From 69114be15b35a4d7ff084a6415fad018da648942 Mon Sep 17 00:00:00 2001 From: Koakuma Date: Tue, 29 Oct 2024 21:49:07 +0700 Subject: [PATCH 1/4] sparc/build: Put usage of -fcall-used* flags behind cc-option Place -fcall-used* flags behind cc-option so that clang (which doesn't support them) can still compile the kernel. This is a safe change, the reasoning is as follows: In the (normal) 32-bit ABI, %g5 and %g7 is normally reserved, and in the 64-bit ABI, %g7 is the reserved one. Linux turns them into volatile registers by the way of -fcall-used-*, but on the other hand, omitting the flags shouldn't be harmful; compilers will now simply refuse to touch them, and any assembly code that happens to touch them would still work like usual (because Linux' conventions already treats them as volatile anyway). Signed-off-by: Koakuma Reviewed-by: Nathan Chancellor Tested-by: Nathan Chancellor Reviewed-by: Andreas Larsson Link: https://lore.kernel.org/r/20241029-sparc-cflags-v3-1-b28745a6bd71@protonmail.com Signed-off-by: Andreas Larsson --- arch/sparc/Makefile | 4 ++-- arch/sparc/vdso/Makefile | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/sparc/Makefile b/arch/sparc/Makefile index 757451c3ea1d..0400078076e5 100644 --- a/arch/sparc/Makefile +++ b/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 diff --git a/arch/sparc/vdso/Makefile b/arch/sparc/vdso/Makefile index 243dbfc4609d..50ec2978cda5 100644 --- a/arch/sparc/vdso/Makefile +++ b/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) From f6dee26d26e3ef2a00620703fb5bf272dd459f47 Mon Sep 17 00:00:00 2001 From: Koakuma Date: Tue, 29 Oct 2024 21:49:08 +0700 Subject: [PATCH 2/4] sparc/build: Add SPARC target flags for compiling with clang clang only supports building 64-bit kernel, so we use the sparc64-linux-gnu target. See also: https://lore.kernel.org/lkml/e26PTXUXEz8OYXmaeKn4Mpuejr4IOlFfFwdB5vpsluXlYiqDdlyQTYcDtdAny_o4gO4SfPeQCCN2qpyT6e0nog5EaP3xk2SeUPTrF54p1gM=@protonmail.com/T/#m068e010dcf8b99d3510a90d7532bcdb70e2e2c6b Signed-off-by: Koakuma Acked-by: Masahiro Yamada Acked-by: Nathan Chancellor Reviewed-by: Andreas Larsson Link: https://lore.kernel.org/r/20241029-sparc-cflags-v3-2-b28745a6bd71@protonmail.com Signed-off-by: Andreas Larsson --- Documentation/kbuild/llvm.rst | 3 +++ scripts/Makefile.clang | 1 + 2 files changed, 4 insertions(+) diff --git a/Documentation/kbuild/llvm.rst b/Documentation/kbuild/llvm.rst index 6dc66b4f31a7..bc8a283bc44b 100644 --- a/Documentation/kbuild/llvm.rst +++ b/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`` diff --git a/scripts/Makefile.clang b/scripts/Makefile.clang index 6c23c6af797f..2435efae67f5 100644 --- a/scripts/Makefile.clang +++ b/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)) From 8467d8b282b54d87121f70ce78061af004471d0c Mon Sep 17 00:00:00 2001 From: Thorsten Blum Date: Mon, 11 Nov 2024 21:47:21 +0100 Subject: [PATCH 3/4] sparc: Replace one-element array with flexible array member Replace the deprecated one-element array with a modern flexible array member in the struct hvtramp_descr. Additionally, 15 unnecessary bytes were allocated for hdesc, but instead of fixing the parentheses in the open-coded version, use struct_size() to calculate the correct number of bytes. Link: https://github.com/KSPP/linux/issues/79 Signed-off-by: Thorsten Blum Fixes: 64658743fdd4 ("[SPARC64]: Remove most limitations to kernel image size.") Reviewed-by: Andreas Larsson Link: https://lore.kernel.org/r/20241111204724.165263-2-thorsten.blum@linux.dev Signed-off-by: Andreas Larsson --- arch/sparc/include/asm/hvtramp.h | 2 +- arch/sparc/kernel/smp_64.c | 4 +--- 2 files changed, 2 insertions(+), 4 deletions(-) diff --git a/arch/sparc/include/asm/hvtramp.h b/arch/sparc/include/asm/hvtramp.h index 688ea43af0f5..ce2453ea4f2b 100644 --- a/arch/sparc/include/asm/hvtramp.h +++ b/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); diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c index e40c395db202..5cbd6ed5ef6f 100644 --- a/arch/sparc/kernel/smp_64.c +++ b/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 " From b6370b338e71cf24c61e33880b8f1a0dd5ad0a44 Mon Sep 17 00:00:00 2001 From: Koakuma Date: Thu, 8 Aug 2024 09:05:00 +0700 Subject: [PATCH 4/4] sparc/vdso: Add helper function for 64-bit right shift on 32-bit target Add helper function for 64-bit right shift on 32-bit target so that clang does not emit a runtime library call. Signed-off-by: Koakuma Reviewed-by: Andreas Larsson Link: https://lore.kernel.org/r/20240808-sparc-shr64-v2-1-fd18f1b2cea9@protonmail.com Signed-off-by: Andreas Larsson --- arch/sparc/vdso/vclock_gettime.c | 28 ++++++++++++++++++++++++---- 1 file changed, 24 insertions(+), 4 deletions(-) diff --git a/arch/sparc/vdso/vclock_gettime.c b/arch/sparc/vdso/vclock_gettime.c index e794edde6755..79607804ea1b 100644 --- a/arch/sparc/vdso/vclock_gettime.c +++ b/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);