Merge tag 'riscv-for-linus-4.20-mw0' of git://git.kernel.org/pub/scm/…

…linux/kernel/git/palmer/riscv-linux

Pull RISC-V updates from Palmer Dabbelt:
 "This patch set contains a lot (at least, for me) of improvements to
  the RISC-V kernel port:

   - The removal of some cacheinfo values that were bogus.

   - On systems with F but without D the kernel will not show the F
     extension to userspace, as it isn't actually supported.

   - Support for futexes.

   - Removal of some unused code.

   - Cleanup of some menuconfig entries.

   - Support for systems without a floating-point unit, and for building
     kernels that will never use the floating-point unit.

   - More fixes to the RV32I port, which regressed again. It's really
     time to get this into a regression test somewhere so I stop
     breaking it. Thanks to Zong for resurrecting it again!

   - Various fixes that resulted from a year old review of our original
     patch set that I finally got around to.

   - Various improvements to SMP support, largely based around having
     switched to logical hart numbering, as well as some interrupt
     improvements. This one is in the same patch set as above, thanks to
     Atish for sheparding everything though as my patch set was a bit of
     a mess.

  I'm pretty sure this is our largest patch set since the original
  kernel contribution, and it's certainly the one with the most
  contributors. While I don't have anything else I know I'm going to
  submit for the merge window, I would be somewhat surprised if I didn't
  screw anything up.

  Thanks for the help, everyone!"

* tag 'riscv-for-linus-4.20-mw0' of git://git.kernel.org/pub/scm/linux/kernel/git/palmer/riscv-linux: (31 commits)
  RISC-V: Cosmetic menuconfig changes
  riscv: move GCC version check for ARCH_SUPPORTS_INT128 to Kconfig
  RISC-V: remove the unused return_to_handler export
  RISC-V: Add futex support.
  RISC-V: Add FP register ptrace support for gdb.
  RISC-V: Mask out the F extension on systems without D
  RISC-V: Don't set cacheinfo.{physical_line_partition,attributes}
  RISC-V: Show IPI stats
  RISC-V: Show CPU ID and Hart ID separately in /proc/cpuinfo
  RISC-V: Use Linux logical CPU number instead of hartid
  RISC-V: Add logical CPU indexing for RISC-V
  RISC-V: Use WRITE_ONCE instead of direct access
  RISC-V: Use mmgrab()
  RISC-V: Rename im_okay_therefore_i_am to found_boot_cpu
  RISC-V: Rename riscv_of_processor_hart to riscv_of_processor_hartid
  RISC-V: Provide a cleaner raw_smp_processor_id()
  RISC-V: Disable preemption before enabling interrupts
  RISC-V: Comment on the TLB flush in smp_callin()
  RISC-V: Filter ISA and MMU values in cpuinfo
  RISC-V: Don't set cacheinfo.{physical_line_partition,attributes}
  ...

arch/riscv/Kconfig

@@ -31,6 +31,7 @@ config RISCV
 	select HAVE_MEMBLOCK
 	select HAVE_MEMBLOCK_NODE_MAP
 	select HAVE_DMA_CONTIGUOUS
+	select HAVE_FUTEX_CMPXCHG if FUTEX
 	select HAVE_GENERIC_DMA_COHERENT
 	select HAVE_PERF_EVENTS
 	select IRQ_DOMAIN
@@ -108,10 +109,12 @@ config ARCH_RV32I
 	select GENERIC_LIB_ASHRDI3
 	select GENERIC_LIB_LSHRDI3
 	select GENERIC_LIB_UCMPDI2
+	select GENERIC_LIB_UMODDI3
 
 config ARCH_RV64I
 	bool "RV64I"
 	select 64BIT
+	select ARCH_SUPPORTS_INT128 if GCC_VERSION >= 50000
 	select HAVE_FUNCTION_TRACER
 	select HAVE_FUNCTION_GRAPH_TRACER
 	select HAVE_FTRACE_MCOUNT_RECORD
@@ -208,14 +211,61 @@ config RISCV_BASE_PMU
 
 endmenu
 
+config FPU
+	bool "FPU support"
+	default y
+	help
+	  Say N here if you want to disable all floating-point related procedure
+	  in the kernel.
+
+	  If you don't know what to do here, say Y.
+
 endmenu
 
