Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1267
Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
---
linux-user/i386/vdso-asmoffset.h | 6 ++
linux-user/elfload.c | 16 +++-
linux-user/i386/signal.c | 11 +++
linux-user/i386/Makefile.vdso | 5 ++
linux-user/i386/meson.build | 7 ++
linux-user/i386/vdso.S | 143 +++++++++++++++++++++++++++++++
linux-user/i386/vdso.ld | 76 ++++++++++++++++
linux-user/i386/vdso.so | Bin 0 -> 2672 bytes
8 files changed, 262 insertions(+), 2 deletions(-)
create mode 100644 linux-user/i386/vdso-asmoffset.h
create mode 100644 linux-user/i386/Makefile.vdso
create mode 100644 linux-user/i386/vdso.S
create mode 100644 linux-user/i386/vdso.ld
create mode 100755 linux-user/i386/vdso.so
diff --git a/linux-user/i386/vdso-asmoffset.h b/linux-user/i386/vdso-asmoffset.h
new file mode 100644
index 0000000000..4e5ee0dd49
--- /dev/null
+++ b/linux-user/i386/vdso-asmoffset.h
@@ -0,0 +1,6 @@
+/*
+ * offsetof(struct sigframe, sc.eip)
+ * offsetof(struct rt_sigframe, uc.tuc_mcontext.eip)
+ */
+#define SIGFRAME_SIGCONTEXT_eip 64
+#define RT_SIGFRAME_SIGCONTEXT_eip 220
diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index f94963638a..7e02765954 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -309,12 +309,24 @@ static void elf_core_copy_regs(target_elf_gregset_t
*regs, const CPUX86State *en
(*regs)[15] = tswapreg(env->regs[R_ESP]);
(*regs)[16] = tswapreg(env->segs[R_SS].selector & 0xffff);
}
-#endif
+
+/*
+ * i386 is the only target which supplies AT_SYSINFO for the vdso.
+ * All others only supply AT_SYSINFO_EHDR.
+ */
+#define DLINFO_ARCH_ITEMS 1
+#define ARCH_DLINFO NEW_AUX_ENT(AT_SYSINFO, vdso_info->entry);
+
+#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
-#endif
+#endif /* TARGET_I386 */
#ifdef TARGET_ARM
diff --git a/linux-user/i386/signal.c b/linux-user/i386/signal.c
index 60fa07d6f9..bc5d45302e 100644
--- a/linux-user/i386/signal.c
+++ b/linux-user/i386/signal.c
@@ -214,6 +214,17 @@ struct rt_sigframe {
};
#define TARGET_RT_SIGFRAME_FXSAVE_OFFSET ( \
offsetof(struct rt_sigframe, fpstate) + TARGET_FPSTATE_FXSAVE_OFFSET)
+
+/*
+ * Verify that vdso-asmoffset.h constants match.
+ */
+#include "i386/vdso-asmoffset.h"
+
+QEMU_BUILD_BUG_ON(offsetof(struct sigframe, sc.eip)
+ != SIGFRAME_SIGCONTEXT_eip);
+QEMU_BUILD_BUG_ON(offsetof(struct rt_sigframe, uc.tuc_mcontext.eip)
+ != RT_SIGFRAME_SIGCONTEXT_eip);
+
#else
struct rt_sigframe {
diff --git a/linux-user/i386/Makefile.vdso b/linux-user/i386/Makefile.vdso
new file mode 100644
index 0000000000..26bc993cda
--- /dev/null
+++ b/linux-user/i386/Makefile.vdso
@@ -0,0 +1,5 @@
+CROSS_CC ?= i686-linux-gnu-gcc
+
+vdso.so: vdso.S vdso.ld Makefile.vdso
+ $(CROSS_CC) -m32 -nostdlib -shared -Wl,-T,vdso.ld -Wl,--build-id=sha1 \
+ -Wl,-h,linux-gate.so.1 -Wl,--hash-style=both vdso.S -o $@
diff --git a/linux-user/i386/meson.build b/linux-user/i386/meson.build
index ee523019a5..b729d73686 100644
--- a/linux-user/i386/meson.build
+++ b/linux-user/i386/meson.build
@@ -3,3 +3,10 @@ syscall_nr_generators += {
arguments: [ meson.current_source_dir() / 'syscallhdr.sh',
'@INPUT@', '@OUTPUT@', '@EXTRA_ARGS@' ],
output: '@BASENAME@_nr.h')
}
+
+gen = [
+ gen_vdso.process('vdso.so', extra_args: ['-s', '__kernel_sigreturn',
+ '-r', '__kernel_rt_sigreturn'])
+]
+
+linux_user_ss.add(when: 'TARGET_I386', if_true: gen)
diff --git a/linux-user/i386/vdso.S b/linux-user/i386/vdso.S
new file mode 100644
index 0000000000..e7a1f333a1
--- /dev/null
+++ b/linux-user/i386/vdso.S
@@ -0,0 +1,143 @@
+/*
+ * i386 linux replacement vdso.
