Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 asm updates from Ingo Molnar:
 "Most of the changes relate to Peter Zijlstra's cleanup of ptregs
  handling, in particular the i386 part is now much simplified and
  standardized - no more partial ptregs stack frames via the esp/ss
  oddity. This simplifies ftrace, kprobes, the unwinder, ptrace, kdump
  and kgdb.

  There's also a CR4 hardening enhancements by Kees Cook, to make the
  generic platform functions such as native_write_cr4() less useful as
  ROP gadgets that disable SMEP/SMAP. Also protect the WP bit of CR0
  against similar attacks.

  The rest is smaller cleanups/fixes"

* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/alternatives: Add int3_emulate_call() selftest
  x86/stackframe/32: Allow int3_emulate_push()
  x86/stackframe/32: Provide consistent pt_regs
  x86/stackframe, x86/ftrace: Add pt_regs frame annotations
  x86/stackframe, x86/kprobes: Fix frame pointer annotations
  x86/stackframe: Move ENCODE_FRAME_POINTER to asm/frame.h
  x86/entry/32: Clean up return from interrupt preemption path
  x86/asm: Pin sensitive CR0 bits
  x86/asm: Pin sensitive CR4 bits
  Documentation/x86: Fix path to entry_32.S
  x86/asm: Remove unused TASK_TI_flags from asm-offsets.c

1 files changed, 12 insertions, 17 deletions

diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 6afd8061dbae..bd17dbb15d6a 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -56,7 +56,7 @@
 DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
 DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
 
-#define stack_addr(regs) ((unsigned long *)kernel_stack_pointer(regs))
+#define stack_addr(regs) ((unsigned long *)regs->sp)
 
 #define W(row, b0, b1, b2, b3, b4, b5, b6, b7, b8, b9, ba, bb, bc, bd, be, bf)\
 	(((b0##UL << 0x0)|(b1##UL << 0x1)|(b2##UL << 0x2)|(b3##UL << 0x3) |   \
@@ -718,29 +718,27 @@ asm(
 	".global kretprobe_trampoline\n"
 	".type kretprobe_trampoline, @function\n"
 	"kretprobe_trampoline:\n"
-#ifdef CONFIG_X86_64
 	/* We don't bother saving the ss register */
+#ifdef CONFIG_X86_64
 	"	pushq %rsp\n"
 	"	pushfq\n"
 	SAVE_REGS_STRING
 	"	movq %rsp, %rdi\n"
 	"	call trampoline_handler\n"
 	/* Replace saved sp with true return address. */
-	"	movq %rax, 152(%rsp)\n"
+	"	movq %rax, 19*8(%rsp)\n"
 	RESTORE_REGS_STRING
 	"	popfq\n"
 #else
-	"	pushf\n"
+	"	pushl %esp\n"
+	"	pushfl\n"
 	SAVE_REGS_STRING
 	"	movl %esp, %eax\n"
 	"	call trampoline_handler\n"
-	/* Move flags to cs */
-	"	movl 56(%esp), %edx\n"
-	"	movl %edx, 52(%esp)\n"
-	/* Replace saved flags with true return address. */
-	"	movl %eax, 56(%esp)\n"
+	/* Replace saved sp with true return address. */
+	"	movl %eax, 15*4(%esp)\n"
 	RESTORE_REGS_STRING
-	"	popf\n"
+	"	popfl\n"
 #endif
 	"	ret\n"
 	".size kretprobe_trampoline, .-kretprobe_trampoline\n"
@@ -781,16 +779,13 @@ __used __visible void *trampoline_handler(struct pt_regs *regs)
 	INIT_HLIST_HEAD(&empty_rp);
 	kretprobe_hash_lock(current, &head, &flags);
 	/* fixup registers */
-#ifdef CONFIG_X86_64
 	regs->cs = __KERNEL_CS;
-	/* On x86-64, we use pt_regs->sp for return address holder. */
-	frame_pointer = &regs->sp;
-#else
-	regs->cs = __KERNEL_CS | get_kernel_rpl();
+#ifdef CONFIG_X86_32
+	regs->cs |= get_kernel_rpl();
 	regs->gs = 0;
-	/* On x86-32, we use pt_regs->flags for return address holder. */
-	frame_pointer = &regs->flags;
 #endif
+	/* We use pt_regs->sp for return address holder. */
+	frame_pointer = &regs->sp;
 	regs->ip = trampoline_address;
 	regs->orig_ax = ~0UL;