Merge branch 'linus' into x86/urgent, to refresh the tree

Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 58 insertions, 109 deletions

diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 2b1519bc5381..b24eb4eb9984 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -157,79 +157,6 @@ is_prefetch(struct pt_regs *regs, unsigned long error_code, unsigned long addr)
 	return prefetch;
 }
 
-/*
- * A protection key fault means that the PKRU value did not allow
- * access to some PTE.  Userspace can figure out what PKRU was
- * from the XSAVE state, and this function fills out a field in
- * siginfo so userspace can discover which protection key was set
- * on the PTE.
- *
- * If we get here, we know that the hardware signaled a X86_PF_PK
- * fault and that there was a VMA once we got in the fault
- * handler.  It does *not* guarantee that the VMA we find here
- * was the one that we faulted on.
- *
- * 1. T1   : mprotect_key(foo, PAGE_SIZE, pkey=4);
- * 2. T1   : set PKRU to deny access to pkey=4, touches page
- * 3. T1   : faults...
- * 4.    T2: mprotect_key(foo, PAGE_SIZE, pkey=5);
- * 5. T1   : enters fault handler, takes mmap_sem, etc...
- * 6. T1   : reaches here, sees vma_pkey(vma)=5, when we really
- *	     faulted on a pte with its pkey=4.
- */
-static void fill_sig_info_pkey(int si_signo, int si_code, siginfo_t *info,
-		u32 *pkey)
-{
-	/* This is effectively an #ifdef */
-	if (!boot_cpu_has(X86_FEATURE_OSPKE))
-		return;
-
-	/* Fault not from Protection Keys: nothing to do */
-	if ((si_code != SEGV_PKUERR) || (si_signo != SIGSEGV))
-		return;
-	/*
-	 * force_sig_info_fault() is called from a number of
-	 * contexts, some of which have a VMA and some of which
-	 * do not.  The X86_PF_PK handing happens after we have a
-	 * valid VMA, so we should never reach this without a
-	 * valid VMA.
-	 */
-	if (!pkey) {
-		WARN_ONCE(1, "PKU fault with no VMA passed in");
-		info->si_pkey = 0;
-		return;
-	}
-	/*
-	 * si_pkey should be thought of as a strong hint, but not
-	 * absolutely guranteed to be 100% accurate because of
-	 * the race explained above.
-	 */
-	info->si_pkey = *pkey;
-}
-
-static void
-force_sig_info_fault(int si_signo, int si_code, unsigned long address,
-		     struct task_struct *tsk, u32 *pkey, int fault)
-{
-	unsigned lsb = 0;
-	siginfo_t info;
-
-	clear_siginfo(&info);
-	info.si_signo	= si_signo;
-	info.si_errno	= 0;
-	info.si_code	= si_code;
-	info.si_addr	= (void __user *)address;
-	if (fault & VM_FAULT_HWPOISON_LARGE)
-		lsb = hstate_index_to_shift(VM_FAULT_GET_HINDEX(fault)); 
-	if (fault & VM_FAULT_HWPOISON)
-		lsb = PAGE_SHIFT;
-	info.si_addr_lsb = lsb;
-
-	fill_sig_info_pkey(si_signo, si_code, &info, pkey);
-
-	force_sig_info(si_signo, &info, tsk);
-}
-
 DEFINE_SPINLOCK(pgd_lock);
 LIST_HEAD(pgd_list);
 
@@ -734,8 +661,8 @@ no_context(struct pt_regs *regs, unsigned long error_code,
 			tsk->thread.cr2 = address;
 
 			/* XXX: hwpoison faults will set the wrong code. */
-			force_sig_info_fault(signal, si_code, address,
-					     tsk, NULL, 0);
+			force_sig_fault(signal, si_code, (void __user *)address,
+					tsk);
 		}
 
 		/*
@@ -862,7 +789,7 @@ static bool is_vsyscall_vaddr(unsigned long vaddr)
 
 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;
 
@@ -898,7 +825,10 @@ __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
 		tsk->thread.error_code	= error_code;
 		tsk->thread.trap_nr	= X86_TRAP_PF;
 
