crash/SOURCES/0016-arm64-use-TCR_EL1_T1SZ-to-get-the-correct-info-if-va.patch
2023-03-29 01:34:48 +00:00

112 lines
3.6 KiB
Diff

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