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[PATCH 1/2] linux-user: Build vdso for x64.
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From: |
Richard Henderson |
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Subject: |
[PATCH 1/2] linux-user: Build vdso for x64. |
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Date: |
Tue, 19 May 2020 12:44:51 -0700 |
From: Richard Henderson <address@hidden>
... Well, sortof. The Makefile bits are broken.
Patch to load the vdso into the running program to follow.
Signed-off-by: Richard Henderson <address@hidden>
---
Makefile | 4 +-
pc-bios/Makefile | 5 ++
pc-bios/vdso-linux-x64.S | 115 ++++++++++++++++++++++++++++++++++++++
pc-bios/vdso-linux-x64.ld | 81 +++++++++++++++++++++++++++
pc-bios/vdso-linux-x64.so | Bin 0 -> 7500 bytes
5 files changed, 203 insertions(+), 2 deletions(-)
create mode 100644 pc-bios/vdso-linux-x64.S
create mode 100644 pc-bios/vdso-linux-x64.ld
create mode 100755 pc-bios/vdso-linux-x64.so
diff --git a/Makefile b/Makefile
index 40e4f7677b..73e380ac6a 100644
--- a/Makefile
+++ b/Makefile
@@ -848,8 +848,8 @@ qemu_vga.ndrv \
edk2-licenses.txt \
hppa-firmware.img \
opensbi-riscv32-sifive_u-fw_jump.bin opensbi-riscv32-virt-fw_jump.bin \
-opensbi-riscv64-sifive_u-fw_jump.bin opensbi-riscv64-virt-fw_jump.bin
-
+opensbi-riscv64-sifive_u-fw_jump.bin opensbi-riscv64-virt-fw_jump.bin \
+vdso-linux-x64.so
DESCS=50-edk2-i386-secure.json 50-edk2-x86_64-secure.json \
60-edk2-aarch64.json 60-edk2-arm.json 60-edk2-i386.json 60-edk2-x86_64.json
diff --git a/pc-bios/Makefile b/pc-bios/Makefile
index 315288df84..70e2485e2e 100644
--- a/pc-bios/Makefile
+++ b/pc-bios/Makefile
@@ -15,5 +15,10 @@ all: $(TARGETS)
%.dtb: %.dts
dtc -I dts -O dtb -o $@ $<
+vdso-linux-x64.so: vdso-linux-x64.o vdso-linux-x64.ld
+ $(CC) -nostdlib -shared -Wl,-T,vdso-linux-x64.ld \
+ -Wl,-h,linux-vdso.so.1 -Wl,--hash-style=both \
+ vdso-linux-x64.o -o $@
+
clean:
rm -f $(TARGETS) *.o *~
diff --git a/pc-bios/vdso-linux-x64.S b/pc-bios/vdso-linux-x64.S
new file mode 100644
index 0000000000..090d82c26a
--- /dev/null
+++ b/pc-bios/vdso-linux-x64.S
@@ -0,0 +1,115 @@
+/*
+ * x86-64 linux replacement vdso.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#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_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/pc-bios/vdso-linux-x64.ld b/pc-bios/vdso-linux-x64.ld
new file mode 100644
index 0000000000..2ef21fbcab
--- /dev/null
+++ b/pc-bios/vdso-linux-x64.ld
@@ -0,0 +1,81 @@
+/*
+ * Linker script for linux x64 replacement vdso.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+VERSION {
+ LINUX_2.6 {
+ global:
+ clock_gettime;
+ __vdso_clock_gettime;
+ gettimeofday;
+ __vdso_gettimeofday;
+ getcpu;
+ __vdso_getcpu;
+ time;
+ __vdso_time;
+ 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);
+ note PT_NOTE FLAGS(4);
+ /* ??? Various versions of ld don't know PT_GNU_EH_FRAME. */
+ eh_frame_hdr 0x6474e550;
+}
+
+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. */
+ .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.*)
+ }
+
+ . += 4096;
+ .hash : { *(.hash) } :text
+ .gnu.hash : { *(.gnu.hash) }
+ .dynstr : { *(.dynstr) }
+ .gnu.version : { *(.gnu.version) }
+ .gnu.version_d : { *(.gnu.version_d) }
+ .gnu.version_r : { *(.gnu.version_r) }
+ .note : { *(.note*) } :text :note
+ .eh_frame_hdr : { *(.eh_frame_hdr) } :text :eh_frame_hdr
+ .eh_frame : { *(.eh_frame) } :text
+ .rodata : { *(.rodata) }
+
+ . = ALIGN(0x100);
+ .text : { *(.text*) } :text =0x90909090
+}
diff --git a/pc-bios/vdso-linux-x64.so b/pc-bios/vdso-linux-x64.so
new file mode 100755
index
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GIT binary patch
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--
2.20.1