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https://github.com/torvalds/linux
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779df22487
Add a small vdso for 31 bit compat application that provides trampolines for calls to sigreturn,rt_sigreturn,syscall_restart. This is requird for moving these syscalls away from the signal frame to the vdso. Note that this patch effectively disables CONFIG_COMPAT when using clang to compile the kernel. clang doesn't support 31 bit mode. We want to redirect sigreturn and restart_syscall to the vdso. However, the kernel cannot parse the ELF vdso file, so we need to generate header files which contain the offsets of the syscall instructions in the vdso page. Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
22 lines
541 B
ArmAsm
22 lines
541 B
ArmAsm
/* SPDX-License-Identifier: GPL-2.0 */
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#include <asm/unistd.h>
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#include <asm/dwarf.h>
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.macro vdso_syscall func,syscall
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.globl __kernel_compat_\func
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.type __kernel_compat_\func,@function
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.align 8
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__kernel_compat_\func:
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CFI_STARTPROC
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svc \syscall
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/* Make sure we notice when a syscall returns, which shouldn't happen */
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.word 0
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CFI_ENDPROC
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.size __kernel_compat_\func,.-__kernel_compat_\func
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.endm
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vdso_syscall restart_syscall,__NR_restart_syscall
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vdso_syscall sigreturn,__NR_sigreturn
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vdso_syscall rt_sigreturn,__NR_rt_sigreturn
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