[PATCH 00/11] Bump the minimum supported version of LLVM to 13.0.1

[PATCH 00/11] Bump the minimum supported version of LLVM to 13.0.1

[Nathan Chancellor]

Hi all,

This series bumps the minimum supported version of LLVM for building the
kernel to 13.0.1. The first patch does the bump and all subsequent
patches clean up all the various workarounds and checks for earlier
versions.

Quoting the first patch's commit message for those that were only on CC
for the clean ups:

  When __builtin_mul_overflow() has arguments that differ in terms of
  signedness and width, LLVM may generate a libcall to __muloti4 because
  it performs the checks in terms of 65-bit multiplication. This issue
  becomes harder to hit (but still possible) after LLVM 12.0.0, which
  includes a special case for matching widths but different signs.

  To gain access to this special case, which the kernel can take advantage
  of when calls to __muloti4 appear, bump the minimum supported version of
  LLVM for building the kernel to 13.0.1. 13.0.1 was chosen because there
  is minimal impact to distribution support while allowing a few more
  workarounds to be dropped in the kernel source than if 12.0.0 were
  chosen. Looking at container images of up to date distribution versions:

    archlinux:latest              clang version 16.0.6
    debian:oldoldstable-slim      clang version 7.0.1-8+deb10u2 (tags/RELEASE_701/final)
    debian:oldstable-slim         Debian clang version 11.0.1-2
    debian:stable-slim            Debian clang version 14.0.6
    debian:testing-slim           Debian clang version 16.0.6 (19)
    debian:unstable-slim          Debian clang version 16.0.6 (19)
    fedora:38                     clang version 16.0.6 (Fedora 16.0.6-3.fc38)
    fedora:latest                 clang version 17.0.6 (Fedora 17.0.6-1.fc39)
    fedora:rawhide                clang version 17.0.6 (Fedora 17.0.6-1.fc40)
    opensuse/leap:latest          clang version 15.0.7
    opensuse/tumbleweed:latest    clang version 17.0.6
    ubuntu:focal                  clang version 10.0.0-4ubuntu1
    ubuntu:latest                 Ubuntu clang version 14.0.0-1ubuntu1.1
    ubuntu:rolling                Ubuntu clang version 16.0.6 (15)
    ubuntu:devel                  Ubuntu clang version 17.0.6 (3)

  The only distribution that gets left behind is Debian Bullseye, as the
  default version is 11.0.1; other distributions either have a newer
  version than 13.0.1 or one older than the current minimum of 11.0.0.
  Debian has easy access to more recent LLVM versions through
  apt.llvm.org, so this is not as much of a concern. There are also the
  kernel.org LLVM toolchains, which should work with distributions with
  glibc 2.28 and newer.

  Another benefit of slimming up the number of supported versions of LLVM
  for building the kernel is reducing the build capacity needed to support
  a matrix that builds with each supported version, which allows a matrix
  to reallocate the freed up build capacity towards something else, such
  as more configuration combinations.

This passes my build matrix with all supported versions.

This is based on Andrew's mm-nonmm-unstable to avoid trivial conflicts
with my series to update the LLVM links across the repository [1] but I
can easily rebase it to linux-kbuild if Masahiro would rather these
patches go through there (and defer the conflict resolution to the merge
window).

[1]: https://lore.kernel.org/20240109-update-llvm-links-v1-0-eb09b59db071@kernel.org/

---
Nathan Chancellor (11):
      kbuild: Raise the minimum supported version of LLVM to 13.0.1
      Makefile: Drop warn-stack-size plugin opt
      x86: Drop stack-alignment plugin opt
      ARM: Remove Thumb2 __builtin_thread_pointer workaround for Clang
      arm64: Kconfig: Clean up tautological LLVM version checks
      powerpc: Kconfig: Remove tautology in CONFIG_COMPAT
      riscv: Remove MCOUNT_NAME workaround
      riscv: Kconfig: Remove version dependency from CONFIG_CLANG_SUPPORTS_DYNAMIC_FTRACE
      fortify: Drop Clang version check for 12.0.1 or newer
      lib/Kconfig.debug: Update Clang version check in CONFIG_KCOV
      compiler-clang.h: Update __diag_clang() macros for minimum version bump

