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[PATCH v2 22/36] linux-user/i386: Add vdso and use it for sigreturn
From: |
Richard Henderson |
Subject: |
[PATCH v2 22/36] linux-user/i386: Add vdso and use it for sigreturn |
Date: |
Tue, 6 Jul 2021 16:49:18 -0700 |
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.henderson@linaro.org>
---
linux-user/elfload.c | 16 +++-
linux-user/i386/signal.c | 39 ++++-----
linux-user/i386/Makefile.vdso | 5 ++
linux-user/i386/meson.build | 7 ++
linux-user/i386/vdso.S | 149 ++++++++++++++++++++++++++++++++++
linux-user/i386/vdso.ld | 76 +++++++++++++++++
linux-user/i386/vdso.so | Bin 0 -> 5528 bytes
7 files changed, 271 insertions(+), 21 deletions(-)
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/elfload.c b/linux-user/elfload.c
index ec3a854b44..7a598f9f76 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -276,12 +276,24 @@ static void elf_core_copy_regs(target_elf_gregset_t
*regs, const CPUX86State *en
(*regs)[15] = env->regs[R_ESP];
(*regs)[16] = 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 9894e7c9ac..8e4677e800 100644
--- a/linux-user/i386/signal.c
+++ b/linux-user/i386/signal.c
@@ -313,7 +313,7 @@ get_sigframe(struct target_sigaction *ka, CPUX86State *env,
size_t frame_size)
void setup_frame(int sig, struct target_sigaction *ka,
target_sigset_t *set, CPUX86State *env)
{
- abi_ulong frame_addr;
+ abi_ulong frame_addr, retcode_addr;
struct sigframe *frame;
int i;
@@ -335,19 +335,19 @@ void setup_frame(int sig, struct target_sigaction *ka,
/* Set up to return from userspace. If provided, use a stub
already in userspace. */
if (ka->sa_flags & TARGET_SA_RESTORER) {
- __put_user(ka->sa_restorer, &frame->pretcode);
+ retcode_addr = ka->sa_restorer;
} else {
- uint16_t val16;
- abi_ulong retcode_addr;
- retcode_addr = frame_addr + offsetof(struct sigframe, retcode);
- __put_user(retcode_addr, &frame->pretcode);
- /* This is popl %eax ; movl $,%eax ; int $0x80 */
- val16 = 0xb858;
- __put_user(val16, (uint16_t *)(frame->retcode+0));
+ /*
+ * This is popl %eax ; movl $,%eax ; int $0x80.
+ * This is no longer used, but is retained for ABI compatibility.
+ */
+ __put_user(0xb858, (uint16_t *)(frame->retcode+0));
__put_user(TARGET_NR_sigreturn, (int *)(frame->retcode+2));
- val16 = 0x80cd;
- __put_user(val16, (uint16_t *)(frame->retcode+6));
+ __put_user(0x80cd, (uint16_t *)(frame->retcode+6));
+
+ retcode_addr = default_sigreturn;
}
+ __put_user(retcode_addr, &frame->pretcode);
/* Set up registers for signal handler */
env->regs[R_ESP] = frame_addr;
@@ -373,7 +373,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
target_siginfo_t *info,
target_sigset_t *set, CPUX86State *env)
{
- abi_ulong frame_addr;
+ abi_ulong frame_addr, retcode_addr;
#ifndef TARGET_X86_64
abi_ulong addr;
#endif
@@ -412,22 +412,23 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
/* Set up to return from userspace. If provided, use a stub
already in userspace. */
if (ka->sa_flags & TARGET_SA_RESTORER) {
- __put_user(ka->sa_restorer, &frame->pretcode);
+ retcode_addr = ka->sa_restorer;
} else {
#ifdef TARGET_X86_64
/* For x86_64, SA_RESTORER is required ABI. */
goto give_sigsegv;
#else
- uint16_t val16;
- addr = frame_addr + offsetof(struct rt_sigframe, retcode);
- __put_user(addr, &frame->pretcode);
- /* This is movl $,%eax ; int $0x80 */
+ /*
+ * This is movl $,%eax ; int $0x80
+ * This is no longer used, but is retained for ABI compatibility.
