Index: head/sys/conf/kern.mk
===================================================================
--- head/sys/conf/kern.mk	(revision 352033)
+++ head/sys/conf/kern.mk	(revision 352034)
@@ -1,298 +1,308 @@
 # $FreeBSD$
 
 #
 # Warning flags for compiling the kernel and components of the kernel:
 #
 CWARNFLAGS?=	-Wall -Wredundant-decls -Wnested-externs -Wstrict-prototypes \
 		-Wmissing-prototypes -Wpointer-arith -Wcast-qual \
 		-Wundef -Wno-pointer-sign ${FORMAT_EXTENSIONS} \
 		-Wmissing-include-dirs -fdiagnostics-show-option \
 		-Wno-unknown-pragmas \
 		${CWARNEXTRA}
 #
 # The following flags are next up for working on:
 #	-Wextra
 
 # Disable a few warnings for clang, since there are several places in the
 # kernel where fixing them is more trouble than it is worth, or where there is
 # a false positive.
 .if ${COMPILER_TYPE} == "clang"
 NO_WCONSTANT_CONVERSION=	-Wno-error-constant-conversion
 NO_WSHIFT_COUNT_NEGATIVE=	-Wno-shift-count-negative
 NO_WSHIFT_COUNT_OVERFLOW=	-Wno-shift-count-overflow
 NO_WSELF_ASSIGN=		-Wno-self-assign
 NO_WUNNEEDED_INTERNAL_DECL=	-Wno-error-unneeded-internal-declaration
 NO_WSOMETIMES_UNINITIALIZED=	-Wno-error-sometimes-uninitialized
 NO_WCAST_QUAL=			-Wno-error-cast-qual
 NO_WTAUTOLOGICAL_POINTER_COMPARE= -Wno-tautological-pointer-compare
 # Several other warnings which might be useful in some cases, but not severe
 # enough to error out the whole kernel build.  Display them anyway, so there is
 # some incentive to fix them eventually.
 CWARNEXTRA?=	-Wno-error-tautological-compare -Wno-error-empty-body \
 		-Wno-error-parentheses-equality -Wno-error-unused-function \
 		-Wno-error-pointer-sign
 .if ${COMPILER_VERSION} >= 30700
 CWARNEXTRA+=	-Wno-error-shift-negative-value
 .endif
 .if ${COMPILER_VERSION} >= 40000
 CWARNEXTRA+=	-Wno-address-of-packed-member
 .endif
 .endif
 
 .if ${COMPILER_TYPE} == "gcc"
 .if ${COMPILER_VERSION} >= 40800
 # Catch-all for all the things that are in our tree, but for which we're
 # not yet ready for this compiler.
 NO_WUNUSED_BUT_SET_VARIABLE = -Wno-unused-but-set-variable
 CWARNEXTRA?=	-Wno-error=address				\
 		-Wno-error=aggressive-loop-optimizations	\
 		-Wno-error=array-bounds				\
 		-Wno-error=attributes				\
 		-Wno-error=cast-qual				\
 		-Wno-error=enum-compare				\
 		-Wno-error=inline				\
 		-Wno-error=maybe-uninitialized			\
 		-Wno-error=overflow				\
 		-Wno-error=sequence-point			\
 		-Wno-unused-but-set-variable
 .if ${COMPILER_VERSION} >= 60100
 CWARNEXTRA+=	-Wno-error=misleading-indentation		\
 		-Wno-error=nonnull-compare			\
 		-Wno-error=shift-overflow			\
 		-Wno-error=tautological-compare
 .endif
 .if ${COMPILER_VERSION} >= 70200
 CWARNEXTRA+=	-Wno-error=memset-elt-size
 .endif
 .if ${COMPILER_VERSION} >= 80000
 CWARNEXTRA+=	-Wno-error=packed-not-aligned
 .endif
 .else
 # For gcc 4.2, eliminate the too-often-wrong warnings about uninitialized vars.
 CWARNEXTRA?=	-Wno-uninitialized
 # GCC 4.2 doesn't have -Wno-error=cast-qual, so just disable the warning for
 # the few files that are already known to generate cast-qual warnings.
 NO_WCAST_QUAL= -Wno-cast-qual
 NO_WNONNULL=	-Wno-nonnull
 .endif
 .endif
 
 # This warning is utter nonsense
 CWARNFLAGS+=	-Wno-format-zero-length
 
 # External compilers may not support our format extensions.  Allow them
 # to be disabled.  WARNING: format checking is disabled in this case.
 .if ${MK_FORMAT_EXTENSIONS} == "no"
 FORMAT_EXTENSIONS=	-Wno-format
 .elif ${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} >= 30600
 FORMAT_EXTENSIONS=	-D__printf__=__freebsd_kprintf__
 .else
 FORMAT_EXTENSIONS=	-fformat-extensions
 .endif
 
