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>

4 files changed, 363 insertions, 0 deletions

diff --git a/arch/x86/vdso/vdso32/int80.S b/arch/x86/vdso/vdso32/int80.S
new file mode 100644
index 00000000000..3c8e4c62ace
--- /dev/null
+++ b/arch/x86/vdso/vdso32/int80.S
@@ -0,0 +1,53 @@
+/*
+ * Code for the vsyscall page.  This version uses the old int $0x80 method.
+ *
+ * NOTE:
+ * 1) __kernel_vsyscall _must_ be first in this page.
+ * 2) there are alignment constraints on this stub, see vsyscall-sigreturn.S
+ *    for details.
+ */
+
+	.text
+	.globl __kernel_vsyscall
+	.type __kernel_vsyscall,@function
+__kernel_vsyscall:
+.LSTART_vsyscall:
+	int $0x80
+	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
+	.align 4
+.LENDFDEDLSI:
+	.previous
+
+/*
+ * Get the common code for the sigreturn entry points.
+ */
+#include "sigreturn.S"
diff --git a/arch/x86/vdso/vdso32/note.S b/arch/x86/vdso/vdso32/note.S
new file mode 100644
index 00000000000..0cf934f2633
--- /dev/null
+++ b/arch/x86/vdso/vdso32/note.S
@@ -0,0 +1,45 @@
+/*
+ * This supplies .note.* sections to go into the PT_NOTE inside the vDSO text.
+ * Here we can supply some information useful to userland.
+ */
+
+#include <linux/version.h>
+#include <linux/elfnote.h>
+
+/* Ideally this would use UTS_NAME, but using a quoted string here
+   doesn't work. Remember to change this when changing the
+   kernel's name. */
+ELFNOTE_START(Linux, 0, "a")
+	.long LINUX_VERSION_CODE
+ELFNOTE_END
+
+#ifdef CONFIG_XEN
+/*
+ * Add a special note telling glibc's dynamic linker a fake hardware
+ * flavor that it will use to choose the search path for libraries in the
+ * same way it uses real hardware capabilities like "mmx".
+ * We supply "nosegneg" as the fake capability, to indicate that we
+ * do not like negative offsets in instructions using segment overrides,
+ * since we implement those inefficiently.  This makes it possible to
+ * install libraries optimized to avoid those access patterns in someplace
+ * like /lib/i686/tls/nosegneg.  Note that an /etc/ld.so.conf.d/file
+ * corresponding to the bits here is needed to make ldconfig work right.
+ * It should contain:
+ *	hwcap 1 nosegneg
+ * to match the mapping of bit to name that we give here.
+ *
+ * At runtime, the fake hardware feature will be considered to be present
+ * if its bit is set in the mask word.  So, we start with the mask 0, and
+ * at boot time we set VDSO_NOTE_NONEGSEG_BIT if running under Xen.
+ */
+
+#include "../../xen/vdso.h"	/* Defines VDSO_NOTE_NONEGSEG_BIT.  */
+
+	.globl VDSO_NOTE_MASK
+ELFNOTE_START(GNU, 2, "a")
+	.long 1			/* ncaps */
+VDSO_NOTE_MASK:
+	.long 0			/* mask */
+	.byte VDSO_NOTE_NONEGSEG_BIT; .asciz "nosegneg"	/* bit, name */
+ELFNOTE_END
+#endif
diff --git a/arch/x86/vdso/vdso32/sigreturn.S b/arch/x86/vdso/vdso32/sigreturn.S
new file mode 100644
index 00000000000..778f4649e32
--- /dev/null
+++ b/arch/x86/vdso/vdso32/sigreturn.S
@@ -0,0 +1,143 @@
+/*
+ * Common code for the sigreturn entry points on the vsyscall page.
+ * So far this code is the same for both int80 and sysenter versions.
+ * This file is #include'd by vsyscall-*.S to define them after the
+ * vsyscall entry point.  The kernel assumes that the addresses of these
+ * routines are constant for all vsyscall implementations.
+ */
+
+#include <asm/unistd.h>
+#include <asm/asm-offsets.h>
+
+
+/* XXX
+   Should these be named "_sigtramp" or something?
+*/
+
+	.text
+	.org __kernel_vsyscall+32,0x90
+	.globl __kernel_sigreturn
+	.type __kernel_sigreturn,@function
+__kernel_sigreturn:
+.LSTART_sigreturn:
+	popl %eax		/* XXX does this mean it needs unwind info? */
+	movl $__NR_sigreturn, %eax
+	int $0x80
+.LEND_sigreturn:
+	.size __kernel_sigreturn,.-.LSTART_sigreturn
+
+	.balign 32
+	.globl __kernel_rt_sigreturn
+	.type __kernel_rt_sigreturn,@function
+__kernel_rt_sigreturn:
+.LSTART_rt_sigreturn:
+	movl $__NR_rt_sigreturn, %eax
+	int $0x80
+.LEND_rt_sigreturn:
+	.size __kernel_rt_sigreturn,.-.LSTART_rt_sigreturn
+	.balign 32
+	.previous
+
+	.section .eh_frame,"a",@progbits
+.LSTARTFRAMEDLSI1:
+	.long .LENDCIEDLSI1-.LSTARTCIEDLSI1
+.LSTARTCIEDLSI1:
+	.long 0			/* CIE ID */
+	.byte 1			/* Version number */
+	.string "zRS"		/* 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 0			/* DW_CFA_nop */
+	.align 4
+.LENDCIEDLSI1:
+	.long .LENDFDEDLSI1-.LSTARTFDEDLSI1 /* Length FDE */
+.LSTARTFDEDLSI1:
+	.long .LSTARTFDEDLSI1-.LSTARTFRAMEDLSI1 /* CIE pointer */
+	/* HACK: The dwarf2 unwind routines will subtract 1 from the
+	   return address to get an address in the middle of the
+	   presumed call instruction.  Since we didn't get here via
+	   a call, we need to include the nop before the real start
+	   to make up for it.  */
+	.long .LSTART_sigreturn-1-.	/* PC-relative start address */
+	.long .LEND_sigreturn-.LSTART_sigreturn+1
+	.uleb128 0			/* Augmentation */
+	/* What follows are the instructions for the table generation.
