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List: user-mode-linux-user
Subject: [uml-user] [RFC PATCH 7/10] SKAS4 - Host get_mm and switch_mm
From: Jeff Dike <jdike () addtoit ! com>
Date: 2008-01-28 21:38:31
Message-ID: 20080128213831.GA10256 () c2 ! user-mode-linux ! org
[Download RAW message or body]
This is the new_mm, switch_mm, and /proc/<pid>/mm implementation for
32- and 64-bit x86 and UML, plus 32-bit support on 64-bit x86.
diff --git a/arch/um/include/skas_ptrace.h b/arch/um/include/skas_ptrace.h
index cd2327d..6b55c52 100644
--- a/arch/um/include/skas_ptrace.h
+++ b/arch/um/include/skas_ptrace.h
@@ -7,7 +7,9 @@
#define __SKAS_PTRACE_H
#define PTRACE_FAULTINFO 52
-#define PTRACE_SWITCH_MM 55
+#ifndef OLD_PTRACE_SWITCH_MM
+#define OLD_PTRACE_SWITCH_MM 55
+#endif
#include "sysdep/skas_ptrace.h"
diff --git a/arch/um/kernel/ptrace.c b/arch/um/kernel/ptrace.c
index 47b57b4..913037e 100644
--- a/arch/um/kernel/ptrace.c
+++ b/arch/um/kernel/ptrace.c
@@ -192,7 +192,7 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
}
#endif
#ifdef CONFIG_PROC_MM
- case PTRACE_SWITCH_MM: {
+ case OLD_PTRACE_SWITCH_MM: {
struct mm_struct *old = child->mm;
struct mm_struct *new = proc_mm_get_mm(data);
@@ -292,3 +292,19 @@ void syscall_trace(struct uml_pt_regs *regs, int entryexit)
current->exit_code = 0;
}
}
+
+int copyin_user_regs(struct user_regs *to, unsigned long __user *from)
+{
+ return copy_from_user(&to->regs, from, sizeof(to->regs));
+}
+
+int ptrace_to_pt_regs(struct pt_regs *to, struct user_regs *from)
+{
+ memcpy(to, &from->regs, sizeof(from->regs));
+ return 0;
+}
+
+int pt_regs_to_ptrace(unsigned long __user *to, struct pt_regs *from)
+{
+ return copy_to_user(to, &from->regs.gp, sizeof(from->regs.gp));
+}
diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
index 82a0780..522d0f1 100644
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -627,7 +627,7 @@ void __switch_mm(struct mm_id *mm_idp)
/* FIXME: need cpu pid in __switch_mm */
if (proc_mm) {
- err = ptrace(PTRACE_SWITCH_MM, userspace_pid[0], 0,
+ err = ptrace(OLD_PTRACE_SWITCH_MM, userspace_pid[0], 0,
mm_idp->u.mm_fd);
if (err)
panic("__switch_mm - PTRACE_SWITCH_MM failed, "
diff --git a/arch/um/sys-i386/syscalls.c b/arch/um/sys-i386/syscalls.c
index e2d1426..85621a2 100644
--- a/arch/um/sys-i386/syscalls.c
+++ b/arch/um/sys-i386/syscalls.c
@@ -200,3 +200,11 @@ long sys_sigaction(int sig, const struct old_sigaction __user *act,
return ret;
}
+
+extern long do_switch_mm(int fd, int flags, long __user *new,
+ long __user *save, struct pt_regs *regs);
+
+long sys_switch_mm(int fd, int flags, long __user *new, long __user *save)
+{
+ return do_switch_mm(fd, flags, new, save, ¤t->thread.regs);
+}
diff --git a/arch/um/sys-x86_64/syscalls.c b/arch/um/sys-x86_64/syscalls.c
index 86f6b18..ff012ba 100644
--- a/arch/um/sys-x86_64/syscalls.c
+++ b/arch/um/sys-x86_64/syscalls.c
@@ -112,3 +112,11 @@ void arch_switch_to(struct task_struct *from, struct task_struct *to)
arch_prctl(to, ARCH_SET_FS, (void __user *) to->thread.arch.fs);
}
+
