0100301bfd
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>
72 lines
1.5 KiB
C
72 lines
1.5 KiB
C
#ifndef __LINUX_KBUILD_H
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# error "Please do not build this file directly, build asm-offsets.c instead"
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#endif
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#include <asm/ia32.h>
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#define __SYSCALL_64(nr, sym, qual) [nr] = 1,
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static char syscalls_64[] = {
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#include <asm/syscalls_64.h>
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};
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#define __SYSCALL_I386(nr, sym, qual) [nr] = 1,
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static char syscalls_ia32[] = {
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#include <asm/syscalls_32.h>
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};
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int main(void)
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{
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#ifdef CONFIG_PARAVIRT
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OFFSET(PV_IRQ_adjust_exception_frame, pv_irq_ops, adjust_exception_frame);
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OFFSET(PV_CPU_usergs_sysret64, pv_cpu_ops, usergs_sysret64);
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OFFSET(PV_CPU_swapgs, pv_cpu_ops, swapgs);
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BLANK();
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#endif
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#define ENTRY(entry) OFFSET(pt_regs_ ## entry, pt_regs, entry)
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ENTRY(bx);
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ENTRY(cx);
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ENTRY(dx);
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ENTRY(sp);
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ENTRY(bp);
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ENTRY(si);
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ENTRY(di);
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ENTRY(r8);
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ENTRY(r9);
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ENTRY(r10);
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ENTRY(r11);
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ENTRY(r12);
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ENTRY(r13);
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ENTRY(r14);
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ENTRY(r15);
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ENTRY(flags);
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BLANK();
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#undef ENTRY
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#define ENTRY(entry) OFFSET(saved_context_ ## entry, saved_context, entry)
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ENTRY(cr0);
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ENTRY(cr2);
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ENTRY(cr3);
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ENTRY(cr4);
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ENTRY(cr8);
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ENTRY(gdt_desc);
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BLANK();
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#undef ENTRY
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OFFSET(TSS_ist, tss_struct, x86_tss.ist);
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OFFSET(TSS_sp0, tss_struct, x86_tss.sp0);
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BLANK();
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#ifdef CONFIG_CC_STACKPROTECTOR
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DEFINE(stack_canary_offset, offsetof(union irq_stack_union, stack_canary));
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BLANK();
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#endif
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DEFINE(__NR_syscall_max, sizeof(syscalls_64) - 1);
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DEFINE(NR_syscalls, sizeof(syscalls_64));
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DEFINE(__NR_syscall_compat_max, sizeof(syscalls_ia32) - 1);
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DEFINE(IA32_NR_syscalls, sizeof(syscalls_ia32));
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return 0;
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}
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