 #
 # On i386, do not align the stack to 16-byte boundaries.  Otherwise GCC 2.95
 # and above adds code to the entry and exit point of every function to align the
 # stack to 16-byte boundaries -- thus wasting approximately 12 bytes of stack
 # per function call.  While the 16-byte alignment may benefit micro benchmarks,
 # it is probably an overall loss as it makes the code bigger (less efficient
 # use of code cache tag lines) and uses more stack (less efficient use of data
 # cache tag lines).  Explicitly prohibit the use of FPU, SSE and other SIMD
 # operations inside the kernel itself.  These operations are exclusively
 # reserved for user applications.
 #
 # gcc:
 # Setting -mno-mmx implies -mno-3dnow
 # Setting -mno-sse implies -mno-sse2, -mno-sse3 and -mno-ssse3
 #
 # clang:
 # Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa
 # Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42
 #
 .if ${MACHINE_CPUARCH} == "i386"
 CFLAGS.gcc+=	-mno-align-long-strings -mpreferred-stack-boundary=2
 CFLAGS.clang+=	-mno-aes -mno-avx
 CFLAGS+=	-mno-mmx -mno-sse -msoft-float
 INLINE_LIMIT?=	8000
 .endif
 
 .if ${MACHINE_CPUARCH} == "arm"
 INLINE_LIMIT?=	8000
 .endif
 
 .if ${MACHINE_CPUARCH} == "aarch64"
 # We generally don't want fpu instructions in the kernel.
 CFLAGS += -mgeneral-regs-only
 # Reserve x18 for pcpu data
 CFLAGS += -ffixed-x18
 INLINE_LIMIT?=	8000
 .endif
 
+#
+# For RISC-V we specify the soft-float ABI (lp64) to avoid the use of floating
+# point registers within the kernel. We also specify the "medium" code model,
+# which generates code suitable for a 2GiB addressing range located at any
+# offset, allowing modules to be located anywhere in the 64-bit address space.
+# Note that clang and GCC refer to this code model as "medium" and "medany"
+# respectively.
+#
 .if ${MACHINE_CPUARCH} == "riscv"
-CFLAGS.gcc+=	-mcmodel=medany -march=rv64imafdc -mabi=lp64
+CFLAGS+=	-march=rv64imafdc -mabi=lp64
+CFLAGS.clang+=	-mcmodel=medium
+CFLAGS.gcc+=	-mcmodel=medany
 INLINE_LIMIT?=	8000
 .endif
 
 #
 # For sparc64 we want the medany code model so modules may be located
 # anywhere in the 64-bit address space.  We also tell GCC to use floating
 # point emulation.  This avoids using floating point registers for integer
 # operations which it has a tendency to do.
 #
 .if ${MACHINE_CPUARCH} == "sparc64"
 CFLAGS.clang+=	-mcmodel=large -fno-dwarf2-cfi-asm
 CFLAGS.gcc+=	-mcmodel=medany -msoft-float
 INLINE_LIMIT?=	15000
 .endif
 
 #
 # For AMD64, we explicitly prohibit the use of FPU, SSE and other SIMD
 # operations inside the kernel itself.  These operations are exclusively
 # reserved for user applications.
 #
 # gcc:
 # Setting -mno-mmx implies -mno-3dnow
 # Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3 and -mfpmath=387
 #
 # clang:
 # Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa
 # Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42
 # (-mfpmath= is not supported)
 #
 .if ${MACHINE_CPUARCH} == "amd64"
 CFLAGS.clang+=	-mno-aes -mno-avx
 CFLAGS+=	-mcmodel=kernel -mno-red-zone -mno-mmx -mno-sse -msoft-float \
 		-fno-asynchronous-unwind-tables
 INLINE_LIMIT?=	8000
 .endif
 
 #
 # For PowerPC we tell gcc to use floating point emulation.  This avoids using
 # floating point registers for integer operations which it has a tendency to do.
 # Also explicitly disable Altivec instructions inside the kernel.
 #
 .if ${MACHINE_CPUARCH} == "powerpc"
 CFLAGS+=	-mno-altivec -msoft-float
 INLINE_LIMIT?=	15000
 .endif
 
 .if ${MACHINE_ARCH} == "powerpcspe"
 CFLAGS.gcc+=	-mno-spe
 .endif
 
 #
 # Use dot symbols (or, better, the V2 ELF ABI) on powerpc64 to make
 # DDB happy. ELFv2, if available, has some other efficiency benefits.
 #
 .if ${MACHINE_ARCH} == "powerpc64"
 .if ${COMPILER_VERSION} >= 40900
 CFLAGS.gcc+=	-mabi=elfv2
 .else
 CFLAGS.gcc+=	-mcall-aixdesc
 .endif
 CFLAGS.clang+=	-mabi=elfv2
 .endif
 
