| Message ID | 5ef2acc655abfbe8bfa2cd30ecc5c2286b8fdfa3.1546551693.git.stefan@agner.ch (mailing list archive) |
|---|---|
| State | Mainlined, archived |
| Commit | 32fdb046ac43aa884d960165072ca37b26d78543 |
| Headers | show |
| Series | ARM: trivial assembly fixes to enable LLVM as | expand |
On Thu, 3 Jan 2019, Stefan Agner wrote: > Convert the conditional infix to a postfix to make sure this inline > assembly is unified syntax. Since gcc assumes non-unified syntax > when emitting ARM instructions, make sure to define the syntax as > unified. > > This allows to use LLVM's integrated assembler. > > Signed-off-by: Stefan Agner <stefan@agner.ch> > --- > Changes since v1: > - Explicitly use unified syntax for inline assembly > > > arch/arm/include/asm/uaccess.h | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h > index 6390a40f16e7..a50f9b4e2574 100644 > --- a/arch/arm/include/asm/uaccess.h > +++ b/arch/arm/include/asm/uaccess.h > @@ -86,7 +86,8 @@ static inline void set_fs(mm_segment_t fs) > #define __range_ok(addr, size) ({ \ > unsigned long flag, roksum; \ > __chk_user_ptr(addr); \ > - __asm__("adds %1, %2, %3; sbcccs %1, %1, %0; movcc %0, #0" \ > + __asm__(".syntax unified\n" \ > + "adds %1, %2, %3; sbcscc %1, %1, %0; movcc %0, #0" \ Instead of sprinkling ".syntax unified" around, you could consider including <asm/unified.h> when needed. Nicolas
On 05.01.2019 17:12, Nicolas Pitre wrote: > On Thu, 3 Jan 2019, Stefan Agner wrote: > >> Convert the conditional infix to a postfix to make sure this inline >> assembly is unified syntax. Since gcc assumes non-unified syntax >> when emitting ARM instructions, make sure to define the syntax as >> unified. >> >> This allows to use LLVM's integrated assembler. >> >> Signed-off-by: Stefan Agner <stefan@agner.ch> >> --- >> Changes since v1: >> - Explicitly use unified syntax for inline assembly >> >> >> arch/arm/include/asm/uaccess.h | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h >> index 6390a40f16e7..a50f9b4e2574 100644 >> --- a/arch/arm/include/asm/uaccess.h >> +++ b/arch/arm/include/asm/uaccess.h >> @@ -86,7 +86,8 @@ static inline void set_fs(mm_segment_t fs) >> #define __range_ok(addr, size) ({ \ >> unsigned long flag, roksum; \ >> __chk_user_ptr(addr); \ >> - __asm__("adds %1, %2, %3; sbcccs %1, %1, %0; movcc %0, #0" \ >> + __asm__(".syntax unified\n" \ >> + "adds %1, %2, %3; sbcscc %1, %1, %0; movcc %0, #0" \ > > Instead of sprinkling ".syntax unified" around, you could consider > including <asm/unified.h> when needed. This seems not to help in this case. When I include <asm/unified.h> at the beginning of uaccess.h GCC still seems to emit ".syntax unified". I guess this is since we are dealing with inline assembly. As far as I understand its really gcc which emits a ".syntax divided" by default when compiling ARM mode. There is an option "-masm-syntax-unified" which according to the gcc man page should do what we need, but it seems broken, see also: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88648 I agree this patch is not particularly pretty, but it is the only solution I found to make this inline assembly work with gcc and Clang. -- Stefan
diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h index 6390a40f16e7..a50f9b4e2574 100644 --- a/arch/arm/include/asm/uaccess.h +++ b/arch/arm/include/asm/uaccess.h @@ -86,7 +86,8 @@ static inline void set_fs(mm_segment_t fs) #define __range_ok(addr, size) ({ \ unsigned long flag, roksum; \ __chk_user_ptr(addr); \ - __asm__("adds %1, %2, %3; sbcccs %1, %1, %0; movcc %0, #0" \ + __asm__(".syntax unified\n" \ + "adds %1, %2, %3; sbcscc %1, %1, %0; movcc %0, #0" \ : "=&r" (flag), "=&r" (roksum) \ : "r" (addr), "Ir" (size), "0" (current_thread_info()->addr_limit) \ : "cc"); \
Convert the conditional infix to a postfix to make sure this inline assembly is unified syntax. Since gcc assumes non-unified syntax when emitting ARM instructions, make sure to define the syntax as unified. This allows to use LLVM's integrated assembler. Signed-off-by: Stefan Agner <stefan@agner.ch> --- Changes since v1: - Explicitly use unified syntax for inline assembly arch/arm/include/asm/uaccess.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)