On 02.03.2022 16:46, Roger Pau Monné wrote: > On Wed, Mar 02, 2022 at 03:41:21PM +0100, Jan Beulich wrote: >> On 02.03.2022 14:44, Roger Pau Monne wrote: >>> @@ -292,6 +295,9 @@ SECTIONS >>> *(.data) >>> *(.data.rel) >>> *(.data.rel.*) >>> +#ifdef CONFIG_LIVEPATCH >>> + *(.data.*) >>> +#endif >>> CONSTRUCTORS >>> } PHDR(text) >>> >>> @@ -308,6 +314,9 @@ SECTIONS >>> . = ALIGN(SMP_CACHE_BYTES); >>> __per_cpu_data_end = .; >>> *(.bss) >>> +#ifdef CONFIG_LIVEPATCH >>> + *(.bss.*) >>> +#endif >> >> ... are these two really in need of being conditional? > > Will drop if you agree. I didn't want to risk introducing unwanted > changes in the !CONFIG_LIVEPATCH case.
The only "unwanted" change I can imagine here would be that we place a section which the linker would otherwise need to guess how to place, for being "orphan". >>> --- a/xen/common/Kconfig >>> +++ b/xen/common/Kconfig >>> @@ -353,7 +353,9 @@ config CRYPTO >>> config LIVEPATCH >>> bool "Live patching support" >>> default X86 >>> - depends on "$(XEN_HAS_BUILD_ID)" = "y" >>> + depends on "$(XEN_HAS_BUILD_ID)" = "y" && \ >>> + $(cc-option,-ffunction-sections) && \ >>> + $(cc-option,-fdata-sections) >> >> Is this for certain Clang versions? Gcc has been supporting this in >> 4.1.x already (didn't check when it was introduced). > > I've checked clang and it seems to be prevent in at least Clang 5, > which is likely enough? Clang5 accepts the options fine here. But that wouldn't be enough, ./README says "Clang/LLVM 3.5 or later". > I've added the check just to be on the safe side. Well, yes, if you're unsure and the old version can't be checked, then perhaps indeed better to probe. Jan
