kconfig: Remove the architecture specific config for Propeller

The CONFIG_PROPELLER_CLANG option currently depends on
ARCH_SUPPORTS_PROPELLER_CLANG, but this dependency seems unnecessary.

Remove ARCH_SUPPORTS_PROPELLER_CLANG and allow users to control
Propeller builds solely through CONFIG_PROPELLER_CLANG. This simplifies
the kconfig and avoids potential confusion.

Move the .llvm_bb_addr_map sections grouping to
include/asm-generic/vmlinux.lds.h.

The Propeller documentation has been updated to reflect the most
recent tool location and now includes instructions for arm64.

Contributor Acknowledgments:
  * SPE instructions: Daniel Hoekwater <hoekwater@google.com>

Signed-off-by: Rong Xu <xur@google.com>
Suggested-by: Will Deacon <will@kernel.org>
Suggested-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Yabin Cui <yabinc@google.com>
Reviewed-by: Kees Cook <kees@kernel.org>
Link: https://patch.msgid.link/20260604195612.3757860-3-xur@google.com
Signed-off-by: Nathan Chancellor <nathan@kernel.org>

diff --git a/Documentation/dev-tools/propeller.rst b/Documentation/dev-tools/propeller.rst
index 92195958e3dbcaff594f1bfb603fc9187cf3bb9c..e927319941c955a98766bffa9b348b9f9d7c5eaf 100644 (file)
--- a/Documentation/dev-tools/propeller.rst
+++ b/Documentation/dev-tools/propeller.rst
@@ -28,8 +28,10 @@ A few important notes about adopting Propeller optimization:
    and the linker(ld.lld).
 
 #. In addition to LLVM toolchain, Propeller requires a profiling
-   conversion tool: https://github.com/google/autofdo with a release
-   after v0.30.1: https://github.com/google/autofdo/releases/tag/v0.30.1.
+   conversion tool: https://github.com/google/llvm-propeller.
+
+Current supported architectures include x86/X86_64 (via LBR),
+and arm64 (via SPE).
 
 The Propeller optimization process involves the following steps:
 
@@ -124,17 +126,30 @@ Here is an example workflow for building an AutoFDO+Propeller kernel:
 
       $ perf record --pfm-event RETIRED_TAKEN_BRANCH_INSTRUCTIONS:k -a -N -b -c <count> -o <perf_file> -- <loadtest>
 
-   Note you can repeat the above steps to collect multiple <perf_file>s.
+   - For arm64 with SPE::
+     There are a few kernel features that must be enabled to collect SPE profiles on Arm.
+     Below is a list of the required features:
+
+      - CONFIG_ARM_SPE_PMU=y
+      - CONFIG_PID_IN_CONTEXTIDR=y
+      - kpti=off
+
+     Use the following command to generate SPE perf data file::
+
+      $ perf record -e 'arm_spe_0/branch_filter=1,load_filter=0,store_filter=0/' -a -N -c <count> --no-switch-events -o <perf_file> -- <loadtest>
+
+     Note you can repeat the above steps to collect multiple <perf_file>s.
 
 4) (Optional) Download the raw perf file(s) to the host machine.
 
-5) Use the create_llvm_prof tool (https://github.com/google/autofdo) to
+5) Use the generate_propeller_profiles tool (https://github.com/google/llvm-propeller) to
    generate Propeller profile. ::
 
-      $ create_llvm_prof --binary=<vmlinux> --profile=<perf_file>
-                         --format=propeller --propeller_output_module_name
-                         --out=<propeller_profile_prefix>_cc_profile.txt
-                         --propeller_symorder=<propeller_profile_prefix>_ld_profile.txt
+      $ generate_propeller_profiles \
+             --binary=<vmlinux> --profile=<perf_file> \
+             --format=propeller --propeller_output_module_name \
+             --out=<propeller_profile_prefix>_cc_profile.txt \
+             --propeller_symorder=<propeller_profile_prefix>_ld_profile.txt
 
    "<propeller_profile_prefix>" can be something like "/home/user/dir/any_string".
 
