Merge tag 'rust-fixes-7.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux

Pull Rust fixes from Miguel Ojeda:
 "Toolchain and infrastructure:

   - Fix 'rustc-option' (the Makefile one) when cross-compiling that
     leads to build or boot failures in certain configs

   - Work around a Rust compiler bug (already fixed for Rust 1.98.0)
     thats lead to boot failures in certain configs due to missing
     'uwtable' LLVM module flags

   - Support a Rust compiler change (starting with Rust 1.98.0) in the
     unstable target specification JSON files

   - Forbid Rust + arm + KASAN configs, which do not build

  'kernel' crate:

   - Fix NOMMU build by adding a missing helper"

* tag 'rust-fixes-7.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux:
  rust: x86: support Rust >= 1.98.0 target spec
  rust: arm64: set uwtable llvm module flag for CONFIG_UNWIND_TABLES
  rust: helpers: add is_vmalloc_addr wrapper for NOMMU builds
  rust: kasan/kbuild: fix rustc-option when cross-compiling
  ARM: Do not select HAVE_RUST when KASAN is enabled

8 files changed, 31 insertions, 5 deletions

diff --git a/Makefile b/Makefile
index d8da45199699..e3aabcda1ff7 100644
--- a/Makefile
+++ b/Makefile
@@ -607,6 +607,7 @@ KBUILD_RUSTFLAGS := $(rust_common_flags) \
 		    -Crelocation-model=static \
 		    -Zfunction-sections=n \
 		    -Wclippy::float_arithmetic
+KBUILD_RUSTFLAGS_OPTION_CHKS :=
 
 KBUILD_AFLAGS_KERNEL :=
 KBUILD_CFLAGS_KERNEL :=
@@ -643,7 +644,7 @@ export KBUILD_USERCFLAGS KBUILD_USERLDFLAGS
 
 export KBUILD_CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS KBUILD_LDFLAGS
 export KBUILD_CFLAGS CFLAGS_KERNEL CFLAGS_MODULE
-export KBUILD_RUSTFLAGS RUSTFLAGS_KERNEL RUSTFLAGS_MODULE
+export KBUILD_RUSTFLAGS RUSTFLAGS_KERNEL RUSTFLAGS_MODULE KBUILD_RUSTFLAGS_OPTION_CHKS
 export KBUILD_AFLAGS AFLAGS_KERNEL AFLAGS_MODULE
 export KBUILD_AFLAGS_MODULE KBUILD_CFLAGS_MODULE KBUILD_RUSTFLAGS_MODULE KBUILD_LDFLAGS_MODULE
 export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL KBUILD_RUSTFLAGS_KERNEL
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 71fc5dd4123f..73e6647bea46 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -136,7 +136,7 @@ config ARM
 	select MMU_GATHER_RCU_TABLE_FREE if SMP && ARM_LPAE
 	select HAVE_REGS_AND_STACK_ACCESS_API
 	select HAVE_RSEQ
-	select HAVE_RUST if CPU_LITTLE_ENDIAN && CPU_32v7
+	select HAVE_RUST if CPU_LITTLE_ENDIAN && CPU_32v7 && !KASAN
 	select HAVE_STACKPROTECTOR
 	select HAVE_SYSCALL_TRACEPOINTS
 	select HAVE_UID16
diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index 73a10f65ce8b..6b005c8fef70 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -63,6 +63,9 @@ else
 KBUILD_CFLAGS	+= -fasynchronous-unwind-tables
 KBUILD_AFLAGS	+= -fasynchronous-unwind-tables
 KBUILD_RUSTFLAGS += -Cforce-unwind-tables=y -Zuse-sync-unwind=n
+# Work around rustc bug on compilers without
+# https://github.com/rust-lang/rust/pull/156973.
+KBUILD_RUSTFLAGS += $(if $(call rustc-min-version,109800),,-Zllvm_module_flag=uwtable:u32:2:max)
 endif
 
 ifeq ($(CONFIG_STACKPROTECTOR_PER_TASK),y)
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 46fec0b08487..1d526a5d2a83 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -77,6 +77,10 @@ KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx -mno-sse4a
 KBUILD_RUSTFLAGS += --target=$(objtree)/scripts/target.json
 KBUILD_RUSTFLAGS += -Ctarget-feature=-sse,-sse2,-sse3,-ssse3,-sse4.1,-sse4.2,-avx,-avx2
 