+extern long do_switch_mm(int fd, int flags, long __user *new,
+ long __user *save, struct pt_regs *regs);
+
+long stub_switch_mm(int fd, int flags, long __user *new, long __user *save)
+{
+ return do_switch_mm(fd, flags, new, save, ¤t->thread.regs);
+}
diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index df588f0..1992458 100644
--- a/arch/x86/ia32/ia32entry.S
+++ b/arch/x86/ia32/ia32entry.S
@@ -374,6 +374,7 @@ quiet_ni_syscall:
PTREGSCALL stub32_vfork, sys_vfork, %rdi
PTREGSCALL stub32_iopl, sys_iopl, %rsi
PTREGSCALL stub32_rt_sigsuspend, sys_rt_sigsuspend, %rdx
+ PTREGSCALL stub32_switch_mm, sys_switch_mm, %r8
ENTRY(ia32_ptregs_common)
popq %r11
@@ -726,4 +727,6 @@ ia32_sys_call_table:
.quad compat_sys_timerfd
.quad sys_eventfd
.quad sys32_fallocate
+ .quad sys_new_mm /* 325 */
+ .quad stub32_switch_mm
ia32_syscall_end:
diff --git a/arch/x86/ia32/ptrace32.c b/arch/x86/ia32/ptrace32.c
index 4a233ad..5c0caa4 100644
--- a/arch/x86/ia32/ptrace32.c
+++ b/arch/x86/ia32/ptrace32.c
@@ -38,7 +38,7 @@
#define R32(l,q) \
case offsetof(struct user32, regs.l): stack[offsetof(struct pt_regs, q)/8] = val; break
-static int putreg32(struct task_struct *child, unsigned regno, u32 val)
+int putreg32(struct task_struct *child, unsigned regno, u32 val)
{
int i;
__u64 *stack = (__u64 *)task_pt_regs(child);
@@ -139,7 +139,7 @@ static int putreg32(struct task_struct *child, unsigned regno, u32 val)
#define R32(l,q) \
case offsetof(struct user32, regs.l): *val = stack[offsetof(struct pt_regs, q)/8]; break
-static int getreg32(struct task_struct *child, unsigned regno, u32 *val)
+int getreg32(struct task_struct *child, unsigned regno, u32 *val)
{
__u64 *stack = (__u64 *)task_pt_regs(child);
@@ -248,6 +248,7 @@ asmlinkage long sys32_ptrace(long request, u32 pid, u32 addr, u32 data)
case PTRACE_SETOPTIONS:
case PTRACE_SET_THREAD_AREA:
case PTRACE_GET_THREAD_AREA:
+ case PTRACE_SWITCH_MM:
return sys_ptrace(request, pid, addr, data);
default:
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index e70f388..103ad9c 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -412,6 +412,7 @@ END(\label)
PTREGSCALL stub_rt_sigsuspend, sys_rt_sigsuspend, %rdx
PTREGSCALL stub_sigaltstack, sys_sigaltstack, %rdx
PTREGSCALL stub_iopl, sys_iopl, %rsi
+ PTREGSCALL stub_switch_mm, sys_switch_mm, %r8
ENTRY(ptregscall_common)
popq %r11
diff --git a/arch/x86/kernel/ptrace_32.c b/arch/x86/kernel/ptrace_32.c
index ff5431c..a35dd5f 100644
--- a/arch/x86/kernel/ptrace_32.c
+++ b/arch/x86/kernel/ptrace_32.c
@@ -83,8 +83,8 @@ static inline int put_stack_long(struct task_struct *task, int offset,
return 0;
}
-static int putreg(struct task_struct *child,
- unsigned long regno, unsigned long value)
+int putreg(struct task_struct *child,
+ unsigned long regno, unsigned long value)
{
switch (regno >> 2) {
case GS:
@@ -116,7 +116,7 @@ static int putreg(struct task_struct *child,
return 0;
}
-static unsigned long getreg(struct task_struct *child,
+unsigned long getreg(struct task_struct *child,
unsigned long regno)
{
unsigned long retval = ~0UL;
