diff mbox series

[v6,18/19] linux-user/s390x: Add vdso

Message ID 20230930021529.987950-19-richard.henderson@linaro.org
State Superseded
Headers show
Series linux-user: Implement VDSOs | expand

Commit Message

Richard Henderson Sept. 30, 2023, 2:15 a.m. UTC 
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/s390x/vdso-asmoffset.h |   2 +
 linux-user/elfload.c              |   2 +
 linux-user/s390x/signal.c         |   4 +-
 linux-user/s390x/Makefile.vdso    |  11 +++++
 linux-user/s390x/meson.build      |   6 +++
 linux-user/s390x/vdso.S           |  61 ++++++++++++++++++++++++++
 linux-user/s390x/vdso.ld          |  69 ++++++++++++++++++++++++++++++
 linux-user/s390x/vdso.so          | Bin 0 -> 3464 bytes
 8 files changed, 152 insertions(+), 3 deletions(-)
 create mode 100644 linux-user/s390x/vdso-asmoffset.h
 create mode 100644 linux-user/s390x/Makefile.vdso
 create mode 100644 linux-user/s390x/vdso.S
 create mode 100644 linux-user/s390x/vdso.ld
 create mode 100755 linux-user/s390x/vdso.so

GIT binary patch
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Comments

Philippe Mathieu-Daudé Oct. 3, 2023, 1:07 p.m. UTC | #1 
Hi Richard,

On 30/9/23 04:15, Richard Henderson wrote:
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>   linux-user/s390x/vdso-asmoffset.h |   2 +
>   linux-user/elfload.c              |   2 +
>   linux-user/s390x/signal.c         |   4 +-
>   linux-user/s390x/Makefile.vdso    |  11 +++++
>   linux-user/s390x/meson.build      |   6 +++
>   linux-user/s390x/vdso.S           |  61 ++++++++++++++++++++++++++
>   linux-user/s390x/vdso.ld          |  69 ++++++++++++++++++++++++++++++
>   linux-user/s390x/vdso.so          | Bin 0 -> 3464 bytes
>   8 files changed, 152 insertions(+), 3 deletions(-)
>   create mode 100644 linux-user/s390x/vdso-asmoffset.h
>   create mode 100644 linux-user/s390x/Makefile.vdso
>   create mode 100644 linux-user/s390x/vdso.S
>   create mode 100644 linux-user/s390x/vdso.ld
>   create mode 100755 linux-user/s390x/vdso.so


