x86 vDSO: arch/x86/vdso/vdso32
This moves the i386 vDSO sources into arch/x86/vdso/vdso32/, a
new directory. This patch is a pure renaming, but paves the way
for consolidating the vDSO build logic.
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/vdso32/sysenter.S b/arch/x86/vdso/vdso32/sysenter.S
new file mode 100644
index 0000000..4b98fc4
--- /dev/null
+++ b/arch/x86/vdso/vdso32/sysenter.S
@@ -0,0 +1,122 @@
+/*
+ * Code for the vsyscall page. This version uses the sysenter instruction.
+ *
+ * NOTE:
+ * 1) __kernel_vsyscall _must_ be first in this page.
+ * 2) there are alignment constraints on this stub, see vsyscall-sigreturn.S
+ * for details.
+ */
+
+/*
+ * The caller puts arg2 in %ecx, which gets pushed. The kernel will use
+ * %ecx itself for arg2. The pushing is because the sysexit instruction
+ * (found in entry.S) requires that we clobber %ecx with the desired %esp.
+ * User code might expect that %ecx is unclobbered though, as it would be
+ * for returning via the iret instruction, so we must push and pop.
+ *
+ * The caller puts arg3 in %edx, which the sysexit instruction requires
+ * for %eip. Thus, exactly as for arg2, we must push and pop.
+ *
+ * Arg6 is different. The caller puts arg6 in %ebp. Since the sysenter
+ * instruction clobbers %esp, the user's %esp won't even survive entry
+ * into the kernel. We store %esp in %ebp. Code in entry.S must fetch
+ * arg6 from the stack.
+ *
+ * You can not use this vsyscall for the clone() syscall because the
+ * three dwords on the parent stack do not get copied to the child.
+ */
+ .text
+ .globl __kernel_vsyscall
+ .type __kernel_vsyscall,@function
+__kernel_vsyscall:
+.LSTART_vsyscall:
+ push %ecx
+.Lpush_ecx:
+ push %edx
+.Lpush_edx:
+ push %ebp
+.Lenter_kernel:
+ movl %esp,%ebp
+ sysenter
+
+ /* 7: align return point with nop's to make disassembly easier */
+ .space 7,0x90
+
+ /* 14: System call restart point is here! (SYSENTER_RETURN-2) */
+ jmp .Lenter_kernel
+ /* 16: System call normal return point is here! */
+ .globl SYSENTER_RETURN /* Symbol used by sysenter.c */
+SYSENTER_RETURN:
+ pop %ebp
+.Lpop_ebp:
+ pop %edx
+.Lpop_edx:
+ pop %ecx
+.Lpop_ecx:
+ ret
+.LEND_vsyscall:
+ .size __kernel_vsyscall,.-.LSTART_vsyscall
+ .previous
+
+ .section .eh_frame,"a",@progbits
+.LSTARTFRAMEDLSI:
+ .long .LENDCIEDLSI-.LSTARTCIEDLSI
+.LSTARTCIEDLSI:
+ .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
+.LENDCIEDLSI:
+ .long .LENDFDEDLSI-.LSTARTFDEDLSI /* Length FDE */
+.LSTARTFDEDLSI:
+ .long .LSTARTFDEDLSI-.LSTARTFRAMEDLSI /* CIE pointer */
+ .long .LSTART_vsyscall-. /* PC-relative start address */
+ .long .LEND_vsyscall-.LSTART_vsyscall
+ .uleb128 0
+ /* What follows are the instructions for the table generation.
+ We have to record all changes of the stack pointer. */
+ .byte 0x04 /* DW_CFA_advance_loc4 */
+ .long .Lpush_ecx-.LSTART_vsyscall
+ .byte 0x0e /* DW_CFA_def_cfa_offset */
+ .byte 0x08 /* RA at offset 8 now */
+ .byte 0x04 /* DW_CFA_advance_loc4 */
+ .long .Lpush_edx-.Lpush_ecx
+ .byte 0x0e /* DW_CFA_def_cfa_offset */
+ .byte 0x0c /* RA at offset 12 now */
+ .byte 0x04 /* DW_CFA_advance_loc4 */
+ .long .Lenter_kernel-.Lpush_edx
+ .byte 0x0e /* DW_CFA_def_cfa_offset */
+ .byte 0x10 /* RA at offset 16 now */
+ .byte 0x85, 0x04 /* DW_CFA_offset %ebp -16 */
+ /* Finally the epilogue. */
+ .byte 0x04 /* DW_CFA_advance_loc4 */
+ .long .Lpop_ebp-.Lenter_kernel
+ .byte 0x0e /* DW_CFA_def_cfa_offset */
+ .byte 0x0c /* RA at offset 12 now */
+ .byte 0xc5 /* DW_CFA_restore %ebp */
+ .byte 0x04 /* DW_CFA_advance_loc4 */
+ .long .Lpop_edx-.Lpop_ebp
+ .byte 0x0e /* DW_CFA_def_cfa_offset */
+ .byte 0x08 /* RA at offset 8 now */
+ .byte 0x04 /* DW_CFA_advance_loc4 */
+ .long .Lpop_ecx-.Lpop_edx
+ .byte 0x0e /* DW_CFA_def_cfa_offset */
+ .byte 0x04 /* RA at offset 4 now */
+ .align 4
+.LENDFDEDLSI:
+ .previous
+
+/*
+ * Get the common code for the sigreturn entry points.
+ */
+#include "sigreturn.S"