@@ -715,3 +715,36 @@ out:
audit_syscall_exit(AUDITSC_RESULT(regs->eax), regs->eax);
return 1;
}
+
+int copyin_user_regs(struct user_regs *to, unsigned long __user *from)
+{
+ return copy_from_user(&to->regs, from, sizeof(to->regs));
+}
+
+int ptrace_to_pt_regs(struct pt_regs *regs, struct user_regs *ptrace)
+{
+ int i, err;
+
+ for (i = 0; i < FRAME_SIZE; i++){
+ err = putreg(current, i * 4, ptrace->regs[i]);
+ if (err)
+ return err;
+ }
+
+ return 0;
+}
+
+int pt_regs_to_ptrace(unsigned long __user *ptrace, struct pt_regs *regs)
+{
+ int i;
+
+ if (!access_ok(VERIFY_WRITE, ptrace, FRAME_SIZE * sizeof(long)))
+ return -EFAULT;
+
+ for (i = 0; i < FRAME_SIZE; i++){
+ unsigned long n = getreg(current, i * 4), err;
+ err = put_user(n, &ptrace[i]);
+ }
+
+ return 0;
+}
diff --git a/arch/x86/kernel/ptrace_64.c b/arch/x86/kernel/ptrace_64.c
index 607085f..ab8954d 100644
--- a/arch/x86/kernel/ptrace_64.c
+++ b/arch/x86/kernel/ptrace_64.c
@@ -226,7 +226,7 @@ void ptrace_disable(struct task_struct *child)
clear_singlestep(child);
}
-static int putreg(struct task_struct *child,
+int putreg(struct task_struct *child,
unsigned long regno, unsigned long value)
{
unsigned long tmp;
@@ -283,7 +283,7 @@ static int putreg(struct task_struct *child,
return 0;
}
-static unsigned long getreg(struct task_struct *child, unsigned long regno)
+unsigned long getreg(struct task_struct *child, unsigned long regno)
{
unsigned long val;
switch (regno) {
@@ -619,3 +619,101 @@ asmlinkage void syscall_trace_leave(struct pt_regs *regs)
&& (current->ptrace & PT_PTRACED))
syscall_trace(regs);
}
+
+int copyin_user_regs(struct user_regs *to, unsigned long __user *from)
+{
+#ifdef CONFIG_IA32_EMULATION
+ if (test_thread_flag(TIF_IA32))
+ return copy_from_user(&to->u.regs32, from,
+ sizeof(to->u.regs32));
+#endif
+ return copy_from_user(&to->u.regs64, from, sizeof(to->u.regs64));
+}
+
+extern int putreg32(struct task_struct *child, unsigned regno, u32 val);
+
+int ptrace_to_pt_regs(struct pt_regs *regs, struct user_regs *ptrace)
+{
+ int i, err;
+
+#ifdef CONFIG_IA32_EMULATION
+ if (test_thread_flag(TIF_IA32)) {
+ for (i = 0; i < MAX_REG32_NR; i++){
+ err = putreg32(current, i * 4, ptrace->u.regs32[i]);
+ if (err)
+ return err;
+ }
+
+ return 0;
+ }
+#endif
+ for (i = 0; i < MAX_REG_NR; i++){
+ err = putreg(current, i * 8, ptrace->u.regs64[i]);
+ if (err)
+ return err;
+ }
+
+ return 0;
+}
+
+extern int getreg32(struct task_struct *child, unsigned regno, u32 *val);
+
+int pt_regs_to_ptrace(unsigned long __user *ptrace, struct pt_regs *regs)
+{
+ int i, err;
+
+#ifdef CONFIG_IA32_EMULATION
+ if (test_thread_flag(TIF_IA32)) {
+ u32 __user *ptrace32 = (u32 __user *) ptrace;
+
+ if (!access_ok(VERIFY_WRITE, ptrace32, MAX_REG32_NR * 4))
+ return -EFAULT;
+
+ for (i = 0; i < MAX_REG32_NR; i++){
+ u32 n;
+
+ err = getreg32(current, i * 4, &n);
+ if (err)
+ return err;
+
+ err = __put_user(n, &ptrace32[i]);
+ if (err)
+ return err;
+ }
+
+ return 0;
+ }
+#endif
+ if (!access_ok(VERIFY_WRITE, ptrace, MAX_REG_NR * 8))
+ return -EFAULT;
+
+ for (i = 0; i < MAX_REG_NR; i++){
