112 lines
3.6 KiB
Diff
112 lines
3.6 KiB
Diff
From 28a41ec7a471474094d8ab39f3a69b44d0f9ebcf Mon Sep 17 00:00:00 2001
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From: Huang Shijie <shijie@os.amperecomputing.com>
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Date: Mon, 22 Aug 2022 09:29:32 +0000
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Subject: [PATCH 16/28] arm64: use TCR_EL1_T1SZ to get the correct info if
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vabits_actual is missing
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After kernel commit 0d9b1ffefabe ("arm64: mm: make vabits_actual a build
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time constant if possible"), the vabits_actual is not compiled to kernel
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symbols when "VA_BITS > 48" is false.
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So the crash will not find the vabits_actual symbol, and it will fail
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in the end like this:
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# ./crash
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...
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WARNING: VA_BITS: calculated: 46 vmcoreinfo: 48
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crash: invalid kernel virtual address: ffff88177ffff000 type: "pud page"
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This patch introduces the arm64_set_va_bits_by_tcr(), and if crash cannot
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find vabits_actual symbol, it will use the TCR_EL1_T1SZ register to get
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the correct VA_BITS_ACTUAL/VA_BITS/VA_START.
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Tested this patch with:
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1.) the live mode with /proc/kcore
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2.) the kdump file with /proc/vmcore.
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Signed-off-by: Huang Shijie <shijie@os.amperecomputing.com>
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Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
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---
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arm64.c | 51 ++++++++++++++++++++++++++++++++++-----------------
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1 file changed, 34 insertions(+), 17 deletions(-)
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diff --git a/arm64.c b/arm64.c
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index b6b7aa11f4fe..c3e26a371a61 100644
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--- a/arm64.c
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+++ b/arm64.c
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@@ -4586,6 +4586,36 @@ arm64_IS_VMALLOC_ADDR(ulong vaddr)
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(vaddr >= ms->modules_vaddr && vaddr <= ms->modules_end));
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}
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+/* Return TRUE if we succeed, return FALSE on failure. */
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+static int
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+arm64_set_va_bits_by_tcr(void)
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+{
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+ ulong value;
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+ char *string;
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+
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+ if ((string = pc->read_vmcoreinfo("NUMBER(TCR_EL1_T1SZ)")) ||
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+ (string = pc->read_vmcoreinfo("NUMBER(tcr_el1_t1sz)"))) {
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+ /* See ARMv8 ARM for the description of
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+ * TCR_EL1.T1SZ and how it can be used
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+ * to calculate the vabits_actual
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+ * supported by underlying kernel.
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+ *
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+ * Basically:
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+ * vabits_actual = 64 - T1SZ;
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+ */
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+ value = 64 - strtoll(string, NULL, 0);
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+ if (CRASHDEBUG(1))
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+ fprintf(fp, "vmcoreinfo : vabits_actual: %ld\n", value);
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+ free(string);
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+ machdep->machspec->VA_BITS_ACTUAL = value;
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+ machdep->machspec->VA_BITS = value;
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+ machdep->machspec->VA_START = _VA_START(machdep->machspec->VA_BITS_ACTUAL);
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+ return TRUE;
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+ }
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+
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+ return FALSE;
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+}
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+
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static void
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arm64_calc_VA_BITS(void)
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{
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@@ -4616,23 +4646,8 @@ arm64_calc_VA_BITS(void)
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} else if (ACTIVE())
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error(FATAL, "cannot determine VA_BITS_ACTUAL: please use /proc/kcore\n");
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else {
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- if ((string = pc->read_vmcoreinfo("NUMBER(TCR_EL1_T1SZ)")) ||
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- (string = pc->read_vmcoreinfo("NUMBER(tcr_el1_t1sz)"))) {
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- /* See ARMv8 ARM for the description of
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- * TCR_EL1.T1SZ and how it can be used
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- * to calculate the vabits_actual
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- * supported by underlying kernel.
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- *
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- * Basically:
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- * vabits_actual = 64 - T1SZ;
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- */
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- value = 64 - strtoll(string, NULL, 0);
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- if (CRASHDEBUG(1))
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- fprintf(fp, "vmcoreinfo : vabits_actual: %ld\n", value);
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- free(string);
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- machdep->machspec->VA_BITS_ACTUAL = value;
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- machdep->machspec->VA_BITS = value;
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- machdep->machspec->VA_START = _VA_START(machdep->machspec->VA_BITS_ACTUAL);
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+ if (arm64_set_va_bits_by_tcr()) {
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+ /* nothing */
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} else if (machdep->machspec->VA_BITS_ACTUAL) {
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machdep->machspec->VA_BITS = machdep->machspec->VA_BITS_ACTUAL;
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machdep->machspec->VA_START = _VA_START(machdep->machspec->VA_BITS_ACTUAL);
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@@ -4654,6 +4669,8 @@ arm64_calc_VA_BITS(void)
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*/
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machdep->flags |= FLIPPED_VM;
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return;
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+ } else if (arm64_set_va_bits_by_tcr()) {
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+ return;
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}
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if (!(sp = symbol_search("swapper_pg_dir")) &&
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--
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2.37.1
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