Merge git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile

Pull Tile arch updates from Chris Metcalf:
 "These changes bring in a bunch of new functionality that has been
  maintained internally at Tilera over the last year, plus other stray
  bits of work that I've taken into the tile tree from other folks.

  The changes include some PCI root complex work, interrupt-driven
  console support, support for performing fast-path unaligned data
  fixups by kernel-based JIT code generation, CONFIG_PREEMPT support,
  vDSO support for gettimeofday(), a serial driver for the tilegx
  on-chip UART, KGDB support, more optimized string routines, support
  for ftrace and kprobes, improved ASLR, and many bug fixes.

  We also remove support for the old TILE64 chip, which is no longer
  buildable"

* git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile: (85 commits)
  tile: refresh tile defconfig files
  tile: rework <asm/cmpxchg.h>
  tile PCI RC: make default consistent DMA mask 32-bit
  tile: add null check for kzalloc in tile/kernel/setup.c
  tile: make __write_once a synonym for __read_mostly
  tile: remove support for TILE64
  tile: use asm-generic/bitops/builtin-*.h
  tile: eliminate no-op "noatomichash" boot argument
  tile: use standard tile_bundle_bits type in traps.c
  tile: simplify code referencing hypervisor API addresses
  tile: change <asm/system.h> to <asm/switch_to.h> in comments
  tile: mark pcibios_init() as __init
  tile: check for correct compiler earlier in asm-offsets.c
  tile: use standard 'generic-y' model for <asm/hw_irq.h>
  tile: use asm-generic version of <asm/local64.h>
  tile PCI RC: add comment about "PCI hole" problem
  tile: remove DEBUG_EXTRA_FLAGS kernel config option
  tile: add virt_to_kpte() API and clean up and document behavior
  tile: support FRAME_POINTER
  tile: support reporting Tilera hypervisor statistics
  ...

1 files changed, 68 insertions, 21 deletions

diff --git a/arch/tile/kernel/traps.c b/arch/tile/kernel/traps.c
index 5b19a23c8908..6b603d556ca6 100644
--- a/arch/tile/kernel/traps.c
+++ b/arch/tile/kernel/traps.c
@@ -15,6 +15,7 @@
 #include <linux/sched.h>
 #include <linux/kernel.h>
 #include <linux/kprobes.h>
+#include <linux/kdebug.h>
 #include <linux/module.h>
 #include <linux/reboot.h>
 #include <linux/uaccess.h>
@@ -29,7 +30,7 @@
 
 void __init trap_init(void)
 {
-	/* Nothing needed here since we link code at .intrpt1 */
+	/* Nothing needed here since we link code at .intrpt */
 }
 
 int unaligned_fixup = 1;
@@ -100,13 +101,7 @@ static int retry_gpv(unsigned int gpv_reason)
 
 #endif /* CHIP_HAS_TILE_DMA() */
 
-#ifdef __tilegx__
-#define bundle_bits tilegx_bundle_bits
-#else
-#define bundle_bits tile_bundle_bits
-#endif
-
-extern bundle_bits bpt_code;
+extern tile_bundle_bits bpt_code;
 
 asm(".pushsection .rodata.bpt_code,\"a\";"
     ".align 8;"
@@ -114,7 +109,7 @@ asm(".pushsection .rodata.bpt_code,\"a\";"
     ".size bpt_code,.-bpt_code;"
     ".popsection");
 
-static int special_ill(bundle_bits bundle, int *sigp, int *codep)
+static int special_ill(tile_bundle_bits bundle, int *sigp, int *codep)
 {
 	int sig, code, maxcode;
 
@@ -214,24 +209,73 @@ static const char *const int_name[] = {
 #endif
 };
 
