linux-kernel - [REVIEW][PATCH 19/20] signal/x86: Pass pkey by value

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Date:   Tue, 18 Sep 2018 02:05:45 +0200
From:   "Eric W. Biederman" <ebiederm@...ssion.com>
To:     linux-kernel@...r.kernel.org
Cc:     linux-arch@...r.kernel.org, Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, x86@...nel.org,
        "Eric W. Biederman" <ebiederm@...ssion.com>
Subject: [REVIEW][PATCH 19/20] signal/x86: Pass pkey by value

Now that si_code == SEGV_PKUERR is the flag indicating that a pkey
is present there is no longer a need to pass a pointer to a local
pkey value, instead pkey can be passed more efficiently by value.

Signed-off-by: "Eric W. Biederman" <ebiederm@...ssion.com>
---
 arch/x86/mm/fault.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 548396aa03e1..c09a0c2fa614 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -769,7 +769,7 @@ show_signal_msg(struct pt_regs *regs, unsigned long error_code,
 
 static void
 __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
-		       unsigned long address, u32 *pkey, int si_code)
+		       unsigned long address, u32 pkey, int si_code)
 {
 	struct task_struct *tsk = current;
 
@@ -818,7 +818,7 @@ __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
 		tsk->thread.trap_nr	= X86_TRAP_PF;
 
 		if (si_code == SEGV_PKUERR)
-			force_sig_pkuerr((void __user *)address, *pkey);
+			force_sig_pkuerr((void __user *)address, pkey);
 
 		force_sig_fault(SIGSEGV, si_code, (void __user *)address, tsk);
 
@@ -835,12 +835,12 @@ static noinline void
 bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
 		     unsigned long address)
 {
-	__bad_area_nosemaphore(regs, error_code, address, NULL, SEGV_MAPERR);
+	__bad_area_nosemaphore(regs, error_code, address, 0, SEGV_MAPERR);
 }
 
 static void
 __bad_area(struct pt_regs *regs, unsigned long error_code,
-	   unsigned long address, u32 *pkey, int si_code)
+	   unsigned long address, u32 pkey, int si_code)
 {
 	struct mm_struct *mm = current->mm;
 	/*
@@ -855,7 +855,7 @@ __bad_area(struct pt_regs *regs, unsigned long error_code,
 static noinline void
 bad_area(struct pt_regs *regs, unsigned long error_code, unsigned long address)
 {
-	__bad_area(regs, error_code, address, NULL, SEGV_MAPERR);
+	__bad_area(regs, error_code, address, 0, SEGV_MAPERR);
 }
 
 static inline bool bad_area_access_from_pkeys(unsigned long error_code,
@@ -906,10 +906,10 @@ bad_area_access_error(struct pt_regs *regs, unsigned long error_code,
 		 *	     faulted on a pte with its pkey=4.
 		 */
 		u32 pkey = vma_pkey(vma);
-		__bad_area(regs, error_code, address, &pkey, SEGV_PKUERR);
+		__bad_area(regs, error_code, address, pkey, SEGV_PKUERR);
 	}
 	else
-		__bad_area(regs, error_code, address, NULL, SEGV_ACCERR);
+		__bad_area(regs, error_code, address, 0, SEGV_ACCERR);
 }
 
 static void
-- 
2.17.1