> diff --git a/linux-user/s390x/Makefile.vdso b/linux-user/s390x/Makefile.vdso
> new file mode 100644
> index 0000000000..e82bf9e29f
> --- /dev/null
> +++ b/linux-user/s390x/Makefile.vdso
> @@ -0,0 +1,11 @@
> +include $(BUILD_DIR)/tests/tcg/s390x-linux-user/config-target.mak
> +
> +SUBDIR = $(SRC_PATH)/linux-user/s390x
> +VPATH += $(SUBDIR)
> +
> +all: $(SUBDIR)/vdso.so
> +
> +$(SUBDIR)/vdso.so: vdso.S vdso.ld vdso-asmoffset.h
> +	$(CC) -o $@ -nostdlib -shared -Wl,-h,linux-vdso64.so.1 \
> +	  -Wl,--build-id=sha1 -Wl,--hash-style=both \
> +	  -Wl,-T,$(SUBDIR)/vdso.ld $<
> diff --git a/linux-user/s390x/meson.build b/linux-user/s390x/meson.build
> index 0781ccea1d..a7a25ed9ce 100644
> --- a/linux-user/s390x/meson.build
> +++ b/linux-user/s390x/meson.build
> @@ -3,3 +3,9 @@ syscall_nr_generators += {
>                        arguments: [ meson.current_source_dir() / 'syscallhdr.sh', '@INPUT@', '@OUTPUT@', '@EXTRA_ARGS@' ],
>                        output: '@BASENAME@_nr.h')
>   }
> +
> +vdso_inc = gen_vdso.process('vdso.so', extra_args: [
> +                                '-s', '__kernel_sigreturn',
> +                                '-r', '__kernel_rt_sigreturn'
> +                            ])
> +linux_user_ss.add(when: 'TARGET_S390X', if_true: vdso_inc)
> diff --git a/linux-user/s390x/vdso.S b/linux-user/s390x/vdso.S
> new file mode 100644
> index 0000000000..3332492477
> --- /dev/null
> +++ b/linux-user/s390x/vdso.S
> @@ -0,0 +1,61 @@
> +/*
> + * s390x 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 raw_syscall n
> +        .ifne	\n < 0x100
> +	svc	\n
> +	.else
> +	lghi	%r1, \n
> +	svc	0
> +        .endif
> +.endm
> +
> +.macro vdso_syscall name, nr
> +\name:
> +	.cfi_startproc
> +	aghi	%r15, -(STACK_FRAME_OVERHEAD + 16)
> +	.cfi_adjust_cfa_offset STACK_FRAME_OVERHEAD + 16
> +	stg	%r14, STACK_FRAME_OVERHEAD(%r15)
> +	.cfi_rel_offset %r14, STACK_FRAME_OVERHEAD
> +	raw_syscall \nr
> +	lg	%r14, STACK_FRAME_OVERHEAD(%r15)
> +	aghi	%r15, STACK_FRAME_OVERHEAD + 16
> +	.cfi_restore %r14
> +	.cfi_adjust_cfa_offset -(STACK_FRAME_OVERHEAD + 16)
> +	br	%r14
> +	.cfi_endproc
> +endf	\name
> +.endm
> +
> +vdso_syscall __kernel_gettimeofday, __NR_gettimeofday
> +vdso_syscall __kernel_clock_gettime, __NR_clock_gettime
> +vdso_syscall __kernel_clock_getres, __NR_clock_getres
> +vdso_syscall __kernel_getcpu, __NR_getcpu
> +
> +/*
> + * TODO unwind info, though we're ok without it.
> + * The kernel supplies bogus empty unwind info, and it is likely ignored
> + * by all users.  Without it we get the fallback signal frame handling.
> + */
> +
> +__kernel_sigreturn:
> +	raw_syscall __NR_sigreturn
> +endf	__kernel_sigreturn
> +
> +__kernel_rt_sigreturn:
> +	raw_syscall __NR_rt_sigreturn
> +endf	__kernel_rt_sigreturn
> diff --git a/linux-user/s390x/vdso.ld b/linux-user/s390x/vdso.ld
> new file mode 100644
> index 0000000000..2a30ff382a
> --- /dev/null
> +++ b/linux-user/s390x/vdso.ld
> @@ -0,0 +1,69 @@
> +/*
> + * Linker script for linux x86-64 replacement vdso.
> + *
> + * Copyright 2023 Linaro, Ltd.
> + *
> + * SPDX-License-Identifier: GPL-2.0-or-later
> + */
> +
> +VERSION {
> +        LINUX_2.6.29 {
> +        global:
> +                __kernel_gettimeofday;
> +                __kernel_clock_gettime;
> +                __kernel_clock_getres;
> +                __kernel_getcpu;
> +                __kernel_restart_syscall;

Where is __kernel_restart_syscall defined?

> +                __kernel_rt_sigreturn;
> +                __kernel_sigreturn;
> +        local: *;
> +        };
> +}
Richard Henderson Oct. 3, 2023, 11:01 p.m. UTC | #2 
On 10/3/23 06:07, Philippe Mathieu-Daudé wrote:
>> +++ b/linux-user/s390x/vdso.ld
>> @@ -0,0 +1,69 @@
>> +/*
>> + * Linker script for linux x86-64 replacement vdso.
>> + *
>> + * Copyright 2023 Linaro, Ltd.
>> + *
>> + * SPDX-License-Identifier: GPL-2.0-or-later
>> + */
>> +
>> +VERSION {
>> +        LINUX_2.6.29 {
>> +        global:
>> +                __kernel_gettimeofday;
>> +                __kernel_clock_gettime;
>> +                __kernel_clock_getres;
>> +                __kernel_getcpu;
>> +                __kernel_restart_syscall;
> 
> Where is __kernel_restart_syscall defined?

It isn't, and I guess isn't needed for qemu (we have QEMU_ERESTARTSYS).
I'm not sure why it's an exported symbol for the s390x vdso for the kernel, even if they 
do require some user-space code.

Anyway, I'll remove the symbol here.


r~
Philippe Mathieu-Daudé Oct. 5, 2023, 4:14 p.m. UTC | #3 
On 4/10/23 01:01, Richard Henderson wrote:
> On 10/3/23 06:07, Philippe Mathieu-Daudé wrote:
>>> +++ b/linux-user/s390x/vdso.ld
>>> @@ -0,0 +1,69 @@
>>> +/*
>>> + * Linker script for linux x86-64 replacement vdso.
>>> + *
>>> + * Copyright 2023 Linaro, Ltd.
>>> + *
>>> + * SPDX-License-Identifier: GPL-2.0-or-later
>>> + */
>>> +
>>> +VERSION {
>>> +        LINUX_2.6.29 {
>>> +        global:
>>> +                __kernel_gettimeofday;
>>> +                __kernel_clock_gettime;
>>> +                __kernel_clock_getres;
>>> +                __kernel_getcpu;
>>> +                __kernel_restart_syscall;
>>
>> Where is __kernel_restart_syscall defined?
> 
> It isn't, and I guess isn't needed for qemu (we have QEMU_ERESTARTSYS).
> I'm not sure why it's an exported symbol for the s390x vdso for the 
> kernel, even if they do require some user-space code.
> 
> Anyway, I'll remove the symbol here.

