> [<2100bd8d>] (unwind_backtrace) from [<2100b13b>] (show_stack+0xb/0xc) >> [<2100b13b>] (show_stack) from [<2100b87b>] (__invalid_entry+0x4b/0x4c) >> >> Fix the problem by using a logical or instead of an addition. This is >> less efficient but guaranteed to work. >> >> Signed-off-by: Guenter Roeck <linux@roeck-us.net> >> --- >> RFC: I don't really like this, but my ARM assembler knowledge is quite >> limited. Just dropping the "+ 1" from badr doesn't work because some >> other code needs it (the image hangs completely if I try that). >> Ultimately I don't even know if the invoke_syscall macro should just >> have used adr instead of badr (but then how did this ever work ?). >> >> Seen with various toolchains based on gcc 7.x and binutils 2.30 when >> building and testing MPS2 images. >> > > Hello Guenter, > > This issue has been discussed before. It appears the binutils people > suddenly started caring about the thumb annotation of local function > symbols, resulting in behavior that is not backwards compatible. > > https://marc.info/?l=linux-arm-kernel&m=151143776213636&w=2 > https://sourceware.org/bugzilla/show_bug.cgi?id=21458 > > Can you try the fix below please? > >> arch/arm/include/asm/assembler.h | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h >> index 0cd4dccbae78..24c87ff2060f 100644 >> --- a/arch/arm/include/asm/assembler.h >> +++ b/arch/arm/include/asm/assembler.h >> @@ -195,7 +195,8 @@ >> .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 >> + adr\c \rd, \sym >> + orr \rd, #1 >> #else >> adr\c \rd, \sym >> #endif >> -- >> 2.7.4 > > ----------8<------------ > From: Ard Biesheuvel <ard.biesheuvel@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 local symbol > typed as 'object', stripping the ARM/Thumb annotation. > > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> > > diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h > index 6ae42ad29518..dd2ff94ad90b 100644 > --- a/arch/arm/include/asm/assembler.h > +++ b/arch/arm/include/asm/assembler.h > @@ -195,13 +195,19 @@ > .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 > + .eqv .Lsym\@, \sym > + adr\c \rd, .Lsym\@ + 1 > + .endm > + > /* > * Get current thread_info. > */ Never mind - it doesn't work. (I tested it locally but with the wrong kernel)
Hi Ard, On 06/19/2018 12:48 AM, Ard Biesheuvel wrote: > On 19 June 2018 at 07:07, Guenter Roeck <linux@roeck-us.net> wrote: >> Modern assemblers may take the ISA into account when resolving local >> symbols. This can result in bad address calculations when using badr >> in the wrong location since the offset + 1 may be added twice, resulting >> in an even address target for THUMB instructions. This in turn results >> in an exception at (destination address + 2). >> >> Unhandled exception: IPSR = 00000006 LR = fffffff1 >> CPU: 0 PID: 1 Comm: init Not tainted 4.18.0-rc1-00026-gf773e5bdf0c9 #15 >> Hardware name: MPS2 (Device Tree Support) >> PC is at ret_fast_syscall+0x2/0x58 >> LR is at tty_ioctl+0x2a5/0x528 >> pc : [<21009002>] lr : [<210d1535>] psr: 4000000b >> sp : 21825fa8 ip : 0000001c fp : 21a95892 >> r10: 00000000 r9 : 21824000 r8 : 210091c0 >> r7 : 00000036 r6 : 21ae1ee0 r5 : 00000000 r4 : 21ae1f3c >> r3 : 00000000 r2 : 3d9adc25 r1 : 00000000 r0 : 00000000 >> xPSR: 4000000b >> CPU: 0 PID: 1 Comm: init Not tainted 4.18.0-rc1-00026-gf773e5bdf0c9 #15 >> Hardware name: MPS2 (Device Tree Support) >> [<2100bd8d>] (unwind_backtrace) from [<2100b13b>] (show_stack+0xb/0xc) >> [<2100b13b>] (show_stack) from [<2100b87b>] (__invalid_entry+0x4b/0x4c) >> >> Fix the problem by using a logical or instead of an addition. This is >> less efficient but guaranteed to work. >> >> Signed-off-by: Guenter Roeck <linux@roeck-us.net> >> --- >> RFC: I don't really like this, but my ARM assembler knowledge is quite >> limited. Just dropping the "+ 1" from badr doesn't work because some >> other code needs it (the image hangs completely if I try that). >> Ultimately I don't even know if the invoke_syscall macro should just >> have used adr instead of badr (but then how did this ever work ?). >> >> Seen with various toolchains based on gcc 7.x and binutils 2.30 when >> building and testing MPS2 images. >> > > Hello Guenter, > > This issue has been discussed before. It appears the binutils people > suddenly started caring about the thumb annotation of local function > symbols, resulting in behavior that is not backwards compatible. > > https://marc.info/?l=linux-arm-kernel&m=151143776213636&w=2 > https://sourceware.org/bugzilla/show_bug.cgi?id=21458 > > Can you try the fix below please? > >> arch/arm/include/asm/assembler.h | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h >> index 0cd4dccbae78..24c87ff2060f 100644 >> --- a/arch/arm/include/asm/assembler.h >> +++ b/arch/arm/include/asm/assembler.h >> @@ -195,7 +195,8 @@ >> .