Building the vdso itself is not actually wired up to anything, since
we require a cross-compiler. Just check in that file for now.
Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
---
linux-user/elfload.c | 4 +-
linux-user/x86_64/Makefile.vdso | 5 ++
linux-user/x86_64/meson.build | 6 ++
linux-user/x86_64/vdso.S | 122 ++++++++++++++++++++++++++++++++
linux-user/x86_64/vdso.ld | 74 +++++++++++++++++++
linux-user/x86_64/vdso.so | Bin 0 -> 6008 bytes
6 files changed, 209 insertions(+), 2 deletions(-)
create mode 100644 linux-user/x86_64/Makefile.vdso
create mode 100644 linux-user/x86_64/vdso.S
create mode 100644 linux-user/x86_64/vdso.ld
create mode 100755 linux-user/x86_64/vdso.so
diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 486f5c4982..80587c155e 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -317,12 +317,12 @@ static void elf_core_copy_regs(target_elf_gregset_t
*regs, const CPUX86State *en
#define DLINFO_ARCH_ITEMS 1
#define ARCH_DLINFO NEW_AUX_ENT(AT_SYSINFO, vdso_info->entry);
+#endif /* TARGET_X86_64 */
+
#include "vdso.c.inc"
#define vdso_image_info() &vdso_image_info
-#endif /* TARGET_X86_64 */
-
#define USE_ELF_CORE_DUMP
#define ELF_EXEC_PAGESIZE 4096
diff --git a/linux-user/x86_64/Makefile.vdso b/linux-user/x86_64/Makefile.vdso
new file mode 100644
index 0000000000..532c9d6964
--- /dev/null
+++ b/linux-user/x86_64/Makefile.vdso
@@ -0,0 +1,5 @@
+CROSS_CC ?= $(CC)
+
+vdso.so: vdso.S vdso.ld Makefile.vdso
+ $(CROSS_CC) -nostdlib -shared -Wl,-T,vdso.ld -Wl,--build-id=sha1 \
+ -Wl,-h,linux-vdso.so.1 -Wl,--hash-style=both vdso.S -o $@
diff --git a/linux-user/x86_64/meson.build b/linux-user/x86_64/meson.build
index 203af9a60c..f6a0015953 100644
--- a/linux-user/x86_64/meson.build
+++ b/linux-user/x86_64/meson.build
@@ -3,3 +3,9 @@ syscall_nr_generators += {
arguments: [ meson.current_source_dir() /
'syscallhdr.sh', '@INPUT@', '@OUTPUT@', '@EXTRA_ARGS@' ],
output: '@BASENAME@_nr.h')
}
+
+gen = [
+ gen_vdso.process('vdso.so')
+]
+
+linux_user_ss.add(when: 'TARGET_X86_64', if_true: gen)
diff --git a/linux-user/x86_64/vdso.S b/linux-user/x86_64/vdso.S
new file mode 100644
index 0000000000..bbd75a79aa
--- /dev/null
+++ b/linux-user/x86_64/vdso.S
@@ -0,0 +1,122 @@
+/*
+ * x86-64 linux replacement vdso.
+ *
+ * Copyright 2021 Linaro, Ltd.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include <asm/unistd.h>
+
+ .globl __vdso_clock_gettime
+ .type __vdso_clock_gettime, @function
+ .balign 16
+ .cfi_startproc
+__vdso_clock_gettime:
+ mov $__NR_clock_gettime, %eax
+ syscall
+ ret
+ .cfi_endproc
+ .size __vdso_clock_gettime, . - __vdso_clock_gettime
+
+clock_gettime = __vdso_clock_gettime
+ .weak clock_gettime
+
+ .globl __vdso_clock_getres
+ .type __vdso_clock_getres, @function
+ .balign 16
+ .cfi_startproc
+__vdso_clock_getres:
+ mov $__NR_clock_getres, %eax
+ syscall
+ ret
+ .cfi_endproc
+ .size __vdso_clock_getres, . - __vdso_clock_getres
+
+clock_getres = __vdso_clock_getres
+ .weak clock_getres
+
+ .globl __vdso_gettimeofday
+ .type __vdso_gettimeofday, @function
+ .balign 16
+ .cfi_startproc
+__vdso_gettimeofday:
+ mov $__NR_gettimeofday, %eax
+ syscall
+ ret
+ .cfi_endproc
+ .size __vdso_gettimeofday, . - __vdso_gettimeofday
+
+gettimeofday = __vdso_gettimeofday
+ .weak gettimeofday
+
+
+ .globl __vdso_time
+ .type __vdso_time, @function
+ .balign 16
+ .cfi_startproc
+__vdso_time:
+ mov $__NR_time, %eax
+ syscall
+ ret
+ .cfi_endproc
+ .size __vdso_time, . - __vdso_time
+
+time = __vdso_time
+ .weak time
+
+
+ .globl __vdso_getcpu
+ .type __vdso_getcpu, @function
+ .balign 16
+ .cfi_startproc
+__vdso_getcpu:
+ /*
+ * ??? There is no syscall number for this allocated on x64.