 Documentation/process/changes.rst |  2 +-
 Makefile                          |  8 --------
 arch/arm/include/asm/current.h    |  8 +-------
 arch/arm64/Kconfig                |  5 +----
 arch/powerpc/Kconfig              |  1 -
 arch/riscv/Kconfig                |  2 --
 arch/riscv/include/asm/ftrace.h   | 14 ++------------
 arch/riscv/kernel/mcount.S        | 10 +++++-----
 arch/x86/Makefile                 |  6 ------
 include/linux/compiler-clang.h    |  8 ++------
 lib/Kconfig.debug                 |  2 +-
 scripts/min-tool-version.sh       |  2 +-
 scripts/recordmcount.pl           |  2 +-
 security/Kconfig                  |  2 --
 14 files changed, 15 insertions(+), 57 deletions(-)
---
base-commit: 979741ebd48f75ed6d101c7290e3325340d361ff
change-id: 20240124-bump-min-llvm-ver-to-13-0-1-39f84dd36b19

Best regards,
-- 
Nathan Chancellor <nathan@kernel.org>


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[PATCH 04/11] ARM: Remove Thumb2 __builtin_thread_pointer workaround for Clang

[Nathan Chancellor]

Now that the minimum supported version of LLVM for building the kernel
has been bumped to 13.0.1, the conditional expression added to
get_current() by commit c1e42efacb9b ("ARM: 9151/1: Thumb2: avoid
__builtin_thread_pointer() on Clang") is always true, as the build will
fail during the configuration stage for older LLVM versions. Remove it,
effectively reverting the aforementioned change.

Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
Cc: linux@armlinux.org.uk
Cc: ardb@kernel.org
Cc: linux-arm-kernel@lists.infradead.org
---
 arch/arm/include/asm/current.h | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/arch/arm/include/asm/current.h b/arch/arm/include/asm/current.h
index 1e1178bf176d..5225cb1c803b 100644
--- a/arch/arm/include/asm/current.h
+++ b/arch/arm/include/asm/current.h
@@ -18,18 +18,12 @@ static __always_inline __attribute_const__ struct task_struct *get_current(void)
 {
 	struct task_struct *cur;
 
-#if __has_builtin(__builtin_thread_pointer) && \
-    defined(CONFIG_CURRENT_POINTER_IN_TPIDRURO) && \
-    !(defined(CONFIG_THUMB2_KERNEL) && \
-      defined(CONFIG_CC_IS_CLANG) && CONFIG_CLANG_VERSION < 130001)
+#if __has_builtin(__builtin_thread_pointer) && defined(CONFIG_CURRENT_POINTER_IN_TPIDRURO)
 	/*
 	 * Use the __builtin helper when available - this results in better
 	 * code, especially when using GCC in combination with the per-task
 	 * stack protector, as the compiler will recognize that it needs to
 	 * load the TLS register only once in every function.
-	 *
-	 * Clang < 13.0.1 gets this wrong for Thumb2 builds:
-	 * https://github.com/ClangBuiltLinux/linux/issues/1485
 	 */
 	cur = __builtin_thread_pointer();
 #elif defined(CONFIG_CURRENT_POINTER_IN_TPIDRURO) || defined(CONFIG_SMP)

-- 
2.43.0


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[PATCH 05/11] arm64: Kconfig: Clean up tautological LLVM version checks

[Nathan Chancellor]

Now that the minimum supported version of LLVM for building the kernel
has been bumped to 13.0.1, several conditions become tautologies, as
they will always be true because the build will fail during the
configuration stage for older LLVM versions. Drop them, as they are
unnecessary.

Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
Cc: catalin.marinas@arm.com
Cc: will@kernel.org
Cc: mark.rutland@arm.com
Cc: linux-arm-kernel@lists.infradead.org
---
 arch/arm64/Kconfig | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 5a8acca4dbf4..cb34e7d780c0 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -383,7 +383,7 @@ config BUILTIN_RETURN_ADDRESS_STRIPS_PAC
 	bool
 	# Clang's __builtin_return_adddress() strips the PAC since 12.0.0
 	# https://github.com/llvm/llvm-project/commit/2a96f47c5ffca84cd774ad402cacd137f4bf45e2
-	default y if CC_IS_CLANG && (CLANG_VERSION >= 120000)
+	default y if CC_IS_CLANG
 	# GCC's __builtin_return_address() strips the PAC since 11.1.0,
 	# and this was backported to 10.2.0, 9.4.0, 8.5.0, but not earlier
 	# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94891
@@ -1387,7 +1387,6 @@ choice
 
