Merge tag 'powerpc-5.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc updates from Michael Ellerman:

 - Support for userspace to send requests directly to the on-chip GZIP
   accelerator on Power9.

 - Rework of our lockless page table walking (__find_linux_pte()) to
   make it safe against parallel page table manipulations without
   relying on an IPI for serialisation.

 - A series of fixes & enhancements to make our machine check handling
   more robust.

 - Lots of plumbing to add support for "prefixed" (64-bit) instructions
   on Power10.

 - Support for using huge pages for the linear mapping on 8xx (32-bit).

 - Remove obsolete Xilinx PPC405/PPC440 support, and an associated sound
   driver.

 - Removal of some obsolete 40x platforms and associated cruft.

 - Initial support for booting on Power10.

 - Lots of other small features, cleanups & fixes.

Thanks to: Alexey Kardashevskiy, Alistair Popple, Andrew Donnellan,
Andrey Abramov, Aneesh Kumar K.V, Balamuruhan S, Bharata B Rao, Bulent
Abali, Cédric Le Goater, Chen Zhou, Christian Zigotzky, Christophe
JAILLET, Christophe Leroy, Dmitry Torokhov, Emmanuel Nicolet, Erhard F.,
Gautham R. Shenoy, Geoff Levand, George Spelvin, Greg Kurz, Gustavo A.
R. Silva, Gustavo Walbon, Haren Myneni, Hari Bathini, Joel Stanley,
Jordan Niethe, Kajol Jain, Kees Cook, Leonardo Bras, Madhavan
Srinivasan., Mahesh Salgaonkar, Markus Elfring, Michael Neuling, Michal
Simek, Nathan Chancellor, Nathan Lynch, Naveen N. Rao, Nicholas Piggin,
Oliver O'Halloran, Paul Mackerras, Pingfan Liu, Qian Cai, Ram Pai,
Raphael Moreira Zinsly, Ravi Bangoria, Sam Bobroff, Sandipan Das, Segher
Boessenkool, Stephen Rothwell, Sukadev Bhattiprolu, Tyrel Datwyler,
Wolfram Sang, Xiongfeng Wang.

* tag 'powerpc-5.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (299 commits)
  powerpc/pseries: Make vio and ibmebus initcalls pseries specific
  cxl: Remove dead Kconfig options
  powerpc: Add POWER10 architected mode
  powerpc/dt_cpu_ftrs: Add MMA feature
  powerpc/dt_cpu_ftrs: Enable Prefixed Instructions
  powerpc/dt_cpu_ftrs: Advertise support for ISA v3.1 if selected
  powerpc: Add support for ISA v3.1
  powerpc: Add new HWCAP bits
  powerpc/64s: Don't set FSCR bits in INIT_THREAD
  powerpc/64s: Save FSCR to init_task.thread.fscr after feature init
  powerpc/64s: Don't let DT CPU features set FSCR_DSCR
  powerpc/64s: Don't init FSCR_DSCR in __init_FSCR()
  powerpc/32s: Fix another build failure with CONFIG_PPC_KUAP_DEBUG
  powerpc/module_64: Use special stub for _mcount() with -mprofile-kernel
  powerpc/module_64: Simplify check for -mprofile-kernel ftrace relocations
  powerpc/module_64: Consolidate ftrace code
  powerpc/32: Disable KASAN with pages bigger than 16k
  powerpc/uaccess: Don't set KUEP by default on book3s/32
  powerpc/uaccess: Don't set KUAP by default on book3s/32
  powerpc/8xx: Reduce time spent in allow_user_access() and friends
  ...

1 files changed, 61 insertions, 31 deletions

diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index 84af6c8eecf7..2393ed9d84bb 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -41,18 +41,19 @@
 #include <asm/siginfo.h>
 #include <asm/debug.h>
 #include <asm/kup.h>
+#include <asm/inst.h>
 
 /*
  * Check whether the instruction inst is a store using
  * an update addressing form which will update r1.
  */
-static bool store_updates_sp(unsigned int inst)
+static bool store_updates_sp(struct ppc_inst inst)
 {
 	/* check for 1 in the rA field */
-	if (((inst >> 16) & 0x1f) != 1)
+	if (((ppc_inst_val(inst) >> 16) & 0x1f) != 1)
 		return false;
 	/* check major opcode */
-	switch (inst >> 26) {
+	switch (ppc_inst_primary_opcode(inst)) {
 	case OP_STWU:
 	case OP_STBU:
 	case OP_STHU:
@@ -60,10 +61,10 @@ static bool store_updates_sp(unsigned int inst)
 	case OP_STFDU:
 		return true;
 	case OP_STD:	/* std or stdu */
-		return (inst & 3) == 1;
+		return (ppc_inst_val(inst) & 3) == 1;
 	case OP_31:
 		/* check minor opcode */
-		switch ((inst >> 1) & 0x3ff) {
+		switch ((ppc_inst_val(inst) >> 1) & 0x3ff) {
 		case OP_31_XOP_STDUX:
 		case OP_31_XOP_STWUX:
 		case OP_31_XOP_STBUX:
@@ -118,9 +119,34 @@ static noinline int bad_area(struct pt_regs *regs, unsigned long address)
 	return __bad_area(regs, address, SEGV_MAPERR);
 }
 