+ unsigned long n = getreg(current, i * 8);
+ err = __put_user(n, &ptrace[i]);
+ if (err)
+ return err;
+ }
+
+ return 0;
+}
+
+#define RIP_INDEX (128 / sizeof(long))
+#define RSP_INDEX (152 / sizeof(long))
+
+unsigned long ptrace_ip(struct user_regs *regs)
+{
+#ifdef CONFIG_IA32_EMULATION
+ if (test_thread_flag(TIF_IA32))
+ return ptrace_ip32(regs->u.regs32);
+#endif
+ return regs->u.regs64[RIP_INDEX];
+}
+
+unsigned long ptrace_sp(struct user_regs *regs)
+{
+#ifdef CONFIG_IA32_EMULATION
+ if (test_thread_flag(TIF_IA32))
+ return ptrace_sp32(regs->u.regs32);
+#endif
+ return regs->u.regs64[RSP_INDEX];
+}
diff --git a/arch/x86/kernel/sys_i386_32.c b/arch/x86/kernel/sys_i386_32.c
index a86d26f..7b9d43b 100644
--- a/arch/x86/kernel/sys_i386_32.c
+++ b/arch/x86/kernel/sys_i386_32.c
@@ -261,3 +261,12 @@ int kernel_execve(const char *filename, char *const argv[], char *const envp[])
: "0" (__NR_execve),"ri" (filename),"c" (argv), "d" (envp) : "memory");
return __res;
}
+
+extern long do_switch_mm(int fd, int flags, long __user *new, long __user *save,
+ struct pt_regs *regs);
+
+asmlinkage long sys_switch_mm(struct pt_regs regs)
+{
+ return do_switch_mm(regs.ebx, regs.ecx, (long __user *) regs.edx,
+ (long __user *) regs.esi, ®s);
+}
diff --git a/arch/x86/kernel/sys_x86_64.c b/arch/x86/kernel/sys_x86_64.c
index 907942e..ddc1c98 100644
--- a/arch/x86/kernel/sys_x86_64.c
+++ b/arch/x86/kernel/sys_x86_64.c
@@ -153,3 +153,12 @@ asmlinkage long sys_uname(struct new_utsname __user * name)
err |= copy_to_user(&name->machine, "i686", 5);
return err ? -EFAULT : 0;
}
+
+extern long do_switch_mm(int fd, int flags, long __user *new,
+ long __user *save, struct pt_regs *regs);
+
+asmlinkage long sys_switch_mm(int fd, int flags, long __user *new,
+ long __user *save, struct pt_regs *regs)
+{
+ return do_switch_mm(fd, flags, new, save, regs);
+}
diff --git a/arch/x86/kernel/syscall_table_32.S b/arch/x86/kernel/syscall_table_32.S
index 8344c70..3346997 100644
--- a/arch/x86/kernel/syscall_table_32.S
+++ b/arch/x86/kernel/syscall_table_32.S
@@ -324,3 +324,5 @@ ENTRY(sys_call_table)
.long sys_timerfd
.long sys_eventfd
.long sys_fallocate
+ .long sys_new_mm
+ .long sys_switch_mm
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 91fa8e6..03475a0 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2259,6 +2259,34 @@ static int proc_pid_io_accounting(struct task_struct *task, char *buffer)
}
#endif
+static int proc_pid_mm_open(struct inode *inode, struct file *file)
+{
+ struct task_struct *task = pid_task(proc_pid(inode), PIDTYPE_PID);
+
+ if (task == NULL)
+ return -ENOENT;
+
+ if(task->mm != NULL)
+ atomic_inc(&task->mm->mm_users);
+ file->private_data = task->mm;
+ return 0;
+}
+
+static int proc_pid_mm_release(struct inode *inode, struct file *file)
+{
+ struct mm_struct *mm = file->private_data;
+
+ if(mm != NULL)
+ mmput(mm);
+
+ return 0;
+}
+
+const struct file_operations proc_pid_mm_operations = {
+ .open = proc_pid_mm_open,
+ .release = proc_pid_mm_release,
+};
+
/*
* Thread groups
*/
