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linux-7.2.3/arch/x86/um/os-Linux/Makefile

@@ -0,0 +1,12 @@
+#
+# Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+# Licensed under the GPL
+#
+
+obj-y = registers.o mcontext.o
+
+obj-$(CONFIG_X86_32) += tls.o
+
+USER_OBJS := $(obj-y)
+
+include $(srctree)/arch/um/scripts/Makefile.rules

linux-7.2.3/arch/x86/um/os-Linux/mcontext.c

@@ -0,0 +1,266 @@
+// SPDX-License-Identifier: GPL-2.0
+#define __FRAME_OFFSETS
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <sys/ucontext.h>
+#include <asm/ptrace.h>
+/*
+ * musl defines struct sigcontext in <bits/signal.h>.  Rename the kernel's
+ * copy to avoid redefinition while keeping the FP-state types available.
+ */
+#define sigcontext __kernel_sigcontext
+#include <asm/sigcontext.h>
+#undef sigcontext
+#include <sysdep/ptrace.h>
+#include <sysdep/mcontext.h>
+#include <arch.h>
+
+void get_regs_from_mc(struct uml_pt_regs *regs, mcontext_t *mc)
+{
+#ifdef __i386__
+#define COPY2(X,Y) regs->gp[X] = mc->gregs[REG_##Y]
+#define COPY(X) regs->gp[X] = mc->gregs[REG_##X]
+#define COPY_SEG(X) regs->gp[X] = mc->gregs[REG_##X] & 0xffff;
+#define COPY_SEG_CPL3(X) regs->gp[X] = (mc->gregs[REG_##X] & 0xffff) | 3;
+	COPY_SEG(GS); COPY_SEG(FS); COPY_SEG(ES); COPY_SEG(DS);
+	COPY(EDI); COPY(ESI); COPY(EBP);
+	COPY2(UESP, ESP); /* sic */
+	COPY(EBX); COPY(EDX); COPY(ECX); COPY(EAX);
+	COPY(EIP); COPY_SEG_CPL3(CS); COPY(EFL); COPY_SEG_CPL3(SS);
+#undef COPY2
+#undef COPY
+#undef COPY_SEG
+#undef COPY_SEG_CPL3
+#else
+#define COPY2(X,Y) regs->gp[X/sizeof(unsigned long)] = mc->gregs[REG_##Y]
+#define COPY(X) regs->gp[X/sizeof(unsigned long)] = mc->gregs[REG_##X]
+	COPY(R8); COPY(R9); COPY(R10); COPY(R11);
+	COPY(R12); COPY(R13); COPY(R14); COPY(R15);
+	COPY(RDI); COPY(RSI); COPY(RBP); COPY(RBX);
+	COPY(RDX); COPY(RAX); COPY(RCX); COPY(RSP);
+	COPY(RIP);
+	COPY2(EFLAGS, EFL);
+	COPY2(CS, CSGSFS);
+	regs->gp[SS / sizeof(unsigned long)] = mc->gregs[REG_CSGSFS] >> 48;
+#undef COPY2
+#undef COPY
+#endif
+}
+
+void mc_set_rip(void *_mc, void *target)
+{
+	mcontext_t *mc = _mc;
+
+#ifdef __i386__
+	mc->gregs[REG_EIP] = (unsigned long)target;
+#else
+	mc->gregs[REG_RIP] = (unsigned long)target;
+#endif
+}
+
+/* Same thing, but the copy macros are turned around. */
+void get_mc_from_regs(struct uml_pt_regs *regs, mcontext_t *mc, int single_stepping)
+{
+#ifdef __i386__
+#define COPY2(X,Y) mc->gregs[REG_##Y] = regs->gp[X]
+#define COPY(X) mc->gregs[REG_##X] = regs->gp[X]
+#define COPY_SEG(X) mc->gregs[REG_##X] = regs->gp[X] & 0xffff;
+#define COPY_SEG_CPL3(X) mc->gregs[REG_##X] = (regs->gp[X] & 0xffff) | 3;
+	COPY_SEG(GS); COPY_SEG(FS); COPY_SEG(ES); COPY_SEG(DS);
+	COPY(EDI); COPY(ESI); COPY(EBP);
+	COPY2(UESP, ESP); /* sic */