-		force_sig_info_fault(SIGSEGV, si_code, address, tsk, pkey, 0);
+		if (si_code == SEGV_PKUERR)
+			force_sig_pkuerr((void __user *)address, pkey);
+
+		force_sig_fault(SIGSEGV, si_code, (void __user *)address, tsk);
 
 		return;
 	}
@@ -911,35 +841,29 @@ __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
 
 static noinline void
 bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
-		     unsigned long address, u32 *pkey)
+		     unsigned long address)
 {
-	__bad_area_nosemaphore(regs, error_code, address, pkey, 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,  struct vm_area_struct *vma, int si_code)
+	   unsigned long address, u32 pkey, int si_code)
 {
 	struct mm_struct *mm = current->mm;
-	u32 pkey;
-
-	if (vma)
-		pkey = vma_pkey(vma);
-
 	/*
 	 * Something tried to access memory that isn't in our memory map..
 	 * Fix it, but check if it's kernel or user first..
 	 */
 	up_read(&mm->mmap_sem);
 
-	__bad_area_nosemaphore(regs, error_code, address,
-			       (vma) ? &pkey : NULL, si_code);
+	__bad_area_nosemaphore(regs, error_code, address, pkey, si_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,
@@ -968,18 +892,40 @@ bad_area_access_error(struct pt_regs *regs, unsigned long error_code,
 	 * But, doing it this way allows compiler optimizations
 	 * if pkeys are compiled out.
 	 */
-	if (bad_area_access_from_pkeys(error_code, vma))
-		__bad_area(regs, error_code, address, vma, SEGV_PKUERR);
-	else
-		__bad_area(regs, error_code, address, vma, SEGV_ACCERR);
+	if (bad_area_access_from_pkeys(error_code, vma)) {
+		/*
+		 * A protection key fault means that the PKRU value did not allow
+		 * access to some PTE.  Userspace can figure out what PKRU was
+		 * from the XSAVE state.  This function captures the pkey from
+		 * the vma and passes it to userspace so userspace can discover
+		 * which protection key was set on the PTE.
+		 *
+		 * If we get here, we know that the hardware signaled a X86_PF_PK
+		 * fault and that there was a VMA once we got in the fault
+		 * handler.  It does *not* guarantee that the VMA we find here
+		 * was the one that we faulted on.
+		 *
+		 * 1. T1   : mprotect_key(foo, PAGE_SIZE, pkey=4);
+		 * 2. T1   : set PKRU to deny access to pkey=4, touches page
+		 * 3. T1   : faults...
+		 * 4.    T2: mprotect_key(foo, PAGE_SIZE, pkey=5);
+		 * 5. T1   : enters fault handler, takes mmap_sem, etc...
+		 * 6. T1   : reaches here, sees vma_pkey(vma)=5, when we really
+		 *	     faulted on a pte with its pkey=4.
+		 */
+		u32 pkey = vma_pkey(vma);
+
+		__bad_area(regs, error_code, address, pkey, SEGV_PKUERR);
+	} else {
+		__bad_area(regs, error_code, address, 0, SEGV_ACCERR);
+	}
 }
 
 static void
 do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address,
-	  u32 *pkey, unsigned int fault)
+	  unsigned int fault)
 {
 	struct task_struct *tsk = current;
-	int code = BUS_ADRERR;
 
 	/* Kernel mode? Handle exceptions or die: */
 	if (!(error_code & X86_PF_USER)) {
@@ -997,18 +943,25 @@ do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address,
 
 #ifdef CONFIG_MEMORY_FAILURE
 	if (fault & (VM_FAULT_HWPOISON|VM_FAULT_HWPOISON_LARGE)) {
-		printk(KERN_ERR
+		unsigned lsb = 0;
+
+		pr_err(
 	"MCE: Killing %s:%d due to hardware memory corruption fault at %lx\n",
 			tsk->comm, tsk->pid, address);
-		code = BUS_MCEERR_AR;
+		if (fault & VM_FAULT_HWPOISON_LARGE)
+			lsb = hstate_index_to_shift(VM_FAULT_GET_HINDEX(fault));
+		if (fault & VM_FAULT_HWPOISON)
+			lsb = PAGE_SHIFT;
+		force_sig_mceerr(BUS_MCEERR_AR, (void __user *)address, lsb, tsk);
+		return;
 	}
 #endif
-	force_sig_info_fault(SIGBUS, code, address, tsk, pkey, fault);
+	force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)address, tsk);
 }
 
