Re: [PATCH] s390/jump_label: Correct asm contraint

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 1/23/19 5:24 AM, Heiko Carstens wrote:
On Wed, Jan 23, 2019 at 01:55:13PM +0100, Laura Abbott wrote:
There's a build failure with gcc9:

  ./arch/s390/include/asm/jump_label.h: Assembler messages:
  ./arch/s390/include/asm/jump_label.h:23: Error: bad expression
  ./arch/s390/include/asm/jump_label.h:23: Error: junk at end of line, first unrecognized character is `r'
  make[1]: *** [scripts/Makefile.build:277: init/main.o] Error 1

According to the toolchain people, the actual issue is the use of
"X" constraint which is too permissive. Switch to using "i" instead.

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1668703
Signed-off-by: Laura Abbott <labbott@xxxxxxxxxx>
---
  arch/s390/include/asm/jump_label.h | 4 ++--
  1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/s390/include/asm/jump_label.h b/arch/s390/include/asm/jump_label.h
index e2d3e6c43395..41dabfd8518d 100644
--- a/arch/s390/include/asm/jump_label.h
+++ b/arch/s390/include/asm/jump_label.h
@@ -22,7 +22,7 @@ static inline bool arch_static_branch(struct static_key *key, bool branch)
  			  ".long	0b-.,%l[label]-.\n"
  			  ".quad	%0-.\n"
  			  ".popsection\n"
-			  : : "X" (&((char *)key)[branch]) : : label);
+			  : : "i" (&((char *)key)[branch]) : : label);
  	return false;
  label:
  	return true;

Hmmm, this works only for the kernel image, but not for modules, which
we compile with "-fPIC", which again doesn't work as described in the
referenced bugzilla:

In file included from ././include/linux/compiler_types.h:68,
                  from <command-line>:
./arch/s390/include/asm/jump_label.h: In function 'kvm_vcpu_ioctl':
./include/linux/compiler-gcc.h:124:38: warning: asm operand 0 probably doesn't match constraints
  #define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
                                       ^~~
./arch/s390/include/asm/jump_label.h:19:2: note: in expansion of macro 'asm_volatile_goto'
   asm_volatile_goto("0: brcl 0,"__stringify(JUMP_LABEL_NOP_OFFSET)"\n"
   ^~~~~~~~~~~~~~~~~
./include/linux/compiler-gcc.h:124:38: error: impossible constraint in 'asm'
  #define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
                                       ^~~
./arch/s390/include/asm/jump_label.h:19:2: note: in expansion of macro 'asm_volatile_goto'
   asm_volatile_goto("0: brcl 0,"__stringify(JUMP_LABEL_NOP_OFFSET)"\n"

Andreas, Ilya, any idea how to fix this?


I've had to turn off s390 in Fedora until this gets fixed :(




[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Index of Archives]     [Kernel Development]     [Kernel Newbies]     [IDE]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite Info]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux ATA RAID]     [Samba]     [Linux Media]     [Device Mapper]

  Powered by Linux