redonkable
/
alistair23-linux
1
0
Fork 0
Code Releases Activity

efi/memreserve: Register reservations as 'reserved' in /proc/iomem 

Memory regions that are reserved using efi_mem_reserve_persistent()
are recorded in a special EFI config table which survives kexec,
allowing the incoming kernel to honour them as well. However,
such reservations are not visible in /proc/iomem, and so the kexec
tools that load the incoming kernel and its initrd into memory may
overwrite these reserved regions before the incoming kernel has a
chance to reserve them from further use.

Address this problem by adding these reservations to /proc/iomem as
they are created. Note that reservations that are inherited from a
previous kernel are memblock_reserve()'d early on, so they are already
visible in /proc/iomem.

Tested-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
Tested-by: Bhupesh Sharma <bhsharma@redhat.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Bhupesh Sharma <bhsharma@redhat.com>
Cc: <stable@vger.kernel.org> # v5.4+
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Arvind Sankar <nivedita@alum.mit.edu>
Cc: linux-efi@vger.kernel.org
Link: https://lkml.kernel.org/r/20191206165542.31469-2-ardb@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
alistair/sunxi64-5.5-dsi
Ard Biesheuvel 2019-12-06 16:55:37 +00:00 committed by Ingo Molnar
parent 63de37476e
commit ab0eb16205
1 changed files with 26 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
drivers/firmware/efi/efi.c
View File

@ -979,6 +979,24 @@ static int __init efi_memreserve_map_root(void)
return 0;
}
static int efi_mem_reserve_iomem(phys_addr_t addr, u64 size)
{
struct resource *res, *parent;
res = kzalloc(sizeof(struct resource), GFP_ATOMIC);
if (!res)
return -ENOMEM;
res->name = "reserved";
res->flags = IORESOURCE_MEM;
res->start = addr;
res->end = addr + size - 1;
/* we expect a conflict with a 'System RAM' region */
parent = request_resource_conflict(&iomem_resource, res);
return parent ? request_resource(parent, res) : 0;
}
int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size)
{
struct linux_efi_memreserve *rsv;
@ -1003,7 +1021,7 @@ int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size)
rsv->entry[index].size = size;
memunmap(rsv);
return 0;
return efi_mem_reserve_iomem(addr, size);
}
memunmap(rsv);
}
@ -1013,6 +1031,12 @@ int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size)
if (!rsv)
return -ENOMEM;
rc = efi_mem_reserve_iomem(__pa(rsv), SZ_4K);
if (rc) {
free_page((unsigned long)rsv);
return rc;
}
/*
* The memremap() call above assumes that a linux_efi_memreserve entry
* never crosses a page boundary, so let's ensure that this remains true
@ -1029,7 +1053,7 @@ int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size)
efi_memreserve_root->next = __pa(rsv);
spin_unlock(&efi_mem_reserve_persistent_lock);
return 0;
return efi_mem_reserve_iomem(addr, size);
}
static int __init efi_memreserve_root_init(void)