+	COPY(EBX); COPY(EDX); COPY(ECX); COPY(EAX);
+	COPY(EIP); COPY_SEG_CPL3(CS); COPY(EFL); COPY_SEG_CPL3(SS);
+#else
+#define COPY2(X,Y) mc->gregs[REG_##Y] = regs->gp[X/sizeof(unsigned long)]
+#define COPY(X) mc->gregs[REG_##X] = regs->gp[X/sizeof(unsigned long)]
+	COPY(R8); COPY(R9); COPY(R10); COPY(R11);
+	COPY(R12); COPY(R13); COPY(R14); COPY(R15);
+	COPY(RDI); COPY(RSI); COPY(RBP); COPY(RBX);
+	COPY(RDX); COPY(RAX); COPY(RCX); COPY(RSP);
+	COPY(RIP);
+	COPY2(EFLAGS, EFL);
+	mc->gregs[REG_CSGSFS] = mc->gregs[REG_CSGSFS] & 0xffffffffffffl;
+	mc->gregs[REG_CSGSFS] |= (regs->gp[SS / sizeof(unsigned long)] & 0xffff) << 48;
+#endif
+
+	if (single_stepping)
+		mc->gregs[REG_EFL] |= X86_EFLAGS_TF;
+	else
+		mc->gregs[REG_EFL] &= ~X86_EFLAGS_TF;
+}
+
+#ifdef CONFIG_X86_32
+struct _xstate_64 {
+	struct _fpstate_64		fpstate;
+	struct _header			xstate_hdr;
+	struct _ymmh_state		ymmh;
+	/* New processor state extensions go here: */
+};
+
+/* Not quite the right structures as these contain more information */
+int um_i387_from_fxsr(struct _fpstate_32 *i387,
+		      const struct _fpstate_64 *fxsave);
+int um_fxsr_from_i387(struct _fpstate_64 *fxsave,
+		      const struct _fpstate_32 *from);
+#else
+#define _xstate_64 _xstate
+#endif
+
+static struct _fpstate *get_fpstate(struct stub_data *data,
+				    mcontext_t *mcontext,
+				    int *fp_size)
+{
+	struct _fpstate *res;
+
+	/* Assume floating point registers are on the same page */
+	res = (void *)(((unsigned long)mcontext->fpregs &
+			(UM_KERN_PAGE_SIZE - 1)) +
+		       (unsigned long)&data->sigstack[0]);
+
+	if ((void *)res + sizeof(struct _fpstate) >
+	    (void *)data->sigstack + sizeof(data->sigstack))
+		return NULL;
+
+	if (res->sw_reserved.magic1 != FP_XSTATE_MAGIC1) {
+		*fp_size = sizeof(struct _fpstate);
+	} else {
+		char *magic2_addr;
+
+		magic2_addr = (void *)res;
+		magic2_addr += res->sw_reserved.extended_size;
+		magic2_addr -= FP_XSTATE_MAGIC2_SIZE;
+
+		/* We still need to be within our stack */
+		if ((void *)magic2_addr >
+		    (void *)data->sigstack + sizeof(data->sigstack))
+			return NULL;
+
+		/* If we do not read MAGIC2, then we did something wrong */
+		if (*(__u32 *)magic2_addr != FP_XSTATE_MAGIC2)
+			return NULL;
+
+		/* Remove MAGIC2 from the size, we do not save/restore it */
+		*fp_size = res->sw_reserved.extended_size -
+			   FP_XSTATE_MAGIC2_SIZE;
+	}
+
+	return res;
+}
+
+int get_stub_state(struct uml_pt_regs *regs, struct stub_data *data,
+		   unsigned long *fp_size_out)
+{
+	mcontext_t *mcontext;
+	struct _fpstate *fpstate_stub;
+	struct _xstate_64 *xstate_stub;
+	int fp_size, xstate_size;
+
+	/* mctx_offset is verified by wait_stub_done_seccomp */
+	mcontext = (void *)&data->sigstack[data->mctx_offset];
+
+	get_regs_from_mc(regs, mcontext);
+