+static int do_bpt(struct pt_regs *regs)
+{
+	unsigned long bundle, bcode, bpt;
+
+	bundle = *(unsigned long *)instruction_pointer(regs);
+
+	/*
+	 * bpt shoule be { bpt; nop }, which is 0x286a44ae51485000ULL.
+	 * we encode the unused least significant bits for other purpose.
+	 */
+	bpt = bundle & ~((1ULL << 12) - 1);
+	if (bpt != TILE_BPT_BUNDLE)
+		return 0;
+
+	bcode = bundle & ((1ULL << 12) - 1);
+	/*
+	 * notify the kprobe handlers, if instruction is likely to
+	 * pertain to them.
+	 */
+	switch (bcode) {
+	/* breakpoint_insn */
+	case 0:
+		notify_die(DIE_BREAK, "debug", regs, bundle,
+			INT_ILL, SIGTRAP);
+		break;
+	/* compiled_bpt */
+	case DIE_COMPILED_BPT:
+		notify_die(DIE_COMPILED_BPT, "debug", regs, bundle,
+			INT_ILL, SIGTRAP);
+		break;
+	/* breakpoint2_insn */
+	case DIE_SSTEPBP:
+		notify_die(DIE_SSTEPBP, "single_step", regs, bundle,
+			INT_ILL, SIGTRAP);
+		break;
+	default:
+		return 0;
+	}
+
+	return 1;
+}
+
 void __kprobes do_trap(struct pt_regs *regs, int fault_num,
 		       unsigned long reason)
 {
 	siginfo_t info = { 0 };
 	int signo, code;
 	unsigned long address = 0;
-	bundle_bits instr;
+	tile_bundle_bits instr;
+	int is_kernel = !user_mode(regs);
+
+	/* Handle breakpoints, etc. */
+	if (is_kernel && fault_num == INT_ILL && do_bpt(regs))
+		return;
 
-	/* Re-enable interrupts. */
-	local_irq_enable();
+	/* Re-enable interrupts, if they were previously enabled. */
+	if (!(regs->flags & PT_FLAGS_DISABLE_IRQ))
+		local_irq_enable();
 
 	/*
 	 * If it hits in kernel mode and we can't fix it up, just exit the
 	 * current process and hope for the best.
 	 */
-	if (!user_mode(regs)) {
+	if (is_kernel) {
 		const char *name;
-		if (fixup_exception(regs))  /* only UNALIGN_DATA in practice */
+		char buf[100];
+		if (fixup_exception(regs))  /* ILL_TRANS or UNALIGN_DATA */
 			return;
 		if (fault_num >= 0 &&
 		    fault_num < sizeof(int_name)/sizeof(int_name[0]) &&
@@ -239,10 +283,16 @@ void __kprobes do_trap(struct pt_regs *regs, int fault_num,
 			name = int_name[fault_num];
 		else
 			name = "Unknown interrupt";
-		pr_alert("Kernel took bad trap %d (%s) at PC %#lx\n",
-			 fault_num, name, regs->pc);
 		if (fault_num == INT_GPV)
-			pr_alert("GPV_REASON is %#lx\n", reason);
+			snprintf(buf, sizeof(buf), "; GPV_REASON %#lx", reason);
+#ifdef __tilegx__
+		else if (fault_num == INT_ILL_TRANS)
+			snprintf(buf, sizeof(buf), "; address %#lx", reason);
+#endif
+		else
+			buf[0] = '\0';
+		pr_alert("Kernel took bad trap %d (%s) at PC %#lx%s\n",
+			 fault_num, name, regs->pc, buf);
 		show_regs(regs);
 		do_exit(SIGKILL);  /* FIXME: implement i386 die() */
 		return;
@@ -324,11 +374,8 @@ void __kprobes do_trap(struct pt_regs *regs, int fault_num,
 		fill_ra_stack();
 
 		signo = SIGSEGV;
+		address = reason;
 		code = SEGV_MAPERR;
-		if (reason & SPR_ILL_TRANS_REASON__I_STREAM_VA_RMASK)
-			address = regs->pc;
-		else
-			address = 0;  /* FIXME: GX: single-step for address */
 		break;
 	}
 #endif