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Commit 06e727d2 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-tip 

* 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-tip:
  x86-64: Rework vsyscall emulation and add vsyscall= parameter
  x86-64: Wire up getcpu syscall
  x86: Remove unnecessary compile flag tweaks for vsyscall code
  x86-64: Add vsyscall:emulate_vsyscall trace event
  x86-64: Add user_64bit_mode paravirt op
  x86-64, xen: Enable the vvar mapping
  x86-64: Work around gold bug 13023
  x86-64: Move the "user" vsyscall segment out of the data segment.
  x86-64: Pad vDSO to a page boundary
parents e68ff9cd 3ae36655

Documentation/kernel-parameters.txt

+21 −0
Original line number Diff line number Diff line
@@ -2680,6 +2680,27 @@ bytes respectively. Such letter suffixes can also be entirely omitted. 
	vmpoff=		[KNL,S390] Perform z/VM CP command after power off.

			Format: <command>



	vsyscall=	[X86-64]

			Controls the behavior of vsyscalls (i.e. calls to

			fixed addresses of 0xffffffffff600x00 from legacy

			code).  Most statically-linked binaries and older

			versions of glibc use these calls.  Because these

			functions are at fixed addresses, they make nice

			targets for exploits that can control RIP.



			emulate     [default] Vsyscalls turn into traps and are

			            emulated reasonably safely.



			native      Vsyscalls are native syscall instructions.

			            This is a little bit faster than trapping

			            and makes a few dynamic recompilers work

			            better than they would in emulation mode.

			            It also makes exploits much easier to write.



			none        Vsyscalls don't work at all.  This makes

			            them quite hard to use for exploits but

			            might break your system.



	vt.cur_default=	[VT] Default cursor shape.

			Format: 0xCCBBAA, where AA, BB, and CC are the same as

			the parameters of the <Esc>[?A;B;Cc escape sequence;

arch/x86/include/asm/desc.h

+2 −2
Original line number Diff line number Diff line
@@ -27,8 +27,8 @@ static inline void fill_ldt(struct desc_struct *desc, const struct user_desc *in 


	desc->base2		= (info->base_addr & 0xff000000) >> 24;

	/*

	 * Don't allow setting of the lm bit. It is useless anyway

	 * because 64bit system calls require __USER_CS:

	 * Don't allow setting of the lm bit. It would confuse

	 * user_64bit_mode and would get overridden by sysret anyway.

	 */

	desc->l			= 0;

}

arch/x86/include/asm/irq_vectors.h

+0 −4
Original line number Diff line number Diff line
@@ -17,7 +17,6 @@ 
 *  Vectors   0 ...  31 : system traps and exceptions - hardcoded events

 *  Vectors  32 ... 127 : device interrupts

 *  Vector  128         : legacy int80 syscall interface

 *  Vector  204         : legacy x86_64 vsyscall emulation

 *  Vectors 129 ... INVALIDATE_TLB_VECTOR_START-1 except 204 : device interrupts

 *  Vectors INVALIDATE_TLB_VECTOR_START ... 255 : special interrupts

 *
@@ -51,9 +50,6 @@ 
#ifdef CONFIG_X86_32

# define SYSCALL_VECTOR			0x80

#endif

#ifdef CONFIG_X86_64

# define VSYSCALL_EMU_VECTOR		0xcc

#endif



/*

 * Vectors 0x30-0x3f are used for ISA interrupts.

arch/x86/include/asm/paravirt_types.h

+6 −0
Original line number Diff line number Diff line
@@ -41,6 +41,7 @@ 


#include <asm/desc_defs.h>

#include <asm/kmap_types.h>

#include <asm/pgtable_types.h>



struct page;

struct thread_struct;
@@ -63,6 +64,11 @@ struct paravirt_callee_save { 
struct pv_info {

	unsigned int kernel_rpl;

	int shared_kernel_pmd;



#ifdef CONFIG_X86_64

	u16 extra_user_64bit_cs;  /* __USER_CS if none */

#endif



	int paravirt_enabled;

	const char *name;

};

arch/x86/include/asm/ptrace.h

+19 −0
Original line number Diff line number Diff line
@@ -131,6 +131,9 @@ struct pt_regs { 
#ifdef __KERNEL__



#include <linux/init.h>

#ifdef CONFIG_PARAVIRT

#include <asm/paravirt_types.h>

#endif



struct cpuinfo_x86;

struct task_struct;
@@ -187,6 +190,22 @@ static inline int v8086_mode(struct pt_regs *regs) 
#endif

}



#ifdef CONFIG_X86_64

static inline bool user_64bit_mode(struct pt_regs *regs)

{

#ifndef CONFIG_PARAVIRT

	/*

	 * On non-paravirt systems, this is the only long mode CPL 3

	 * selector.  We do not allow long mode selectors in the LDT.

	 */

	return regs->cs == __USER_CS;

#else

	/* Headers are too twisted for this to go in paravirt.h. */

	return regs->cs == __USER_CS || regs->cs == pv_info.extra_user_64bit_cs;

#endif

}

#endif



/*

 * X86_32 CPUs don't save ss and esp if the CPU is already in kernel mode

 * when it traps.  The previous stack will be directly underneath the saved