| Message ID | fed4850fb5d8a8ca874affa05d8d116d53e25b88.1549532513.git.stefan@agner.ch (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | ARM: convert to unified syntax | expand |
Thanks for the reviews so far. During some more testing I stumbled upon another issue: On 07.02.2019 10:48, Stefan Agner wrote: > Use unified assembler syntax (UAL) in inline assembler. Divided > syntax is considered depricated. This will also allow to build > the kernel using LLVM's integrated assembler. > > Signed-off-by: Stefan Agner <stefan@agner.ch> > --- > arch/arm/mm/copypage-v4mc.c | 2 +- > arch/arm/mm/copypage-v4wb.c | 2 +- > arch/arm/mm/copypage-v4wt.c | 2 +- > 3 files changed, 3 insertions(+), 3 deletions(-) > > diff --git a/arch/arm/mm/copypage-v4mc.c b/arch/arm/mm/copypage-v4mc.c > index b03202cddddb..b19c7ad1a6de 100644 > --- a/arch/arm/mm/copypage-v4mc.c > +++ b/arch/arm/mm/copypage-v4mc.c > @@ -56,7 +56,7 @@ static void mc_copy_user_page(void *from, void *to) > ldmia %0!, {r2, r3, ip, lr} @ 4\n\ > subs %2, %2, #1 @ 1\n\ > stmia %1!, {r2, r3, ip, lr} @ 4\n\ > - ldmneia %0!, {r2, r3, ip, lr} @ 4\n\ > + ldmiane %0!, {r2, r3, ip, lr} @ 4\n\ > bne 1b @ " > : "+&r" (from), "+&r" (to), "=&r" (tmp) > : "2" (PAGE_SIZE / 64) > diff --git a/arch/arm/mm/copypage-v4wb.c b/arch/arm/mm/copypage-v4wb.c > index cd3e165afeed..6e3c9b69dd25 100644 > --- a/arch/arm/mm/copypage-v4wb.c > +++ b/arch/arm/mm/copypage-v4wb.c > @@ -38,7 +38,7 @@ static void v4wb_copy_user_page(void *kto, const void *kfrom) > ldmia %1!, {r3, r4, ip, lr} @ 4\n\ > subs %2, %2, #1 @ 1\n\ > stmia %0!, {r3, r4, ip, lr} @ 4\n\ > - ldmneia %1!, {r3, r4, ip, lr} @ 4\n\ > + ldmiane %1!, {r3, r4, ip, lr} @ 4\n\ > bne 1b @ 1\n\ > mcr p15, 0, %1, c7, c10, 4 @ 1 drain WB" > : "+&r" (kto), "+&r" (kfrom), "=&r" (tmp) > diff --git a/arch/arm/mm/copypage-v4wt.c b/arch/arm/mm/copypage-v4wt.c > index 8614572e1296..4a40fa1cbc2a 100644 > --- a/arch/arm/mm/copypage-v4wt.c > +++ b/arch/arm/mm/copypage-v4wt.c > @@ -34,7 +34,7 @@ static void v4wt_copy_user_page(void *kto, const void *kfrom) > ldmia %1!, {r3, r4, ip, lr} @ 4\n\ > subs %2, %2, #1 @ 1\n\ > stmia %0!, {r3, r4, ip, lr} @ 4\n\ > - ldmneia %1!, {r3, r4, ip, lr} @ 4\n\ > + ldmiane %1!, {r3, r4, ip, lr} @ 4\n\ > bne 1b @ 1\n\ > mcr p15, 0, %2, c7, c7, 0 @ flush ID cache" > : "+&r" (kto), "+&r" (kfrom), "=&r" (tmp) When compiling with gcc, this leads to: /tmp/ccrvA1wy.s: Assembler messages: /tmp/ccrvA1wy.s:180: Error: bad instruction `ldmiane r0!,{r3,r4,ip,lr}' make[1]: *** [scripts/Makefile.build:277: arch/arm/mm/copypage-v4wb.o] Error 1 make: *** [Makefile:1042: arch/arm/mm] Error 2 Unfortunately, the gcc option -masm-syntax-unified which allows unified syntax in inline assembly is broken (see also https://lkml.org/lkml/2019/1/7/1320). So this requires to sprinkle those inline assembly with ".syntax unified" strings, similar to how I've done it in uaccess.h. -- Stefan
