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From: Chris Metcalf <cmetcalf@tilera.com>
To: linux-kernel@vger.kernel.org
Subject: [PATCH] arch/tile: fix two bugs in the backtracer code
Date: Mon, 28 Feb 2011 15:30:16 -0500	[thread overview]
Message-ID: <201103011934.p21JYdCi010307@farm-0010.internal.tilera.com> (raw)
In-Reply-To: <201103011931.p21JVtqp010237@farm-0010.internal.tilera.com>

The first is that we were using an incorrect hand-rolled variant
of __kernel_text_address() which didn't handle module PCs.  We now
just use the standard API.

The second was that we weren't accounting for the three-level
page table when we were trying to pre-verify the addresses on
the 64-bit TILE-Gx processor; we now do that correctly.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
---
 arch/tile/kernel/stack.c |   28 +++++++++++++++++++---------
 1 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/arch/tile/kernel/stack.c b/arch/tile/kernel/stack.c
index 0d54106..dd81713 100644
--- a/arch/tile/kernel/stack.c
+++ b/arch/tile/kernel/stack.c
@@ -44,13 +44,6 @@ static int in_kernel_stack(struct KBacktraceIterator *kbt, VirtualAddress sp)
 	return sp >= kstack_base && sp < kstack_base + THREAD_SIZE;
 }
 
-/* Is address in the specified kernel code? */
-static int in_kernel_text(VirtualAddress address)
-{
-	return (address >= MEM_SV_INTRPT &&
-		address < MEM_SV_INTRPT + HPAGE_SIZE);
-}
-
 /* Is address valid for reading? */
 static int valid_address(struct KBacktraceIterator *kbt, VirtualAddress address)
 {
@@ -63,6 +56,23 @@ static int valid_address(struct KBacktraceIterator *kbt, VirtualAddress address)
 	if (l1_pgtable == NULL)
 		return 0;	/* can't read user space in other tasks */
 
+#ifdef CONFIG_64BIT
+	/* Find the real l1_pgtable by looking in the l0_pgtable. */
+	pte = l1_pgtable[HV_L0_INDEX(address)];
+	if (!hv_pte_get_present(pte))
+		return 0;
+	pfn = hv_pte_get_pfn(pte);
+	if (pte_huge(pte)) {
+		if (!pfn_valid(pfn)) {
+			pr_err("L0 huge page has bad pfn %#lx\n", pfn);
+			return 0;
+		}
+		return hv_pte_get_present(pte) && hv_pte_get_readable(pte);
+	}
+	page = pfn_to_page(pfn);
+	BUG_ON(PageHighMem(page));  /* No HIGHMEM on 64-bit. */
+	l1_pgtable = (HV_PTE *)pfn_to_kaddr(pfn);
+#endif
 	pte = l1_pgtable[HV_L1_INDEX(address)];
 	if (!hv_pte_get_present(pte))
 		return 0;
@@ -92,7 +102,7 @@ static bool read_memory_func(void *result, VirtualAddress address,
 {
 	int retval;
 	struct KBacktraceIterator *kbt = (struct KBacktraceIterator *)vkbt;
-	if (in_kernel_text(address)) {
+	if (__kernel_text_address(address)) {
 		/* OK to read kernel code. */
 	} else if (address >= PAGE_OFFSET) {
 		/* We only tolerate kernel-space reads of this task's stack */
@@ -132,7 +142,7 @@ static struct pt_regs *valid_fault_handler(struct KBacktraceIterator* kbt)
 		}
 	}
 	if (EX1_PL(p->ex1) == KERNEL_PL &&
-	    in_kernel_text(p->pc) &&
+	    __kernel_text_address(p->pc) &&
 	    in_kernel_stack(kbt, p->sp) &&
 	    p->sp >= sp) {
 		if (kbt->verbose)
-- 
1.6.5.2


  parent reply	other threads:[~2011-03-01 19:40 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-02-27 23:52 arch/tile: various fixes for 2.6.39 Chris Metcalf
2011-02-27 23:52 ` [PATCH] arch/tile: catch up with section naming convention in 2.6.35 Chris Metcalf
2011-03-01 20:52   ` Sam Ravnborg
2011-03-01 21:17     ` Chris Metcalf
2011-02-28 18:08 ` [PATCH] arch/tile: bug fix: exec'ed task thought it was still single-stepping Chris Metcalf
2011-02-28 18:21 ` [PATCH] arch/tile: fix __ndelay etc to work better Chris Metcalf
2011-02-28 18:24 ` [PATCH] arch/tile: stop disabling INTCTRL_1 interrupts during hypervisor downcalls Chris Metcalf
2011-02-28 18:32 ` [PATCH] arch/tile: warn and retry if an IPI is not accepted by the target cpu Chris Metcalf
2011-02-28 18:35 ` [PATCH] arch/tile: export <asm/hardwall.h> to userspace Chris Metcalf
2011-02-28 20:01 ` [PATCH] arch/tile: avoid a simulator warning during bootup Chris Metcalf
2011-02-28 20:14 ` [PATCH] arch/tile: fix reversed test of strict_strtol() return value Chris Metcalf
2011-02-28 20:19 ` [PATCH] arch/tile: sync up with <arch/sim.h> and <arch/sim_def.h> changes Chris Metcalf
2011-02-28 20:22 ` [PATCH] arch/tile: use a cleaner technique to enable interrupt for cpu_idle() Chris Metcalf
2011-02-28 20:28 ` [PATCH] arch/tile: use extended assembly to inline __mb_incoherent() Chris Metcalf
2011-02-28 20:30 ` Chris Metcalf [this message]
2011-02-28 20:48 ` [PATCH] arch/tile: enhance existing finv_buffer_remote() routine Chris Metcalf
2011-02-28 20:51 ` [PATCH] arch/tile: export some additional module symbols Chris Metcalf
2011-02-28 20:58 ` [PATCH] arch/tile: fix some comments and whitespace Chris Metcalf
2011-02-28 21:01 ` [PATCH] arch/tile: add some more VMSPLIT options and use consistent naming Chris Metcalf
2011-02-28 21:37 ` [PATCH] arch/tile: support 4KB page size as well as 64KB Chris Metcalf

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