Merge tag 'for-v4.6-rc/omap-fixes-a' of git://git.kernel.org/pub/scm/linux/kernel/git/pjw/omap-pending into omap-for-v4.6/fixes

ARM: OMAP2+: first hwmod fix for v4.6-rc

Fix a longstanding bug in the hwmod code that could cause
hardware SYSCONFIG register values to not match the kernel's
idea of what they should be, and that could result in lower
performance during IP block idle entry.

Basic build, boot, and PM test logs are available here:

http://www.pwsan.com/omap/testlogs/omap-hwmod-fixes-a-for-v4.6-rc/20160326231727/

1 files changed, 140 insertions, 27 deletions

diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index eef44d9a3f77..5ce1ed02f7e8 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -15,12 +15,14 @@
 #include <linux/context_tracking.h>	/* exception_enter(), ...	*/
 #include <linux/uaccess.h>		/* faulthandler_disabled()	*/
 
+#include <asm/cpufeature.h>		/* boot_cpu_has, ...		*/
 #include <asm/traps.h>			/* dotraplinkage, ...		*/
 #include <asm/pgalloc.h>		/* pgd_*(), ...			*/
 #include <asm/kmemcheck.h>		/* kmemcheck_*(), ...		*/
 #include <asm/fixmap.h>			/* VSYSCALL_ADDR		*/
 #include <asm/vsyscall.h>		/* emulate_vsyscall		*/
 #include <asm/vm86.h>			/* struct vm86			*/
+#include <asm/mmu_context.h>		/* vma_pkey()			*/
 
 #define CREATE_TRACE_POINTS
 #include <asm/trace/exceptions.h>
@@ -33,6 +35,7 @@
  *   bit 2 ==	 0: kernel-mode access	1: user-mode access
  *   bit 3 ==				1: use of reserved bit detected
  *   bit 4 ==				1: fault was an instruction fetch
+ *   bit 5 ==				1: protection keys block access
  */
 enum x86_pf_error_code {
 
@@ -41,6 +44,7 @@ enum x86_pf_error_code {
 	PF_USER		=		1 << 2,
 	PF_RSVD		=		1 << 3,
 	PF_INSTR	=		1 << 4,
+	PF_PK		=		1 << 5,
 };
 
 /*
@@ -167,9 +171,60 @@ 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 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_code, siginfo_t *info,
+		struct vm_area_struct *vma)
+{
+	/* 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)
+		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 PF_PK handing happens after we have a
+	 * valid VMA, so we should never reach this without a
+	 * valid VMA.
+	 */
+	if (!vma) {
+		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 = vma_pkey(vma);
+}
+
 static void
 force_sig_info_fault(int si_signo, int si_code, unsigned long address,
-		     struct task_struct *tsk, int fault)
+		     struct task_struct *tsk, struct vm_area_struct *vma,
+		     int fault)
 {
 	unsigned lsb = 0;
 	siginfo_t info;
@@ -184,6 +239,8 @@ force_sig_info_fault(int si_signo, int si_code, unsigned long address,
 		lsb = PAGE_SHIFT;
 	info.si_addr_lsb = lsb;
 
+	fill_sig_info_pkey(si_code, &info, vma);
+
 	force_sig_info(si_signo, &info, tsk);
 }
 
@@ -287,6 +344,9 @@ static noinline int vmalloc_fault(unsigned long address)
 	if (!pmd_k)
 		return -1;
 
+	if (pmd_huge(*pmd_k))
+		return 0;
+
 	pte_k = pte_offset_kernel(pmd_k, address);
 	if (!pte_present(*pte_k))
 		return -1;
@@ -360,8 +420,6 @@ void vmalloc_sync_all(void)
  * 64-bit:
  *
  *   Handle a fault on the vmalloc area
- *
- * This assumes no large pages in there.
  */
 static noinline int vmalloc_fault(unsigned long address)
 {
@@ -403,17 +461,23 @@ static noinline int vmalloc_fault(unsigned long address)
 	if (pud_none(*pud_ref))
 		return -1;
 
-	if (pud_none(*pud) || pud_page_vaddr(*pud) != pud_page_vaddr(*pud_ref))
+	if (pud_none(*pud) || pud_pfn(*pud) != pud_pfn(*pud_ref))
 		BUG();
 
