Commit-ID:  7fdfe1e40b225b1d163f9afed2fa3f04442dbaad
Gitweb:     https://git.kernel.org/tip/7fdfe1e40b225b1d163f9afed2fa3f04442dbaad
Author:     Rick Edgecombe <rick.p.edgeco...@intel.com>
AuthorDate: Thu, 25 Apr 2019 17:11:39 -0700
Committer:  Ingo Molnar <mi...@kernel.org>
CommitDate: Tue, 30 Apr 2019 12:38:00 +0200

x86/ftrace: Use vmalloc special flag

Use new flag VM_FLUSH_RESET_PERMS for handling freeing of special
permissioned memory in vmalloc and remove places where memory was set NX
and RW before freeing which is no longer needed.

Tested-by: Steven Rostedt (VMware) <rost...@goodmis.org>
Signed-off-by: Rick Edgecombe <rick.p.edgeco...@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org>
Acked-by: Steven Rostedt (VMware) <rost...@goodmis.org>
Cc: <a...@linux-foundation.org>
Cc: <ard.biesheu...@linaro.org>
Cc: <deneen.t.d...@intel.com>
Cc: <kernel-harden...@lists.openwall.com>
Cc: <kris...@linux.intel.com>
Cc: <linux_...@icloud.com>
Cc: <will.dea...@arm.com>
Cc: Andy Lutomirski <l...@kernel.org>
Cc: Borislav Petkov <b...@alien8.de>
Cc: Dave Hansen <dave.han...@linux.intel.com>
Cc: H. Peter Anvin <h...@zytor.com>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Nadav Amit <nadav.a...@gmail.com>
Cc: Rik van Riel <r...@surriel.com>
Cc: Thomas Gleixner <t...@linutronix.de>
Link: https://lkml.kernel.org/r/20190426001143.4983-20-na...@vmware.com
Signed-off-by: Ingo Molnar <mi...@kernel.org>
---
 arch/x86/kernel/ftrace.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 53ba1aa3a01f..0caf8122d680 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -678,12 +678,8 @@ static inline void *alloc_tramp(unsigned long size)
 {
        return module_alloc(size);
 }
-static inline void tramp_free(void *tramp, int size)
+static inline void tramp_free(void *tramp)
 {
-       int npages = PAGE_ALIGN(size) >> PAGE_SHIFT;
-
-       set_memory_nx((unsigned long)tramp, npages);
-       set_memory_rw((unsigned long)tramp, npages);
        module_memfree(tramp);
 }
 #else
@@ -692,7 +688,7 @@ static inline void *alloc_tramp(unsigned long size)
 {
        return NULL;
 }
-static inline void tramp_free(void *tramp, int size) { }
+static inline void tramp_free(void *tramp) { }
 #endif
 
 /* Defined as markers to the end of the ftrace default trampolines */
@@ -808,6 +804,8 @@ create_trampoline(struct ftrace_ops *ops, unsigned int 
*tramp_size)
        /* ALLOC_TRAMP flags lets us know we created it */
        ops->flags |= FTRACE_OPS_FL_ALLOC_TRAMP;
 
+       set_vm_flush_reset_perms(trampoline);
+
        /*
         * Module allocation needs to be completed by making the page
         * executable. The page is still writable, which is a security hazard,
@@ -816,7 +814,7 @@ create_trampoline(struct ftrace_ops *ops, unsigned int 
*tramp_size)
        set_memory_x((unsigned long)trampoline, npages);
        return (unsigned long)trampoline;
 fail:
-       tramp_free(trampoline, *tramp_size);
+       tramp_free(trampoline);
        return 0;
 }
 
@@ -947,7 +945,7 @@ void arch_ftrace_trampoline_free(struct ftrace_ops *ops)
        if (!ops || !(ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP))
                return;
 
-       tramp_free((void *)ops->trampoline, ops->trampoline_size);
+       tramp_free((void *)ops->trampoline);
        ops->trampoline = 0;
 }
 

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