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 >> + adr\c \rd, \sym >> + orr \rd, #1 >> #else >> adr\c \rd, \sym >> #endif >> -- >> 2.7.4 > > ----------8<------------ > From: Ard Biesheuvel <ard.biesheuvel@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 local symbol > typed as 'object', stripping the ARM/Thumb annotation. > > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> > > diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h > index 6ae42ad29518..dd2ff94ad90b 100644 > --- a/arch/arm/include/asm/assembler.h > +++ b/arch/arm/include/asm/assembler.h > @@ -195,13 +195,19 @@ > .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 > + .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 ? Thanks, Guenter
On 19 June 2018 at 15:29, Guenter Roeck <linux@roeck-us.net> wrote: > Hi Ard, > > > On 06/19/2018 12:48 AM, Ard Biesheuvel wrote: >> >> On 19 June 2018 at 07:07, Guenter Roeck <linux@roeck-us.net> wrote: >>> >>> Modern assemblers may take the ISA into account when resolving local >>> symbols. This can result in bad address calculations when using badr >>> in the wrong location since the offset + 1 may be added twice, resulting >>> in an even address target for THUMB instructions. This in turn results >>> in an exception at (destination address + 2). >>> >>> Unhandled exception: IPSR = 00000006 LR = fffffff1 >>> CPU: 0 PID: 1 Comm: init Not tainted 4.18.0-rc1-00026-gf773e5bdf0c9 #15 >>> Hardware name: MPS2 (Device Tree Support) >>> PC is at ret_fast_syscall+0x2/0x58 >>> LR is at tty_ioctl+0x2a5/0x528 >>> pc : [<21009002>] lr : [<210d1535>] psr: 4000000b >>> sp : 21825fa8 ip : 0000001c fp : 21a95892 >>> r10: 00000000 r9 : 21824000 r8 : 210091c0 >>> r7 : 00000036 r6 : 21ae1ee0 r5 : 00000000 r4 : 21ae1f3c >>> r3 : 00000000 r2 : 3d9adc25 r1 : 00000000 r0 : 00000000 >>> xPSR: 4000000b >>> CPU: 0 PID: 1 Comm: init Not tainted 4.18.0-rc1-00026-gf773e5bdf0c9 #15 >>> Hardware name: MPS2 (Device Tree Support) >>> [<2100bd8d>] (unwind_backtrace) from [<2100b13b>] (show_stack+0xb/0xc) >>> [<2100b13b>] (show_stack) from [<2100b87b>] (__invalid_entry+0x4b/0x4c) >>> >>> Fix the problem by using a logical or instead of an addition. This is >>> less efficient but guaranteed to work. >>> >>> Signed-off-by: Guenter Roeck <linux@roeck-us.net> >>> --- >>> RFC: I don't really like this, but my ARM assembler knowledge is quite >>> limited. Just dropping the "+ 1" from badr doesn't work because some >>> other code needs it (the image hangs completely if I try that). >>> Ultimately I don't even know if the invoke_syscall macro should just >>> have used adr instead of badr (but then how did this ever work ?). >>> >>> Seen with various toolchains based on gcc 7.x and binutils 2.30 when >>> building and testing MPS2 images. >>> >> >> Hello Guenter, >> >> This issue has been discussed before. It appears the binutils people >> suddenly started caring about the thumb annotation of local function >> symbols, resulting in behavior that is not backwards compatible. >> >> https://marc.info/?l=linux-arm-kernel&m=151143776213636&w=2 >> https://sourceware.org/bugzilla/show_bug.cgi?id=21458 >> >> Can you try the fix below please? >> >>> arch/arm/include/asm/assembler.h | 3 ++- >>> 1 file changed, 2 insertions(+), 1 deletion(-) >>> >>> diff --git a/arch/arm/include/asm/assembler.h >>> b/arch/arm/include/asm/assembler.h >>> index 0cd4dccbae78..24c87ff2060f 100644 >>> --- a/arch/arm/include/asm/assembler.h >>> +++ b/arch/arm/include/asm/assembler.h >>> @@ -195,7 +195,8 @@ >>> .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 >>> + adr\c \rd, \sym >>> + orr \rd, #1 >>> #else >>> adr\c \rd, \sym >>> #endif >>> -- >>> 2.7.4 >> >> >> ----------8<------------ >> From: Ard Biesheuvel <ard.biesheuvel@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 local symbol >> typed as 'object', stripping the ARM/Thumb annotation. >> >> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> >> >> diff --git a/arch/arm/include/asm/assembler.h >> b/arch/arm/include/asm/assembler.h >> index 6ae42ad29518..dd2ff94ad90b 100644 >> --- a/arch/arm/include/asm/assembler.h >> +++ b/arch/arm/include/asm/assembler.h >> @@ -195,13 +195,19 @@ >> .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 >> + .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? If so, then yes, it makes sense, although it still seems fragile, since we are relying on \sym being resolved without the Thumb bit in the context of the .eqv pseudo op. But if this works across all implementations we care about, I would be fine with it. Russell?