 #
 # For MIPS we also tell gcc to use floating point emulation
 #
 .if ${MACHINE_CPUARCH} == "mips"
 CFLAGS+=	-msoft-float
 INLINE_LIMIT?=	8000
 .endif
 
 #
 # GCC 3.0 and above like to do certain optimizations based on the
 # assumption that the program is linked against libc.  Stop this.
 #
 CFLAGS+=	-ffreestanding
 
 #
 # The C standard leaves signed integer overflow behavior undefined.
 # gcc and clang opimizers take advantage of this.  The kernel makes
 # use of signed integer wraparound mechanics so we need the compiler
 # to treat it as a wraparound and not take shortcuts.
 #
 CFLAGS+=	-fwrapv
 
 #
 # GCC SSP support
 #
 .if ${MK_SSP} != "no" && \
     ${MACHINE_CPUARCH} != "arm" && ${MACHINE_CPUARCH} != "mips"
 CFLAGS+=	-fstack-protector
 .endif
 
 #
 # Retpoline speculative execution vulnerability mitigation (CVE-2017-5715)
 #
 .if defined(COMPILER_FEATURES) && ${COMPILER_FEATURES:Mretpoline} != "" && \
     ${MK_KERNEL_RETPOLINE} != "no"
 CFLAGS+=	-mretpoline
 .endif
 
 #
 # Add -gdwarf-2 when compiling -g. The default starting in clang v3.4
 # and gcc 4.8 is to generate DWARF version 4. However, our tools don't
 # cope well with DWARF 4, so force it to genereate DWARF2, which they
 # understand. Do this unconditionally as it is harmless when not needed,
 # but critical for these newer versions.
 #
 .if ${CFLAGS:M-g} != "" && ${CFLAGS:M-gdwarf*} == ""
 CFLAGS+=	-gdwarf-2
 .endif
 
 CFLAGS+= ${CWARNFLAGS:M*} ${CWARNFLAGS.${.IMPSRC:T}}
 CFLAGS+= ${CFLAGS.${COMPILER_TYPE}} ${CFLAGS.${.IMPSRC:T}}
 
 # Tell bmake not to mistake standard targets for things to be searched for
 # or expect to ever be up-to-date.
 PHONY_NOTMAIN = afterdepend afterinstall all beforedepend beforeinstall \
 		beforelinking build build-tools buildfiles buildincludes \
 		checkdpadd clean cleandepend cleandir cleanobj configure \
 		depend distclean distribute exe \
 		html includes install installfiles installincludes \
 		obj objlink objs objwarn \
 		realinstall regress \
 		tags whereobj
 
 .PHONY: ${PHONY_NOTMAIN}
 .NOTMAIN: ${PHONY_NOTMAIN}
 
 CSTD=		c99
 
 .if ${CSTD} == "k&r"
 CFLAGS+=        -traditional
 .elif ${CSTD} == "c89" || ${CSTD} == "c90"
 CFLAGS+=        -std=iso9899:1990
 .elif ${CSTD} == "c94" || ${CSTD} == "c95"
 CFLAGS+=        -std=iso9899:199409
 .elif ${CSTD} == "c99"
 CFLAGS+=        -std=iso9899:1999
 .else # CSTD
 CFLAGS+=        -std=${CSTD}
 .endif # CSTD
 
 # Set target-specific linker emulation name.
 LD_EMULATION_aarch64=aarch64elf
 LD_EMULATION_amd64=elf_x86_64_fbsd
 LD_EMULATION_arm=armelf_fbsd
 LD_EMULATION_armv6=armelf_fbsd
 LD_EMULATION_armv7=armelf_fbsd
 LD_EMULATION_i386=elf_i386_fbsd
 LD_EMULATION_mips= elf32btsmip_fbsd
 LD_EMULATION_mipshf= elf32btsmip_fbsd
 LD_EMULATION_mips64= elf64btsmip_fbsd
 LD_EMULATION_mips64hf= elf64btsmip_fbsd
 LD_EMULATION_mipsel= elf32ltsmip_fbsd
 LD_EMULATION_mipselhf= elf32ltsmip_fbsd
 LD_EMULATION_mips64el= elf64ltsmip_fbsd
 LD_EMULATION_mips64elhf= elf64ltsmip_fbsd
 LD_EMULATION_mipsn32= elf32btsmipn32_fbsd
 LD_EMULATION_mipsn32el= elf32btsmipn32_fbsd   # I don't think this is a thing that works
 LD_EMULATION_powerpc= elf32ppc_fbsd
 LD_EMULATION_powerpcspe= elf32ppc_fbsd
 LD_EMULATION_powerpc64= elf64ppc_fbsd
 LD_EMULATION_riscv64= elf64lriscv
 LD_EMULATION_sparc64= elf64_sparc_fbsd
 LD_EMULATION=${LD_EMULATION_${MACHINE_ARCH}}