OK.

I dare to give:

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>

But still I'm Cc'ing David / Thomas who better know s390x :)
Thomas Huth Oct. 6, 2023, 7:30 a.m. UTC | #4 
On 05/10/2023 18.14, Philippe Mathieu-Daudé wrote:
> On 4/10/23 01:01, Richard Henderson wrote:
>> On 10/3/23 06:07, Philippe Mathieu-Daudé wrote:
>>>> +++ b/linux-user/s390x/vdso.ld
>>>> @@ -0,0 +1,69 @@
>>>> +/*
>>>> + * Linker script for linux x86-64 replacement vdso.

Should that be s390x instead of x86-64 ?

>>>> + * Copyright 2023 Linaro, Ltd.
>>>> + *
>>>> + * SPDX-License-Identifier: GPL-2.0-or-later
>>>> + */
>>>> +
>>>> +VERSION {
>>>> +        LINUX_2.6.29 {
>>>> +        global:
>>>> +                __kernel_gettimeofday;
>>>> +                __kernel_clock_gettime;
>>>> +                __kernel_clock_getres;
>>>> +                __kernel_getcpu;
>>>> +                __kernel_restart_syscall;
>>>
>>> Where is __kernel_restart_syscall defined?
>>
>> It isn't, and I guess isn't needed for qemu (we have QEMU_ERESTARTSYS).
>> I'm not sure why it's an exported symbol for the s390x vdso for the 
>> kernel, even if they do require some user-space code.
>>
>> Anyway, I'll remove the symbol here.
> 
> OK.
> 
> I dare to give:
> 
> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> 
> But still I'm Cc'ing David / Thomas who better know s390x :)

Uh, oh, vdso ... I remember some dark magic here on the real kernels on 
s390x, involving access registers ... good that we don't need those here :-)

I quickly glanced through the code, and apart from the typo above, it looks 
good to me, so:

Acked-by: Thomas Huth <thuth@redhat.com>
diff mbox series

Patch

diff --git a/linux-user/s390x/vdso-asmoffset.h b/linux-user/s390x/vdso-asmoffset.h
new file mode 100644
index 0000000000..27a062d6c1
--- /dev/null
+++ b/linux-user/s390x/vdso-asmoffset.h
@@ -0,0 +1,2 @@ 
+/* Minimum stack frame size */
+#define STACK_FRAME_OVERHEAD    160
diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 4a2d21a1f9..7450f9eab0 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -1886,6 +1886,8 @@  static void elf_core_copy_regs(target_elf_gregset_t *regs,
 #define USE_ELF_CORE_DUMP
 #define ELF_EXEC_PAGESIZE 4096
 
+#define VDSO_HEADER "vdso.c.inc"
+
 #endif /* TARGET_S390X */
 
 #ifdef TARGET_RISCV
diff --git a/linux-user/s390x/signal.c b/linux-user/s390x/signal.c
index 0f8b8e04bf..b40f738a70 100644
--- a/linux-user/s390x/signal.c
+++ b/linux-user/s390x/signal.c
@@ -21,14 +21,12 @@ 
 #include "user-internals.h"
 #include "signal-common.h"
 #include "linux-user/trace.h"
+#include "vdso-asmoffset.h"
 
