Commit 54ae36f2 authored by Jeff Dike's avatar Jeff Dike Committed by Linus Torvalds
Browse files

uml: fix stub address calculations 



The calculation of CONFIG_STUB_CODE and CONFIG_STUB_DATA didn't take into
account anything but 3G/1G and 2G/2G, leaving the other vmsplits out in the
cold.

I'd rather not duplicate the four known host vmsplit cases for each of these
symbols.  I'd also like to calculate them based on the highest userspace
address.

The Kconfig language seems not to allow calculation of hex constants, so I
moved this to as-layout.h.  CONFIG_STUB_CODE, CONFIG_STUB_DATA, and
CONFIG_STUB_START are now gone.  In their place are STUB_CODE, STUB_DATA, and
STUB_START in as-layout.h.

i386 and x86_64 seem to differ as to whether an unadorned constant is an int
or a long, so I cast them to unsigned long so they can be printed
consistently.  However, they are also used in stub.S, where C types don't work
so well.  So, there are ASM_ versions of these constants for use in stub.S.  I
also ifdef-ed the non-asm-friendly portion of as-layout.h.

With this in place, most of the rest of this patch is changing CONFIG_STUB_*
to STUB_*, except in stub.S, where they are changed to ASM_STUB_*.

defconfig has the old symbols deleted.

I also print these addresses out in case there is any problem mapping them on
the host.

The two stub.S files had some trailing whitespace, so that is cleaned up here.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: default avatarJeff Dike <jdike@linux.intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 605c1e57

arch/um/Kconfig.i386

+0 −14
Original line number Diff line number Diff line
@@ -65,20 +65,6 @@ config 3_LEVEL_PGTABLES 
	However, this it experimental on 32-bit architectures, so if unsure say

	N (on x86-64 it's automatically enabled, instead, as it's safe there).



config STUB_CODE

	hex

	default 0xbfffe000 if !HOST_VMSPLIT_2G

	default 0x7fffe000 if HOST_VMSPLIT_2G



config STUB_DATA

	hex

	default 0xbffff000 if !HOST_VMSPLIT_2G

	default 0x7ffff000 if HOST_VMSPLIT_2G



config STUB_START

	hex

	default STUB_CODE



config ARCH_HAS_SC_SIGNALS

	bool

	default y

arch/um/Kconfig.x86_64

+1 −13
Original line number Diff line number Diff line
@@ -17,24 +17,12 @@ config SEMAPHORE_SLEEPERS 


config TOP_ADDR

 	hex

	default 0x80000000

	default 0x7fc0000000



config 3_LEVEL_PGTABLES

       bool

       default y



config STUB_CODE

	hex

	default 0x7fbfffe000



config STUB_DATA

	hex

	default 0x7fbffff000



config STUB_START

	hex

	default STUB_CODE



config ARCH_HAS_SC_SIGNALS

	bool

	default n

arch/um/defconfig

+0 −3
Original line number Diff line number Diff line
@@ -59,9 +59,6 @@ CONFIG_SEMAPHORE_SLEEPERS=y 
# CONFIG_HOST_2G_2G is not set

CONFIG_TOP_ADDR=0xc0000000

# CONFIG_3_LEVEL_PGTABLES is not set

CONFIG_STUB_CODE=0xbfffe000

CONFIG_STUB_DATA=0xbffff000

CONFIG_STUB_START=0xbfffe000

CONFIG_ARCH_HAS_SC_SIGNALS=y

CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA=y

CONFIG_GENERIC_HWEIGHT=y

arch/um/include/as-layout.h

+24 −0
Original line number Diff line number Diff line
@@ -6,6 +6,28 @@ 
#ifndef __START_H__

#define __START_H__



#include "uml-config.h"

#include "kern_constants.h"



/*

 * Assembly doesn't want any casting, but C does, so define these

 * without casts here, and define new symbols with casts inside the C

 * section.

 */

#define ASM_STUB_CODE (UML_CONFIG_TOP_ADDR - 2 * UM_KERN_PAGE_SIZE)

#define ASM_STUB_DATA (UML_CONFIG_TOP_ADDR - UM_KERN_PAGE_SIZE)

#define ASM_STUB_START ASM_STUB_CODE



/*

 * This file is included by the assembly stubs, which just want the

 * definitions above.

 */

#ifndef __ASSEMBLY__



#define STUB_CODE ((unsigned long) ASM_STUB_CODE)

#define STUB_DATA ((unsigned long) ASM_STUB_DATA)

#define STUB_START ((unsigned long) ASM_STUB_START)



#include "sysdep/ptrace.h"



struct cpu_task {
@@ -32,3 +54,5 @@ extern int linux_main(int argc, char **argv); 
extern void (*sig_info[])(int, struct uml_pt_regs *);



#endif



#endif

arch/um/include/sysdep-i386/stub.h

+6 −5
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ 
#include <sys/mman.h>

#include <asm/ptrace.h>

#include <asm/unistd.h>

#include "as-layout.h"

#include "stub-data.h"

#include "kern_constants.h"

#include "uml-config.h"
@@ -89,12 +90,12 @@ static inline void remap_stack(int fd, unsigned long offset) 
{

	__asm__ volatile ("movl %%eax,%%ebp ; movl %0,%%eax ; int $0x80 ;"

			  "movl %7, %%ebx ; movl %%eax, (%%ebx)"

			  : : "g" (STUB_MMAP_NR), "b" (UML_CONFIG_STUB_DATA), 

			  : : "g" (STUB_MMAP_NR), "b" (STUB_DATA),

			    "c" (UM_KERN_PAGE_SIZE),

			    "d" (PROT_READ | PROT_WRITE),

			    "S" (MAP_FIXED | MAP_SHARED), "D" (fd),

			    "a" (offset),

			    "i" (&((struct stub_data *) UML_CONFIG_STUB_DATA)->err) 

			    "i" (&((struct stub_data *) STUB_DATA)->err)

			  : "memory");

}

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