Messages in this thread Patch in this message | | | From | Will Deacon <> | Subject | [PATCH] Partially revert "compiler: enable CONFIG_OPTIMIZE_INLINING forcibly" | Date | Mon, 30 Sep 2019 12:45:40 +0100 |
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This reverts commit ac7c3e4ff401b304489a031938dbeaab585bfe0a for ARM and arm64.
Building an arm64 kernel with CONFIG_OPTIMIZE_INLINING=y has been shown to violate fixed register allocations of local variables passed to inline assembly with GCC prior to version 9 which can lead to subtle failures at runtime:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91111
A very similar has been reported for 32-bit ARM as well:
https://lkml.kernel.org/r/f5c221f5749e5768c9f0d909175a14910d349456.camel@suse.de
Although GCC 9.1 appears to work for the specific case in the bugzilla above, the exact issue has not been root-caused so play safe and disable the option for now on these architectures.
Cc: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Masahiro Yamada <yamada.masahiro@socionext.com>, Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Will Deacon <will@kernel.org> --- lib/Kconfig.debug | 1 + 1 file changed, 1 insertion(+)
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 93d97f9b0157..c37c72adaeff 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -312,6 +312,7 @@ config HEADERS_CHECK config OPTIMIZE_INLINING def_bool y + depends on !(ARM || ARM64) # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91111 help This option determines if the kernel forces gcc to inline the functions developers have marked 'inline'. Doing so takes away freedom from gcc to -- 2.23.0.444.g18eeb5a265-goog
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