 #define __NUM_GPRS 16
 #define __NUM_FPRS 16
 #define __NUM_ACRS 16
 
-/* Minimum stack frame size */
-#define STACK_FRAME_OVERHEAD    160
-
 #define _SIGCONTEXT_NSIG        64
 #define _SIGCONTEXT_NSIG_BPW    64 /* FIXME: 31-bit mode -> 32 */
 #define _SIGCONTEXT_NSIG_WORDS  (_SIGCONTEXT_NSIG / _SIGCONTEXT_NSIG_BPW)
diff --git a/linux-user/s390x/Makefile.vdso b/linux-user/s390x/Makefile.vdso
new file mode 100644
index 0000000000..e82bf9e29f
--- /dev/null
+++ b/linux-user/s390x/Makefile.vdso
@@ -0,0 +1,11 @@ 
+include $(BUILD_DIR)/tests/tcg/s390x-linux-user/config-target.mak
+
+SUBDIR = $(SRC_PATH)/linux-user/s390x
+VPATH += $(SUBDIR)
+
+all: $(SUBDIR)/vdso.so
+
+$(SUBDIR)/vdso.so: vdso.S vdso.ld vdso-asmoffset.h
+	$(CC) -o $@ -nostdlib -shared -Wl,-h,linux-vdso64.so.1 \
+	  -Wl,--build-id=sha1 -Wl,--hash-style=both \
+	  -Wl,-T,$(SUBDIR)/vdso.ld $<
diff --git a/linux-user/s390x/meson.build b/linux-user/s390x/meson.build
index 0781ccea1d..a7a25ed9ce 100644
--- a/linux-user/s390x/meson.build
+++ b/linux-user/s390x/meson.build
@@ -3,3 +3,9 @@  syscall_nr_generators += {
                      arguments: [ meson.current_source_dir() / 'syscallhdr.sh', '@INPUT@', '@OUTPUT@', '@EXTRA_ARGS@' ],
                      output: '@BASENAME@_nr.h')
 }
+
+vdso_inc = gen_vdso.process('vdso.so', extra_args: [
+                                '-s', '__kernel_sigreturn',
+                                '-r', '__kernel_rt_sigreturn'
+                            ])
+linux_user_ss.add(when: 'TARGET_S390X', if_true: vdso_inc)
diff --git a/linux-user/s390x/vdso.S b/linux-user/s390x/vdso.S
new file mode 100644
index 0000000000..3332492477
--- /dev/null
+++ b/linux-user/s390x/vdso.S
@@ -0,0 +1,61 @@ 
+/*
+ * s390x 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 raw_syscall n
+        .ifne	\n < 0x100
+	svc	\n
+	.else
+	lghi	%r1, \n
+	svc	0
+        .endif
+.endm
+
+.macro vdso_syscall name, nr
+\name:
+	.cfi_startproc
+	aghi	%r15, -(STACK_FRAME_OVERHEAD + 16)
+	.cfi_adjust_cfa_offset STACK_FRAME_OVERHEAD + 16
+	stg	%r14, STACK_FRAME_OVERHEAD(%r15)
+	.cfi_rel_offset %r14, STACK_FRAME_OVERHEAD
+	raw_syscall \nr
+	lg	%r14, STACK_FRAME_OVERHEAD(%r15)
+	aghi	%r15, STACK_FRAME_OVERHEAD + 16
+	.cfi_restore %r14
+	.cfi_adjust_cfa_offset -(STACK_FRAME_OVERHEAD + 16)
+	br	%r14
+	.cfi_endproc
+endf	\name
+.endm
+
+vdso_syscall __kernel_gettimeofday, __NR_gettimeofday
+vdso_syscall __kernel_clock_gettime, __NR_clock_gettime
+vdso_syscall __kernel_clock_getres, __NR_clock_getres
+vdso_syscall __kernel_getcpu, __NR_getcpu
+
+/*
+ * TODO unwind info, though we're ok without it.
+ * The kernel supplies bogus empty unwind info, and it is likely ignored
+ * by all users.  Without it we get the fallback signal frame handling.
+ */
+
+__kernel_sigreturn:
+	raw_syscall __NR_sigreturn
+endf	__kernel_sigreturn
+
+__kernel_rt_sigreturn:
+	raw_syscall __NR_rt_sigreturn
+endf	__kernel_rt_sigreturn
diff --git a/linux-user/s390x/vdso.ld b/linux-user/s390x/vdso.ld
new file mode 100644
index 0000000000..2a30ff382a
--- /dev/null
+++ b/linux-user/s390x/vdso.ld
@@ -0,0 +1,69 @@ 
+/*
+ * Linker script for linux x86-64 replacement vdso.
+ *
+ * Copyright 2023 Linaro, Ltd.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+VERSION {
+        LINUX_2.6.29 {
+        global:
+                __kernel_gettimeofday;
+                __kernel_clock_gettime;
+                __kernel_clock_getres;
+                __kernel_getcpu;
+                __kernel_restart_syscall;
+                __kernel_rt_sigreturn;
+                __kernel_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
+}
diff --git a/linux-user/s390x/vdso.so b/linux-user/s390x/vdso.so
new file mode 100755
index 0000000000000000000000000000000000000000..64130f6f335269b03291653d006225b365be9cd9