iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

uml: borrow const.h techniques

Browse Source 
Suggested by Geert Uytterhoeven - use const.h to get constants that are usable
in both C and assembly.  I can't include it directly since this code can't
include kernel headers.  const.h is also for numeric constants that can be
typed by tacking a "UL" or similar on the end.  The constants here have to be
typed by casting them.

So, the relevant parts of const.h are copied here and modified in order to
allow the constants to be uncasted in assembly and casted in C.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Jeff Dike 2008-02-04 22:30:44 -08:00 committed by Linus Torvalds
parent ee56314b79
commit 4bdf8bc4a1
3 changed files with 29 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

34
arch/um/include/as-layout.h
View File

@ -10,24 +10,32 @@
#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.
* Stolen from linux/const.h, which can't be directly included since
* this is used in userspace code, which has no access to the kernel
* headers. Changed to be suitable for adding casts to the start,
* rather than "UL" to the end.
*/
#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.
/* Some constant macros are used in both assembler and
* C code. Therefore we cannot annotate them always with
* 'UL' and other type specifiers unilaterally. We
* use the following macros to deal with this.
*/
#ifdef __ASSEMBLY__
#define _AC(X, Y) (Y)
#else
#define __AC(X, Y) (X (Y))
#define _AC(X, Y) __AC(X, Y)
#endif
#define STUB_CODE _AC((unsigned long), \
UML_CONFIG_TOP_ADDR - 2 * UM_KERN_PAGE_SIZE)
#define STUB_DATA _AC((unsigned long), UML_CONFIG_TOP_ADDR - UM_KERN_PAGE_SIZE)
#define STUB_START _AC(, STUB_CODE)
#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 {

8
arch/um/sys-i386/stub.S
View File

@ -7,7 +7,7 @@
.globl batch_syscall_stub
batch_syscall_stub:
/* load pointer to first operation */
mov $(ASM_STUB_DATA+8), %esp
mov $(STUB_DATA+8), %esp
again:
/* load length of additional data */
@ -15,12 +15,12 @@ again:
/* if(length == 0) : end of list */
/* write possible 0 to header */
mov %eax, ASM_STUB_DATA+4
mov %eax, STUB_DATA+4
cmpl $0, %eax
jz done
/* save current pointer */
mov %esp, ASM_STUB_DATA+4
mov %esp, STUB_DATA+4
/* skip additional data */
add %eax, %esp
@ -46,7 +46,7 @@ again:
done:
/* save return value */
mov %eax, ASM_STUB_DATA
mov %eax, STUB_DATA
/* stop */
int3

8
arch/um/sys-x86_64/stub.S
View File

@ -8,18 +8,18 @@ syscall_stub:
/* We don't have 64-bit constants, so this constructs the address
* we need.
*/
movq $(ASM_STUB_DATA >> 32), %rbx
movq $(STUB_DATA >> 32), %rbx
salq $32, %rbx
movq $(ASM_STUB_DATA & 0xffffffff), %rcx
movq $(STUB_DATA & 0xffffffff), %rcx
or %rcx, %rbx
movq %rax, (%rbx)
int3
.globl batch_syscall_stub
batch_syscall_stub:
mov $(ASM_STUB_DATA >> 32), %rbx
mov $(STUB_DATA >> 32), %rbx
sal $32, %rbx
mov $(ASM_STUB_DATA & 0xffffffff), %rax
mov $(STUB_DATA & 0xffffffff), %rax
or %rax, %rbx
/* load pointer to first operation */
mov %rbx, %rsp