* unless restricted on specific platforms (e.g. 30-bit on Raspberry Pi 4).
* In such case, ZONE_DMA32 covers the rest of the 32-bit addressable memory,
* otherwise it is empty.
+ *
+ * Memory reservation for crash kernel either done early or deferred
+ * depending on DMA memory zones configs (ZONE_DMA) --
+ *
+ * In absence of ZONE_DMA configs arm64_dma_phys_limit initialized
+ * here instead of max_zone_phys(). This lets early reservation of
+ * crash kernel memory which has a dependency on arm64_dma_phys_limit.
+ * Reserving memory early for crash kernel allows linear creation of block
+ * mappings (greater than page-granularity) for all the memory bank rangs.
+ * In this scheme a comparatively quicker boot is observed.
+ *
+ * If ZONE_DMA configs are defined, crash kernel memory reservation
+ * is delayed until DMA zone memory range size initilazation performed in
+ * zone_sizes_init(). The defer is necessary to steer clear of DMA zone
+ * memory range to avoid overlap allocation. So crash kernel memory boundaries
+ * are not known when mapping all bank memory ranges, which otherwise means
+ * not possible to exclude crash kernel range from creating block mappings
+ * so page-granularity mappings are created for the entire memory range.
+ * Hence a slightly slower boot is observed.
+ *
+ * Note: Page-granularity mapppings are necessary for crash kernel memory
+ * range for shrinking its size via /sys/kernel/kexec_crash_size interface.
*/
-phys_addr_t arm64_dma_phys_limit __ro_after_init;
+#if IS_ENABLED(CONFIG_ZONE_DMA) || IS_ENABLED(CONFIG_ZONE_DMA32)
+phys_addr_t __ro_after_init arm64_dma_phys_limit;
+#else
+phys_addr_t __ro_after_init arm64_dma_phys_limit = PHYS_MASK + 1;
+#endif
- #ifdef CONFIG_KEXEC_CORE
/*
* reserve_crashkernel() - reserves memory for crash kernel
*
#ifndef __ASSEMBLY__
+#if defined(CONFIG_DEBUG_INFO_BTF) && defined(CONFIG_PAHOLE_HAS_BTF_TAG) && \
+ __has_attribute(btf_type_tag)
+# define BTF_TYPE_TAG(value) __attribute__((btf_type_tag(#value)))
+#else
+# define BTF_TYPE_TAG(value) /* nothing */
+#endif
+
+ /* sparse defines __CHECKER__; see Documentation/dev-tools/sparse.rst */
#ifdef __CHECKER__
/* address spaces */
# define __kernel __attribute__((address_space(0)))
depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
depends on BPF_SYSCALL
- depends on !DEBUG_INFO_DWARF5
++ depends on !DEBUG_INFO_DWARF5 || PAHOLE_VERSION >= 121
help
Generate deduplicated BTF type information from DWARF debug info.
Turning this on expects presence of pahole tool, which will convert