This includes the following changes related to sparc64 for v6.13:

- Make sparc64 compilable with clang
 
 - Replace one-element array with flexible array member
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Merge tag 'sparc-for-6.13-tag1' of git://git.kernel.org/pub/scm/linux/kernel/git/alarsson/linux-sparc

Pull sparc updates from Andreas Larsson:

 - Make sparc64 compilable with clang

 - Replace one-element array with flexible array member

* tag 'sparc-for-6.13-tag1' of git://git.kernel.org/pub/scm/linux/kernel/git/alarsson/linux-sparc:
  sparc/vdso: Add helper function for 64-bit right shift on 32-bit target
  sparc: Replace one-element array with flexible array member
  sparc/build: Add SPARC target flags for compiling with clang
  sparc/build: Put usage of -fcall-used* flags behind cc-option

Documentation/kbuild/llvm.rst

@@ -179,6 +179,9 @@ yet. Bug reports are always welcome at the issue tracker below!
    * - s390
      - Maintained
      - ``LLVM=1`` (LLVM >= 18.1.0), ``CC=clang`` (LLVM < 18.1.0)
+   * - sparc (sparc64 only)
+     - Maintained
+     - ``CC=clang LLVM_IAS=0`` (LLVM >= 20)
    * - um (User Mode)
      - Maintained
      - ``LLVM=1``

arch/sparc/Makefile

@@ -29,7 +29,7 @@ UTS_MACHINE    := sparc
 # versions of gcc.  Some gcc versions won't pass -Av8 to binutils when you
 # give -mcpu=v8.  This silently worked with older bintutils versions but
 # does not any more.
-KBUILD_CFLAGS  += -m32 -mcpu=v8 -pipe -mno-fpu -fcall-used-g5 -fcall-used-g7
+KBUILD_CFLAGS  += -m32 -mcpu=v8 -pipe -mno-fpu $(call cc-option,-fcall-used-g5) $(call cc-option,-fcall-used-g7)
 KBUILD_CFLAGS  += -Wa,-Av8
 
 KBUILD_AFLAGS  += -m32 -Wa,-Av8
@@ -45,7 +45,7 @@ export BITS   := 64
 UTS_MACHINE   := sparc64
 
 KBUILD_CFLAGS += -m64 -pipe -mno-fpu -mcpu=ultrasparc -mcmodel=medlow
-KBUILD_CFLAGS += -ffixed-g4 -ffixed-g5 -fcall-used-g7 -Wno-sign-compare
+KBUILD_CFLAGS += -ffixed-g4 -ffixed-g5 $(call cc-option,-fcall-used-g7) -Wno-sign-compare
 KBUILD_CFLAGS += -Wa,--undeclared-regs
 KBUILD_CFLAGS += $(call cc-option,-mtune=ultrasparc3)
 KBUILD_AFLAGS += -m64 -mcpu=ultrasparc -Wa,--undeclared-regs

arch/sparc/include/asm/hvtramp.h

@@ -17,7 +17,7 @@ struct hvtramp_descr {
 	__u64			fault_info_va;
 	__u64			fault_info_pa;
 	__u64			thread_reg;
-	struct hvtramp_mapping	maps[1];
+	struct hvtramp_mapping	maps[];
 };
 
 void hv_cpu_startup(unsigned long hvdescr_pa);

arch/sparc/kernel/smp_64.c

@@ -297,9 +297,7 @@ static void ldom_startcpu_cpuid(unsigned int cpu, unsigned long thread_reg,
 	unsigned long hv_err;
 	int i;
 
-	hdesc = kzalloc(sizeof(*hdesc) +
-			(sizeof(struct hvtramp_mapping) *
-			 num_kernel_image_mappings - 1),
+	hdesc = kzalloc(struct_size(hdesc, maps, num_kernel_image_mappings),
 			GFP_KERNEL);
 	if (!hdesc) {
 		printk(KERN_ERR "ldom_startcpu_cpuid: Cannot allocate "

arch/sparc/vdso/Makefile

@@ -46,7 +46,7 @@ CFL := $(PROFILING) -mcmodel=medlow -fPIC -O2 -fasynchronous-unwind-tables -m64
        -fno-omit-frame-pointer -foptimize-sibling-calls \
        -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO
 