+	if (pud_huge(*pud))
+		return 0;
+
 	pmd = pmd_offset(pud, address);
 	pmd_ref = pmd_offset(pud_ref, address);
 	if (pmd_none(*pmd_ref))
 		return -1;
 
-	if (pmd_none(*pmd) || pmd_page(*pmd) != pmd_page(*pmd_ref))
+	if (pmd_none(*pmd) || pmd_pfn(*pmd) != pmd_pfn(*pmd_ref))
 		BUG();
 
+	if (pmd_huge(*pmd))
+		return 0;
+
 	pte_ref = pte_offset_kernel(pmd_ref, address);
 	if (!pte_present(*pte_ref))
 		return -1;
@@ -654,9 +718,11 @@ no_context(struct pt_regs *regs, unsigned long error_code,
 	struct task_struct *tsk = current;
 	unsigned long flags;
 	int sig;
+	/* No context means no VMA to pass down */
+	struct vm_area_struct *vma = NULL;
 
 	/* Are we prepared to handle this kernel fault? */
-	if (fixup_exception(regs)) {
+	if (fixup_exception(regs, X86_TRAP_PF)) {
 		/*
 		 * Any interrupt that takes a fault gets the fixup. This makes
 		 * the below recursive fault logic only apply to a faults from
@@ -677,7 +743,8 @@ 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, 0);
+			force_sig_info_fault(signal, si_code, address,
+					     tsk, vma, 0);
 		}
 
 		/*
@@ -754,7 +821,8 @@ 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, int si_code)
+		       unsigned long address, struct vm_area_struct *vma,
+		       int si_code)
 {
 	struct task_struct *tsk = current;
 
@@ -797,7 +865,7 @@ __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, 0);
+		force_sig_info_fault(SIGSEGV, si_code, address, tsk, vma, 0);
 
 		return;
 	}
@@ -810,14 +878,14 @@ __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)
+		     unsigned long address, struct vm_area_struct *vma)
 {
-	__bad_area_nosemaphore(regs, error_code, address, SEGV_MAPERR);
+	__bad_area_nosemaphore(regs, error_code, address, vma, SEGV_MAPERR);
 }
 
 static void
 __bad_area(struct pt_regs *regs, unsigned long error_code,
-	   unsigned long address, int si_code)
+	   unsigned long address,  struct vm_area_struct *vma, int si_code)
 {
 	struct mm_struct *mm = current->mm;
 
@@ -827,25 +895,50 @@ __bad_area(struct pt_regs *regs, unsigned long error_code,
 	 */
 	up_read(&mm->mmap_sem);
 
-	__bad_area_nosemaphore(regs, error_code, address, si_code);
+	__bad_area_nosemaphore(regs, error_code, address, vma, si_code);
 }
 
 static noinline void
 bad_area(struct pt_regs *regs, unsigned long error_code, unsigned long address)
 {
-	__bad_area(regs, error_code, address, SEGV_MAPERR);
+	__bad_area(regs, error_code, address, NULL, SEGV_MAPERR);
+}
+
+static inline bool bad_area_access_from_pkeys(unsigned long error_code,
+		struct vm_area_struct *vma)
+{
+	/* This code is always called on the current mm */
+	bool foreign = false;
+
+	if (!boot_cpu_has(X86_FEATURE_OSPKE))
+		return false;
+	if (error_code & PF_PK)
+		return true;
+	/* this checks permission keys on the VMA: */
+	if (!arch_vma_access_permitted(vma, (error_code & PF_WRITE),
+				(error_code & PF_INSTR), foreign))
+		return true;
+	return false;
 }
 
 static noinline void
 bad_area_access_error(struct pt_regs *regs, unsigned long error_code,
-		      unsigned long address)
+		      unsigned long address, struct vm_area_struct *vma)
 {
-	__bad_area(regs, error_code, address, SEGV_ACCERR);
+	/*
+	 * This OSPKE check is not strictly necessary at runtime.
+	 * 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);
 }
 
 static void
 do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address,
-	  unsigned int fault)
+	  struct vm_area_struct *vma, unsigned int fault)
 {
 	struct task_struct *tsk = current;
 	int code = BUS_ADRERR;
@@ -872,12 +965,13 @@ do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address,
 		code = BUS_MCEERR_AR;
 	}
 #endif
-	force_sig_info_fault(SIGBUS, code, address, tsk, fault);
+	force_sig_info_fault(SIGBUS, code, address, tsk, vma, fault);
 }
 