@@ -2325,6 +2353,7 @@ static const struct pid_entry tgid_base_stuff[] = {
#ifdef CONFIG_TASK_IO_ACCOUNTING
INF("io", S_IRUGO, pid_io_accounting),
#endif
+ REG("mm", S_IRUSR | S_IWUSR, pid_mm),
};
static int proc_tgid_base_readdir(struct file * filp,
diff --git a/include/asm-um/ptrace-generic.h b/include/asm-um/ptrace-generic.h
index 6aefcd3..7894c3d 100644
--- a/include/asm-um/ptrace-generic.h
+++ b/include/asm-um/ptrace-generic.h
@@ -34,6 +34,15 @@ struct pt_regs {
#define instruction_pointer(regs) PT_REGS_IP(regs)
+struct user_regs {
+ unsigned long regs[MAX_REG_NR];
+};
+
+extern int copyin_user_regs(struct user_regs *to, unsigned long __user *from);
+extern int ptrace_to_pt_regs(struct pt_regs *ptregs, struct user_regs *regs);
+extern int pt_regs_to_ptrace(unsigned long __user *regs,
+ struct pt_regs *ptregs);
+
struct task_struct;
extern long subarch_ptrace(struct task_struct *child, long request, long addr,
diff --git a/include/asm-um/ptrace-i386.h b/include/asm-um/ptrace-i386.h
index b2d24c5..9bec151 100644
--- a/include/asm-um/ptrace-i386.h
+++ b/include/asm-um/ptrace-i386.h
@@ -40,6 +40,12 @@
#define user_mode(r) UPT_IS_USER(&(r)->regs)
+#define pt_regs_ip(r) (r).regs.gp[EIP]
+#define pt_regs_sp(r) (r).regs.gp[UESP]
+
+#define ptrace_ip(r) (r)->regs[EIP]
+#define ptrace_sp(r) (r)->regs[UESP]
+
/*
* Forward declaration to avoid including sysdep/tls.h, which causes a
* circular include, and compilation failures.
diff --git a/include/asm-um/ptrace-x86_64.h b/include/asm-um/ptrace-x86_64.h
index 4c47535..9c5365e 100644
--- a/include/asm-um/ptrace-x86_64.h
+++ b/include/asm-um/ptrace-x86_64.h
@@ -62,6 +62,12 @@
#define PT_FIX_EXEC_STACK(sp) do ; while(0)
+#define pt_regs_ip(r) (r).regs.gp[RIP / sizeof(long)]
+#define pt_regs_sp(r) (r).regs.gp[RSP / sizeof(long)]
+
+#define ptrace_ip(r) (r)->regs[RIP / sizeof(long)]
+#define ptrace_sp(r) (r)->regs[RSP / sizeof(long)]
+
#define profile_pc(regs) PT_REGS_IP(regs)
static inline int ptrace_get_thread_area(struct task_struct *child, int idx,
diff --git a/include/asm-x86/ptrace.h b/include/asm-x86/ptrace.h
index 51ddb25..229b5b2 100644
--- a/include/asm-x86/ptrace.h
+++ b/include/asm-x86/ptrace.h
@@ -2,6 +2,7 @@
#define _ASM_X86_PTRACE_H
#include <linux/compiler.h> /* For __user */
+#include <asm/user.h>
#include <asm/ptrace-abi.h>
#ifndef __ASSEMBLY__
@@ -64,6 +65,22 @@ static inline int v8086_mode(struct pt_regs *regs)
#define regs_return_value(regs) ((regs)->eax)
extern unsigned long profile_pc(struct pt_regs *regs);
+
+struct user_regs {
+ unsigned long regs[FRAME_SIZE];
+};
+
+#define pt_regs_ip(r) (r).eip
+#define pt_regs_sp(r) (r).esp
+
+#define ptrace_ip(r) (r)->regs[EIP]
+#define ptrace_sp(r) (r)->regs[UESP]
+
+extern int copyin_user_regs(struct user_regs *to, unsigned long __user *from);
+extern int ptrace_to_pt_regs(struct pt_regs *regs, struct user_regs *ptrace);
+extern int pt_regs_to_ptrace(unsigned long __user *ptrace,
+ struct pt_regs *regs);
+
#endif /* __KERNEL__ */
#else /* __i386__ */
@@ -135,6 +152,40 @@ enum {
EF_VIP = 0x00100000, /* virtual interrupt pending */