+	   We record the locations of each register saved.  This is
+	   complicated by the fact that the "CFA" is always assumed to
+	   be the value of the stack pointer in the caller.  This means
+	   that we must define the CFA of this body of code to be the
+	   saved value of the stack pointer in the sigcontext.  Which
+	   also means that there is no fixed relation to the other
+	   saved registers, which means that we must use DW_CFA_expression
+	   to compute their addresses.  It also means that when we
+	   adjust the stack with the popl, we have to do it all over again.  */
+
+#define do_cfa_expr(offset)						\
+	.byte 0x0f;			/* DW_CFA_def_cfa_expression */	\
+	.uleb128 1f-0f;			/*   length */			\
+0:	.byte 0x74;			/*     DW_OP_breg4 */		\
+	.sleb128 offset;		/*      offset */		\
+	.byte 0x06;			/*     DW_OP_deref */		\
+1:
+
+#define do_expr(regno, offset)						\
+	.byte 0x10;			/* DW_CFA_expression */		\
+	.uleb128 regno;			/*   regno */			\
+	.uleb128 1f-0f;			/*   length */			\
+0:	.byte 0x74;			/*     DW_OP_breg4 */		\
+	.sleb128 offset;		/*       offset */		\
+1:
+
+	do_cfa_expr(IA32_SIGCONTEXT_esp+4)
+	do_expr(0, IA32_SIGCONTEXT_eax+4)
+	do_expr(1, IA32_SIGCONTEXT_ecx+4)
+	do_expr(2, IA32_SIGCONTEXT_edx+4)
+	do_expr(3, IA32_SIGCONTEXT_ebx+4)
+	do_expr(5, IA32_SIGCONTEXT_ebp+4)
+	do_expr(6, IA32_SIGCONTEXT_esi+4)
+	do_expr(7, IA32_SIGCONTEXT_edi+4)
+	do_expr(8, IA32_SIGCONTEXT_eip+4)
+
+	.byte 0x42	/* DW_CFA_advance_loc 2 -- nop; popl eax. */
+
+	do_cfa_expr(IA32_SIGCONTEXT_esp)
+	do_expr(0, IA32_SIGCONTEXT_eax)
+	do_expr(1, IA32_SIGCONTEXT_ecx)
+	do_expr(2, IA32_SIGCONTEXT_edx)
+	do_expr(3, IA32_SIGCONTEXT_ebx)
+	do_expr(5, IA32_SIGCONTEXT_ebp)
+	do_expr(6, IA32_SIGCONTEXT_esi)
+	do_expr(7, IA32_SIGCONTEXT_edi)
+	do_expr(8, IA32_SIGCONTEXT_eip)
+
+	.align 4
+.LENDFDEDLSI1:
+
+	.long .LENDFDEDLSI2-.LSTARTFDEDLSI2 /* Length FDE */
+.LSTARTFDEDLSI2:
+	.long .LSTARTFDEDLSI2-.LSTARTFRAMEDLSI1 /* CIE pointer */
+	/* HACK: See above wrt unwind library assumptions.  */
+	.long .LSTART_rt_sigreturn-1-.	/* PC-relative start address */
+	.long .LEND_rt_sigreturn-.LSTART_rt_sigreturn+1
+	.uleb128 0			/* Augmentation */
+	/* What follows are the instructions for the table generation.
+	   We record the locations of each register saved.  This is
+	   slightly less complicated than the above, since we don't
+	   modify the stack pointer in the process.  */
+
+	do_cfa_expr(IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_esp)
+	do_expr(0, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_eax)
+	do_expr(1, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_ecx)
+	do_expr(2, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_edx)
+	do_expr(3, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_ebx)
+	do_expr(5, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_ebp)
+	do_expr(6, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_esi)
+	do_expr(7, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_edi)
+	do_expr(8, IA32_RT_SIGFRAME_sigcontext-4 + IA32_SIGCONTEXT_eip)
+
+	.align 4
+.LENDFDEDLSI2:
+	.previous
diff --git a/arch/x86/vdso/vdso32/sysenter.S b/arch/x86/vdso/vdso32/sysenter.S
new file mode 100644
index 00000000000..4b98fc41d3e
--- /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"