The patch titled
Subject: arm64: implement stack_trace_save_shadow
has been added to the -mm tree. Its filename is
arm64-implement-stack_trace_save_shadow.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/arm64-implement-stack_trace_save_shadow.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/arm64-implement-stack_trace_save_shadow.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
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------------------------------------------------------
From: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Subject: arm64: implement stack_trace_save_shadow
Implement the stack_trace_save_shadow() interface that collects stack
traces based on the Shadow Call Stack (SCS) for arm64.
The implementation walks through available SCS pointers (the per-task one
and the per-interrupt-type ones) and copies the frames.
Note that the frame of the interrupted function is not included into the
stack trace, as it is not yet saved on the SCS when an interrupt happens.
Link: https://lkml.kernel.org/r/0bb72ea8fa88ef9ae3508c23d993952a0ae6f0f9.1648049113.git.andreyknvl@xxxxxxxxxx
Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Andrey Ryabinin <ryabinin.a.a@xxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Evgenii Stepanov <eugenis@xxxxxxxxxx>
Cc: Florian Mayer <fmayer@xxxxxxxxxx>
Cc: Marco Elver <elver@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Peter Collingbourne <pcc@xxxxxxxxxx>
Cc: Sami Tolvanen <samitolvanen@xxxxxxxxxx>
Cc: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/arm64/Kconfig | 1
arch/arm64/kernel/stacktrace.c | 83 +++++++++++++++++++++++++++++++
2 files changed, 84 insertions(+)
--- a/arch/arm64/Kconfig~arm64-implement-stack_trace_save_shadow
+++ a/arch/arm64/Kconfig
@@ -200,6 +200,7 @@ config ARM64
select HAVE_FUNCTION_ARG_ACCESS_API
select MMU_GATHER_RCU_TABLE_FREE
select HAVE_RSEQ
+ select HAVE_SHADOW_STACKTRACE
select HAVE_STACKPROTECTOR
select HAVE_SYSCALL_TRACEPOINTS
select HAVE_KPROBES
--- a/arch/arm64/kernel/stacktrace.c~arm64-implement-stack_trace_save_shadow
+++ a/arch/arm64/kernel/stacktrace.c
@@ -12,9 +12,11 @@
#include <linux/sched/debug.h>
#include <linux/sched/task_stack.h>
#include <linux/stacktrace.h>
+#include <linux/scs.h>
#include <asm/irq.h>
#include <asm/pointer_auth.h>
+#include <asm/scs.h>
#include <asm/stack_pointer.h>
#include <asm/stacktrace.h>
@@ -210,3 +212,84 @@ noinline notrace void arch_stack_walk(st
walk_stackframe(task, &frame, consume_entry, cookie);
}
+
+static const struct {
+ unsigned long ** __percpu saved;
+ unsigned long ** __percpu base;
+} scs_parts[] = {
+#ifdef CONFIG_ARM_SDE_INTERFACE
+ {
+ .saved = &sdei_shadow_call_stack_critical_saved_ptr,
+ .base = &sdei_shadow_call_stack_critical_ptr,
+ },
+ {
+ .saved = &sdei_shadow_call_stack_normal_saved_ptr,
+ .base = &sdei_shadow_call_stack_normal_ptr,
+ },
+#endif /* CONFIG_ARM_SDE_INTERFACE */
+ {
+ .saved = &irq_shadow_call_stack_saved_ptr,
+ .base = &irq_shadow_call_stack_ptr,
+ },
+};
+
+static inline bool walk_shadow_stack_part(
+ unsigned long *scs_top, unsigned long *scs_base,
+ unsigned long *store, unsigned int size,
+ unsigned int *skipnr, unsigned int *len)
+{
+ unsigned long *frame;
+
+ for (frame = scs_top; frame >= scs_base; frame--) {
+ if (*skipnr > 0) {
+ (*skipnr)--;
+ continue;
+ }
+ /*
+ * Do not leak PTR_AUTH tags in stack traces.
+ * Use READ_ONCE_NOCHECK as SCS is poisoned with Generic KASAN.
