Messages in this thread | ![/](/images/icornerl.gif) | | Date | Tue, 23 Apr 2024 19:23:20 +0900 | From | Byungchul Park <> | Subject | Re: [PATCH] x86/e820: apply 'mem=' boot command while reserving memory using boot_params |
| |
On Tue, Apr 23, 2024 at 07:13:23PM +0900, Byungchul Park wrote: > 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)
I should've handled the case that the return value is 0. I will fix it. Before going ahead, it'd be appreciated to tell if this approach is correct. Thank you.
Byungchul
> 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
| ![\](/images/icornerr.gif) |