On Tue, Jun 19, 2018 at 03:35:07PM +0200, Ard Biesheuvel wrote: > On 19 June 2018 at 15:29, Guenter Roeck <linux@roeck-us.net> wrote: > > Hi Ard, > > > > > > On 06/19/2018 12:48 AM, Ard Biesheuvel wrote: > >> > >> On 19 June 2018 at 07:07, Guenter Roeck <linux@roeck-us.net> wrote: > >>> > >>> Modern assemblers may take the ISA into account when resolving local > >>> symbols. This can result in bad address calculations when using badr > >>> in the wrong location since the offset + 1 may be added twice, resulting > >>> in an even address target for THUMB instructions. This in turn results > >>> in an exception at (destination address + 2). > >>> > >>> Unhandled exception: IPSR = 00000006 LR = fffffff1 > >>> CPU: 0 PID: 1 Comm: init Not tainted 4.18.0-rc1-00026-gf773e5bdf0c9 #15 > >>> Hardware name: MPS2 (Device Tree Support) > >>> PC is at ret_fast_syscall+0x2/0x58 > >>> LR is at tty_ioctl+0x2a5/0x528 > >>> pc : [<21009002>] lr : [<210d1535>] psr: 4000000b > >>> sp : 21825fa8 ip : 0000001c fp : 21a95892 > >>> r10: 00000000 r9 : 21824000 r8 : 210091c0 > >>> r7 : 00000036 r6 : 21ae1ee0 r5 : 00000000 r4 : 21ae1f3c > >>> r3 : 00000000 r2 : 3d9adc25 r1 : 00000000 r0 : 00000000 > >>> xPSR: 4000000b > >>> CPU: 0 PID: 1 Comm: init Not tainted 4.18.0-rc1-00026-gf773e5bdf0c9 #15 > >>> Hardware name: MPS2 (Device Tree Support) > >>> [<2100bd8d>] (unwind_backtrace) from [<2100b13b>] (show_stack+0xb/0xc) > >>> [<2100b13b>] (show_stack) from [<2100b87b>] (__invalid_entry+0x4b/0x4c) > >>> > >>> Fix the problem by using a logical or instead of an addition. This is > >>> less efficient but guaranteed to work. > >>> > >>> Signed-off-by: Guenter Roeck <linux@roeck-us.net> > >>> --- > >>> RFC: I don't really like this, but my ARM assembler knowledge is quite > >>> limited. Just dropping the "+ 1" from badr doesn't work because some > >>> other code needs it (the image hangs completely if I try that). > >>> Ultimately I don't even know if the invoke_syscall macro should just > >>> have used adr instead of badr (but then how did this ever work ?). > >>> > >>> Seen with various toolchains based on gcc 7.x and binutils 2.30 when > >>> building and testing MPS2 images. > >>> > >> > >> Hello Guenter, > >> > >> This issue has been discussed before. It appears the binutils people > >> suddenly started caring about the thumb annotation of local function > >> symbols, resulting in behavior that is not backwards compatible. > >> > >> https://marc.info/?l=linux-arm-kernel&m=151143776213636&w=2 > >> https://sourceware.org/bugzilla/show_bug.cgi?id=21458 > >> > >> Can you try the fix below please? > >> > >>> arch/arm/include/asm/assembler.h | 3 ++- > >>> 1 file changed, 2 insertions(+), 1 deletion(-) > >>> > >>> diff --git a/arch/arm/include/asm/assembler.h > >>> b/arch/arm/include/asm/assembler.h > >>> index 0cd4dccbae78..24c87ff2060f 100644 > >>> --- a/arch/arm/include/asm/assembler.h > >>> +++ b/arch/arm/include/asm/assembler.h > >>> @@ -195,7 +195,8 @@ > >>> .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 > >>> + adr\c \rd, \sym > >>> + orr \rd, #1 > >>> #else > >>> adr\c \rd, \sym > >>> #endif > >>> -- > >>> 2.7.4 > >> > >> > >> ----------8<------------ > >> From: Ard Biesheuvel <ard.biesheuvel@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 local symbol > >> typed as 'object', stripping the ARM/Thumb annotation. > >> > >> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> > >> > >> diff --git a/arch/arm/include/asm/assembler.h > >> b/arch/arm/include/asm/assembler.h > >> index 6ae42ad29518..dd2ff94ad90b 100644 > >> --- a/arch/arm/include/asm/assembler.h > >> +++ b/arch/arm/include/asm/assembler.h > >> @@ -195,13 +195,19 @@ > >> .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 > >> + .