linux/arch/x86/kernel/asm-offsets_64.c
Brian Gerst 0100301bfd sched/x86: Rewrite the switch_to() code
Move the low-level context switch code to an out-of-line asm stub instead of
using complex inline asm.  This allows constructing a new stack frame for the
child process to make it seamlessly flow to ret_from_fork without an extra
test and branch in __switch_to().  It also improves code generation for
__schedule() by using the C calling convention instead of clobbering all
registers.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1471106302-10159-5-git-send-email-brgerst@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-24 12:31:41 +02:00

72 lines
1.5 KiB
C

#ifndef __LINUX_KBUILD_H
# error "Please do not build this file directly, build asm-offsets.c instead"
#endif
#include <asm/ia32.h>
#define __SYSCALL_64(nr, sym, qual) [nr] = 1,
static char syscalls_64[] = {
#include <asm/syscalls_64.h>
};
#define __SYSCALL_I386(nr, sym, qual) [nr] = 1,
static char syscalls_ia32[] = {
#include <asm/syscalls_32.h>
};
int main(void)
{
#ifdef CONFIG_PARAVIRT
OFFSET(PV_IRQ_adjust_exception_frame, pv_irq_ops, adjust_exception_frame);
OFFSET(PV_CPU_usergs_sysret64, pv_cpu_ops, usergs_sysret64);
OFFSET(PV_CPU_swapgs, pv_cpu_ops, swapgs);
BLANK();
#endif
#define ENTRY(entry) OFFSET(pt_regs_ ## entry, pt_regs, entry)
ENTRY(bx);
ENTRY(cx);
ENTRY(dx);
ENTRY(sp);
ENTRY(bp);
ENTRY(si);
ENTRY(di);
ENTRY(r8);
ENTRY(r9);
ENTRY(r10);
ENTRY(r11);
ENTRY(r12);
ENTRY(r13);
ENTRY(r14);
ENTRY(r15);
ENTRY(flags);
BLANK();
#undef ENTRY
#define ENTRY(entry) OFFSET(saved_context_ ## entry, saved_context, entry)
ENTRY(cr0);
ENTRY(cr2);
ENTRY(cr3);
ENTRY(cr4);
ENTRY(cr8);
ENTRY(gdt_desc);
BLANK();
#undef ENTRY
OFFSET(TSS_ist, tss_struct, x86_tss.ist);
OFFSET(TSS_sp0, tss_struct, x86_tss.sp0);
BLANK();
#ifdef CONFIG_CC_STACKPROTECTOR
DEFINE(stack_canary_offset, offsetof(union irq_stack_union, stack_canary));
BLANK();
#endif
DEFINE(__NR_syscall_max, sizeof(syscalls_64) - 1);
DEFINE(NR_syscalls, sizeof(syscalls_64));
DEFINE(__NR_syscall_compat_max, sizeof(syscalls_ia32) - 1);
DEFINE(IA32_NR_syscalls, sizeof(syscalls_ia32));
return 0;
}