 static noinline void
 mm_fault_error(struct pt_regs *regs, unsigned long error_code,
-	       unsigned long address, u32 *pkey, vm_fault_t fault)
+	       unsigned long address, vm_fault_t fault)
 {
 	if (fatal_signal_pending(current) && !(error_code & X86_PF_USER)) {
 		no_context(regs, error_code, address, 0, 0);
@@ -1032,9 +985,9 @@ mm_fault_error(struct pt_regs *regs, unsigned long error_code,
 	} else {
 		if (fault & (VM_FAULT_SIGBUS|VM_FAULT_HWPOISON|
 			     VM_FAULT_HWPOISON_LARGE))
-			do_sigbus(regs, error_code, address, pkey, fault);
+			do_sigbus(regs, error_code, address, fault);
 		else if (fault & VM_FAULT_SIGSEGV)
-			bad_area_nosemaphore(regs, error_code, address, pkey);
+			bad_area_nosemaphore(regs, error_code, address);
 		else
 			BUG();
 	}
@@ -1267,7 +1220,7 @@ do_kern_addr_fault(struct pt_regs *regs, unsigned long hw_error_code,
 	 * Don't take the mm semaphore here. If we fixup a prefetch
 	 * fault we could otherwise deadlock:
 	 */
-	bad_area_nosemaphore(regs, hw_error_code, address, NULL);
+	bad_area_nosemaphore(regs, hw_error_code, address);
 }
 NOKPROBE_SYMBOL(do_kern_addr_fault);
 
@@ -1283,7 +1236,6 @@ void do_user_addr_fault(struct pt_regs *regs,
 	struct mm_struct *mm;
 	vm_fault_t fault, major = 0;
 	unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
-	u32 pkey;
 
 	tsk = current;
 	mm = tsk->mm;
@@ -1304,7 +1256,7 @@ void do_user_addr_fault(struct pt_regs *regs,
 	 * pages in the user address space.
 	 */
 	if (unlikely(smap_violation(hw_error_code, regs))) {
-		bad_area_nosemaphore(regs, hw_error_code, address, NULL);
+		bad_area_nosemaphore(regs, hw_error_code, address);
 		return;
 	}
 
@@ -1313,7 +1265,7 @@ void do_user_addr_fault(struct pt_regs *regs,
 	 * in a region with pagefaults disabled then we must not take the fault
 	 */
 	if (unlikely(faulthandler_disabled() || !mm)) {
-		bad_area_nosemaphore(regs, hw_error_code, address, NULL);
+		bad_area_nosemaphore(regs, hw_error_code, address);
 		return;
 	}
 
@@ -1403,7 +1355,7 @@ void do_user_addr_fault(struct pt_regs *regs,
 			 * Fault from code in kernel from
 			 * which we do not expect faults.
 			 */
-			bad_area_nosemaphore(regs, sw_error_code, address, NULL);
+			bad_area_nosemaphore(regs, sw_error_code, address);
 			return;
 		}
 retry:
@@ -1467,10 +1419,7 @@ good_area:
 	 * (potentially after handling any pending signal during the return to
 	 * userland). The return to userland is identified whenever
 	 * FAULT_FLAG_USER|FAULT_FLAG_KILLABLE are both set in flags.
-	 * Thus we have to be careful about not touching vma after handling the
-	 * fault, so we read the pkey beforehand.
 	 */
-	pkey = vma_pkey(vma);
 	fault = handle_mm_fault(vma, address, flags);
 	major |= fault & VM_FAULT_MAJOR;
 
@@ -1499,7 +1448,7 @@ good_area:
 
 	up_read(&mm->mmap_sem);
 	if (unlikely(fault & VM_FAULT_ERROR)) {
-		mm_fault_error(regs, sw_error_code, address, &pkey, fault);
+		mm_fault_error(regs, sw_error_code, address, fault);
 		return;
 	}