+ */
__put_user(0xb8, (char *)(frame->retcode+0));
__put_user(TARGET_NR_rt_sigreturn, (int *)(frame->retcode+1));
- val16 = 0x80cd;
- __put_user(val16, (uint16_t *)(frame->retcode+5));
+ __put_user(0x80cd, (uint16_t *)(frame->retcode+5));
+ retcode_addr = default_rt_sigreturn;
#endif
}
+ __put_user(retcode_addr, &frame->pretcode);
/* Set up registers for signal handler */
env->regs[R_ESP] = frame_addr;
diff --git a/linux-user/i386/Makefile.vdso b/linux-user/i386/Makefile.vdso
new file mode 100644
index 0000000000..42cfc1974b
--- /dev/null
+++ b/linux-user/i386/Makefile.vdso
@@ -0,0 +1,5 @@
+CROSS_CC ?= $(CC)
+
+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..6938c577ec
--- /dev/null
+++ b/linux-user/i386/vdso.S
@@ -0,0 +1,149 @@
+/*
+ * i386 linux replacement vdso.
+ *
+ * Copyright 2021 Linaro, Ltd.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include <asm/unistd.h>
+
+ .balign 16
+__kernel_vsyscall:
+ .cfi_startproc
+ int $0x80
+ ret
+ .cfi_endproc
+
+ .globl __kernel_vsyscall
+ .type __kernel_vsyscall, @function
+ .size __kernel_vsyscall, . - __kernel_vsyscall
+
+ .balign 16
+ .cfi_startproc
+__vdso_clock_gettime:
+ mov $__NR_clock_gettime, %eax
+ int $0x80
+ ret
+ .cfi_endproc
+
+ .globl __vdso_clock_gettime
+ .type __vdso_clock_gettime, @function
+ .size __vdso_clock_gettime, . - __vdso_clock_gettime
+
+ .balign 16
+ .cfi_startproc
+__vdso_clock_gettime64:
+ mov $__NR_clock_gettime64, %eax
+ int $0x80
+ ret
+ .cfi_endproc
+
+ .globl __vdso_clock_gettime64
+ .type __vdso_clock_gettime64, @function
+ .size __vdso_clock_gettime64, . - __vdso_clock_gettime64
+
+ .balign 16
+ .cfi_startproc
+__vdso_clock_getres:
+ mov $__NR_clock_getres, %eax
+ int $0x80
+ ret
+ .cfi_endproc
+
+ .globl __vdso_clock_getres
+ .type __vdso_clock_getres, @function
+ .size __vdso_clock_getres, . - __vdso_clock_getres
+
+ .balign 16
+ .cfi_startproc
+__vdso_gettimeofday:
+ mov $__NR_gettimeofday, %eax
+ int $0x80
+ ret
+ .cfi_endproc
+
+ .globl __vdso_gettimeofday
+ .type __vdso_gettimeofday, @function
+ .size __vdso_gettimeofday, . - __vdso_gettimeofday
+
+ .balign 16
+ .cfi_startproc
+__vdso_time:
+ mov $__NR_time, %eax
+ int $0x80
+ ret
+ .cfi_endproc
+
+ .globl __vdso_time
+ .type __vdso_time, @function
+ .size __vdso_time, . - __vdso_time
+
+ /*
+ * While this frame is marked as a signal frame, that only applies
+ * to how this 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.
+ */
+
+ .balign 16
+ .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 several contexts we have for signal unwinding.
+ * This is far simpler than the DW_CFA_expression form that
+ * the kernel uses, and is equally correct.
