The following patch series introduces %rip-relative addressing to PER_CPU_VAR macro. Instruction with %rip-relative address operand is one byte shorter than its absolute address counterpart and is also compatible with position independent executable (-fpie) build.
The first three patches are cleanups that fix various inconsistencies throughout the assembly code. The last patch introduces (%rip) suffix and uses it for x86_64 target, resulting in a small code size decrease: text data bss dec hex filename 25510677 4386685 808388 30705750 1d48856 vmlinux-new.o 25510629 4386685 808388 30705702 1d48826 vmlinux-old.o Patch series is against current mainline and can be applied independently of the ongoing percpu work. Cc: Juergen Gross <[email protected]> Cc: Boris Ostrovsky <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Dave Hansen <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Uros Bizjak (4): x86/percpu: Use explicit segment registers in lib/cmpxchg{8,16}b_emu.S x86/percpu: Correct PER_CPU_VAR usage to include symbol and its addend x86/percpu, xen: Correct PER_CPU_VAR usage to include symbol and its addend x86/percpu: Introduce %rip-relative addressing to PER_CPU_VAR macro arch/x86/entry/calling.h | 2 +- arch/x86/entry/entry_32.S | 2 +- arch/x86/entry/entry_64.S | 2 +- arch/x86/include/asm/percpu.h | 6 ++++-- arch/x86/kernel/head_64.S | 2 +- arch/x86/lib/cmpxchg16b_emu.S | 12 ++++++------ arch/x86/lib/cmpxchg8b_emu.S | 30 +++++++++++++++++++++--------- arch/x86/xen/xen-asm.S | 10 +++++----- 8 files changed, 40 insertions(+), 26 deletions(-) -- 2.41.0