 config CPU_BIG_ENDIAN
 	bool "Build big-endian kernel"
-	depends on !LD_IS_LLD || LLD_VERSION >= 130000
 	# https://github.com/llvm/llvm-project/commit/1379b150991f70a5782e9a143c2ba5308da1161c
 	depends on AS_IS_GNU || AS_VERSION >= 150000
 	help
@@ -2018,8 +2017,6 @@ config ARM64_BTI_KERNEL
 	depends on !CC_IS_GCC || GCC_VERSION >= 100100
 	# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106671
 	depends on !CC_IS_GCC
-	# https://github.com/llvm/llvm-project/commit/a88c722e687e6780dcd6a58718350dc76fcc4cc9
-	depends on !CC_IS_CLANG || CLANG_VERSION >= 120000
 	depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_ARGS)
 	help
 	  Build the kernel with Branch Target Identification annotations

-- 
2.43.0


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Re: [PATCH 00/11] Bump the minimum supported version of LLVM to 13.0.1

[Kees Cook]

On Thu, Jan 25, 2024 at 03:55:06PM -0700, Nathan Chancellor wrote:
> Hi all,
> 
> This series bumps the minimum supported version of LLVM for building the
> kernel to 13.0.1. The first patch does the bump and all subsequent
> patches clean up all the various workarounds and checks for earlier
> versions.
> 
> Quoting the first patch's commit message for those that were only on CC
> for the clean ups:
> 
>   When __builtin_mul_overflow() has arguments that differ in terms of
>   signedness and width, LLVM may generate a libcall to __muloti4 because
>   it performs the checks in terms of 65-bit multiplication. This issue
>   becomes harder to hit (but still possible) after LLVM 12.0.0, which
>   includes a special case for matching widths but different signs.
> 
>   To gain access to this special case, which the kernel can take advantage
>   of when calls to __muloti4 appear, bump the minimum supported version of
>   LLVM for building the kernel to 13.0.1. 13.0.1 was chosen because there
>   is minimal impact to distribution support while allowing a few more
>   workarounds to be dropped in the kernel source than if 12.0.0 were
>   chosen. Looking at container images of up to date distribution versions:
> 
>     archlinux:latest              clang version 16.0.6
>     debian:oldoldstable-slim      clang version 7.0.1-8+deb10u2 (tags/RELEASE_701/final)
>     debian:oldstable-slim         Debian clang version 11.0.1-2
>     debian:stable-slim            Debian clang version 14.0.6
>     debian:testing-slim           Debian clang version 16.0.6 (19)
>     debian:unstable-slim          Debian clang version 16.0.6 (19)
>     fedora:38                     clang version 16.0.6 (Fedora 16.0.6-3.fc38)
>     fedora:latest                 clang version 17.0.6 (Fedora 17.0.6-1.fc39)
>     fedora:rawhide                clang version 17.0.6 (Fedora 17.0.6-1.fc40)
>     opensuse/leap:latest          clang version 15.0.7
>     opensuse/tumbleweed:latest    clang version 17.0.6
>     ubuntu:focal                  clang version 10.0.0-4ubuntu1
>     ubuntu:latest                 Ubuntu clang version 14.0.0-1ubuntu1.1
>     ubuntu:rolling                Ubuntu clang version 16.0.6 (15)
>     ubuntu:devel                  Ubuntu clang version 17.0.6 (3)
> 
>   The only distribution that gets left behind is Debian Bullseye, as the
>   default version is 11.0.1; other distributions either have a newer
>   version than 13.0.1 or one older than the current minimum of 11.0.0.
>   Debian has easy access to more recent LLVM versions through
>   apt.llvm.org, so this is not as much of a concern. There are also the
>   kernel.org LLVM toolchains, which should work with distributions with
>   glibc 2.28 and newer.
> 
>   Another benefit of slimming up the number of supported versions of LLVM
>   for building the kernel is reducing the build capacity needed to support
>   a matrix that builds with each supported version, which allows a matrix
>   to reallocate the freed up build capacity towards something else, such
>   as more configuration combinations.
> 
> This passes my build matrix with all supported versions.
> 
> This is based on Andrew's mm-nonmm-unstable to avoid trivial conflicts
> with my series to update the LLVM links across the repository [1] but I
> can easily rebase it to linux-kbuild if Masahiro would rather these
> patches go through there (and defer the conflict resolution to the merge
> window).
> 
> [1]: https://lore.kernel.org/20240109-update-llvm-links-v1-0-eb09b59db071@kernel.org/
> 
> ---
> Nathan Chancellor (11):
>       kbuild: Raise the minimum supported version of LLVM to 13.0.1
>       Makefile: Drop warn-stack-size plugin opt
>       x86: Drop stack-alignment plugin opt
>       ARM: Remove Thumb2 __builtin_thread_pointer workaround for Clang
>       arm64: Kconfig: Clean up tautological LLVM version checks
>       powerpc: Kconfig: Remove tautology in CONFIG_COMPAT
>       riscv: Remove MCOUNT_NAME workaround
>       riscv: Kconfig: Remove version dependency from CONFIG_CLANG_SUPPORTS_DYNAMIC_FTRACE
>       fortify: Drop Clang version check for 12.0.1 or newer
>       lib/Kconfig.debug: Update Clang version check in CONFIG_KCOV
>       compiler-clang.h: Update __diag_clang() macros for minimum version bump
> 
>  Documentation/process/changes.rst |  2 +-
>  Makefile                          |  8 --------
>  arch/arm/include/asm/current.h    |  8 +-------
>  arch/arm64/Kconfig                |  5 +----
>  arch/powerpc/Kconfig              |  1 -
>  arch/riscv/Kconfig                |  2 --
>  arch/riscv/include/asm/ftrace.h   | 14 ++------------
>  arch/riscv/kernel/mcount.S        | 10 +++++-----
>  arch/x86/Makefile                 |  6 ------
>  include/linux/compiler-clang.h    |  8 ++------
>  lib/Kconfig.debug                 |  2 +-
>  scripts/min-tool-version.sh       |  2 +-
>  scripts/recordmcount.pl           |  2 +-
>  security/Kconfig                  |  2 --
>  14 files changed, 15 insertions(+), 57 deletions(-)
> ---
> base-commit: 979741ebd48f75ed6d101c7290e3325340d361ff
> change-id: 20240124-bump-min-llvm-ver-to-13-0-1-39f84dd36b19
> 
> Best regards,
> -- 
> Nathan Chancellor <nathan@kernel.org>
> 