EF_ID = 0x00200000, /* id */
};
+
+#ifdef CONFIG_IA32_EMULATION
+#define MAX_REG32_NR 17
+
+#define EIP 12
+#define UESP 15
+
+#define ptrace_ip32(regs) (unsigned long) (regs)[EIP]
+#define ptrace_sp32(regs) (unsigned long) (regs)[UESP]
+
+#endif
+
+#define MAX_REG_NR (sizeof(struct user_regs_struct) / sizeof(long))
+
+struct user_regs {
+ union {
+ unsigned long regs64[MAX_REG_NR];
+#ifdef CONFIG_IA32_EMULATION
+ u32 regs32[MAX_REG32_NR];
+#endif
+ } u;
+};
+
+#define pt_regs_ip(regs) (regs).rip
+#define pt_regs_sp(regs) (regs).rsp
+
+extern unsigned long ptrace_ip(struct user_regs *regs);
+extern unsigned long ptrace_sp(struct user_regs *regs);
+
+extern int copyin_user_regs(struct user_regs *to, unsigned long __user *from);
+extern int ptrace_to_pt_regs(struct pt_regs *regs, struct user_regs *ptrace);
+extern int pt_regs_to_ptrace(unsigned long __user *ptrace,
+ struct pt_regs *regs);
+
#endif /* __KERNEL__ */
#endif /* !__i386__ */
#endif /* !__ASSEMBLY__ */
diff --git a/include/asm-x86/unistd_32.h b/include/asm-x86/unistd_32.h
index 9b15545..3477555 100644
--- a/include/asm-x86/unistd_32.h
+++ b/include/asm-x86/unistd_32.h
@@ -330,10 +330,12 @@
#define __NR_timerfd 322
#define __NR_eventfd 323
#define __NR_fallocate 324
+#define __NR_new_mm 325
+#define __NR_switch_mm 326
#ifdef __KERNEL__
-#define NR_syscalls 325
+#define NR_syscalls 327
#define __ARCH_WANT_IPC_PARSE_VERSION
#define __ARCH_WANT_OLD_READDIR
diff --git a/include/asm-x86/unistd_64.h b/include/asm-x86/unistd_64.h
index 5ff4d3e..baf4c0c 100644
--- a/include/asm-x86/unistd_64.h
+++ b/include/asm-x86/unistd_64.h
@@ -635,6 +635,10 @@ __SYSCALL(__NR_timerfd, sys_timerfd)
__SYSCALL(__NR_eventfd, sys_eventfd)
#define __NR_fallocate 285
__SYSCALL(__NR_fallocate, sys_fallocate)
+#define __NR_new_mm 286
+__SYSCALL(__NR_new_mm, sys_new_mm)
+#define __NR_switch_mm 287
+__SYSCALL(__NR_switch_mm, stub_switch_mm)
#ifndef __NO_STUBS
#define __ARCH_WANT_OLD_READDIR
diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index 3ea5750..6758e86 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -21,6 +21,8 @@
#define PTRACE_SYSCALL 24
+#define PTRACE_SWITCH_MM 33
+
/* 0x4200-0x4300 are reserved for architecture-independent additions. */
#define PTRACE_SETOPTIONS 0x4200
#define PTRACE_GETEVENTMSG 0x4201
diff --git a/include/linux/sched.h b/include/linux/sched.h
index df5b24e..a07f60a 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1707,6 +1707,7 @@ static inline int sas_ss_flags(unsigned long sp)
* Routines for handling mm_structs
*/
extern struct mm_struct * mm_alloc(void);
+extern struct mm_struct *dup_mm(struct task_struct *tsk);
/* mmdrop drops the mm and the page tables */
extern void FASTCALL(__mmdrop(struct mm_struct *));
diff --git a/kernel/fork.c b/kernel/fork.c
index 39d22b3..720f188 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -491,7 +491,7 @@ void mm_release(struct task_struct *tsk, struct mm_struct *mm)
* Allocate a new mm structure and copy contents from the
* mm structure of the passed in task structure.
