On Mon, May 01, 2023 at 09:54:43PM +0200, Ricardo Ribalda wrote:
On Mon, 1 May 2023 at 19:41, Conor Dooley conor@kernel.org wrote:
On Mon, May 01, 2023 at 02:38:22PM +0200, Ricardo Ribalda wrote:
If PGO is enabled, the purgatory ends up with multiple .text sections. This is not supported by kexec and crashes the system.
Cc: stable@vger.kernel.org Fixes: 930457057abe ("kernel/kexec_file.c: split up __kexec_load_puragory") Signed-off-by: Ricardo Ribalda ribalda@chromium.org
arch/riscv/purgatory/Makefile | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/arch/riscv/purgatory/Makefile b/arch/riscv/purgatory/Makefile index 5730797a6b40..cf3a44121a90 100644 --- a/arch/riscv/purgatory/Makefile +++ b/arch/riscv/purgatory/Makefile @@ -35,6 +35,11 @@ CFLAGS_sha256.o := -D__DISABLE_EXPORTS CFLAGS_string.o := -D__DISABLE_EXPORTS CFLAGS_ctype.o := -D__DISABLE_EXPORTS
+# When profile optimization is enabled, llvm emits two different overlapping +# text sections, which is not supported by kexec. Remove profile optimization +# flags. +KBUILD_CFLAGS := $(filter-out -fprofile-sample-use=% -fprofile-use=%,$(KBUILD_CFLAGS))
With the caveat of not being au fait with the workings of either PGO or of purgatory, how come you modify KBUILD_CFLAGS here rather than the purgatory specific PURGATORY_CFLAGS that are used later in the file?
Definitely, not a Makefile expert here, but when I tried this:
@@ -35,6 +40,7 @@ PURGATORY_CFLAGS_REMOVE := -mcmodel=kernel PURGATORY_CFLAGS := -mcmodel=large -ffreestanding -fno-zero-initialized-in-bss -g0 PURGATORY_CFLAGS += $(DISABLE_STACKLEAK_PLUGIN) -DDISABLE_BRANCH_PROFILING PURGATORY_CFLAGS += -fno-stack-protector +PURGATORY_CFLAGS := $(filter-out -fprofile-sample-use=% -fprofile-use=%,$(KBUILD_CFLAGS))
It did not work.
Unfortunately I am oh-so-far from an expert on this kind of thing, but I had thought that PURGATORY_CFLAGS_REMOVE was intended for this sort of purpose.
Fixes: bde971a83bbf ("KVM: arm64: nvhe: Fix build with profile optimization")
does this approach, so this is what I tried and worked.
That doesn't have a specific CFLAGS though afaict. Perhaps Nick etc have a more informed opinion here than I do, sorry.
Thanks, Conor.
# When linking purgatory.ro with -r unresolved symbols are not checked, # also link a purgatory.chk binary without -r to check for unresolved symbols. PURGATORY_LDFLAGS := -e purgatory_start -z nodefaultlib
-- 2.40.1.495.gc816e09b53d-goog
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-- Ricardo Ribalda