This patch set simplifies the switch_to() code, by moving the stack switch code out of line into an asm stub before calling __switch_to(). This ends up being more readable, and using the C calling convention instead of clobbering all registers improves code generation. It also allows newly forked processes to construct a special stack frame to seamlessly flow to ret_from_fork, instead of using a test and branch, or an unbalanced call/ret.
[PATCH 1/4] x86: Save return value from kernel_thread [PATCH 2/4] x86-32, kgdb: Don't use thread.ip in [PATCH 3/4] x86: Rewrite switch_to() code [PATCH 4/4] x86: Pass kernel thread parameters in fork_frame arch/x86/entry/entry_32.S | 68 +++++++++++++----- arch/x86/entry/entry_64.S | 72 +++++++++++++------ arch/x86/include/asm/processor.h | 3 - arch/x86/include/asm/switch_to.h | 137 ++++++------------------------------- arch/x86/include/asm/thread_info.h | 2 - arch/x86/kernel/asm-offsets.c | 6 ++ arch/x86/kernel/asm-offsets_32.c | 5 ++ arch/x86/kernel/asm-offsets_64.c | 5 ++ arch/x86/kernel/kgdb.c | 3 +- arch/x86/kernel/process_32.c | 19 ++--- arch/x86/kernel/process_64.c | 17 +++-- arch/x86/kernel/smpboot.c | 1 - 12 files changed, 153 insertions(+), 185 deletions(-)