-static int bad_key_fault_exception(struct pt_regs *regs, unsigned long address,
-				    int pkey)
+#ifdef CONFIG_PPC_MEM_KEYS
+static noinline int bad_access_pkey(struct pt_regs *regs, unsigned long address,
+				    struct vm_area_struct *vma)
 {
+	struct mm_struct *mm = current->mm;
+	int pkey;
+
+	/*
+	 * We don't try to fetch the pkey from page table because reading
+	 * page table without locking doesn't guarantee stable pte value.
+	 * Hence the pkey value that we return to userspace can be different
+	 * from the pkey that actually caused access error.
+	 *
+	 * 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 AMR 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.
+	 */
+	pkey = vma_pkey(vma);
+
+	up_read(&mm->mmap_sem);
+
 	/*
 	 * If we are in kernel mode, bail out with a SEGV, this will
 	 * be caught by the assembly which will restore the non-volatile
@@ -133,6 +159,7 @@ static int bad_key_fault_exception(struct pt_regs *regs, unsigned long address,
 
 	return 0;
 }
+#endif
 
 static noinline int bad_access(struct pt_regs *regs, unsigned long address)
 {
@@ -255,7 +282,7 @@ static bool bad_stack_expansion(struct pt_regs *regs, unsigned long address,
 	 * expand to 1MB without further checks.
 	 */
 	if (address + 0x100000 < vma->vm_end) {
-		unsigned int __user *nip = (unsigned int __user *)regs->nip;
+		struct ppc_inst __user *nip = (struct ppc_inst __user *)regs->nip;
 		/* get user regs even if this fault is in kernel mode */
 		struct pt_regs *uregs = current->thread.regs;
 		if (uregs == NULL)
@@ -278,9 +305,9 @@ static bool bad_stack_expansion(struct pt_regs *regs, unsigned long address,
 
 		if ((flags & FAULT_FLAG_WRITE) && (flags & FAULT_FLAG_USER) &&
 		    access_ok(nip, sizeof(*nip))) {
-			unsigned int inst;
+			struct ppc_inst inst;
 
-			if (!probe_user_read(&inst, nip, sizeof(inst)))
+			if (!probe_user_read_inst(&inst, nip))
 				return !store_updates_sp(inst);
 			*must_retry = true;
 		}
@@ -289,8 +316,23 @@ static bool bad_stack_expansion(struct pt_regs *regs, unsigned long address,
 	return false;
 }
 
-static bool access_error(bool is_write, bool is_exec,
-			 struct vm_area_struct *vma)
+#ifdef CONFIG_PPC_MEM_KEYS
+static bool access_pkey_error(bool is_write, bool is_exec, bool is_pkey,
+			      struct vm_area_struct *vma)
+{
+	/*
+	 * Make sure to check the VMA so that we do not perform
+	 * faults just to hit a pkey fault as soon as we fill in a
+	 * page. Only called for current mm, hence foreign == 0
+	 */
+	if (!arch_vma_access_permitted(vma, is_write, is_exec, 0))
+		return true;
+
+	return false;
+}
+#endif
+
+static bool access_error(bool is_write, bool is_exec, struct vm_area_struct *vma)
 {
 	/*
 	 * Allow execution from readable areas if the MMU does not
@@ -483,10 +525,6 @@ static int __do_page_fault(struct pt_regs *regs, unsigned long address,
 
 	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
 
-	if (error_code & DSISR_KEYFAULT)
-		return bad_key_fault_exception(regs, address,
-					       get_mm_addr_key(mm, address));
-
 	/*
 	 * We want to do this outside mmap_sem, because reading code around nip
 	 * can result in fault, which will cause a deadlock when called with
@@ -555,6 +593,13 @@ retry:
 		return bad_area(regs, address);
 
 good_area:
+
+#ifdef CONFIG_PPC_MEM_KEYS
+	if (unlikely(access_pkey_error(is_write, is_exec,
+				       (error_code & DSISR_KEYFAULT), vma)))
+		return bad_access_pkey(regs, address, vma);
+#endif /* CONFIG_PPC_MEM_KEYS */
+
 	if (unlikely(access_error(is_write, is_exec, vma)))
 		return bad_access(regs, address);
 
@@ -565,21 +610,6 @@ good_area:
 	 */
 	fault = handle_mm_fault(vma, address, flags);
 
-#ifdef CONFIG_PPC_MEM_KEYS
-	/*
-	 * we skipped checking for access error due to key earlier.
-	 * Check that using handle_mm_fault error return.
-	 */
-	if (unlikely(fault & VM_FAULT_SIGSEGV) &&
-		!arch_vma_access_permitted(vma, is_write, is_exec, 0)) {
-
-		int pkey = vma_pkey(vma);
-
-		up_read(&mm->mmap_sem);
-		return bad_key_fault_exception(regs, address, pkey);
-	}
-#endif /* CONFIG_PPC_MEM_KEYS */
-
 	major |= fault & VM_FAULT_MAJOR;
 
 	if (fault_signal_pending(fault, regs))