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302f5b260c
64-bit syscalls currently have an optimization in which they are called with partial pt_regs. A small handful require full pt_regs. In the 32-bit and compat cases, I cleaned this up by forcing full pt_regs for all syscalls. The performance hit doesn't really matter as the affected system calls are fundamentally heavy and this is the 32-bit compat case. I want to clean up the 64-bit case as well, but I don't want to hurt fast path performance. To do that, I want to force the syscalls that use pt_regs onto the slow path. This will enable us to make slow path syscalls be real ABI-compliant C functions. Use the new syscall entry qualification machinery for this. 'stub_clone' is now 'stub_clone/ptregs'. The next patch will eliminate the stubs, and we'll just have 'sys_clone/ptregs'. As of this patch, two-phase entry tracing is no longer used. It has served its purpose (namely a huge speedup on some workloads prior to more general opportunistic SYSRET support), and once the dust settles I'll send patches to back it out. The implementation is heavily based on a patch from Brian Gerst: http://lkml.kernel.org/g/1449666173-15366-1-git-send-email-brgerst@gmail.com Originally-From: Brian Gerst <brgerst@gmail.com> Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Frédéric Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/b9beda88460bcefec6e7d792bd44eca9b760b0c4.1454022279.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
28 lines
919 B
C
28 lines
919 B
C
/* System call table for x86-64. */
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#include <linux/linkage.h>
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#include <linux/sys.h>
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#include <linux/cache.h>
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#include <asm/asm-offsets.h>
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#include <asm/syscall.h>
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#define __SYSCALL_64_QUAL_(sym) sym
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#define __SYSCALL_64_QUAL_ptregs(sym) ptregs_##sym
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#define __SYSCALL_64(nr, sym, qual) extern asmlinkage long __SYSCALL_64_QUAL_##qual(sym)(unsigned long, unsigned long, unsigned long, unsigned long, unsigned long, unsigned long);
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#include <asm/syscalls_64.h>
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#undef __SYSCALL_64
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#define __SYSCALL_64(nr, sym, qual) [nr] = __SYSCALL_64_QUAL_##qual(sym),
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extern long sys_ni_syscall(unsigned long, unsigned long, unsigned long, unsigned long, unsigned long, unsigned long);
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asmlinkage const sys_call_ptr_t sys_call_table[__NR_syscall_max+1] = {
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/*
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* Smells like a compiler bug -- it doesn't work
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* when the & below is removed.
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*/
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[0 ... __NR_syscall_max] = &sys_ni_syscall,
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#include <asm/syscalls_64.h>
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};
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