Messages in this thread Patch in this message | | | From | "Peng Fan (OSS)" <> | Subject | [PATCH 2/2] arm64: mm: support bootparam max_addr | Date | Wed, 15 Dec 2021 14:45:59 +0800 |
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From: Peng Fan <peng.fan@nxp.com>
There is a "mem=[x]" boot parameter, but when there is a whole reserved by secure TEE, the continuous DRAM area is split with two memblocks.
For example, DRAM area [0x40000000, 0xffffffff], when TEE uses [0x50000000, 0x51000000), the memblock will be split into [0x40000000, 0x50000000) and [0x51000000, 0xffffffff].
If pass "mem=1024MB", the actually max addr will be 0x81000000. However if need the max addr be 0x80000000, mem=1008MB should be used.
There also might be multiple other holes that no visible to Linux, when we wanna to limit the max addr usable by Linux, using "max_addr=[X]" is much easier than "mem=[X]"
Signed-off-by: Peng Fan <peng.fan@nxp.com> --- arch/arm64/mm/init.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+)
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index db63cc885771..3364b5e7a7fe 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -173,6 +173,7 @@ int pfn_is_map_memory(unsigned long pfn) EXPORT_SYMBOL(pfn_is_map_memory); static phys_addr_t memory_limit __ro_after_init = PHYS_ADDR_MAX; +static phys_addr_t max_addr __ro_after_init = PHYS_ADDR_MAX; /* * Limit the memory size that was specified via FDT. @@ -189,6 +190,18 @@ static int __init early_mem(char *p) } early_param("mem", early_mem); +static int __init set_max_addr(char *p) +{ + if (!p) + return 1; + + max_addr = memparse(p, &p) & PAGE_MASK; + pr_notice("Memory max addr set to 0x%llx\n", max_addr); + + return 0; +} +early_param("max_addr", set_max_addr); + void __init arm64_memblock_init(void) { s64 linear_region_size = PAGE_END - _PAGE_OFFSET(vabits_actual); @@ -253,6 +266,9 @@ void __init arm64_memblock_init(void) memblock_add(__pa_symbol(_text), (u64)(_end - _text)); } + if (max_addr != PHYS_ADDR_MAX) + memblock_cap_memory_range(0, max_addr); + if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && phys_initrd_size) { /* * Add back the memory we just removed if it results in the @@ -427,4 +443,9 @@ void dump_mem_limit(void) } else { pr_emerg("Memory Limit: none\n"); } + + if (max_addr != PHYS_ADDR_MAX) + pr_emerg("Max addr: 0x%llx\n", max_addr); + else + pr_emerg("Max addr: none\n"); } -- 2.25.1
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