+ *
+ * Copyright 2023 Linaro, Ltd.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include <asm/unistd.h>
+#include "vdso-asmoffset.h"
+
+.macro endf name
+ .globl \name
+ .type \name, @function
+ .size \name, . - \name
+.endm
+
+.macro vdso_syscall1 name, nr
+\name:
+ .cfi_startproc
+ mov %ebx, %edx
+ .cfi_register %ebx, %edx
+ mov 4(%esp), %ebx
+ mov $\nr, %eax
+ int $0x80
+ mov %edx, %ebx
+ ret
+ .cfi_endproc
+endf \name
+.endm
+
+.macro vdso_syscall2 name, nr
+\name:
+ .cfi_startproc
+ mov %ebx, %edx
+ .cfi_register %ebx, %edx
+ mov 4(%esp), %ebx
+ mov 8(%esp), %ecx
+ mov $\nr, %eax
+ int $0x80
+ mov %edx, %ebx
+ ret
+ .cfi_endproc
+endf \name
+.endm
+
+.macro vdso_syscall3 name, nr
+\name:
+ .cfi_startproc
+ push %ebx
+ .cfi_adjust_cfa_offset 4
+ .cfi_rel_offset %ebx, 0
+ mov 8(%esp), %ebx
+ mov 12(%esp), %ecx
+ mov 16(%esp), %edx
+ mov $\nr, %eax
+ int $0x80
+ pop %ebx
+ .cfi_adjust_cfa_offset -4
+ .cfi_restore %ebx
+ ret
+ .cfi_endproc
+endf \name
+.endm
+
+__kernel_vsyscall:
+ .cfi_startproc
+ int $0x80
+ ret
+ .cfi_endproc
+endf __kernel_vsyscall
+
+vdso_syscall2 __vdso_clock_gettime, __NR_clock_gettime
+vdso_syscall2 __vdso_clock_gettime64, __NR_clock_gettime64
+vdso_syscall2 __vdso_clock_getres, __NR_clock_getres
+vdso_syscall2 __vdso_gettimeofday, __NR_gettimeofday
+vdso_syscall1 __vdso_time, __NR_time
+vdso_syscall3 __vdso_getcpu, __NR_gettimeofday
+
+/*
+ * Signal return handlers.
+ */
+
+ .cfi_startproc simple
+ .cfi_signal_frame
+
+/*
+ * For convenience, put the cfa just above eip in sigcontext, and count
+ * offsets backward from there. Re-compute the cfa in the two contexts
+ * we have for signal unwinding. This is far simpler than the
+ * DW_CFA_expression form that the kernel uses, and is equally correct.
+ */
+
+ .cfi_def_cfa %esp, SIGFRAME_SIGCONTEXT_eip + 4
+
+ .cfi_offset %eip, -4
+ /* err, -8 */
+ /* trapno, -12 */
+ .cfi_offset %eax, -16
+ .cfi_offset %ecx, -20
+ .cfi_offset %edx, -24
+ .cfi_offset %ebx, -28
+ .cfi_offset %esp, -32
+ .cfi_offset %ebp, -36
+ .cfi_offset %esi, -40
+ .cfi_offset %edi, -44
+
+/*
+ * While this frame is marked as a signal frame, that only applies to how
+ * the return address is handled for the outer frame. The return address
+ * that arrived here, from the inner frame, is not marked as a signal frame
+ * and so the unwinder still tries to subtract 1 to examine the presumed
+ * call insn. Thus we must extend the unwind info to a nop before the start.
+ */
+ nop
+
+__kernel_sigreturn:
+ popl %eax /* pop sig */
+ .cfi_adjust_cfa_offset -4
+ movl $__NR_sigreturn, %eax
+ int $0x80
+endf __kernel_sigreturn
+
+ .cfi_def_cfa_offset RT_SIGFRAME_SIGCONTEXT_eip + 4
+ nop
+
+__kernel_rt_sigreturn:
+ movl $__NR_rt_sigreturn, %eax
+ int $0x80
+endf __kernel_rt_sigreturn
+
+ .cfi_endproc
+
+/*
+ * TODO: 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/i386/vdso.ld b/linux-user/i386/vdso.ld
new file mode 100644
index 0000000000..326b7a8f98
--- /dev/null
+++ b/linux-user/i386/vdso.ld
@@ -0,0 +1,76 @@
+/*
+ * Linker script for linux i386 replacement vdso.
+ *
+ * Copyright 2023 Linaro, Ltd.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+ENTRY(__kernel_vsyscall)
+
+VERSION {
+ LINUX_2.6 {
+ global:
+ __vdso_clock_gettime;
+ __vdso_gettimeofday;
+ __vdso_time;
+ __vdso_clock_getres;
+ __vdso_clock_gettime64;
+ __vdso_getcpu;
+ };
+
+ LINUX_2.5 {
+ global:
+ __kernel_vsyscall;
+ __kernel_sigreturn;
+ __kernel_rt_sigreturn;
+ local: *;
+ };
+}
+
+PHDRS {
+ phdr PT_PHDR FLAGS(4) PHDRS;
+ load PT_LOAD FLAGS(7) FILEHDR PHDRS; /* FLAGS=RWX */
+ dynamic PT_DYNAMIC FLAGS(4);
+ eh_frame_hdr PT_GNU_EH_FRAME;
+ note PT_NOTE FLAGS(4);
+}
+
+SECTIONS {
+ . = 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*) } :load :note
+ .dynamic : { *(.dynamic) } :load :dynamic
+ .dynsym : { *(.dynsym) } :load
+ .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) } :load :eh_frame_hdr
+ .eh_frame : { *(.eh_frame) } :load
+
+ .text : { *(.text*) } :load =0x90909090
+}
diff --git a/linux-user/i386/vdso.so b/linux-user/i386/vdso.so
new file mode 100755
index
0000000000000000000000000000000000000000..bdece5dfcf8da036d013262d4e37208350283cfa
GIT binary patch
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--
2.34.1
