linux-user/aarch64: Add vdso

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2021-06-15 10:21:37 -07:00
parent 6b1a9d38b5
commit ee95fae075
8 changed files with 176 additions and 0 deletions

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@ -0,0 +1,15 @@
include $(BUILD_DIR)/tests/tcg/aarch64-linux-user/config-target.mak
SUBDIR = $(SRC_PATH)/linux-user/aarch64
VPATH += $(SUBDIR)
all: $(SUBDIR)/vdso-be.so $(SUBDIR)/vdso-le.so
LDFLAGS = -nostdlib -shared -Wl,-h,linux-vdso.so.1 -Wl,--build-id=sha1 \
-Wl,--hash-style=both -Wl,-T,$(SUBDIR)/vdso.ld
$(SUBDIR)/vdso-be.so: vdso.S vdso.ld
$(CC) -o $@ $(LDFLAGS) -mbig-endian $<
$(SUBDIR)/vdso-le.so: vdso.S vdso.ld
$(CC) -o $@ $(LDFLAGS) -mlittle-endian $<

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@ -0,0 +1,11 @@
# TARGET_BIG_ENDIAN is defined to 'n' for little-endian; which means it
# is always true as far as source_set.apply() is concerned. Always build
# both header files and include the right one via #if.
vdso_be_inc = gen_vdso.process('vdso-be.so',
extra_args: ['-r', '__kernel_rt_sigreturn'])
vdso_le_inc = gen_vdso.process('vdso-le.so',
extra_args: ['-r', '__kernel_rt_sigreturn'])
linux_user_ss.add(when: 'TARGET_AARCH64', if_true: [vdso_be_inc, vdso_le_inc])

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linux-user/aarch64/vdso-be.so Executable file

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linux-user/aarch64/vdso-le.so Executable file

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71
linux-user/aarch64/vdso.S Normal file
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/*
* aarch64 linux replacement vdso.
*
* Copyright 2023 Linaro, Ltd.
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include <asm/unistd.h>
/* ??? These are in include/elf.h, which is not ready for inclusion in asm. */
#define NT_GNU_PROPERTY_TYPE_0 5
#define GNU_PROPERTY_AARCH64_FEATURE_1_AND 0xc0000000
#define GNU_PROPERTY_AARCH64_FEATURE_1_BTI (1U << 0)
#define GNU_PROPERTY_AARCH64_FEATURE_1_PAC (1U << 1)
#define GNU_PROPERTY_AARCH64_FEATURE_1_DEFAULT \
(GNU_PROPERTY_AARCH64_FEATURE_1_BTI | GNU_PROPERTY_AARCH64_FEATURE_1_PAC)
.section .note.gnu.property
.align 3
.long 2f - 1f
.long 6f - 3f
.long NT_GNU_PROPERTY_TYPE_0
1: .string "GNU"
2: .align 3
3: .long GNU_PROPERTY_AARCH64_FEATURE_1_AND
.long 5f - 4f
4: .long GNU_PROPERTY_AARCH64_FEATURE_1_DEFAULT
5: .align 3
6:
.text
.macro endf name
.globl \name
.type \name, @function
.size \name, . - \name
.endm
.macro vdso_syscall name, nr
\name:
bti c
mov x8, #\nr
svc #0
ret
endf \name
.endm
.cfi_startproc
vdso_syscall __kernel_gettimeofday, __NR_gettimeofday
vdso_syscall __kernel_clock_gettime, __NR_clock_gettime
vdso_syscall __kernel_clock_getres, __NR_clock_getres
.cfi_endproc
/*
* TODO: The kernel makes a big deal of turning off the .cfi directives,
* because they cause libgcc to crash, but that's because they're wrong.
*
* For now, elide the unwind info for __kernel_rt_sigreturn and rely on
* the libgcc fallback routine as we have always done. This requires
* that the code sequence used be exact.
*/
__kernel_rt_sigreturn:
/* No BTI C insn here -- we arrive via RET. */
mov x8, #__NR_rt_sigreturn
svc #0
endf __kernel_rt_sigreturn

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@ -0,0 +1,72 @@
/*
* Linker script for linux aarch64 replacement vdso.
*
* Copyright 2021 Linaro, Ltd.
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
VERSION {
LINUX_2.6.39 {
global:
__kernel_rt_sigreturn;
__kernel_gettimeofday;
__kernel_clock_gettime;
__kernel_clock_getres;
local: *;
};
}
PHDRS {
phdr PT_PHDR FLAGS(4) PHDRS;
load PT_LOAD FLAGS(7) FILEHDR PHDRS;
dynamic PT_DYNAMIC FLAGS(4);
eh_frame_hdr PT_GNU_EH_FRAME;
note PT_NOTE FLAGS(4);
}
SECTIONS {
/*
* We can't 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*) } :load :note
.dynamic : { *(.dynamic) } :load :dynamic
.dynsym : { *(.dynsym) } :load
/*
* There ought not be any real read-write data.
* But since we manipulated the segment layout,
* we have to put these sections somewhere.
*/
.data : {
*(.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 =0xd503201f
}

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@ -944,6 +944,12 @@ const char *elf_hwcap2_str(uint32_t bit)
#undef GET_FEATURE_ID
#if TARGET_BIG_ENDIAN
# define VDSO_HEADER "vdso-be.c.inc"
#else
# define VDSO_HEADER "vdso-le.c.inc"
#endif
#endif /* not TARGET_AARCH64 */
#endif /* TARGET_ARM */

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@ -35,6 +35,7 @@ gen_vdso_exe = executable('gen-vdso', 'gen-vdso.c',
gen_vdso = generator(gen_vdso_exe, output: '@BASENAME@.c.inc',
arguments: ['-o', '@OUTPUT@', '@EXTRA_ARGS@', '@INPUT@'])
subdir('aarch64')
subdir('alpha')
subdir('arm')
subdir('hppa')