+# The target.json file is not available when invoking rustc-option, so use the
+# built-in target when checking whether flags are supported instead.
+KBUILD_RUSTFLAGS_OPTION_CHKS += --target=x86_64-unknown-none
+
 #
 # CFLAGS for compiling floating point code inside the kernel.
 #
diff --git a/arch/x86/Makefile.um b/arch/x86/Makefile.um
index 19c13afa474e..9adecd65639f 100644
--- a/arch/x86/Makefile.um
+++ b/arch/x86/Makefile.um
@@ -14,6 +14,14 @@ endif
 
 KBUILD_RUSTFLAGS += --target=$(objtree)/scripts/target.json
 
+# The target.json file is not available when invoking rustc-option, so use the
+# built-in target when checking whether flags are supported instead.
+ifeq ($(CONFIG_X86_32),y)
+KBUILD_RUSTFLAGS_OPTION_CHKS += --target=i686-unknown-linux-gnu
+else
+KBUILD_RUSTFLAGS_OPTION_CHKS += --target=x86_64-unknown-linux-gnu
+endif
+
 ifeq ($(CONFIG_X86_32),y)
 START := 0x8048000
 
diff --git a/rust/helpers/vmalloc.c b/rust/helpers/vmalloc.c
index 326b030487a2..6aed13292313 100644
--- a/rust/helpers/vmalloc.c
+++ b/rust/helpers/vmalloc.c
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 
+#include <linux/mm.h>
 #include <linux/vmalloc.h>
 
 __rust_helper void *__must_check __realloc_size(2)
@@ -8,3 +9,8 @@ rust_helper_vrealloc_node_align(const void *p, size_t size, unsigned long align,
 {
 	return vrealloc_node_align(p, size, align, flags, node);
 }
+
+__rust_helper bool rust_helper_is_vmalloc_addr(const void *x)
+{
+	return is_vmalloc_addr(x);
+}
diff --git a/scripts/Makefile.compiler b/scripts/Makefile.compiler
index ef91910de265..06bbe29c846c 100644
--- a/scripts/Makefile.compiler
+++ b/scripts/Makefile.compiler
@@ -80,7 +80,7 @@ ld-option = $(call try-run, $(LD) $(KBUILD_LDFLAGS) $(1) -v,$(1),$(2),$(3))
 # TODO: remove RUSTC_BOOTSTRAP=1 when we raise the minimum GNU Make version to 4.4
 __rustc-option = $(call try-run,\
 	echo '$(pound)![allow(missing_docs)]$(pound)![feature(no_core)]$(pound)![no_core]' | RUSTC_BOOTSTRAP=1\
-	$(1) --sysroot=/dev/null $(filter-out --sysroot=/dev/null --target=%,$(2)) $(3)\
+	$(1) --sysroot=/dev/null $(KBUILD_RUSTFLAGS_OPTION_CHKS) $(filter-out --sysroot=/dev/null --target=%target.json,$(2)) $(3)\
 	--crate-type=rlib --out-dir=$(TMPOUT) --emit=obj=- - >/dev/null,$(3),$(4))
 
 # rustc-option
diff --git a/scripts/generate_rust_target.rs b/scripts/generate_rust_target.rs
index 38b3416bb979..16f7e855e012 100644
--- a/scripts/generate_rust_target.rs
+++ b/scripts/generate_rust_target.rs
@@ -196,7 +196,9 @@ fn main() {
         }
     } else if cfg.has("X86_64") {
         ts.push("arch", "x86_64");
-        if cfg.rustc_version_atleast(1, 86, 0) {
+        if cfg.rustc_version_atleast(1, 98, 0) {
+            ts.push("rustc-abi", "softfloat");
+        } else if cfg.rustc_version_atleast(1, 86, 0) {
             ts.push("rustc-abi", "x86-softfloat");
         }
         ts.push(
@@ -236,7 +238,9 @@ fn main() {
             panic!("32-bit x86 only works under UML");
         }
         ts.push("arch", "x86");
-        if cfg.rustc_version_atleast(1, 86, 0) {
+        if cfg.rustc_version_atleast(1, 98, 0) {
+            ts.push("rustc-abi", "softfloat");
+        } else if cfg.rustc_version_atleast(1, 86, 0) {
             ts.push("rustc-abi", "x86-softfloat");
         }
         ts.push(