Yes, please. :) This looks reasonable -- I appreciate the review of
default Clang versions across distros!

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook

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Re: [PATCH 04/11] ARM: Remove Thumb2 __builtin_thread_pointer workaround for Clang

[Ard Biesheuvel]

On Thu, 25 Jan 2024 at 23:56, Nathan Chancellor <nathan@kernel.org> wrote:
>
> Now that the minimum supported version of LLVM for building the kernel
> has been bumped to 13.0.1, the conditional expression added to
> get_current() by commit c1e42efacb9b ("ARM: 9151/1: Thumb2: avoid
> __builtin_thread_pointer() on Clang") is always true, as the build will
> fail during the configuration stage for older LLVM versions. Remove it,
> effectively reverting the aforementioned change.
>
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>

Reviewed-by: Ard Biesheuvel <ardb@kernel.org>

> ---
> Cc: linux@armlinux.org.uk
> Cc: ardb@kernel.org
> Cc: linux-arm-kernel@lists.infradead.org
> ---
>  arch/arm/include/asm/current.h | 8 +-------
>  1 file changed, 1 insertion(+), 7 deletions(-)
>
> diff --git a/arch/arm/include/asm/current.h b/arch/arm/include/asm/current.h
> index 1e1178bf176d..5225cb1c803b 100644
> --- a/arch/arm/include/asm/current.h
> +++ b/arch/arm/include/asm/current.h
> @@ -18,18 +18,12 @@ static __always_inline __attribute_const__ struct task_struct *get_current(void)
>  {
>         struct task_struct *cur;
>
> -#if __has_builtin(__builtin_thread_pointer) && \
> -    defined(CONFIG_CURRENT_POINTER_IN_TPIDRURO) && \
> -    !(defined(CONFIG_THUMB2_KERNEL) && \
> -      defined(CONFIG_CC_IS_CLANG) && CONFIG_CLANG_VERSION < 130001)
> +#if __has_builtin(__builtin_thread_pointer) && defined(CONFIG_CURRENT_POINTER_IN_TPIDRURO)
>         /*
>          * Use the __builtin helper when available - this results in better
>          * code, especially when using GCC in combination with the per-task
>          * stack protector, as the compiler will recognize that it needs to
>          * load the TLS register only once in every function.
> -        *
> -        * Clang < 13.0.1 gets this wrong for Thumb2 builds:
> -        * https://github.com/ClangBuiltLinux/linux/issues/1485
>          */
>         cur = __builtin_thread_pointer();
>  #elif defined(CONFIG_CURRENT_POINTER_IN_TPIDRURO) || defined(CONFIG_SMP)
>
> --
> 2.43.0
>