-SPARC_REG_CFLAGS = -ffixed-g4 -ffixed-g5 -fcall-used-g5 -fcall-used-g7
+SPARC_REG_CFLAGS = -ffixed-g4 -ffixed-g5 $(call cc-option,-fcall-used-g5) $(call cc-option,-fcall-used-g7)
 
 $(vobjs): KBUILD_CFLAGS := $(filter-out $(RANDSTRUCT_CFLAGS) $(GCC_PLUGINS_CFLAGS) $(SPARC_REG_CFLAGS),$(KBUILD_CFLAGS)) $(CFL)
 

arch/sparc/vdso/vclock_gettime.c

@@ -86,6 +86,11 @@ notrace static long vdso_fallback_gettimeofday(struct __kernel_old_timeval *tv,
 }
 
 #ifdef	CONFIG_SPARC64
+notrace static __always_inline u64 __shr64(u64 val, int amt)
+{
+	return val >> amt;
+}
+
 notrace static __always_inline u64 vread_tick(void)
 {
 	u64	ret;
@@ -102,6 +107,21 @@ notrace static __always_inline u64 vread_tick_stick(void)
 	return ret;
 }
 #else
+notrace static __always_inline u64 __shr64(u64 val, int amt)
+{
+	u64 ret;
+
+	__asm__ __volatile__("sllx %H1, 32, %%g1\n\t"
+			     "srl %L1, 0, %L1\n\t"
+			     "or %%g1, %L1, %%g1\n\t"
+			     "srlx %%g1, %2, %L0\n\t"
+			     "srlx %L0, 32, %H0"
+			     : "=r" (ret)
+			     : "r" (val), "r" (amt)
+			     : "g1");
+	return ret;
+}
+
 notrace static __always_inline u64 vread_tick(void)
 {
 	register unsigned long long ret asm("o4");
@@ -154,7 +174,7 @@ notrace static __always_inline int do_realtime(struct vvar_data *vvar,
 		ts->tv_sec = vvar->wall_time_sec;
 		ns = vvar->wall_time_snsec;
 		ns += vgetsns(vvar);
-		ns >>= vvar->clock.shift;
+		ns = __shr64(ns, vvar->clock.shift);
 	} while (unlikely(vvar_read_retry(vvar, seq)));
 
 	ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
@@ -174,7 +194,7 @@ notrace static __always_inline int do_realtime_stick(struct vvar_data *vvar,
 		ts->tv_sec = vvar->wall_time_sec;
 		ns = vvar->wall_time_snsec;
 		ns += vgetsns_stick(vvar);
-		ns >>= vvar->clock.shift;
+		ns = __shr64(ns, vvar->clock.shift);
 	} while (unlikely(vvar_read_retry(vvar, seq)));
 
 	ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
@@ -194,7 +214,7 @@ notrace static __always_inline int do_monotonic(struct vvar_data *vvar,
 		ts->tv_sec = vvar->monotonic_time_sec;
 		ns = vvar->monotonic_time_snsec;
 		ns += vgetsns(vvar);
-		ns >>= vvar->clock.shift;
+		ns = __shr64(ns, vvar->clock.shift);
 	} while (unlikely(vvar_read_retry(vvar, seq)));
 
 	ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
@@ -214,7 +234,7 @@ notrace static __always_inline int do_monotonic_stick(struct vvar_data *vvar,
 		ts->tv_sec = vvar->monotonic_time_sec;
 		ns = vvar->monotonic_time_snsec;
 		ns += vgetsns_stick(vvar);
-		ns >>= vvar->clock.shift;
+		ns = __shr64(ns, vvar->clock.shift);
 	} while (unlikely(vvar_read_retry(vvar, seq)));
 
 	ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);

scripts/Makefile.clang

@@ -10,6 +10,7 @@ CLANG_TARGET_FLAGS_mips		:= mipsel-linux-gnu
 CLANG_TARGET_FLAGS_powerpc	:= powerpc64le-linux-gnu
 CLANG_TARGET_FLAGS_riscv	:= riscv64-linux-gnu
 CLANG_TARGET_FLAGS_s390		:= s390x-linux-gnu
+CLANG_TARGET_FLAGS_sparc	:= sparc64-linux-gnu
 CLANG_TARGET_FLAGS_x86		:= x86_64-linux-gnu
 CLANG_TARGET_FLAGS_um		:= $(CLANG_TARGET_FLAGS_$(SUBARCH))
 CLANG_TARGET_FLAGS		:= $(CLANG_TARGET_FLAGS_$(SRCARCH))