[PATCH v3 1/3] syscalls,x86 Expose arch_prctl on x86-32.
From: Kyle Huey
Date: Thu Sep 15 2016 - 19:34:11 EST
arch_prctl is currently 64-bit only. Wire it up for 32-bits, as a no-op for
now. Rename the second arg to a more generic name.
Signed-off-by: Kyle Huey <khuey@xxxxxxxxxxxx>
---
arch/x86/entry/syscalls/syscall_32.tbl | 1 +
arch/x86/include/asm/proto.h | 5 ++++-
arch/x86/kernel/process.c | 10 ++++++++++
arch/x86/kernel/process_64.c | 33 +++++++++++++++++++++------------
arch/x86/kernel/ptrace.c | 8 ++++----
arch/x86/um/Makefile | 2 +-
arch/x86/um/syscalls_32.c | 7 +++++++
arch/x86/um/syscalls_64.c | 4 ++--
include/linux/compat.h | 2 ++
9 files changed, 52 insertions(+), 20 deletions(-)
create mode 100644 arch/x86/um/syscalls_32.c
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index f848572..666fa61 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -386,3 +386,4 @@
377 i386 copy_file_range sys_copy_file_range
378 i386 preadv2 sys_preadv2 compat_sys_preadv2
379 i386 pwritev2 sys_pwritev2 compat_sys_pwritev2
+380 i386 arch_prctl compat_sys_arch_prctl compat_sys_arch_prctl
diff --git a/arch/x86/include/asm/proto.h b/arch/x86/include/asm/proto.h
index 9b9b30b..f0e86aa 100644
--- a/arch/x86/include/asm/proto.h
+++ b/arch/x86/include/asm/proto.h
@@ -30,6 +30,9 @@ void x86_report_nx(void);
extern int reboot_force;
-long do_arch_prctl(struct task_struct *task, int code, unsigned long addr);
+long do_arch_prctl_common(struct task_struct *task, int code, unsigned long addr);
+#ifdef CONFIG_X86_64
+long do_arch_prctl_64(struct task_struct *task, int code, unsigned long addr);
+#endif
#endif /* _ASM_X86_PROTO_H */
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 62c0b0e..1421451 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -567,3 +567,13 @@ unsigned long get_wchan(struct task_struct *p)
} while (count++ < 16 && p->state != TASK_RUNNING);
return 0;
}
+
+long do_arch_prctl_common(struct task_struct *task, int code, unsigned long arg2)
+{
+ return -EINVAL;
+}
+
+asmlinkage long compat_sys_arch_prctl(int code, unsigned long arg2)
+{
+ return do_arch_prctl_common(current, code, arg2);
+}
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 63236d8..0e44608 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -35,6 +35,7 @@
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/ftrace.h>
+#include <linux/syscalls.h>
#include <asm/pgtable.h>
#include <asm/processor.h>
@@ -196,7 +197,7 @@ int copy_thread_tls(unsigned long clone_flags, unsigned long sp,
(struct user_desc __user *)tls, 0);
else
#endif
- err = do_arch_prctl(p, ARCH_SET_FS, tls);
+ err = do_arch_prctl_64(p, ARCH_SET_FS, tls);
if (err)
goto out;
}
@@ -524,7 +525,7 @@ void set_personality_ia32(bool x32)
}
EXPORT_SYMBOL_GPL(set_personality_ia32);
-long do_arch_prctl(struct task_struct *task, int code, unsigned long addr)
+long do_arch_prctl_64(struct task_struct *task, int code, unsigned long arg2)
{
int ret = 0;
int doit = task == current;
@@ -532,48 +533,50 @@ long do_arch_prctl(struct task_struct *task, int code, unsigned long addr)
switch (code) {
case ARCH_SET_GS:
- if (addr >= TASK_SIZE_MAX)
+ if (arg2 >= TASK_SIZE_MAX)
return -EPERM;
cpu = get_cpu();
task->thread.gsindex = 0;
- task->thread.gsbase = addr;
+ task->thread.gsbase = arg2;
if (doit) {
load_gs_index(0);
- ret = wrmsrl_safe(MSR_KERNEL_GS_BASE, addr);
+ ret = wrmsrl_safe(MSR_KERNEL_GS_BASE, arg2);
}
put_cpu();
break;
case ARCH_SET_FS:
/* Not strictly needed for fs, but do it for symmetry
with gs */
- if (addr >= TASK_SIZE_MAX)
+ if (arg2 >= TASK_SIZE_MAX)
return -EPERM;
cpu = get_cpu();
task->thread.fsindex = 0;
- task->thread.fsbase = addr;
+ task->thread.fsbase = arg2;
if (doit) {
/* set the selector to 0 to not confuse __switch_to */
loadsegment(fs, 0);
- ret = wrmsrl_safe(MSR_FS_BASE, addr);
+ ret = wrmsrl_safe(MSR_FS_BASE, arg2);
}
put_cpu();
break;
case ARCH_GET_FS: {
unsigned long base;
+
if (doit)