+ */
+ store[(*len)++] =
+ ptrauth_strip_insn_pac(READ_ONCE_NOCHECK(*frame));
+ if (*len >= size)
+ return true;
+ }
+
+ return false;
+}
+
+noinline notrace int arch_stack_walk_shadow(unsigned long *store,
+ unsigned int size,
+ unsigned int skipnr)
+{
+ unsigned long *scs_top, *scs_base, *scs_next;
+ unsigned int len = 0, part;
+
+ preempt_disable();
+
+ /* Get the SCS pointer. */
+ asm volatile("mov %0, x18" : "=&r" (scs_top));
+
+ /* The top SCS slot is empty. */
+ scs_top -= 1;
+
+ /* Handle SDEI and hardirq frames. */
+ for (part = 0; part < ARRAY_SIZE(scs_parts); part++) {
+ scs_next = *this_cpu_ptr(scs_parts[part].saved);
+ if (scs_next) {
+ scs_base = *this_cpu_ptr(scs_parts[part].base);
+ if (walk_shadow_stack_part(scs_top, scs_base, store,
+ size, &skipnr, &len))
+ goto out;
+ scs_top = scs_next;
+ }
+ }
+
+ /* Handle task and softirq frames. */
+ scs_base = task_scs(current);
+ walk_shadow_stack_part(scs_top, scs_base, store, size, &skipnr, &len);
+
+out:
+ preempt_enable();
+ return len;
+}
_
Patches currently in -mm which might be from andreyknvl@xxxxxxxxxx are
kasan-page_alloc-deduplicate-should_skip_kasan_poison.patch
kasan-page_alloc-move-tag_clear_highpage-out-of-kernel_init_free_pages.patch
kasan-page_alloc-merge-kasan_free_pages-into-free_pages_prepare.patch
kasan-page_alloc-simplify-kasan_poison_pages-call-site.patch
kasan-page_alloc-init-memory-of-skipped-pages-on-free.patch
kasan-drop-skip_kasan_poison-variable-in-free_pages_prepare.patch
mm-clarify-__gfp_zerotags-comment.patch
kasan-only-apply-__gfp_zerotags-when-memory-is-zeroed.patch
kasan-page_alloc-refactor-init-checks-in-post_alloc_hook.patch
kasan-page_alloc-merge-kasan_alloc_pages-into-post_alloc_hook.patch
kasan-page_alloc-combine-tag_clear_highpage-calls-in-post_alloc_hook.patch
kasan-page_alloc-move-setpageskipkasanpoison-in-post_alloc_hook.patch
kasan-page_alloc-move-kernel_init_free_pages-in-post_alloc_hook.patch
kasan-page_alloc-rework-kasan_unpoison_pages-call-site.patch
kasan-clean-up-metadata-byte-definitions.patch
kasan-define-kasan_vmalloc_invalid-for-sw_tags.patch
kasan-x86-arm64-s390-rename-functions-for-modules-shadow.patch
kasan-vmalloc-drop-outdated-vm_kasan-comment.patch
kasan-reorder-vmalloc-hooks.patch
kasan-add-wrappers-for-vmalloc-hooks.patch
kasan-vmalloc-reset-tags-in-vmalloc-functions.patch
kasan-fork-reset-pointer-tags-of-vmapped-stacks.patch
kasan-arm64-reset-pointer-tags-of-vmapped-stacks.patch
kasan-vmalloc-add-vmalloc-tagging-for-sw_tags.patch
kasan-vmalloc-arm64-mark-vmalloc-mappings-as-pgprot_tagged.patch
kasan-vmalloc-unpoison-vm_alloc-pages-after-mapping.patch
kasan-mm-only-define-___gfp_skip_kasan_poison-with-hw_tags.patch
kasan-page_alloc-allow-skipping-unpoisoning-for-hw_tags.patch
kasan-page_alloc-allow-skipping-memory-init-for-hw_tags.patch
kasan-vmalloc-add-vmalloc-tagging-for-hw_tags.patch
kasan-vmalloc-only-tag-normal-vmalloc-allocations.patch
kasan-arm64-dont-tag-executable-vmalloc-allocations.patch
kasan-mark-kasan_arg_stacktrace-as-__initdata.patch
kasan-clean-up-feature-flags-for-hw_tags-mode.patch
kasan-add-kasanvmalloc-command-line-flag.patch
kasan-allow-enabling-kasan_vmalloc-and-sw-hw_tags.patch
arm64-select-kasan_vmalloc-for-sw-hw_tags-modes.patch
kasan-documentation-updates.patch
kasan-improve-vmalloc-tests.patch
kasan-test-support-async-again-and-asymm-modes-for-hw_tags.patch
kasan-print-virtual-mapping-info-in-reports.patch
kasan-drop-addr-check-from-describe_object_addr.patch
kasan-more-line-breaks-in-reports.patch
kasan-rearrange-stack-frame-info-in-reports.patch
kasan-improve-stack-frame-info-in-reports.patch
kasan-print-basic-stack-frame-info-for-sw_tags.patch
kasan-simplify-async-check-in-end_report.patch
kasan-simplify-kasan_update_kunit_status-and-call-sites.patch
kasan-check-config_kasan_kunit_test-instead-of-config_kunit.patch
kasan-move-update_kunit_status-to-start_report.patch
kasan-move-disable_trace_on_warning-to-start_report.patch
kasan-split-out-print_report-from-__kasan_report.patch
kasan-simplify-kasan_find_first_bad_addr-call-sites.patch
kasan-restructure-kasan_report.patch
kasan-merge-__kasan_report-into-kasan_report.patch
kasan-call-print_report-from-kasan_report_invalid_free.patch
kasan-move-and-simplify-kasan_report_async.patch
kasan-rename-kasan_access_info-to-kasan_report_info.patch
kasan-add-comment-about-uaccess-regions-to-kasan_report.patch
kasan-respect-kasan_bit_reported-in-all-reporting-routines.patch
kasan-reorder-reporting-functions.patch
kasan-move-and-hide-kasan_save_enable-restore_multi_shot.patch
kasan-disable-lockdep-when-printing-reports.patch
stacktrace-add-interface-based-on-shadow-call-stack.patch
arm64-scs-save-scs_sp-values-per-cpu-when-switching-stacks.patch
arm64-implement-stack_trace_save_shadow.patch
kasan-use-stack_trace_save_shadow.patch