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? > > If so, then yes, it makes sense, although it still seems fragile, > since we are relying on \sym being resolved without the Thumb bit in > the context of the .eqv pseudo op. But if this works across all > implementations we care about, I would be fine with it. > > Russell? Apart from my thoughts about the toolchain changing behaviour after many years... It seems that the .eqv solution works on my assembler for the files I've tested it with, which is great. However... I'm left wondering how long it will be before the toolchain people decide to propagate the thumb bit through the .eqv - is the behaviour there explicitly documented that it won't, or is the above relying on observed behaviour with a particular assembler version. It could also be that there's versions out there that do this already. I think it's really up to _toolchain people_ to tell us how to solve the problem _they've_ created, rather than us floundering around in the dark using undocumented behaviour that could well change in the future. So, I'm going to continue sitting on the fence on this, and basically take the attitude that it's better that people don't use the new binutils until binutils people can provide us with an officially sanctioned solution that's going to work for both older and future assemblers.
On Tue, Jun 19, 2018 at 04:12:35PM +0100, Russell King - ARM Linux wrote: > > So, I'm going to continue sitting on the fence on this, and basically > take the attitude that it's better that people don't use the new > binutils until binutils people can provide us with an officially > sanctioned solution that's going to work for both older and future > assemblers. > I would so much love if people were working together instead of against each other :-(. Never mind, I'll try a toolchain with binutils 2.28.1. At least that is still supported with buildroot. Guenter
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. Guenter
On Tue, Jun 19, 2018 at 10:14:24AM -0700, Guenter Roeck wrote: > On Tue, Jun 19, 2018 at 04:12:35PM +0100, Russell King - ARM Linux wrote: > > > > So, I'm going to continue sitting on the fence on this, and basically > > take the attitude that it's better that people don't use the new > > binutils until binutils people can provide us with an officially > > sanctioned solution that's going to work for both older and future > > assemblers. > > > I would so much love if people were working together instead of against > each other :-(. Never mind, I'll try a toolchain with binutils 2.28.1. > At least that is still supported with buildroot. You could say that about the toolchain people who decided to change the behaviour in this area that has existed before July 2009, and broke multiple software packages in the process. What I don't want to do is to change it in some way that breaks existing setups, or that ends up breaking again in the future. This is why I want input _from the toolchain people_ before we try to fix the problem. That isn't "against each other" - it's a request _for_ toolchain people to be involved in this. The fact that this thread doesn't involve any toolchain people says a lot about the "working together" aspect. So, please don't try and lump this on me being "un-cooperative". What I'm saying is talk to the toolchain people and find a solution in conjunction _with_ them that we can be sure will work, rather than guessing at some obscure undocumented method that could end up breaking again. Remember, _you_ have the problem, _I_ don't. It's not for me to go off and talk to the toolchain people on your behalf. Thanks.
diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h index 6ae42ad29518..dd2ff94ad90b 100644 --- a/arch/arm/include/asm/assembler.h +++ b/arch/arm/include/asm/assembler.h @@ -195,13 +195,19 @@ .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 + .eqv .Lsym\@, \sym + adr\c \rd, .Lsym\@ + 1 + .endm + /* * Get current thread_info. */