Commit 504cae45 authored by Baoquan He's avatar Baoquan He Committed by Will Deacon
Browse files

arm64: kdump: defer the crashkernel reservation for platforms with no DMA memory zones 



In commit 03149563 ("arm64: Do not defer reserve_crashkernel() for
platforms with no DMA memory zones"), reserve_crashkernel() is called
much earlier in arm64_memblock_init() to avoid causing base apge
mapping on platforms with no DMA meomry zones.

With taking off protection on crashkernel memory region, no need to call
reserve_crashkernel() specially in advance. The deferred invocation of
reserve_crashkernel() in bootmem_init() can cover all cases. So revert
the whole commit now.

Signed-off-by: default avatarBaoquan He <bhe@redhat.com>
Reviewed-by: default avatarZhen Lei <thunder.leizhen@huawei.com>
Link: https://lore.kernel.org/r/20230407011507.17572-4-bhe@redhat.com


Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent 04a2a7af

arch/arm64/include/asm/memory.h

+0 −5
Original line number Diff line number Diff line
@@ -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/mm/init.c

+3 −31
Original line number Diff line number Diff line
@@ -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;

}
@@ -457,7 +430,6 @@ 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();



	memblock_dump_all();