rdmsrl(MSR_FS_BASE, base);
else
base = task->thread.fsbase;
- ret = put_user(base, (unsigned long __user *)addr);
+ ret = put_user(base, (unsigned long __user *)arg2);
break;
}
case ARCH_GET_GS: {
unsigned long base;
+
if (doit)
rdmsrl(MSR_KERNEL_GS_BASE, base);
else
base = task->thread.gsbase;
- ret = put_user(base, (unsigned long __user *)addr);
+ ret = put_user(base, (unsigned long __user *)arg2);
break;
}
@@ -585,9 +588,15 @@ long do_arch_prctl(struct task_struct *task, int code, unsigned long addr)
return ret;
}
-long sys_arch_prctl(int code, unsigned long addr)
+SYSCALL_DEFINE2(arch_prctl, int, code, unsigned long, arg2)
{
- return do_arch_prctl(current, code, addr);
+ long ret;
+
+ ret = do_arch_prctl_64(current, code, arg2);
+ if (ret == -EINVAL)
+ ret = do_arch_prctl_common(current, code, arg2);
+
+ return ret;
}
unsigned long KSTK_ESP(struct task_struct *task)
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index f79576a..030cbc5 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -395,12 +395,12 @@ static int putreg(struct task_struct *child,
if (value >= TASK_SIZE_MAX)
return -EIO;
/*
- * When changing the segment base, use do_arch_prctl
+ * When changing the segment base, use do_arch_prctl_64
* to set either thread.fs or thread.fsindex and the
* corresponding GDT slot.
*/
if (child->thread.fsbase != value)
- return do_arch_prctl(child, ARCH_SET_FS, value);
+ return do_arch_prctl_64(child, ARCH_SET_FS, value);
return 0;
case offsetof(struct user_regs_struct,gs_base):
/*
@@ -409,7 +409,7 @@ static int putreg(struct task_struct *child,
if (value >= TASK_SIZE_MAX)
return -EIO;
if (child->thread.gsbase != value)
- return do_arch_prctl(child, ARCH_SET_GS, value);
+ return do_arch_prctl_64(child, ARCH_SET_GS, value);
return 0;
#endif
}
@@ -868,7 +868,7 @@ long arch_ptrace(struct task_struct *child, long request,
Works just like arch_prctl, except that the arguments
are reversed. */
case PTRACE_ARCH_PRCTL:
- ret = do_arch_prctl(child, data, addr);
+ ret = do_arch_prctl_64(child, data, addr);
break;
#endif
diff --git a/arch/x86/um/Makefile b/arch/x86/um/Makefile
index 3ee2bb6..5e039d6 100644
--- a/arch/x86/um/Makefile
+++ b/arch/x86/um/Makefile
@@ -16,7 +16,7 @@ obj-y = bug.o bugs_$(BITS).o delay.o fault.o ksyms.o ldt.o \
ifeq ($(CONFIG_X86_32),y)
-obj-y += checksum_32.o
+obj-y += checksum_32.o syscalls_32.o
obj-$(CONFIG_ELF_CORE) += elfcore.o
subarch-y = ../lib/string_32.o ../lib/atomic64_32.o ../lib/atomic64_cx8_32.o
diff --git a/arch/x86/um/syscalls_32.c b/arch/x86/um/syscalls_32.c
new file mode 100644
index 0000000..c6812c1
--- /dev/null
+++ b/arch/x86/um/syscalls_32.c
@@ -0,0 +1,7 @@
+#include <linux/syscalls.h>
+#include <os.h>
+
+long compat_sys_arch_prctl(int code, unsigned long arg2)
+{
+ return -EINVAL;
+}
diff --git a/arch/x86/um/syscalls_64.c b/arch/x86/um/syscalls_64.c
index e655227..d0a7160 100644
--- a/arch/x86/um/syscalls_64.c
+++ b/arch/x86/um/syscalls_64.c
@@ -72,9 +72,9 @@ long arch_prctl(struct task_struct *task, int code, unsigned long __user *addr)
return ret;
}
-long sys_arch_prctl(int code, unsigned long addr)
+long sys_arch_prctl(int code, unsigned long arg2)
{
- return arch_prctl(current, code, (unsigned long __user *) addr);
+ return arch_prctl(current, code, (unsigned long __user *) arg2);
}
void arch_switch_to(struct task_struct *to)
diff --git a/include/linux/compat.h b/include/linux/compat.h
index f964ef7..0039d53 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -722,6 +722,8 @@ asmlinkage long compat_sys_sched_rr_get_interval(compat_pid_t pid,
asmlinkage long compat_sys_fanotify_mark(int, unsigned int, __u32, __u32,
int, const char __user *);
+asmlinkage long compat_sys_arch_prctl(int, unsigned long);
+
/*
* For most but not all architectures, "am I in a compat syscall?" and
* "am I a compat task?" are the same question. For architectures on which
--
2.9.3
base-commit: 4cea8776571b18db7485930cb422faa739580c8c