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

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In commit 031495635b ("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: Baoquan He <bhe@redhat.com>
Reviewed-by: Zhen Lei <thunder.leizhen@huawei.com>
Link: https://lore.kernel.org/r/20230407011507.17572-4-bhe@redhat.com
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Baoquan He 2023-04-07 09:15:07 +08:00 committed by Will Deacon
parent 04a2a7af3d
commit 504cae453f
2 changed files with 3 additions and 36 deletions
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5
arch/arm64/include/asm/memory.h
View File

@ -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 */
/*

34
arch/arm64/mm/init.c
View File

@ -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();
}