7911b650a0
The current LDT code has a few issues that mean it should be redone in a different way once we always start with a fresh MM even when cloning. In a new and better world, the kernel would just ensure its own LDT is clear at startup. At that point, all that is needed is a simple function to populate the LDT from another MM in arch_dup_mmap combined with some tracking of the installed LDT entries for each MM. Note that the old implementation was even incorrect with regard to reading, as it copied out the LDT entries in the internal format rather than converting them to the userspace structure. Removal should be fine as the LDT is not used for thread-local storage anymore. Signed-off-by: Benjamin Berg <benjamin.berg@intel.com> Link: https://patch.msgid.link/20240703134536.1161108-7-benjamin@sipsolutions.net Signed-off-by: Johannes Berg <johannes.berg@intel.com>
70 lines
1.3 KiB
C
70 lines
1.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2021 Benjamin Berg <benjamin@sipsolutions.net>
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*/
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#include <sysdep/stub.h>
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static __always_inline int syscall_handler(struct stub_data *d)
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{
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int i;
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unsigned long res;
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for (i = 0; i < d->syscall_data_len; i++) {
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struct stub_syscall *sc = &d->syscall_data[i];
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switch (sc->syscall) {
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case STUB_SYSCALL_MMAP:
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res = stub_syscall6(STUB_MMAP_NR,
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sc->mem.addr, sc->mem.length,
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sc->mem.prot,
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MAP_SHARED | MAP_FIXED,
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sc->mem.fd, sc->mem.offset);
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if (res != sc->mem.addr) {
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d->err = res;
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d->syscall_data_len = i;
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return -1;
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}
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break;
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case STUB_SYSCALL_MUNMAP:
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res = stub_syscall2(__NR_munmap,
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sc->mem.addr, sc->mem.length);
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if (res) {
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d->err = res;
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d->syscall_data_len = i;
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return -1;
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}
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break;
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case STUB_SYSCALL_MPROTECT:
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res = stub_syscall3(__NR_mprotect,
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sc->mem.addr, sc->mem.length,
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sc->mem.prot);
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if (res) {
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d->err = res;
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d->syscall_data_len = i;
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return -1;
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}
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break;
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default:
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d->err = -95; /* EOPNOTSUPP */
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d->syscall_data_len = i;
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return -1;
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}
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}
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d->err = 0;
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d->syscall_data_len = 0;
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return 0;
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}
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void __section(".__syscall_stub")
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stub_syscall_handler(void)
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{
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struct stub_data *d = get_stub_data();
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syscall_handler(d);
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trap_myself();
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}
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