On Sat, Feb 9, 2019 at 9:28 AM Stefan Agner <stefan@agner.ch> wrote: > > Thanks for the reviews so far. > > During some more testing I stumbled upon another issue: > > On 07.02.2019 10:48, Stefan Agner wrote: > > Use unified assembler syntax (UAL) in inline assembler. Divided > > syntax is considered depricated. This will also allow to build > > the kernel using LLVM's integrated assembler. > > > > Signed-off-by: Stefan Agner <stefan@agner.ch> > > --- > > arch/arm/mm/copypage-v4mc.c | 2 +- > > arch/arm/mm/copypage-v4wb.c | 2 +- > > arch/arm/mm/copypage-v4wt.c | 2 +- > > 3 files changed, 3 insertions(+), 3 deletions(-) > > > > diff --git a/arch/arm/mm/copypage-v4mc.c b/arch/arm/mm/copypage-v4mc.c > > index b03202cddddb..b19c7ad1a6de 100644 > > --- a/arch/arm/mm/copypage-v4mc.c > > +++ b/arch/arm/mm/copypage-v4mc.c > > @@ -56,7 +56,7 @@ static void mc_copy_user_page(void *from, void *to) > > ldmia %0!, {r2, r3, ip, lr} @ 4\n\ > > subs %2, %2, #1 @ 1\n\ > > stmia %1!, {r2, r3, ip, lr} @ 4\n\ > > - ldmneia %0!, {r2, r3, ip, lr} @ 4\n\ > > + ldmiane %0!, {r2, r3, ip, lr} @ 4\n\ > > bne 1b @ " > > : "+&r" (from), "+&r" (to), "=&r" (tmp) > > : "2" (PAGE_SIZE / 64) > > diff --git a/arch/arm/mm/copypage-v4wb.c b/arch/arm/mm/copypage-v4wb.c > > index cd3e165afeed..6e3c9b69dd25 100644 > > --- a/arch/arm/mm/copypage-v4wb.c > > +++ b/arch/arm/mm/copypage-v4wb.c > > @@ -38,7 +38,7 @@ static void v4wb_copy_user_page(void *kto, const void *kfrom) > > ldmia %1!, {r3, r4, ip, lr} @ 4\n\ > > subs %2, %2, #1 @ 1\n\ > > stmia %0!, {r3, r4, ip, lr} @ 4\n\ > > - ldmneia %1!, {r3, r4, ip, lr} @ 4\n\ > > + ldmiane %1!, {r3, r4, ip, lr} @ 4\n\ > > bne 1b @ 1\n\ > > mcr p15, 0, %1, c7, c10, 4 @ 1 drain WB" > > : "+&r" (kto), "+&r" (kfrom), "=&r" (tmp) > > diff --git a/arch/arm/mm/copypage-v4wt.c b/arch/arm/mm/copypage-v4wt.c > > index 8614572e1296..4a40fa1cbc2a 100644 > > --- a/arch/arm/mm/copypage-v4wt.c > > +++ b/arch/arm/mm/copypage-v4wt.c > > @@ -34,7 +34,7 @@ static void v4wt_copy_user_page(void *kto, const void *kfrom) > > ldmia %1!, {r3, r4, ip, lr} @ 4\n\ > > subs %2, %2, #1 @ 1\n\ > > stmia %0!, {r3, r4, ip, lr} @ 4\n\ > > - ldmneia %1!, {r3, r4, ip, lr} @ 4\n\ > > + ldmiane %1!, {r3, r4, ip, lr} @ 4\n\ > > bne 1b @ 1\n\ > > mcr p15, 0, %2, c7, c7, 0 @ flush ID cache" > > : "+&r" (kto), "+&r" (kfrom), "=&r" (tmp) > > When compiling with gcc, this leads to: > > /tmp/ccrvA1wy.s: Assembler messages: > /tmp/ccrvA1wy.s:180: Error: bad instruction `ldmiane r0!,{r3,r4,ip,lr}' > make[1]: *** [scripts/Makefile.build:277: arch/arm/mm/copypage-v4wb.o] > Error 1 > make: *** [Makefile:1042: arch/arm/mm] Error 2 > > Unfortunately, the gcc option -masm-syntax-unified which allows unified > syntax in inline assembly is broken (see also > https://lkml.org/lkml/2019/1/7/1320). > > So this requires to sprinkle those inline assembly with ".syntax > unified" strings, similar to how I've done it in uaccess.h. Not sure if this is purely a bug in GCC; Clang treats inline asm statements as unique, so asm directives do not carry over from one inline asm statement to another. This has caused issues in other arch's inline assembly, where we need to repeat asm directives repeatedly for each inline asm statement. https://bugs.llvm.org/show_bug.cgi?id=19749
