x86 vDSO: ia32 vdso32-syscall build

This puts the syscall version of the 32-bit vDSO in arch/x86/vdso/vdso32/
for 64-bit IA32 support.  This is not used yet, but it paves the way for
consolidating the 32-bit vDSO source and build logic all in one place.

Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/arch/x86/vdso/Makefile b/arch/x86/vdso/Makefile
index 1efe785979a2e85ce91273bb306747fded172aa7..1127c716df028d44a0b77ced2ec2ce3495264e1e 100644 (file)
--- a/arch/x86/vdso/Makefile
+++ b/arch/x86/vdso/Makefile
@@ -71,6 +71,7 @@ $(obj)/%-syms.lds: $(obj)/%.so.dbg FORCE
 #
 obj-$(VDSO32-y)                        += vdso32-syms.lds
 vdso32.so-$(CONFIG_X86_32)     += int80
+vdso32.so-$(CONFIG_COMPAT)     += syscall
 vdso32.so-$(VDSO32-y)          += sysenter
 
 CPPFLAGS_vdso32.lds = $(CPPFLAGS_vdso.lds)

diff --git a/arch/x86/vdso/vdso32/sigreturn.S b/arch/x86/vdso/vdso32/sigreturn.S
index 778f4649e32f77005823f43a14512af31ce542da..8d65a0a0eb702202d639b1844b0edbbeeddac490 100644 (file)
--- a/arch/x86/vdso/vdso32/sigreturn.S
+++ b/arch/x86/vdso/vdso32/sigreturn.S
@@ -6,9 +6,12 @@
  * routines are constant for all vsyscall implementations.
  */
 
-#include <asm/unistd.h>
+#include <asm/unistd_32.h>
 #include <asm/asm-offsets.h>
 
+#ifndef SYSCALL_ENTER_KERNEL
+#define        SYSCALL_ENTER_KERNEL    int $0x80
+#endif
 
 /* XXX
    Should these be named "_sigtramp" or something?
@@ -22,7 +25,7 @@ __kernel_sigreturn:
 .LSTART_sigreturn:
        popl %eax               /* XXX does this mean it needs unwind info? */
        movl $__NR_sigreturn, %eax
-       int $0x80
+       SYSCALL_ENTER_KERNEL
 .LEND_sigreturn:
        .size __kernel_sigreturn,.-.LSTART_sigreturn
 
@@ -32,7 +35,7 @@ __kernel_sigreturn:
 __kernel_rt_sigreturn:
 .LSTART_rt_sigreturn:
        movl $__NR_rt_sigreturn, %eax
-       int $0x80
+       SYSCALL_ENTER_KERNEL
 .LEND_rt_sigreturn:
        .size __kernel_rt_sigreturn,.-.LSTART_rt_sigreturn
        .balign 32

diff --git a/arch/x86/vdso/vdso32/syscall.S b/arch/x86/vdso/vdso32/syscall.S
new file mode 100644 (file)
index 0000000..333bfb5
--- /dev/null
+++ b/arch/x86/vdso/vdso32/syscall.S
@@ -0,0 +1,69 @@
+/*
+ * Code for the vsyscall page.  This version uses the syscall instruction.
+ */
+
+#include <asm/asm-offsets.h>
+#include <asm/segment.h>
+
+       .text
+       .globl __kernel_vsyscall
+       .type __kernel_vsyscall,@function
+__kernel_vsyscall:
+.LSTART_vsyscall:
+       push    %ebp
+.Lpush_ebp:
+       movl    %ecx, %ebp
+       syscall
+       movl    $__USER32_DS, %ecx
+       movl    %ecx, %ss
+       movl    %ebp, %ecx
+       popl    %ebp
+.Lpop_ebp:
+       ret
+.LEND_vsyscall:
+       .size __kernel_vsyscall,.-.LSTART_vsyscall
+
+       .section .eh_frame,"a",@progbits
+.LSTARTFRAME:
+       .long .LENDCIE-.LSTARTCIE
+.LSTARTCIE:
+       .long 0                 /* CIE ID */
+       .byte 1                 /* Version number */
+       .string "zR"            /* NUL-terminated augmentation string */
+       .uleb128 1              /* Code alignment factor */
+       .sleb128 -4             /* Data alignment factor */
+       .byte 8                 /* Return address register column */
+       .uleb128 1              /* Augmentation value length */
+       .byte 0x1b              /* DW_EH_PE_pcrel|DW_EH_PE_sdata4. */
+       .byte 0x0c              /* DW_CFA_def_cfa */
+       .uleb128 4
+       .uleb128 4
+       .byte 0x88              /* DW_CFA_offset, column 0x8 */
+       .uleb128 1
+       .align 4
+.LENDCIE:
+
+       .long .LENDFDE1-.LSTARTFDE1     /* Length FDE */
+.LSTARTFDE1:
+       .long .LSTARTFDE1-.LSTARTFRAME  /* CIE pointer */
+       .long .LSTART_vsyscall-.        /* PC-relative start address */
+       .long .LEND_vsyscall-.LSTART_vsyscall
+       .uleb128 0                      /* Augmentation length */
+       /* What follows are the instructions for the table generation.
+          We have to record all changes of the stack pointer.  */
+       .byte 0x40 + .Lpush_ebp-.LSTART_vsyscall /* DW_CFA_advance_loc */
+       .byte 0x0e              /* DW_CFA_def_cfa_offset */
+       .uleb128 8
+       .byte 0x85, 0x02        /* DW_CFA_offset %ebp -8 */
+       .byte 0x40 + .Lpop_ebp-.Lpush_ebp /* DW_CFA_advance_loc */
+       .byte 0xc5              /* DW_CFA_restore %ebp */
+       .byte 0x0e              /* DW_CFA_def_cfa_offset */
+       .uleb128 4
+       .align 4
+.LENDFDE1:
+
+/*
+ * Get the common code for the sigreturn entry points.
+ */
+#define SYSCALL_ENTER_KERNEL   syscall
+#include "sigreturn.S"