+ */
+#define IA32_SIGCONTEXT_cfa 60
+#define IA32_RT_SIGFRAME_sigcontext 164
+
+ .cfi_def_cfa %esp, IA32_SIGCONTEXT_cfa + 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
+
+ nop
+__kernel_sigreturn:
+ popl %eax /* pop sig */
+ .cfi_adjust_cfa_offset -4
+ movl $__NR_sigreturn, %eax
+ int $0x80
+
+ .globl __kernel_sigreturn
+ .type __kernel_sigreturn, @function
+ .size __kernel_sigreturn, . - __kernel_sigreturn
+
+ .cfi_adjust_cfa_offset IA32_RT_SIGFRAME_sigcontext - 4
+ nop
+__kernel_rt_sigreturn:
+ movl $__NR_rt_sigreturn, %eax
+ int $0x80
+
+ .globl __kernel_rt_sigreturn
+ .type __kernel_rt_sigreturn, @function
+ .size __kernel_rt_sigreturn, . - __kernel_rt_sigreturn
+ .cfi_endproc
+
+/*
+ * ??? 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/i386/vdso.ld b/linux-user/i386/vdso.ld
new file mode 100644
index 0000000000..18937710c9
--- /dev/null
+++ b/linux-user/i386/vdso.ld
@@ -0,0 +1,76 @@
+/*
+ * Linker script for linux x86-64 replacement vdso.
+ *
+ * Copyright 2021 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;
+ };
+
+ LINUX_2.5 {
+ global:
+ __kernel_vsyscall;
+ __kernel_sigreturn;
+ __kernel_rt_sigreturn;
+ 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/i386/vdso.so b/linux-user/i386/vdso.so
new file mode 100755
index
0000000000000000000000000000000000000000..7a78ee23182f904f091b3fca9fbb354282372773
GIT binary patch
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literal 0
HcmV?d00001
--
2.25.1
- [PATCH v2 12/36] linux-user/aarch64: Add vdso and use it for rt_sigreturn, (continued)
- [PATCH v2 12/36] linux-user/aarch64: Add vdso and use it for rt_sigreturn, Richard Henderson, 2021/07/06
- [PATCH v2 15/36] target/arm: Add isar_feature_aa32_a32, Richard Henderson, 2021/07/06
- [PATCH v2 17/36] linux-user/alpha: Implement setup_sigtramp, Richard Henderson, 2021/07/06
- [PATCH v2 18/36] linux-user/cris: Implement setup_sigtramp, Richard Henderson, 2021/07/06
- [PATCH v2 16/36] linux-user/arm: Add vdso and use it for rt_sigreturn, Richard Henderson, 2021/07/06
- [PATCH v2 19/36] linux-user/hexagon: Implement setup_sigtramp, Richard Henderson, 2021/07/06
- [PATCH v2 20/36] linux-user/hppa: Add vdso and use it for rt_sigreturn, Richard Henderson, 2021/07/06
- [PATCH v2 21/36] linux-user/x86_64: Raise SIGSEGV if SA_RESTORER not set, Richard Henderson, 2021/07/06
- [PATCH v2 23/36] linux-user/x86_64: Add vdso, Richard Henderson, 2021/07/06
- [PATCH v2 22/36] linux-user/i386: Add vdso and use it for sigreturn,
Richard Henderson <=
- [PATCH v2 28/36] linux-user/nios2: Document non-use of setup_sigtramp, Richard Henderson, 2021/07/06
- [PATCH v2 25/36] linux-user/microblaze: Implement setup_sigtramp, Richard Henderson, 2021/07/06
- [PATCH v2 29/36] linux-user/openrisc: Implement setup_sigtramp, Richard Henderson, 2021/07/06
- [PATCH v2 27/36] linux-user/mips: Implement setup_sigtramp, Richard Henderson, 2021/07/06
- [PATCH v2 26/36] linux-user/mips: Tidy install_sigtramp, Richard Henderson, 2021/07/06
- [PATCH v2 24/36] linux-user/m68k: Implement setup_sigtramp, Richard Henderson, 2021/07/06
- [PATCH v2 30/36] target/ppc: Simplify encode_trampoline, Richard Henderson, 2021/07/06
- [PATCH v2 31/36] linux-user/ppc: Implement setup_sigtramp, Richard Henderson, 2021/07/06
- [PATCH v2 33/36] linux-user/s390x: Implement setup_sigtramp, Richard Henderson, 2021/07/06