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charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240823_052434_755241_D69E0AF4 X-CRM114-Status: GOOD ( 27.48 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Aug 20, 2024 at 05:13:58PM +0200, Alice Ryhl wrote: > On Tue, Aug 20, 2024 at 4:35 PM Will Deacon wrote: > > On Tue, Aug 06, 2024 at 10:01:44AM +0000, Alice Ryhl wrote: > > > diff --git a/init/Kconfig b/init/Kconfig > > > index fe76c5d0a72e..d857f6f90885 100644 > > > --- a/init/Kconfig > > > +++ b/init/Kconfig > > > @@ -1909,7 +1909,7 @@ config RUST > > > depends on !MODVERSIONS > > > depends on !GCC_PLUGINS > > > depends on !RANDSTRUCT > > > - depends on !SHADOW_CALL_STACK > > > + depends on !SHADOW_CALL_STACK || RUSTC_VERSION >= 108000 && UNWIND_PATCH_PAC_INTO_SCS > > > > Sorry, I didn't spot this in v4, but since UNWIND_PATCH_PAC_INTO_SCS is > > specific to arm64 and the only other architecture selecting > > ARCH_SUPPORTS_SHADOW_CALL_STACK is riscv, I can't help but feel it would > > be cleaner to move this logic into the arch code selecting HAVE_RUST. > > > > That is, it's up to the architecture to make sure that it has whatever > > it needs for SCS to work with Rust if it claims to support Rust. > > > > What do you think? > > The `select RUST if ...` is going to get really complicated if we > apply that rule in general. Having options here allows us to split > them across several `depends on` clauses. I'm not sure it will even > work, I had issues with cyclic Kconfig errors previously. I also don't > think it's unreasonable for the architecture to say it supports both > options when it really does support both; they are just mutually > exclusive. I also think there is value in having all of the options > that Rust doesn't work with in one place. I'm not sure I follow why this will get really complicated. Isn't it as straightforward as the diff below, or did I miss something? Will --->8 diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index a2f8ff354ca6..2f5702cb9dac 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -231,7 +231,7 @@ config ARM64 select HAVE_FUNCTION_ARG_ACCESS_API select MMU_GATHER_RCU_TABLE_FREE select HAVE_RSEQ - select HAVE_RUST if CPU_LITTLE_ENDIAN + select HAVE_RUST if RUSTC_SUPPORTS_ARM64 select HAVE_STACKPROTECTOR select HAVE_SYSCALL_TRACEPOINTS select HAVE_KPROBES @@ -265,6 +265,11 @@ config ARM64 help ARM 64-bit (AArch64) Linux support. +config RUSTC_SUPPORTS_ARM64 + bool + depends on CPU_LITTLE_ENDIAN + depends on !SHADOW_CALL_STACK || RUSTC_VERSION >= 108000 && UNWIND_PATCH_PAC_INTO_SC + config CLANG_SUPPORTS_DYNAMIC_FTRACE_WITH_ARGS def_bool CC_IS_CLANG # https://github.com/ClangBuiltLinux/linux/issues/1507 diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 0f3cd7c3a436..93858dbfefc0 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -172,7 +172,7 @@ config RISCV select HAVE_REGS_AND_STACK_ACCESS_API select HAVE_RETHOOK if !XIP_KERNEL select HAVE_RSEQ - select HAVE_RUST if 64BIT + select HAVE_RUST if 64BIT && !SHADOW_CALL_STACK select HAVE_SAMPLE_FTRACE_DIRECT select HAVE_SAMPLE_FTRACE_DIRECT_MULTI select HAVE_STACKPROTECTOR diff --git a/init/Kconfig b/init/Kconfig index 5783a0b87517..3ada33b1d681 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1902,7 +1902,6 @@ config RUST depends on !MODVERSIONS depends on !GCC_PLUGINS depends on !RANDSTRUCT - depends on !SHADOW_CALL_STACK depends on !DEBUG_INFO_BTF || PAHOLE_HAS_LANG_EXCLUDE help Enables Rust support in the kernel.