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Re: [PATCH 05/11] arm64: Kconfig: Clean up tautological LLVM version checks

[Mark Rutland]

On Thu, Jan 25, 2024 at 03:55:11PM -0700, Nathan Chancellor wrote:
> Now that the minimum supported version of LLVM for building the kernel
> has been bumped to 13.0.1, several conditions become tautologies, as
> they will always be true because the build will fail during the
> configuration stage for older LLVM versions. Drop them, as they are
> unnecessary.
> 
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>
> ---
> Cc: catalin.marinas@arm.com
> Cc: will@kernel.org
> Cc: mark.rutland@arm.com
> Cc: linux-arm-kernel@lists.infradead.org
> ---
>  arch/arm64/Kconfig | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
> 
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 5a8acca4dbf4..cb34e7d780c0 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -383,7 +383,7 @@ config BUILTIN_RETURN_ADDRESS_STRIPS_PAC
>  	bool
>  	# Clang's __builtin_return_adddress() strips the PAC since 12.0.0
>  	# https://github.com/llvm/llvm-project/commit/2a96f47c5ffca84cd774ad402cacd137f4bf45e2
> -	default y if CC_IS_CLANG && (CLANG_VERSION >= 120000)
> +	default y if CC_IS_CLANG
>  	# GCC's __builtin_return_address() strips the PAC since 11.1.0,
>  	# and this was backported to 10.2.0, 9.4.0, 8.5.0, but not earlier
>  	# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94891
> @@ -1387,7 +1387,6 @@ choice
>  
>  config CPU_BIG_ENDIAN
>  	bool "Build big-endian kernel"
> -	depends on !LD_IS_LLD || LLD_VERSION >= 130000
>  	# https://github.com/llvm/llvm-project/commit/1379b150991f70a5782e9a143c2ba5308da1161c

We can delete the URL here, since that was just to describe why this depended
upon LLVM 13+; it's weird for it to sit here on its own.

The URL above for __builtin_return_address() can stay or go; it may as well
stay since we have the comment aboout LLvm 12+ above it.

With that:

Acked-by: Mark Rutland <mark.rutland@arm.com>

Mark.

>  	depends on AS_IS_GNU || AS_VERSION >= 150000
>  	help
> @@ -2018,8 +2017,6 @@ config ARM64_BTI_KERNEL
>  	depends on !CC_IS_GCC || GCC_VERSION >= 100100
>  	# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106671
>  	depends on !CC_IS_GCC
> -	# https://github.com/llvm/llvm-project/commit/a88c722e687e6780dcd6a58718350dc76fcc4cc9
> -	depends on !CC_IS_CLANG || CLANG_VERSION >= 120000
>  	depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_ARGS)
>  	help
>  	  Build the kernel with Branch Target Identification annotations
> 
> -- 
> 2.43.0
> 

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Re: [PATCH 05/11] arm64: Kconfig: Clean up tautological LLVM version checks

[Nathan Chancellor]

On Fri, Jan 26, 2024 at 12:59:55PM +0000, Mark Rutland wrote:
> On Thu, Jan 25, 2024 at 03:55:11PM -0700, Nathan Chancellor wrote:
> > Now that the minimum supported version of LLVM for building the kernel
> > has been bumped to 13.0.1, several conditions become tautologies, as
> > they will always be true because the build will fail during the
> > configuration stage for older LLVM versions. Drop them, as they are
> > unnecessary.
> > 
> > Signed-off-by: Nathan Chancellor <nathan@kernel.org>
> > ---
> > Cc: catalin.marinas@arm.com
> > Cc: will@kernel.org
> > Cc: mark.rutland@arm.com
> > Cc: linux-arm-kernel@lists.infradead.org
> > ---
> >  arch/arm64/Kconfig | 5 +----
> >  1 file changed, 1 insertion(+), 4 deletions(-)
> > 
> > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> > index 5a8acca4dbf4..cb34e7d780c0 100644
> > --- a/arch/arm64/Kconfig
> > +++ b/arch/arm64/Kconfig
> > @@ -383,7 +383,7 @@ config BUILTIN_RETURN_ADDRESS_STRIPS_PAC
> >  	bool
> >  	# Clang's __builtin_return_adddress() strips the PAC since 12.0.0
> >  	# https://github.com/llvm/llvm-project/commit/2a96f47c5ffca84cd774ad402cacd137f4bf45e2
> > -	default y if CC_IS_CLANG && (CLANG_VERSION >= 120000)
> > +	default y if CC_IS_CLANG
> >  	# GCC's __builtin_return_address() strips the PAC since 11.1.0,
> >  	# and this was backported to 10.2.0, 9.4.0, 8.5.0, but not earlier
> >  	# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94891
> > @@ -1387,7 +1387,6 @@ choice
> >  
> >  config CPU_BIG_ENDIAN
> >  	bool "Build big-endian kernel"
> > -	depends on !LD_IS_LLD || LLD_VERSION >= 130000
> >  	# https://github.com/llvm/llvm-project/commit/1379b150991f70a5782e9a143c2ba5308da1161c
> 
> We can delete the URL here, since that was just to describe why this depended
> upon LLVM 13+; it's weird for it to sit here on its own.

