Josh Triplett <[email protected]> wrote: > On Tue, May 15, 2018 at 07:11:08AM -0700, Nadav Amit wrote: >> GCC considers the number of statements in inlined assembly blocks, >> according to new-lines and semicolons, as an indication to the cost of >> the block in time and space. This data is distorted by the kernel code, >> which puts information in alternative sections. As a result, the >> compiler may perform incorrect inlining and branch optimizations. >> >> In the case of objtool, this distortion is extreme, since anyhow the >> annotations of objtool are discarded during linkage. >> >> The solution is to set an assembly macro and call it from the inlinedv >> assembly block. As a result GCC considers the inline assembly block as >> a single instruction. >> >> This patch slightly increases the kernel size. >> >> text data bss dec hex filename >> 18126699 10066728 2936832 31130259 1db0293 ./vmlinux before >> 18126824 10067268 2936832 31130924 1db052c ./vmlinux after (+665) > > With what kernel config? What's the text size change for an allnoconfig?
I use my custom config and to include the drivers in the image. Other configs were not too appropriate: defconfig does not enable paravirt and allyesconfig is too heavy. There is no effect with allnoconfig on size: text data bss dec hex filename 1018441 230148 1215604 2464193 2599c1 ./vmlinux 1018441 230148 1215604 2464193 2599c1 ./vmlinux I think it is expected since CONFIG_STACK_VALIDATION is off. No? Thanks, Nadav