+ * We can handle this several ways:
+ *
+ * (1) Invent a syscall number for use within qemu.
+ * It should be easy enough to pick a number that
+ * is well out of the way of the kernel numbers.
+ *
+ * (2) Force the emulated cpu to support the rdtscp insn,
+ * and initialize the TSC_AUX value the appropriate value.
+ *
+ * (3) Pretend that we're always running on cpu 0.
+ *
+ * This last is the one that's implemented here, with the
+ * tiny bit of extra code to support rdtscp in place.
+ */
+ xor %ecx, %ecx /* rdtscp w/ tsc_aux = 0 */
+
+ /* if (cpu != NULL) *cpu = (ecx & 0xfff); */
+ test %rdi, %rdi
+ jz 1f
+ mov %ecx, %eax
+ and $0xfff, %eax
+ mov %eax, (%rdi)
+
+ /* if (node != NULL) *node = (ecx >> 12); */
+1: test %rsi, %rsi
+ jz 2f
+ shr $12, %ecx
+ mov %ecx, (%rsi)
+
+2: xor %eax, %eax
+ ret
+ .cfi_endproc
+ .size __vdso_getcpu, . - __vdso_getcpu
+
+getcpu = __vdso_getcpu
+ .weak getcpu
+
+/*
+ * ??? Perhaps add elf notes. E.g.
+ *
+ * #include <linux/elfnote.h>
+ * ELFNOTE_START(Linux, 0, "a")
+ * .long LINUX_VERSION_CODE
+ * ELFNOTE_END
+ *
+ * but what version number would we set for QEMU?
+ */
diff --git a/linux-user/x86_64/vdso.ld b/linux-user/x86_64/vdso.ld
new file mode 100644
index 0000000000..6630193079
--- /dev/null
+++ b/linux-user/x86_64/vdso.ld
@@ -0,0 +1,74 @@
+/*
+ * Linker script for linux x86-64 replacement vdso.
+ *
+ * Copyright 2021 Linaro, Ltd.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+VERSION {
+ LINUX_2.6 {
+ global:
+ clock_gettime;
+ __vdso_clock_gettime;
+ gettimeofday;
+ __vdso_gettimeofday;
+ getcpu;
+ __vdso_getcpu;
+ time;
+ __vdso_time;
+ clock_getres;
+ __vdso_clock_getres;
+
+ local: *;
+ };
+}
+
+
+PHDRS {
+ phdr PT_PHDR FLAGS(4) PHDRS;
+ data PT_LOAD FLAGS(6) FILEHDR PHDRS;
+ text PT_LOAD FLAGS(5);
+ dynamic PT_DYNAMIC FLAGS(4);
+ eh_frame_hdr PT_GNU_EH_FRAME;
+ note PT_NOTE FLAGS(4);
+}
+
+SECTIONS {
+ /* ??? We can't really prelink to any address without knowing
+ something about the virtual memory space of the host, since
+ that leaks over into the available memory space of the guest. */
+ . = SIZEOF_HEADERS;
+
+ /* The following, including the FILEHDRS and PHDRS, are modified
+ when we relocate the binary. We want them to be initially
+ writable for the relocation; we'll force them read-only after. */
+ .note : { *(.note*) } :data :note
+ .dynamic : { *(.dynamic) } :data :dynamic
+ .dynsym : { *(.dynsym) } :data
+ .data : {
+ /* There ought not be any real read-write data.
+ But since we manipulated the segment layout,
+ we have to put these sections somewhere. */
+ *(.data*)
+ *(.sdata*)
+ *(.got.plt) *(.got)
+ *(.gnu.linkonce.d.*)
+ *(.bss*)
+ *(.dynbss*)
+ *(.gnu.linkonce.b.*)
+ }
+
+ .rodata : { *(.rodata*) }
+ .hash : { *(.hash) }
+ .gnu.hash : { *(.gnu.hash) }
+ .dynstr : { *(.dynstr) }
+ .gnu.version : { *(.gnu.version) }
+ .gnu.version_d : { *(.gnu.version_d) }
+ .gnu.version_r : { *(.gnu.version_r) }
+ .eh_frame_hdr : { *(.eh_frame_hdr) } :data :eh_frame_hdr
+ .eh_frame : { *(.eh_frame) } :data
+
+ . = ALIGN(4096);
+ .text : { *(.text*) } :text =0x90909090
+}
diff --git a/linux-user/x86_64/vdso.so b/linux-user/x86_64/vdso.so
new file mode 100755
index
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--
2.34.1