+	fpstate_stub = get_fpstate(data, mcontext, &fp_size);
+	if (!fpstate_stub)
+		return -EINVAL;
+
+#ifdef CONFIG_X86_32
+	xstate_stub = (void *)&fpstate_stub->_fxsr_env;
+	xstate_size = fp_size - offsetof(struct _fpstate_32, _fxsr_env);
+#else
+	xstate_stub = (void *)fpstate_stub;
+	xstate_size = fp_size;
+#endif
+
+	if (fp_size_out)
+		*fp_size_out = xstate_size;
+
+	if (xstate_size > host_fp_size)
+		return -ENOSPC;
+
+	memcpy(&regs->fp, xstate_stub, xstate_size);
+
+	/* We do not need to read the x86_64 FS_BASE/GS_BASE registers as
+	 * we do not permit userspace to set them directly.
+	 */
+
+#ifdef CONFIG_X86_32
+	/* Read the i387 legacy FP registers */
+	if (um_fxsr_from_i387((void *)&regs->fp, fpstate_stub))
+		return -EINVAL;
+#endif
+
+	return 0;
+}
+
+/* Copied because we cannot include regset.h here. */
+struct task_struct;
+struct user_regset;
+struct membuf {
+	void *p;
+	size_t left;
+};
+
+int fpregs_legacy_get(struct task_struct *target,
+		      const struct user_regset *regset,
+		      struct membuf to);
+
+int set_stub_state(struct uml_pt_regs *regs, struct stub_data *data,
+		   int single_stepping)
+{
+	mcontext_t *mcontext;
+	struct _fpstate *fpstate_stub;
+	struct _xstate_64 *xstate_stub;
+	int fp_size, xstate_size;
+
+	/* mctx_offset is verified by wait_stub_done_seccomp */
+	mcontext = (void *)&data->sigstack[data->mctx_offset];
+
+	if ((unsigned long)mcontext < (unsigned long)data->sigstack ||
+	    (unsigned long)mcontext >
+			(unsigned long) data->sigstack +
+			sizeof(data->sigstack) - sizeof(*mcontext))
+		return -EINVAL;
+
+	get_mc_from_regs(regs, mcontext, single_stepping);
+
+	fpstate_stub = get_fpstate(data, mcontext, &fp_size);
+	if (!fpstate_stub)
+		return -EINVAL;
+
+#ifdef CONFIG_X86_32
+	xstate_stub = (void *)&fpstate_stub->_fxsr_env;
+	xstate_size = fp_size - offsetof(struct _fpstate_32, _fxsr_env);
+#else
+	xstate_stub = (void *)fpstate_stub;
+	xstate_size = fp_size;
+#endif
+
+	memcpy(xstate_stub, &regs->fp, xstate_size);
+
+#ifdef __i386__
+	/*
+	 * On x86, the GDT entries are updated by arch_set_tls.
+	 */
+
+	/* Store the i387 legacy FP registers which the host will use */
+	if (um_i387_from_fxsr(fpstate_stub, (void *)&regs->fp))
+		return -EINVAL;
+#else
+	/*
+	 * On x86_64, we need to sync the FS_BASE/GS_BASE registers using the
+	 * arch specific data.
+	 */
+	if (data->arch_data.fs_base != regs->gp[FS_BASE / sizeof(unsigned long)]) {
+		data->arch_data.fs_base = regs->gp[FS_BASE / sizeof(unsigned long)];
+		data->arch_data.sync |= STUB_SYNC_FS_BASE;
+	}
+	if (data->arch_data.gs_base != regs->gp[GS_BASE / sizeof(unsigned long)]) {
+		data->arch_data.gs_base = regs->gp[GS_BASE / sizeof(unsigned long)];
+		data->arch_data.sync |= STUB_SYNC_GS_BASE;
+	}
+#endif
+
+	return 0;
+}