*/
-static struct mm_struct *dup_mm(struct task_struct *tsk)
+struct mm_struct *dup_mm(struct task_struct *tsk)
{
struct mm_struct *mm, *oldmm = current->mm;
int err;
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index c719bb9..863b786 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -366,6 +366,23 @@ static int ptrace_setsiginfo(struct task_struct *child, siginfo_t __user * data)
return error;
}
+extern struct mm_struct *fd_to_mm(int fd);
+extern void do_switch(struct task_struct *task, struct mm_struct *mm);
+
+static int ptrace_switch_mm(struct task_struct *child, int mm_fd)
+{
+ struct mm_struct *new = fd_to_mm(mm_fd);
+
+ if (IS_ERR(new))
+ return PTR_ERR(new);
+
+ do_switch(child, new);
+
+ mmput(new);
+
+ return 0;
+}
+
int ptrace_request(struct task_struct *child, long request,
long addr, long data)
{
@@ -390,6 +407,9 @@ int ptrace_request(struct task_struct *child, long request,
case PTRACE_DETACH: /* detach a process that was attached. */
ret = ptrace_detach(child, data);
break;
+ case PTRACE_SWITCH_MM:
+ ret = ptrace_switch_mm(child, data);
+ break;
default:
break;
}
diff --git a/mm/Makefile b/mm/Makefile
index 5c0b0ea..9351c4e 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -4,8 +4,8 @@
mmu-y := nommu.o
mmu-$(CONFIG_MMU) := fremap.o highmem.o madvise.o memory.o mincore.o \
- mlock.o mmap.o mprotect.o mremap.o msync.o rmap.o \
- vmalloc.o
+ mlock.o mmap.o mmfs.o mprotect.o mremap.o msync.o \
+ rmap.o vmalloc.o
obj-y := bootmem.o filemap.o mempool.o oom_kill.o fadvise.o \
page_alloc.o page-writeback.o pdflush.o \
diff --git a/mm/mmfs.c b/mm/mmfs.c
new file mode 100644
index 0000000..5ec5e45
--- /dev/null
+++ b/mm/mmfs.c
@@ -0,0 +1,254 @@
+#define __FRAME_OFFSETS
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/mount.h>
+#include <linux/sched.h>
+#include <asm/mmu_context.h>
+#include <asm/ptrace.h>
+#include <asm/uaccess.h>
+#include <asm/user.h>
+
+static int release_mm(struct inode *inode, struct file *file)
+{
+ struct mm_struct *mm = file->private_data;
+
+ mmput(mm);
+ return 0;
+}
+
+#define MM_MAGIC 0xE0AAC500
+
+static int mm_get_sb(struct file_system_type *fs_type,
+ int flags, const char *dev_name, void *data,
+ struct vfsmount *mnt)
+{
+ return get_sb_pseudo(fs_type, "mm:", NULL, MM_MAGIC, mnt);
+}
+
+static struct vfsmount *mm_mnt;
+
+static struct file_system_type mm_fs_type = {
+ .name = "mm",
+ .get_sb = mm_get_sb,
+ .kill_sb = kill_anon_super,
+};
+
+static int __init init_mm_fs(void)
+{
+ int err;
+
+ err = register_filesystem(&mm_fs_type);
+ if (err)
+ return err;
+
+ mm_mnt = kern_mount(&mm_fs_type);
+ if (IS_ERR(mm_mnt)) {
+ err = PTR_ERR(mm_mnt);
+ unregister_filesystem(&mm_fs_type);
+ }
+
+ return err;
+}
+
+static void __exit exit_mm_fs(void)
+{
+ unregister_filesystem(&mm_fs_type);
+ mntput(mm_mnt);
+}
+
+fs_initcall(init_mm_fs);
+module_exit(exit_mm_fs);
+
+static int mm_delete_dentry(struct dentry *dentry)
+{
+ /*
+ * At creation time, we pretended this dentry was hashed
+ * (by clearing DCACHE_UNHASHED bit in d_flags)
+ * At delete time, we restore the truth : not hashed.
+ * (so that dput() can proceed correctly)
+ */
+ dentry->d_flags |= DCACHE_UNHASHED;
+ return 0;
+}
+
+/*
+ * pipefs_dname() is called from d_path().
