summaryrefslogtreecommitdiffstats
path: root/arch/x86/include/asm/ptrace.h
diff options
context:
space:
mode:
authorAndy Lutomirski <luto@kernel.org>2015-03-19 02:33:32 +0100
committerIngo Molnar <mingo@kernel.org>2015-03-23 11:13:51 +0100
commitefa704510342b81ae58d7b8a0c7f676a4289b603 (patch)
tree3162527a9ad26a50eef9f14b012ac02e5cf834c7 /arch/x86/include/asm/ptrace.h
parentx86/asm/entry: Use user_mode_ignore_vm86() where appropriate (diff)
downloadlinux-efa704510342b81ae58d7b8a0c7f676a4289b603.tar.xz
linux-efa704510342b81ae58d7b8a0c7f676a4289b603.zip
x86/asm/entry: Make user_mode() work correctly if regs came from VM86 mode
user_mode() is now identical to user_mode_vm(). Subsequent patches will change all callers of user_mode_vm() to user_mode() and then delete user_mode_vm(). Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brad Spengler <spender@grsecurity.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/0dd03eacb5f0a2b5ba0240de25347a31b493c289.1426728647.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/include/asm/ptrace.h')
-rw-r--r--arch/x86/include/asm/ptrace.h17
1 files changed, 7 insertions, 10 deletions
diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h
index 4a040f0078f2..70c439f9071b 100644
--- a/arch/x86/include/asm/ptrace.h
+++ b/arch/x86/include/asm/ptrace.h
@@ -96,11 +96,13 @@ static inline unsigned long regs_return_value(struct pt_regs *regs)
}
/*
- * user_mode_vm(regs) determines whether a register set came from user mode.
- * This is true if V8086 mode was enabled OR if the register set was from
- * protected mode with RPL-3 CS value. This tricky test checks that with
- * one comparison. Many places in the kernel can bypass this full check
- * if they have already ruled out V8086 mode, so user_mode(regs) can be used.
+ * user_mode(regs) determines whether a register set came from user
+ * mode. On x86_32, this is true if V8086 mode was enabled OR if the
+ * register set was from protected mode with RPL-3 CS value. This
+ * tricky test checks that with one comparison.
+ *
+ * On x86_64, vm86 mode is mercifully nonexistent, and we don't need
+ * the extra check.
*/
static inline int user_mode(struct pt_regs *regs)
{
@@ -113,12 +115,7 @@ static inline int user_mode(struct pt_regs *regs)
static inline int user_mode_vm(struct pt_regs *regs)
{
-#ifdef CONFIG_X86_32
- return ((regs->cs & SEGMENT_RPL_MASK) | (regs->flags & X86_VM_MASK)) >=
- USER_RPL;
-#else
return user_mode(regs);
-#endif
}
/*