-menu "Kernel type"
+menu "Kernel features"
 
 source "kernel/Kconfig.hz"
 
 endmenu
 
+menu "Boot options"
+
+config CMDLINE_BOOL
+	bool "Built-in kernel command line"
+	help
+	  For most platforms, it is firmware or second stage bootloader
+	  that by default specifies the kernel command line options.
+	  However, it might be necessary or advantageous to either override
+	  the default kernel command line or add a few extra options to it.
+	  For such cases, this option allows hardcoding command line options
+	  directly into the kernel.
+
+	  For that, choose 'Y' here and fill in the extra boot parameters
+	  in CONFIG_CMDLINE.
+
+	  The built-in options will be concatenated to the default command
+	  line if CMDLINE_FORCE is set to 'N'. Otherwise, the default
+	  command line will be ignored and replaced by the built-in string.
+
+config CMDLINE
+	string "Built-in kernel command string"
+	depends on CMDLINE_BOOL
+	default ""
+	help
+	  Supply command-line options at build time by entering them here.
+
+config CMDLINE_FORCE
+	bool "Built-in command line overrides bootloader arguments"
+	depends on CMDLINE_BOOL
+	help
+	  Set this option to 'Y' to have the kernel ignore the bootloader
+	  or firmware command line.  Instead, the built-in command line
+	  will be used exclusively.
+
+	  If you don't know what to do here, say N.
+
+endmenu
+
 menu "Bus support"
 
 config PCI

arch/riscv/Kconfig.debug

@@ -1,37 +1,2 @@
-
-config CMDLINE_BOOL
-	bool "Built-in kernel command line"
-	help
-	  For most platforms, it is firmware or second stage bootloader
-	  that by default specifies the kernel command line options.
-	  However, it might be necessary or advantageous to either override
-	  the default kernel command line or add a few extra options to it.
-	  For such cases, this option allows hardcoding command line options
-	  directly into the kernel.
-
-	  For that, choose 'Y' here and fill in the extra boot parameters
-	  in CONFIG_CMDLINE.
-
-	  The built-in options will be concatenated to the default command
-	  line if CMDLINE_FORCE is set to 'N'. Otherwise, the default
-	  command line will be ignored and replaced by the built-in string.
-
-config CMDLINE
-	string "Built-in kernel command string"
-	depends on CMDLINE_BOOL
-	default ""
-	help
-	  Supply command-line options at build time by entering them here.
-
-config CMDLINE_FORCE
-	bool "Built-in command line overrides bootloader arguments"
-	depends on CMDLINE_BOOL
-	help
-	  Set this option to 'Y' to have the kernel ignore the bootloader
-	  or firmware command line.  Instead, the built-in command line
-	  will be used exclusively.
-
-	  If you don't know what to do here, say N.
-
 config EARLY_PRINTK
 	def_bool y

arch/riscv/Makefile

@@ -25,33 +25,28 @@ ifeq ($(CONFIG_ARCH_RV64I),y)
 
 	KBUILD_CFLAGS += -mabi=lp64
 	KBUILD_AFLAGS += -mabi=lp64
-
-	KBUILD_CFLAGS	+= $(call cc-ifversion, -ge, 0500, -DCONFIG_ARCH_SUPPORTS_INT128)
 
-	KBUILD_MARCH = rv64im
 	KBUILD_LDFLAGS += -melf64lriscv
 else
 	BITS := 32
 	UTS_MACHINE := riscv32
 
 	KBUILD_CFLAGS += -mabi=ilp32
 	KBUILD_AFLAGS += -mabi=ilp32
-	KBUILD_MARCH = rv32im
 	KBUILD_LDFLAGS += -melf32lriscv
 endif
 
 KBUILD_CFLAGS += -Wall
 
-ifeq ($(CONFIG_RISCV_ISA_A),y)
-	KBUILD_ARCH_A = a
-endif
-ifeq ($(CONFIG_RISCV_ISA_C),y)
-	KBUILD_ARCH_C = c
-endif
-
-KBUILD_AFLAGS += -march=$(KBUILD_MARCH)$(KBUILD_ARCH_A)fd$(KBUILD_ARCH_C)
+# ISA string setting
+riscv-march-$(CONFIG_ARCH_RV32I)	:= rv32im
+riscv-march-$(CONFIG_ARCH_RV64I)	:= rv64im
+riscv-march-$(CONFIG_RISCV_ISA_A)	:= $(riscv-march-y)a
+riscv-march-$(CONFIG_FPU)		:= $(riscv-march-y)fd
+riscv-march-$(CONFIG_RISCV_ISA_C)	:= $(riscv-march-y)c
+KBUILD_CFLAGS += -march=$(subst fd,,$(riscv-march-y))
+KBUILD_AFLAGS += -march=$(riscv-march-y)
 
