Messages in this thread Patch in this message | | | From | Byungchul Park <> | Subject | [PATCH] x86/e820: apply 'mem=' boot command while reserving memory using boot_params | Date | Tue, 23 Apr 2024 19:13:23 +0900 |
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I might miss something. Please lemme know if I go wrong. Thanks.
Byungchul
--->8--- From 51f3b5b9bf9685aa431c00908771151edd702483 Mon Sep 17 00:00:00 2001 From: Byungchul Park <byungchul@sk.com> Date: Tue, 23 Apr 2024 18:54:48 +0900 Subject: [PATCH] x86/e820: apply 'mem=' boot command while reserving memory using boot_params
When a user specifies 'mem=' boot command, it's expected to limit the maximum address of usable memory for the kernel no matter what the memory map source is. However, 'mem=' boot command doesn't work since it doesn't respect it when reserving memory using boot_params.
Applied the restriction when reserving memory using boot_params. While at it, renamed mem_size to a more specific name, boot_mem_limit.
Signed-off-by: Byungchul Park <byungchul@sk.com> --- arch/x86/kernel/e820.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c index 6f1b379e3b38..af9d1d95ef5a 100644 --- a/arch/x86/kernel/e820.c +++ b/arch/x86/kernel/e820.c @@ -880,11 +880,11 @@ static void __init early_panic(char *msg) static int userdef __initdata; +static u64 boot_mem_limit = U64_MAX; + /* The "mem=nopentium" boot option disables 4MB page tables on 32-bit kernels: */ static int __init parse_memopt(char *p) { - u64 mem_size; - if (!p) return -EINVAL; @@ -899,16 +899,16 @@ static int __init parse_memopt(char *p) } userdef = 1; - mem_size = memparse(p, &p); + boot_mem_limit = memparse(p, &p); /* Don't remove all memory when getting "mem={invalid}" parameter: */ - if (mem_size == 0) + if (boot_mem_limit == 0) return -EINVAL; - e820__range_remove(mem_size, ULLONG_MAX - mem_size, E820_TYPE_RAM, 1); + e820__range_remove(boot_mem_limit, ULLONG_MAX - boot_mem_limit, E820_TYPE_RAM, 1); #ifdef CONFIG_MEMORY_HOTPLUG - max_mem_size = mem_size; + max_mem_size = boot_mem_limit; #endif return 0; @@ -1036,6 +1036,8 @@ void __init e820__reserve_setup_data(void) early_memunmap(data, len); } + e820__range_remove(boot_mem_limit, ULLONG_MAX - boot_mem_limit, + E820_TYPE_RESERVED_KERN, 1); e820__update_table(e820_table); pr_info("extended physical RAM map:\n"); -- 2.17.1
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