linux-7.2.3/arch/x86/um/os-Linux/registers.c

@@ -0,0 +1,109 @@
+/*
+ * Copyright (C) 2004 PathScale, Inc
+ * Copyright (C) 2004 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+ * Licensed under the GPL
+ */
+
+#include <errno.h>
+#include <stdlib.h>
+#include <sys/ptrace.h>
+#ifdef __i386__
+#include <sys/user.h>
+#endif
+#include <longjmp.h>
+#include <sysdep/ptrace_user.h>
+#include <sys/uio.h>
+#include <asm/sigcontext.h>
+#include <linux/elf.h>
+#include <registers.h>
+#include <sys/mman.h>
+
+static unsigned long ptrace_regset;
+unsigned long host_fp_size;
+
+int get_fp_registers(int pid, unsigned long *regs)
+{
+	struct iovec iov = {
+		.iov_base = regs,
+		.iov_len = host_fp_size,
+	};
+
+	if (ptrace(PTRACE_GETREGSET, pid, ptrace_regset, &iov) < 0)
+		return -errno;
+	return 0;
+}
+
+int put_fp_registers(int pid, unsigned long *regs)
+{
+	struct iovec iov = {
+		.iov_base = regs,
+		.iov_len = host_fp_size,
+	};
+
+	if (ptrace(PTRACE_SETREGSET, pid, ptrace_regset, &iov) < 0)
+		return -errno;
+	return 0;
+}
+
+int arch_init_registers(int pid)
+{
+	struct iovec iov = {
+		/* Just use plenty of space, it does not cost us anything */
+		.iov_len = 2 * 1024 * 1024,
+	};
+	int ret;
+
+	iov.iov_base = mmap(NULL, iov.iov_len, PROT_WRITE | PROT_READ,
+			    MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+	if (iov.iov_base == MAP_FAILED)
+		return -ENOMEM;
+
+	/* GDB has x86_xsave_length, which uses x86_cpuid_count */
+	ptrace_regset = NT_X86_XSTATE;
+	ret = ptrace(PTRACE_GETREGSET, pid, ptrace_regset, &iov);
+	if (ret)
+		ret = -errno;
+
+	if (ret == -ENODEV) {
+#ifdef CONFIG_X86_32
+		ptrace_regset = NT_PRXFPREG;
+#else
+		ptrace_regset = NT_PRFPREG;
+#endif
+		iov.iov_len = 2 * 1024 * 1024;
+		ret = ptrace(PTRACE_GETREGSET, pid, ptrace_regset, &iov);
+		if (ret)
+			ret = -errno;
+	}
+
+	munmap(iov.iov_base, 2 * 1024 * 1024);
+
+	host_fp_size = iov.iov_len;
+
+	return ret;
+}
+
+unsigned long get_thread_reg(int reg, jmp_buf *buf)
+{
+	switch (reg) {
+#ifdef __i386__
+	case HOST_IP:
+		return buf[0]->__eip;
+	case HOST_SP:
+		return buf[0]->__esp;
+	case HOST_BP:
+		return buf[0]->__ebp;
+#else
+	case HOST_IP:
+		return buf[0]->__rip;
+	case HOST_SP:
+		return buf[0]->__rsp;
+	case HOST_BP:
+		return buf[0]->__rbp;
+#endif
+	default:
+		printk(UM_KERN_ERR "get_thread_regs - unknown register %d\n",
+		       reg);
+		return 0;
+	}
+}

linux-7.2.3/arch/x86/um/os-Linux/tls.c

@@ -0,0 +1,69 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <errno.h>
+#include <linux/unistd.h>
+
+#include <sys/ptrace.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+
+#include <os.h>
+#include <sysdep/tls.h>
+
+#ifndef PTRACE_GET_THREAD_AREA
+#define PTRACE_GET_THREAD_AREA 25
+#endif
+
+#ifndef PTRACE_SET_THREAD_AREA
+#define PTRACE_SET_THREAD_AREA 26
+#endif
+
+/* Checks whether host supports TLS, and sets *tls_min according to the value
+ * valid on the host.
+ * i386 host have it == 6; x86_64 host have it == 12, for i386 emulation. */
+void check_host_supports_tls(int *supports_tls, int *tls_min)
+{
+	/* Values for x86 and x86_64.*/
+	int val[] = {GDT_ENTRY_TLS_MIN_I386, GDT_ENTRY_TLS_MIN_X86_64};
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(val); i++) {
+		user_desc_t info;
+		info.entry_number = val[i];
+
+		if (syscall(__NR_get_thread_area, &info) == 0) {
+			*tls_min = val[i];
+			*supports_tls = 1;
+			return;
+		} else {
+			if (errno == EINVAL)
+				continue;
+			else if (errno == ENOSYS)
+				*supports_tls = 0;
+			return;
+		}
+	}
+
+	*supports_tls = 0;
+}
+
+int os_set_thread_area(user_desc_t *info, int pid)
+{
+	int ret;
+
+	ret = ptrace(PTRACE_SET_THREAD_AREA, pid, info->entry_number,
+		     (unsigned long) info);
+	if (ret < 0)
+		ret = -errno;
+	return ret;
+}
+
+int os_get_thread_area(user_desc_t *info, int pid)
+{
+	int ret;
+
+	ret = ptrace(PTRACE_GET_THREAD_AREA, pid, info->entry_number,
+		     (unsigned long) info);
+	if (ret < 0)
+		ret = -errno;
+	return ret;
+}