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authorMichael Ellerman <mpe@ellerman.id.au>2024-09-16 15:05:10 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2024-10-04 17:29:48 +0300
commitae619de5000b73562a1ef42ce03d10e7a6fff6a7 (patch)
tree85767ff53c3d32856e6c561ad08cd9aa578fb734 /arch
parenta3765b497a4f5224cb2f7a6a2d3357d3066214ee (diff)
downloadlinux-ae619de5000b73562a1ef42ce03d10e7a6fff6a7.tar.xz
powerpc/atomic: Use YZ constraints for DS-form instructions
commit 39190ac7cff1fd15135fa8e658030d9646fdb5f2 upstream. The 'ld' and 'std' instructions require a 4-byte aligned displacement because they are DS-form instructions. But the "m" asm constraint doesn't enforce that. That can lead to build errors if the compiler chooses a non-aligned displacement, as seen with GCC 14: /tmp/ccuSzwiR.s: Assembler messages: /tmp/ccuSzwiR.s:2579: Error: operand out of domain (39 is not a multiple of 4) make[5]: *** [scripts/Makefile.build:229: net/core/page_pool.o] Error 1 Dumping the generated assembler shows: ld 8,39(8) # MEM[(const struct atomic64_t *)_29].counter, t Use the YZ constraints to tell the compiler either to generate a DS-form displacement, or use an X-form instruction, either of which prevents the build error. See commit 2d43cc701b96 ("powerpc/uaccess: Fix build errors seen with GCC 13/14") for more details on the constraint letters. Fixes: 9f0cbea0d8cc ("[POWERPC] Implement atomic{, 64}_{read, write}() without volatile") Cc: stable@vger.kernel.org # v2.6.24+ Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Closes: https://lore.kernel.org/all/20240913125302.0a06b4c7@canb.auug.org.au Tested-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Segher Boessenkool <segher@kernel.crashing.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://msgid.link/20240916120510.2017749-1-mpe@ellerman.id.au Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/include/asm/asm-compat.h6
-rw-r--r--arch/powerpc/include/asm/atomic.h5
-rw-r--r--arch/powerpc/include/asm/uaccess.h7
3 files changed, 10 insertions, 8 deletions
diff --git a/arch/powerpc/include/asm/asm-compat.h b/arch/powerpc/include/asm/asm-compat.h
index 2bc53c646ccd..83848b534cb1 100644
--- a/arch/powerpc/include/asm/asm-compat.h
+++ b/arch/powerpc/include/asm/asm-compat.h
@@ -39,6 +39,12 @@
#define STDX_BE stringify_in_c(stdbrx)
#endif
+#ifdef CONFIG_CC_IS_CLANG
+#define DS_FORM_CONSTRAINT "Z<>"
+#else
+#define DS_FORM_CONSTRAINT "YZ<>"
+#endif
+
#else /* 32-bit */
/* operations for longs and pointers */
diff --git a/arch/powerpc/include/asm/atomic.h b/arch/powerpc/include/asm/atomic.h
index 5bf6a4d49268..d1ea554c33ed 100644
--- a/arch/powerpc/include/asm/atomic.h
+++ b/arch/powerpc/include/asm/atomic.h
@@ -11,6 +11,7 @@
#include <asm/cmpxchg.h>
#include <asm/barrier.h>
#include <asm/asm-const.h>
+#include <asm/asm-compat.h>
/*
* Since *_return_relaxed and {cmp}xchg_relaxed are implemented with
@@ -197,7 +198,7 @@ static __inline__ s64 arch_atomic64_read(const atomic64_t *v)
if (IS_ENABLED(CONFIG_PPC_KERNEL_PREFIXED))
__asm__ __volatile__("ld %0,0(%1)" : "=r"(t) : "b"(&v->counter));
else
- __asm__ __volatile__("ld%U1%X1 %0,%1" : "=r"(t) : "m<>"(v->counter));
+ __asm__ __volatile__("ld%U1%X1 %0,%1" : "=r"(t) : DS_FORM_CONSTRAINT (v->counter));
return t;
}
@@ -208,7 +209,7 @@ static __inline__ void arch_atomic64_set(atomic64_t *v, s64 i)
if (IS_ENABLED(CONFIG_PPC_KERNEL_PREFIXED))
__asm__ __volatile__("std %1,0(%2)" : "=m"(v->counter) : "r"(i), "b"(&v->counter));
else
- __asm__ __volatile__("std%U0%X0 %1,%0" : "=m<>"(v->counter) : "r"(i));
+ __asm__ __volatile__("std%U0%X0 %1,%0" : "=" DS_FORM_CONSTRAINT (v->counter) : "r"(i));
}
#define ATOMIC64_OP(op, asm_op) \
diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h
index ccc91bf9b034..a81bd825087c 100644
--- a/arch/powerpc/include/asm/uaccess.h
+++ b/arch/powerpc/include/asm/uaccess.h
@@ -6,6 +6,7 @@
#include <asm/page.h>
#include <asm/extable.h>
#include <asm/kup.h>
+#include <asm/asm-compat.h>
#ifdef __powerpc64__
/* We use TASK_SIZE_USER64 as TASK_SIZE is not constant */
@@ -92,12 +93,6 @@ __pu_failed: \
: label)
#endif
-#ifdef CONFIG_CC_IS_CLANG
-#define DS_FORM_CONSTRAINT "Z<>"
-#else
-#define DS_FORM_CONSTRAINT "YZ<>"
-#endif
-
#ifdef __powerpc64__
#ifdef CONFIG_PPC_KERNEL_PREFIXED
#define __put_user_asm2_goto(x, ptr, label) \