Merge branch 'for-next/kdump' into for-next/core

* for-next/kdump:
  arm64: kdump: defer the crashkernel reservation for platforms with no DMA memory zones
  arm64: kdump: do not map crashkernel region specifically
  arm64: kdump : take off the protection on crashkernel memory region

Author: willdeacon

arch/arm64/include/asm/kexec.h

@@ -102,12 +102,6 @@ void cpu_soft_restart(unsigned long el2_switch, unsigned long entry,
 
 int machine_kexec_post_load(struct kimage *image);
 #define machine_kexec_post_load machine_kexec_post_load
-
-void arch_kexec_protect_crashkres(void);
-#define arch_kexec_protect_crashkres arch_kexec_protect_crashkres
-
-void arch_kexec_unprotect_crashkres(void);
-#define arch_kexec_unprotect_crashkres arch_kexec_unprotect_crashkres
 #endif
 
 #define ARCH_HAS_KIMAGE_ARCH

arch/arm64/include/asm/memory.h

@@ -374,11 +374,6 @@ static inline void *phys_to_virt(phys_addr_t x)
 })
 
 void dump_mem_limit(void);
-
-static inline bool defer_reserve_crashkernel(void)
-{
-	return IS_ENABLED(CONFIG_ZONE_DMA) || IS_ENABLED(CONFIG_ZONE_DMA32);
-}
 #endif /* !ASSEMBLY */
 
 /*

arch/arm64/kernel/machine_kexec.c

@@ -268,26 +268,6 @@ void machine_crash_shutdown(struct pt_regs *regs)
 	pr_info("Starting crashdump kernel...\n");
 }
 
-void arch_kexec_protect_crashkres(void)
-{
-	int i;
-
-	for (i = 0; i < kexec_crash_image->nr_segments; i++)
-		set_memory_valid(
-			__phys_to_virt(kexec_crash_image->segment[i].mem),
-			kexec_crash_image->segment[i].memsz >> PAGE_SHIFT, 0);
-}
-
-void arch_kexec_unprotect_crashkres(void)
-{
-	int i;
-
-	for (i = 0; i < kexec_crash_image->nr_segments; i++)
-		set_memory_valid(
-			__phys_to_virt(kexec_crash_image->segment[i].mem),
-			kexec_crash_image->segment[i].memsz >> PAGE_SHIFT, 1);
-}
-
 #ifdef CONFIG_HIBERNATION
 /*
  * To preserve the crash dump kernel image, the relevant memory segments

arch/arm64/mm/init.c

@@ -61,34 +61,8 @@ EXPORT_SYMBOL(memstart_addr);
  * 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 initialization 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 mappings are necessary for crash kernel memory
- * range for shrinking its size via /sys/kernel/kexec_crash_size interface.
  */
-#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
 
 /* Current arm64 boot protocol requires 2MB alignment */
 #define CRASH_ALIGN			SZ_2M
@@ -248,6 +222,8 @@ static void __init zone_sizes_init(void)
 	if (!arm64_dma_phys_limit)
 		arm64_dma_phys_limit = dma32_phys_limit;
 #endif
+	if (!arm64_dma_phys_limit)
+		arm64_dma_phys_limit = PHYS_MASK + 1;
 	max_zone_pfns[ZONE_NORMAL] = max_pfn;
 
 	free_area_init(max_zone_pfns);
@@ -408,9 +384,6 @@ void __init arm64_memblock_init(void)
 
 	early_init_fdt_scan_reserved_mem();
 
-	if (!defer_reserve_crashkernel())
-		reserve_crashkernel();
-
 	high_memory = __va(memblock_end_of_DRAM() - 1) + 1;
 }
 
@@ -457,8 +430,7 @@ void __init bootmem_init(void)
 	 * request_standard_resources() depends on crashkernel's memory being
 	 * reserved, so do it here.
 	 */
-	if (defer_reserve_crashkernel())
-		reserve_crashkernel();
+	reserve_crashkernel();
 
 	memblock_dump_all();
 }

arch/arm64/mm/mmu.c

@@ -510,21 +510,6 @@ void __init mark_linear_text_alias_ro(void)
 			    PAGE_KERNEL_RO);
 }
 
-static bool crash_mem_map __initdata;
-
-static int __init enable_crash_mem_map(char *arg)
-{
-	/*
-	 * Proper parameter parsing is done by reserve_crashkernel(). We only
-	 * need to know if the linear map has to avoid block mappings so that
-	 * the crashkernel reservations can be unmapped later.
-	 */
-	crash_mem_map = true;
-
-	return 0;
-}
-early_param("crashkernel", enable_crash_mem_map);
-
 static void __init map_mem(pgd_t *pgdp)
 {
 	static const u64 direct_map_end = _PAGE_END(VA_BITS_MIN);
@@ -554,16 +539,6 @@ static void __init map_mem(pgd_t *pgdp)
 	 */
 	memblock_mark_nomap(kernel_start, kernel_end - kernel_start);
 
-#ifdef CONFIG_KEXEC_CORE
-	if (crash_mem_map) {
-		if (defer_reserve_crashkernel())
-			flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
-		else if (crashk_res.end)
-			memblock_mark_nomap(crashk_res.start,
-			    resource_size(&crashk_res));
-	}
-#endif
-
 	/* map all the memory banks */
 	for_each_mem_range(i, &start, &end) {
 		if (start >= end)
@@ -590,24 +565,6 @@ static void __init map_mem(pgd_t *pgdp)
 	__map_memblock(pgdp, kernel_start, kernel_end,
 		       PAGE_KERNEL, NO_CONT_MAPPINGS);
 	memblock_clear_nomap(kernel_start, kernel_end - kernel_start);
-
-	/*
-	 * Use page-level mappings here so that we can shrink the region
-	 * in page granularity and put back unused memory to buddy system
-	 * through /sys/kernel/kexec_crash_size interface.
-	 */
-#ifdef CONFIG_KEXEC_CORE
-	if (crash_mem_map && !defer_reserve_crashkernel()) {
-		if (crashk_res.end) {
-			__map_memblock(pgdp, crashk_res.start,
-				       crashk_res.end + 1,
-				       PAGE_KERNEL,
-				       NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS);
-			memblock_clear_nomap(crashk_res.start,
-					     resource_size(&crashk_res));
-		}
-	}
-#endif
 }
 
 void mark_rodata_ro(void)