@@ -146,10 +161,20 @@ Here is an example workflow for building an AutoFDO+Propeller kernel:
    you can create a temp list file "<perf_file_list>" with each line
    containing one perf file name and run::
 
-      $ create_llvm_prof --binary=<vmlinux> --profile=@<perf_file_list>
-                         --format=propeller --propeller_output_module_name
-                         --out=<propeller_profile_prefix>_cc_profile.txt
-                         --propeller_symorder=<propeller_profile_prefix>_ld_profile.txt
+      $ generate_propeller_profiles \
+             --binary=<vmlinux> --profile=@<perf_file_list> \
+             --format=propeller --propeller_output_module_name \
+             --out=<propeller_profile_prefix>_cc_profile.txt \
+             --propeller_symorder=<propeller_profile_prefix>_ld_profile.txt
+
+   For arm64 SPE, add the option '--profiler=perf_spe', like::
+
+      $ generate_propeller_profiles  \
+             --binary=<vmlinux> --profile=<perf_file> \
+             --profiler=perf_spe \
+             --format=propeller --propeller_output_module_name \
+             --out=<propeller_profile_prefix>_cc_profile.txt \
+             --propeller_symorder=<propeller_profile_prefix>_ld_profile.txt
 
 6) Rebuild the kernel using the AutoFDO and Propeller
    profiles. ::

diff --git a/arch/Kconfig b/arch/Kconfig
index 5e878924939a908ea0033c85b9b6540a749a978f..99c2017eb51571af07cbb59d0fdeb6e9270827f5 100644 (file)
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -895,13 +895,10 @@ config AUTOFDO_CLANG
 
          If unsure, say N.
 
-config ARCH_SUPPORTS_PROPELLER_CLANG
-       bool
-
 config PROPELLER_CLANG
        bool "Enable Clang's Propeller build"
-       depends on ARCH_SUPPORTS_PROPELLER_CLANG
        depends on CC_IS_CLANG && CLANG_VERSION >= 190000
+       depends on $(cc-option,-fbasic-block-sections=list=/dev/null)
        help
          This option enables Clang’s Propeller build. When the Propeller
          profiles is specified in variable CLANG_PROPELLER_PROFILE_PREFIX

diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
index e1ac876200a3d6c10a8fcdef089e1a8a4ef8a6de..8aaf404980a7288a81ad774827a0ad7ab6647451 100644 (file)
--- a/arch/arm64/kernel/vmlinux.lds.S
+++ b/arch/arm64/kernel/vmlinux.lds.S
@@ -368,6 +368,7 @@ SECTIONS
 
        STABS_DEBUG
        DWARF_DEBUG
+       PROPELLER_DATA
        MODINFO
        ELF_DETAILS
 

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 10bf3984102e30394e2dcd568658fa42bea46ca5..b875d2f27e48c5b6b693ea340808b226cd9c88e2 100644 (file)
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -130,7 +130,6 @@ config X86
        select ARCH_SUPPORTS_LTO_CLANG
        select ARCH_SUPPORTS_LTO_CLANG_THIN
        select ARCH_SUPPORTS_RT
-       select ARCH_SUPPORTS_PROPELLER_CLANG    if X86_64
        select ARCH_USE_BUILTIN_BSWAP
        select ARCH_USE_CMPXCHG_LOCKREF         if X86_CX8
        select ARCH_USE_MEMTEST

diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index 4711a35e706cde002073b5ba6546634f9309ecee..74e336d7f9dd28738dedfa8d4d0dd7fb2550ebef 100644 (file)
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -423,10 +423,7 @@ SECTIONS
 
        STABS_DEBUG
        DWARF_DEBUG
-#ifdef CONFIG_PROPELLER_CLANG
-       .llvm_bb_addr_map : { *(.llvm_bb_addr_map) }
-#endif
-
+       PROPELLER_DATA
        MODINFO
        ELF_DETAILS
 

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 60c8c22fd3e44f5f47505742ea2ebeb920c959b7..5659f4b5a1252f4055a85545f9e1e292d2ec65bd 100644 (file)
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -1011,6 +1011,12 @@
 #define PERCPU_DECRYPTED_SECTION
 #endif
 
+#ifdef CONFIG_PROPELLER_CLANG
+#define PROPELLER_DATA                                                     \
+       .llvm_bb_addr_map : { *(.llvm_bb_addr_map) }
+#else
+#define PROPELLER_DATA
+#endif
 
 /*
  * Default discarded sections.