I think this is the URL for the fix for the problem brought up by
commit 146a15b87335 ("arm64: Restrict CPU_BIG_ENDIAN to GNU as or LLVM
IAS 15.x or newer"), so I think it should stay? It does not look like I
ever added a link or context for the LLD line, I definitely should have.

> The URL above for __builtin_return_address() can stay or go; it may as well
> stay since we have the comment aboout LLvm 12+ above it.

That's the conclusion I came to as well.

Thanks a lot for taking a look!

Cheers,
Nathan

> With that:
> 
> Acked-by: Mark Rutland <mark.rutland@arm.com>
> 
> Mark.
> 
> >  	depends on AS_IS_GNU || AS_VERSION >= 150000
> >  	help
> > @@ -2018,8 +2017,6 @@ config ARM64_BTI_KERNEL
> >  	depends on !CC_IS_GCC || GCC_VERSION >= 100100
> >  	# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106671
> >  	depends on !CC_IS_GCC
> > -	# https://github.com/llvm/llvm-project/commit/a88c722e687e6780dcd6a58718350dc76fcc4cc9
> > -	depends on !CC_IS_CLANG || CLANG_VERSION >= 120000
> >  	depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_ARGS)
> >  	help
> >  	  Build the kernel with Branch Target Identification annotations
> > 
> > -- 
> > 2.43.0
> > 
> 

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Re: [PATCH 05/11] arm64: Kconfig: Clean up tautological LLVM version checks

[Mark Rutland]

On Fri, Jan 26, 2024 at 09:10:25AM -0700, Nathan Chancellor wrote:
> On Fri, Jan 26, 2024 at 12:59:55PM +0000, Mark Rutland wrote:
> > On Thu, Jan 25, 2024 at 03:55:11PM -0700, Nathan Chancellor wrote:
> > >  config CPU_BIG_ENDIAN
> > >  	bool "Build big-endian kernel"
> > > -	depends on !LD_IS_LLD || LLD_VERSION >= 130000
> > >  	# https://github.com/llvm/llvm-project/commit/1379b150991f70a5782e9a143c2ba5308da1161c
> > 
> > We can delete the URL here, since that was just to describe why this depended
> > upon LLVM 13+; it's weird for it to sit here on its own.
> 
> I think this is the URL for the fix for the problem brought up by
> commit 146a15b87335 ("arm64: Restrict CPU_BIG_ENDIAN to GNU as or LLVM
> IAS 15.x or newer"), so I think it should stay? It does not look like I
> ever added a link or context for the LLD line, I definitely should have.

Whoops; I clearly misread that, and yes it should stay.

Sorry about that; for the patch as-is:

Acked-by: Mark Rutland <mark.rutland@arm.com>

Mark.

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Re: [PATCH 00/11] Bump the minimum supported version of LLVM to 13.0.1

[patchwork-bot+linux-riscv]

Hello:

This series was applied to riscv/linux.git (fixes)
by Andrew Morton <akpm@linux-foundation.org>:

On Thu, 25 Jan 2024 15:55:06 -0700 you wrote:
> Hi all,
> 
> This series bumps the minimum supported version of LLVM for building the
> kernel to 13.0.1. The first patch does the bump and all subsequent
> patches clean up all the various workarounds and checks for earlier
> versions.
> 
> [...]

Here is the summary with links:
  - [07/11] riscv: Remove MCOUNT_NAME workaround
    https://git.kernel.org/riscv/c/de5f3984664e
  - [08/11] riscv: Kconfig: Remove version dependency from CONFIG_CLANG_SUPPORTS_DYNAMIC_FTRACE
    https://git.kernel.org/riscv/c/a38d97181271

You are awesome, thank you!
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