| Message ID | 20201105181542.854788-1-maskray@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | ARM: Change arch/arm/lib/mem*.S to use WEAK instead of .weak | expand |
On Thu, Nov 5, 2020 at 10:15 AM Fangrui Song <maskray@google.com> wrote: > > Commit d6d51a96c7d6 ("ARM: 9014/2: Replace string mem* functions for > KASan") add .weak directives to memcpy/memmove/memset to avoid collision > with KASAN interceptors. > > This does not work with LLVM's integrated assembler (the assembly snippet > `.weak memcpy ... .globl memcpy` produces a STB_GLOBAL memcpy while GNU as > produces a STB_WEAK memcpy). LLVM 12 (since https://reviews.llvm.org/D90108) > will error on such an overridden symbol binding. > > Use the appropriate WEAK macro instead. > > Fixes: d6d51a96c7d6 ("ARM: 9014/2: Replace string mem* functions for KASan") > Reported-by: Nick Desaulniers <ndesaulniers@google.com> > Signed-off-by: Fangrui Song <maskray@google.com> > Link: https://github.com/ClangBuiltLinux/linux/issues/1190 Thank you, this fixes a recent regression for me using LLVM_IAS=1 with ToT LLVM. Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> > --- > arch/arm/lib/memcpy.S | 3 +-- > arch/arm/lib/memmove.S | 3 +-- > arch/arm/lib/memset.S | 3 +-- > 3 files changed, 3 insertions(+), 6 deletions(-) > > diff --git a/arch/arm/lib/memcpy.S b/arch/arm/lib/memcpy.S > index ad4625d16e11..e4caf48c089f 100644 > --- a/arch/arm/lib/memcpy.S > +++ b/arch/arm/lib/memcpy.S > @@ -58,10 +58,9 @@ > > /* Prototype: void *memcpy(void *dest, const void *src, size_t n); */ > > -.weak memcpy > ENTRY(__memcpy) > ENTRY(mmiocpy) > -ENTRY(memcpy) > +WEAK(memcpy) > > #include "copy_template.S" > > diff --git a/arch/arm/lib/memmove.S b/arch/arm/lib/memmove.S > index fd123ea5a5a4..6fecc12a1f51 100644 > --- a/arch/arm/lib/memmove.S > +++ b/arch/arm/lib/memmove.S > @@ -24,9 +24,8 @@ > * occurring in the opposite direction. > */ > > -.weak memmove > ENTRY(__memmove) > -ENTRY(memmove) > +WEAK(memmove) > UNWIND( .fnstart ) > > subs ip, r0, r1 > diff --git a/arch/arm/lib/memset.S b/arch/arm/lib/memset.S > index 0e7ff0423f50..9817cb258c1a 100644 > --- a/arch/arm/lib/memset.S > +++ b/arch/arm/lib/memset.S > @@ -13,10 +13,9 @@ > .text > .align 5 > > -.weak memset > ENTRY(__memset) > ENTRY(mmioset) > -ENTRY(memset) > +WEAK(memset) > UNWIND( .fnstart ) > ands r3, r0, #3 @ 1 unaligned? > mov ip, r0 @ preserve r0 as return value > -- > 2.29.1.341.ge80a0c044ae-goog >
On Thu, Nov 5, 2020 at 7:15 PM Fangrui Song <maskray@google.com> wrote: > Commit d6d51a96c7d6 ("ARM: 9014/2: Replace string mem* functions for > KASan") add .weak directives to memcpy/memmove/memset to avoid collision > with KASAN interceptors. > > This does not work with LLVM's integrated assembler (the assembly snippet > `.weak memcpy ... .globl memcpy` produces a STB_GLOBAL memcpy while GNU as > produces a STB_WEAK memcpy). LLVM 12 (since https://reviews.llvm.org/D90108) > will error on such an overridden symbol binding. > > Use the appropriate WEAK macro instead. > > Fixes: d6d51a96c7d6 ("ARM: 9014/2: Replace string mem* functions for KASan") > Reported-by: Nick Desaulniers <ndesaulniers@google.com> > Signed-off-by: Fangrui Song <maskray@google.com> > Link: https://github.com/ClangBuiltLinux/linux/issues/1190 Acked-by: Linus Walleij <linus.walleij@linaro.org> When you have consensus that this is working, please put the patch into Russell's patch tracker. Yours, Linus Walleij
diff --git a/arch/arm/lib/memcpy.S b/arch/arm/lib/memcpy.S index ad4625d16e11..e4caf48c089f 100644 --- a/arch/arm/lib/memcpy.S +++ b/arch/arm/lib/memcpy.S @@ -58,10 +58,9 @@ /* Prototype: void *memcpy(void *dest, const void *src, size_t n); */ -.weak memcpy ENTRY(__memcpy) ENTRY(mmiocpy) -ENTRY(memcpy) +WEAK(memcpy) #include "copy_template.S" diff --git a/arch/arm/lib/memmove.S b/arch/arm/lib/memmove.S index fd123ea5a5a4..6fecc12a1f51 100644 --- a/arch/arm/lib/memmove.S +++ b/arch/arm/lib/memmove.S @@ -24,9 +24,8 @@ * occurring in the opposite direction. */ -.weak memmove ENTRY(__memmove) -ENTRY(memmove) +WEAK(memmove) UNWIND( .fnstart ) subs ip, r0, r1 diff --git a/arch/arm/lib/memset.S b/arch/arm/lib/memset.S index 0e7ff0423f50..9817cb258c1a 100644 --- a/arch/arm/lib/memset.S +++ b/arch/arm/lib/memset.S @@ -13,10 +13,9 @@ .text .align 5 -.weak memset ENTRY(__memset) ENTRY(mmioset) -ENTRY(memset) +WEAK(memset) UNWIND( .fnstart ) ands r3, r0, #3 @ 1 unaligned? mov ip, r0 @ preserve r0 as return value
Commit d6d51a96c7d6 ("ARM: 9014/2: Replace string mem* functions for KASan") add .weak directives to memcpy/memmove/memset to avoid collision with KASAN interceptors. This does not work with LLVM's integrated assembler (the assembly snippet `.weak memcpy ... .globl memcpy` produces a STB_GLOBAL memcpy while GNU as produces a STB_WEAK memcpy). LLVM 12 (since https://reviews.llvm.org/D90108) will error on such an overridden symbol binding. Use the appropriate WEAK macro instead. Fixes: d6d51a96c7d6 ("ARM: 9014/2: Replace string mem* functions for KASan") Reported-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Fangrui Song <maskray@google.com> Link: https://github.com/ClangBuiltLinux/linux/issues/1190 --- arch/arm/lib/memcpy.S | 3 +-- arch/arm/lib/memmove.S | 3 +-- arch/arm/lib/memset.S | 3 +-- 3 files changed, 3 insertions(+), 6 deletions(-)