 static noinline void
 mm_fault_error(struct pt_regs *regs, unsigned long error_code,
-	       unsigned long address, unsigned int fault)
+	       unsigned long address, struct vm_area_struct *vma,
+	       unsigned int fault)
 {
 	if (fatal_signal_pending(current) && !(error_code & PF_USER)) {
 		no_context(regs, error_code, address, 0, 0);
@@ -901,9 +995,9 @@ 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, fault);
+			do_sigbus(regs, error_code, address, vma, fault);
 		else if (fault & VM_FAULT_SIGSEGV)
-			bad_area_nosemaphore(regs, error_code, address);
+			bad_area_nosemaphore(regs, error_code, address, vma);
 		else
 			BUG();
 	}
@@ -916,6 +1010,12 @@ static int spurious_fault_check(unsigned long error_code, pte_t *pte)
 
 	if ((error_code & PF_INSTR) && !pte_exec(*pte))
 		return 0;
+	/*
+	 * Note: We do not do lazy flushing on protection key
+	 * changes, so no spurious fault will ever set PF_PK.
+	 */
+	if ((error_code & PF_PK))
+		return 1;
 
 	return 1;
 }
@@ -1005,6 +1105,17 @@ int show_unhandled_signals = 1;
 static inline int
 access_error(unsigned long error_code, struct vm_area_struct *vma)
 {
+	/* This is only called for the current mm, so: */
+	bool foreign = false;
+	/*
+	 * Make sure to check the VMA so that we do not perform
+	 * faults just to hit a PF_PK as soon as we fill in a
+	 * page.
+	 */
+	if (!arch_vma_access_permitted(vma, (error_code & PF_WRITE),
+				(error_code & PF_INSTR), foreign))
+		return 1;
+
 	if (error_code & PF_WRITE) {
 		/* write, present and write, not present: */
 		if (unlikely(!(vma->vm_flags & VM_WRITE)))
@@ -1111,7 +1222,7 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code,
 		 * Don't take the mm semaphore here. If we fixup a prefetch
 		 * fault we could otherwise deadlock:
 		 */
-		bad_area_nosemaphore(regs, error_code, address);
+		bad_area_nosemaphore(regs, error_code, address, NULL);
 
 		return;
 	}
@@ -1124,7 +1235,7 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code,
 		pgtable_bad(regs, error_code, address);
 
 	if (unlikely(smap_violation(error_code, regs))) {
-		bad_area_nosemaphore(regs, error_code, address);
+		bad_area_nosemaphore(regs, error_code, address, NULL);
 		return;
 	}
 
@@ -1133,7 +1244,7 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code,
 	 * in a region with pagefaults disabled then we must not take the fault
 	 */
 	if (unlikely(faulthandler_disabled() || !mm)) {
-		bad_area_nosemaphore(regs, error_code, address);
+		bad_area_nosemaphore(regs, error_code, address, NULL);
 		return;
 	}
 
@@ -1157,6 +1268,8 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code,
 
 	if (error_code & PF_WRITE)
 		flags |= FAULT_FLAG_WRITE;
+	if (error_code & PF_INSTR)
+		flags |= FAULT_FLAG_INSTRUCTION;
 
 	/*
 	 * When running in the kernel we expect faults to occur only to
@@ -1177,7 +1290,7 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code,
 	if (unlikely(!down_read_trylock(&mm->mmap_sem))) {
 		if ((error_code & PF_USER) == 0 &&
 		    !search_exception_tables(regs->ip)) {
-			bad_area_nosemaphore(regs, error_code, address);
+			bad_area_nosemaphore(regs, error_code, address, NULL);
 			return;
 		}
 retry:
@@ -1225,7 +1338,7 @@ retry:
 	 */
 good_area:
 	if (unlikely(access_error(error_code, vma))) {
-		bad_area_access_error(regs, error_code, address);
+		bad_area_access_error(regs, error_code, address, vma);
 		return;
 	}
 
@@ -1263,7 +1376,7 @@ good_area:
 
 	up_read(&mm->mmap_sem);
 	if (unlikely(fault & VM_FAULT_ERROR)) {
-		mm_fault_error(regs, error_code, address, fault);
+		mm_fault_error(regs, error_code, address, vma, fault);
 		return;
 	}