On 11.02.2019 19:17, Nick Desaulniers wrote: > On Sat, Feb 9, 2019 at 9:28 AM Stefan Agner <stefan@agner.ch> wrote: >> >> Thanks for the reviews so far. >> >> During some more testing I stumbled upon another issue: >> >> On 07.02.2019 10:48, Stefan Agner wrote: >> > Use unified assembler syntax (UAL) in inline assembler. Divided >> > syntax is considered depricated. This will also allow to build >> > the kernel using LLVM's integrated assembler. >> > >> > Signed-off-by: Stefan Agner <stefan@agner.ch> >> > --- >> > arch/arm/mm/copypage-v4mc.c | 2 +- >> > arch/arm/mm/copypage-v4wb.c | 2 +- >> > arch/arm/mm/copypage-v4wt.c | 2 +- >> > 3 files changed, 3 insertions(+), 3 deletions(-) >> > >> > diff --git a/arch/arm/mm/copypage-v4mc.c b/arch/arm/mm/copypage-v4mc.c >> > index b03202cddddb..b19c7ad1a6de 100644 >> > --- a/arch/arm/mm/copypage-v4mc.c >> > +++ b/arch/arm/mm/copypage-v4mc.c >> > @@ -56,7 +56,7 @@ static void mc_copy_user_page(void *from, void *to) >> > ldmia %0!, {r2, r3, ip, lr} @ 4\n\ >> > subs %2, %2, #1 @ 1\n\ >> > stmia %1!, {r2, r3, ip, lr} @ 4\n\ >> > - ldmneia %0!, {r2, r3, ip, lr} @ 4\n\ >> > + ldmiane %0!, {r2, r3, ip, lr} @ 4\n\ >> > bne 1b @ " >> > : "+&r" (from), "+&r" (to), "=&r" (tmp) >> > : "2" (PAGE_SIZE / 64) >> > diff --git a/arch/arm/mm/copypage-v4wb.c b/arch/arm/mm/copypage-v4wb.c >> > index cd3e165afeed..6e3c9b69dd25 100644 >> > --- a/arch/arm/mm/copypage-v4wb.c >> > +++ b/arch/arm/mm/copypage-v4wb.c >> > @@ -38,7 +38,7 @@ static void v4wb_copy_user_page(void *kto, const void *kfrom) >> > ldmia %1!, {r3, r4, ip, lr} @ 4\n\ >> > subs %2, %2, #1 @ 1\n\ >> > stmia %0!, {r3, r4, ip, lr} @ 4\n\ >> > - ldmneia %1!, {r3, r4, ip, lr} @ 4\n\ >> > + ldmiane %1!, {r3, r4, ip, lr} @ 4\n\ >> > bne 1b @ 1\n\ >> > mcr p15, 0, %1, c7, c10, 4 @ 1 drain WB" >> > : "+&r" (kto), "+&r" (kfrom), "=&r" (tmp) >> > diff --git a/arch/arm/mm/copypage-v4wt.c b/arch/arm/mm/copypage-v4wt.c >> > index 8614572e1296..4a40fa1cbc2a 100644 >> > --- a/arch/arm/mm/copypage-v4wt.c >> > +++ b/arch/arm/mm/copypage-v4wt.c >> > @@ -34,7 +34,7 @@ static void v4wt_copy_user_page(void *kto, const void *kfrom) >> > ldmia %1!, {r3, r4, ip, lr} @ 4\n\ >> > subs %2, %2, #1 @ 1\n\ >> > stmia %0!, {r3, r4, ip, lr} @ 4\n\ >> > - ldmneia %1!, {r3, r4, ip, lr} @ 4\n\ >> > + ldmiane %1!, {r3, r4, ip, lr} @ 4\n\ >> > bne 1b @ 1\n\ >> > mcr p15, 0, %2, c7, c7, 0 @ flush ID cache" >> > : "+&r" (kto), "+&r" (kfrom), "=&r" (tmp) >> >> When compiling with gcc, this leads to: >> >> /tmp/ccrvA1wy.s: Assembler messages: >> /tmp/ccrvA1wy.s:180: Error: bad instruction `ldmiane r0!,{r3,r4,ip,lr}' >> make[1]: *** [scripts/Makefile.build:277: arch/arm/mm/copypage-v4wb.o] >> Error 1 >> make: *** [Makefile:1042: arch/arm/mm] Error 2 >> >> Unfortunately, the gcc option -masm-syntax-unified which allows unified >> syntax in inline assembly is broken (see also >> https://lkml.org/lkml/2019/1/7/1320). >> >> So this requires to sprinkle those inline assembly with ".syntax >> unified" strings, similar to how I've done it in uaccess.h. > > Not sure if this is purely a bug in GCC; Clang treats inline asm > statements as unique, so asm directives do not carry over from one > inline asm statement to another. This has caused issues in other > arch's inline assembly, where we need to repeat asm directives > repeatedly for each inline asm statement. > https://bugs.llvm.org/show_bug.cgi?id=19749 I don't think that this Clang bug is related. GCC always emits a ".syntax xxx". The -masm-syntax-unified flag allows to select unified syntax, but it is broken in current GCC releases. I reported the bug and sent a fix to the GCC community, the upcoming GCC 9, as well as 7 and 8 bugfix releases, will have it fixed. See: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88648 -- Stefan
diff --git a/arch/arm/mm/copypage-v4mc.c b/arch/arm/mm/copypage-v4mc.c index b03202cddddb..b19c7ad1a6de 100644 --- a/arch/arm/mm/copypage-v4mc.c +++ b/arch/arm/mm/copypage-v4mc.c @@ -56,7 +56,7 @@ static void mc_copy_user_page(void *from, void *to) ldmia %0!, {r2, r3, ip, lr} @ 4\n\ subs %2, %2, #1 @ 1\n\ stmia %1!, {r2, r3, ip, lr} @ 4\n\ - ldmneia %0!, {r2, r3, ip, lr} @ 4\n\ + ldmiane %0!, {r2, r3, ip, lr} @ 4\n\ bne 1b @ " : "+&r" (from), "+&r" (to), "=&r" (tmp) : "2" (PAGE_SIZE / 64) diff --git a/arch/arm/mm/copypage-v4wb.c b/arch/arm/mm/copypage-v4wb.c index cd3e165afeed..6e3c9b69dd25 100644 --- a/arch/arm/mm/copypage-v4wb.c +++ b/arch/arm/mm/copypage-v4wb.c @@ -38,7 +38,7 @@ static void v4wb_copy_user_page(void *kto, const void *kfrom) ldmia %1!, {r3, r4, ip, lr} @ 4\n\ subs %2, %2, #1 @ 1\n\ stmia %0!, {r3, r4, ip, lr} @ 4\n\ - ldmneia %1!, {r3, r4, ip, lr} @ 4\n\ + ldmiane %1!, {r3, r4, ip, lr} @ 4\n\ bne 1b @ 1\n\ mcr p15, 0, %1, c7, c10, 4 @ 1 drain WB" : "+&r" (kto), "+&r" (kfrom), "=&r" (tmp) diff --git a/arch/arm/mm/copypage-v4wt.c b/arch/arm/mm/copypage-v4wt.c index 8614572e1296..4a40fa1cbc2a 100644 --- a/arch/arm/mm/copypage-v4wt.c +++ b/arch/arm/mm/copypage-v4wt.c @@ -34,7 +34,7 @@ static void v4wt_copy_user_page(void *kto, const void *kfrom) ldmia %1!, {r3, r4, ip, lr} @ 4\n\ subs %2, %2, #1 @ 1\n\ stmia %0!, {r3, r4, ip, lr} @ 4\n\ - ldmneia %1!, {r3, r4, ip, lr} @ 4\n\ + ldmiane %1!, {r3, r4, ip, lr} @ 4\n\ bne 1b @ 1\n\ mcr p15, 0, %2, c7, c7, 0 @ flush ID cache" : "+&r" (kto), "+&r" (kfrom), "=&r" (tmp)
Use unified assembler syntax (UAL) in inline assembler. Divided syntax is considered depricated. This will also allow to build the kernel using LLVM's integrated assembler. Signed-off-by: Stefan Agner <stefan@agner.ch> --- arch/arm/mm/copypage-v4mc.c | 2 +- arch/arm/mm/copypage-v4wb.c | 2 +- arch/arm/mm/copypage-v4wt.c | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-)