+ */
+static char *mm_dname(struct dentry *dentry, char *buffer, int buflen)
+{
+ return dynamic_dname(dentry, buffer, buflen, "mm:[%lu]",
+ dentry->d_inode->i_ino);
+}
+
+static struct dentry_operations mm_dentry_operations = {
+ .d_delete = mm_delete_dentry,
+ .d_dname = mm_dname,
+};
+
+static struct file_operations mm_fops = {
+ .release = release_mm,
+};
+
+#define MM_FLAGS_MASK 1
+#define MM_INIT_MASK 1
+
+#define MM_COPY 0
+#define MM_EMPTY 1
+
+asmlinkage long sys_new_mm(int flags)
+{
+ struct file *file;
+ struct mm_struct *mm;
+ struct inode *inode;
+ struct dentry *dentry;
+ struct qstr name = { .name = "" };
+ int err, fd;
+
+ if ((flags & ~MM_FLAGS_MASK) != 0)
+ return -EINVAL;
+
+ if ((flags & MM_INIT_MASK) == MM_COPY) {
+ mm = dup_mm(current);
+ if (mm == NULL)
+ return -ENOMEM;
+ }
+ else
+ return -EINVAL;
+
+ fd = get_unused_fd();
+ if (fd < 0) {
+ err = fd;
+ goto out_free;
+ }
+
+ err = -ENOMEM;
+ dentry = d_alloc(mm_mnt->mnt_sb->s_root, &name);
+ if (dentry == NULL)
+ goto out_put;
+
+ dentry->d_op = &mm_dentry_operations;
+ dentry->d_flags &= ~DCACHE_UNHASHED;
+
+ inode = new_inode(mm_mnt->mnt_sb);
+ if (inode == NULL)
+ goto out_dput;
+
+ inode->i_mode = S_IRUSR;
+ inode->i_uid = current->fsuid;
+ inode->i_gid = current->fsgid;
+ inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+
+ d_instantiate(dentry, inode);
+
+ file = alloc_file(mm_mnt, dentry, FMODE_READ, &mm_fops);
+ if (file == NULL)
+ goto out_dput;
+
+ file->f_flags = O_RDONLY;
+ file->private_data = mm;
+
+ fd_install(fd, file);
+
+ return fd;
+
+ out_dput:
+ dput(dentry);
+ out_put:
+ put_unused_fd(fd);
+ out_free:
+ mmput(mm);
+ return err;
+}
+
+extern const struct file_operations proc_pid_mm_operations;
+
+/* Returns with an extra reference on mm */
+struct mm_struct *fd_to_mm(int fd)
+{
+ struct mm_struct *mm;
+ struct file *file = fget(fd);
+
+ if (!file)
+ return ERR_PTR(-EBADF);
+
+ if ((file->f_op != &mm_fops) &&
+ (file->f_op != &proc_pid_mm_operations))
+ mm = ERR_PTR(-EINVAL);
+ else {
+ mm = file->private_data;
+ atomic_inc(&mm->mm_users);
+ }
+
+ fput(file);
+
+ return mm;
+}
+
+void do_switch(struct task_struct *task, struct mm_struct *mm)
+{
+ struct mm_struct *old = task->mm;
+
+ task_lock(task);
+
+ atomic_inc(&mm->mm_users);
+ task->mm = mm;
+ task->active_mm = mm;
+
+ if(task == current)
+ switch_mm(old, task->mm, task);
+
+ task_unlock(task);
+
+ mmput(old);
+}
+
+#define MM_REGS_MASK 1
+
+#define MM_ALL_REGS 0
+#define MM_SP_IP 1
+
+long do_switch_mm(int fd, unsigned long flags, long __user *new,
+ long __user *save, struct pt_regs *regs)
+{
+ struct user_regs new_regs;
+ struct mm_struct *old_mm, *new_mm;
+ int ret = 0;
+
+ if ((flags & ~MM_REGS_MASK) != 0)
+ return -EINVAL;
+
+ old_mm = current->mm;
+ if (old_mm == NULL)
+ return -EINVAL;
+
+ if (new == NULL)
+ return -EINVAL;
+ if (copyin_user_regs(&new_regs, new))
+ return -EFAULT;
+
+ new_mm = fd_to_mm(fd);
+ if (IS_ERR(new_mm))
+ return PTR_ERR(new_mm);
+
+ atomic_inc(&old_mm->mm_users);
+ do_switch(current, new_mm);
+
+ mmput(new_mm);
+
+ if ((save != NULL) && pt_regs_to_ptrace(save, regs)) {
+ do_switch(current, old_mm);
+ ret = EFAULT;
+ goto out;
+ }
+
+ if (flags == MM_SP_IP) {
+ pt_regs_ip(*regs) = ptrace_ip(&new_regs);
+ pt_regs_sp(*regs) = ptrace_sp(&new_regs);
+ }
+ else
+ ret = ptrace_to_pt_regs(regs, &new_regs);
+
+ out:
+ mmput(old_mm);
+ return ret;
+}
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