5298b7cffa
It was reported that qemu may not enable the XSTATE CPU extension, which is a requirement after commit3f17fed214("um: switch to regset API and depend on XSTATE"). Add a fallback to use FXSAVE (FP registers on x86_64 and XFP on i386) which is just a shorter version of the same data. The only difference is that the XSTATE magic should not be set in the signal frame. Note that this still drops support for the older i386 FP register layout as supporting this would require more backward compatibility to build a correct signal frame. Fixes:3f17fed214("um: switch to regset API and depend on XSTATE") Reported-by: SeongJae Park <sj@kernel.org> Closes: https://lore.kernel.org/r/20241203070218.240797-1-sj@kernel.org Tested-by: SeongJae Park <sj@kernel.org> Signed-off-by: Benjamin Berg <benjamin.berg@intel.com> Link: https://patch.msgid.link/20241204074827.1582917-1-benjamin@sipsolutions.net Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Richard Weinberger <richard@nod.at>
109 lines
2.1 KiB
C
109 lines
2.1 KiB
C
/*
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* Copyright (C) 2004 PathScale, Inc
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* Copyright (C) 2004 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
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* Licensed under the GPL
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*/
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#include <errno.h>
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#include <stdlib.h>
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#include <sys/ptrace.h>
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#ifdef __i386__
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#include <sys/user.h>
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#endif
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#include <longjmp.h>
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#include <sysdep/ptrace_user.h>
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#include <sys/uio.h>
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#include <asm/sigcontext.h>
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#include <linux/elf.h>
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#include <registers.h>
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#include <sys/mman.h>
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static unsigned long ptrace_regset;
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unsigned long host_fp_size;
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int get_fp_registers(int pid, unsigned long *regs)
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{
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struct iovec iov = {
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.iov_base = regs,
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.iov_len = host_fp_size,
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};
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if (ptrace(PTRACE_GETREGSET, pid, ptrace_regset, &iov) < 0)
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return -errno;
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return 0;
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}
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int put_fp_registers(int pid, unsigned long *regs)
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{
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struct iovec iov = {
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.iov_base = regs,
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.iov_len = host_fp_size,
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};
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if (ptrace(PTRACE_SETREGSET, pid, ptrace_regset, &iov) < 0)
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return -errno;
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return 0;
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}
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int arch_init_registers(int pid)
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{
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struct iovec iov = {
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/* Just use plenty of space, it does not cost us anything */
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.iov_len = 2 * 1024 * 1024,
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};
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int ret;
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iov.iov_base = mmap(NULL, iov.iov_len, PROT_WRITE | PROT_READ,
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MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
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if (iov.iov_base == MAP_FAILED)
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return -ENOMEM;
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/* GDB has x86_xsave_length, which uses x86_cpuid_count */
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ptrace_regset = NT_X86_XSTATE;
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ret = ptrace(PTRACE_GETREGSET, pid, ptrace_regset, &iov);
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if (ret)
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ret = -errno;
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if (ret == -ENODEV) {
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#ifdef CONFIG_X86_32
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ptrace_regset = NT_PRXFPREG;
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#else
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ptrace_regset = NT_PRFPREG;
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#endif
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iov.iov_len = 2 * 1024 * 1024;
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ret = ptrace(PTRACE_GETREGSET, pid, ptrace_regset, &iov);
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if (ret)
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ret = -errno;
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}
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munmap(iov.iov_base, 2 * 1024 * 1024);
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host_fp_size = iov.iov_len;
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return ret;
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}
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unsigned long get_thread_reg(int reg, jmp_buf *buf)
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{
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switch (reg) {
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#ifdef __i386__
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case HOST_IP:
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return buf[0]->__eip;
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case HOST_SP:
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return buf[0]->__esp;
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case HOST_BP:
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return buf[0]->__ebp;
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#else
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case HOST_IP:
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return buf[0]->__rip;
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case HOST_SP:
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return buf[0]->__rsp;
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case HOST_BP:
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return buf[0]->__rbp;
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#endif
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default:
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printk(UM_KERN_ERR "get_thread_regs - unknown register %d\n",
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reg);
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return 0;
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}
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}
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