-KBUILD_CFLAGS += -march=$(KBUILD_MARCH)$(KBUILD_ARCH_A)$(KBUILD_ARCH_C)
 KBUILD_CFLAGS += -mno-save-restore
 KBUILD_CFLAGS += -DCONFIG_PAGE_OFFSET=$(CONFIG_PAGE_OFFSET)
 

arch/riscv/include/asm/Kbuild

@@ -13,7 +13,6 @@ generic-y += errno.h
 generic-y += exec.h
 generic-y += fb.h
 generic-y += fcntl.h
-generic-y += futex.h
 generic-y += hardirq.h
 generic-y += hash.h
 generic-y += hw_irq.h

arch/riscv/include/asm/futex.h

@@ -0,0 +1,128 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2006  Ralf Baechle (ralf@linux-mips.org)
+ * Copyright (c) 2018  Jim Wilson (jimw@sifive.com)
+ */
+
+#ifndef _ASM_FUTEX_H
+#define _ASM_FUTEX_H
+
+#ifndef CONFIG_RISCV_ISA_A
+/*
+ * Use the generic interrupt disabling versions if the A extension
+ * is not supported.
+ */
+#ifdef CONFIG_SMP
+#error "Can't support generic futex calls without A extension on SMP"
+#endif
+#include <asm-generic/futex.h>
+
+#else /* CONFIG_RISCV_ISA_A */
+
+#include <linux/futex.h>
+#include <linux/uaccess.h>
+#include <linux/errno.h>
+#include <asm/asm.h>
+
+#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)	\
+{								\
+	uintptr_t tmp;						\
+	__enable_user_access();					\
+	__asm__ __volatile__ (					\
+	"1:	" insn "				\n"	\
+	"2:						\n"	\
+	"	.section .fixup,\"ax\"			\n"	\
+	"	.balign 4				\n"	\
+	"3:	li %[r],%[e]				\n"	\
+	"	jump 2b,%[t]				\n"	\
+	"	.previous				\n"	\
+	"	.section __ex_table,\"a\"		\n"	\
+	"	.balign " RISCV_SZPTR "			\n"	\
+	"	" RISCV_PTR " 1b, 3b			\n"	\
+	"	.previous				\n"	\
+	: [r] "+r" (ret), [ov] "=&r" (oldval),			\
+	  [u] "+m" (*uaddr), [t] "=&r" (tmp)			\
+	: [op] "Jr" (oparg), [e] "i" (-EFAULT)			\
+	: "memory");						\
+	__disable_user_access();				\
+}
+
+static inline int
+arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr)
+{
+	int oldval = 0, ret = 0;
+
+	pagefault_disable();
+
+	switch (op) {
+	case FUTEX_OP_SET:
+		__futex_atomic_op("amoswap.w.aqrl %[ov],%z[op],%[u]",
+				  ret, oldval, uaddr, oparg);
+		break;
+	case FUTEX_OP_ADD:
+		__futex_atomic_op("amoadd.w.aqrl %[ov],%z[op],%[u]",
+				  ret, oldval, uaddr, oparg);
+		break;
+	case FUTEX_OP_OR:
+		__futex_atomic_op("amoor.w.aqrl %[ov],%z[op],%[u]",
+				  ret, oldval, uaddr, oparg);
+		break;
+	case FUTEX_OP_ANDN:
+		__futex_atomic_op("amoand.w.aqrl %[ov],%z[op],%[u]",
+				  ret, oldval, uaddr, ~oparg);
+		break;
+	case FUTEX_OP_XOR:
+		__futex_atomic_op("amoxor.w.aqrl %[ov],%z[op],%[u]",
+				  ret, oldval, uaddr, oparg);
+		break;
+	default:
+		ret = -ENOSYS;
+	}
+
+	pagefault_enable();
+
+	if (!ret)
+		*oval = oldval;
+
+	return ret;
+}
+
+static inline int
+futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
+			      u32 oldval, u32 newval)
+{
+	int ret = 0;
+	u32 val;
+	uintptr_t tmp;
+
+	if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
+		return -EFAULT;
+
+	__enable_user_access();
+	__asm__ __volatile__ (
+	"1:	lr.w.aqrl %[v],%[u]			\n"
+	"	bne %[v],%z[ov],3f			\n"
+	"2:	sc.w.aqrl %[t],%z[nv],%[u]		\n"
+	"	bnez %[t],1b				\n"
+	"3:						\n"
+	"	.section .fixup,\"ax\"			\n"
+	"	.balign 4				\n"
+	"4:	li %[r],%[e]				\n"
+	"	jump 3b,%[t]				\n"
+	"	.previous				\n"
+	"	.section __ex_table,\"a\"		\n"
+	"	.balign " RISCV_SZPTR "			\n"
+	"	" RISCV_PTR " 1b, 4b			\n"
+	"	" RISCV_PTR " 2b, 4b			\n"
+	"	.previous				\n"
+	: [r] "+r" (ret), [v] "=&r" (val), [u] "+m" (*uaddr), [t] "=&r" (tmp)
+	: [ov] "Jr" (oldval), [nv] "Jr" (newval), [e] "i" (-EFAULT)
+	: "memory");
+	__disable_user_access();
+
+	*uval = val;
+	return ret;
+}
+
+#endif /* CONFIG_RISCV_ISA_A */
+#endif /* _ASM_FUTEX_H */

arch/riscv/include/asm/processor.h

@@ -88,7 +88,7 @@ static inline void wait_for_interrupt(void)
 }
 
 struct device_node;
-extern int riscv_of_processor_hart(struct device_node *node);
+int riscv_of_processor_hartid(struct device_node *node);
 
 extern void riscv_fill_hwcap(void);
 

arch/riscv/include/asm/smp.h

@@ -14,16 +14,24 @@
 #ifndef _ASM_RISCV_SMP_H
 #define _ASM_RISCV_SMP_H
 
-/* This both needs asm-offsets.h and is used when generating it. */
-#ifndef GENERATING_ASM_OFFSETS
-#include <asm/asm-offsets.h>
-#endif
-
 #include <linux/cpumask.h>
 #include <linux/irqreturn.h>
+#include <linux/thread_info.h>
+
+#define INVALID_HARTID ULONG_MAX
+/*
+ * Mapping between linux logical cpu index and hartid.
+ */
+extern unsigned long __cpuid_to_hartid_map[NR_CPUS];
+#define cpuid_to_hartid_map(cpu)    __cpuid_to_hartid_map[cpu]
+
+struct seq_file;
 
 #ifdef CONFIG_SMP
 
+/* print IPI stats */
+void show_ipi_stats(struct seq_file *p, int prec);
+
 /* SMP initialization hook for setup_arch */
 void __init setup_smp(void);
 
@@ -33,14 +41,31 @@ void arch_send_call_function_ipi_mask(struct cpumask *mask);
 /* Hook for the generic smp_call_function_single() routine. */
 void arch_send_call_function_single_ipi(int cpu);
 
+int riscv_hartid_to_cpuid(int hartid);
+void riscv_cpuid_to_hartid_mask(const struct cpumask *in, struct cpumask *out);
+
 /*
- * This is particularly ugly: it appears we can't actually get the definition
- * of task_struct here, but we need access to the CPU this task is running on.
- * Instead of using C we're using asm-offsets.h to get the current processor
- * ID.
+ * Obtains the hart ID of the currently executing task.  This relies on
+ * THREAD_INFO_IN_TASK, but we define that unconditionally.
  */
-#define raw_smp_processor_id() (*((int*)((char*)get_current() + TASK_TI_CPU)))
+#define raw_smp_processor_id() (current_thread_info()->cpu)
 
-#endif /* CONFIG_SMP */
+#else
+
+static inline void show_ipi_stats(struct seq_file *p, int prec)
+{
+}
 
+static inline int riscv_hartid_to_cpuid(int hartid)
+{
+	return 0;
+}
+
+static inline void riscv_cpuid_to_hartid_mask(const struct cpumask *in,
+					      struct cpumask *out)
+{
+	cpumask_set_cpu(cpuid_to_hartid_map(0), out);
+}
+
+#endif /* CONFIG_SMP */
 #endif /* _ASM_RISCV_SMP_H */