diff options
author | Ard Biesheuvel <ardb@kernel.org> | 2019-12-06 19:55:37 +0300 |
---|---|---|
committer | Ingo Molnar <mingo@kernel.org> | 2019-12-08 14:42:18 +0300 |
commit | ab0eb16205b43ece4c78e2259e681ff3d645ea66 (patch) | |
tree | c93e31432021893a8266d24a56c48d22a2dfc510 /drivers/firmware | |
parent | 63de37476ebd1e9bab6a9e17186dc5aa1da9ea99 (diff) | |
download | linux-ab0eb16205b43ece4c78e2259e681ff3d645ea66.tar.xz |
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>
Diffstat (limited to 'drivers/firmware')
-rw-r--r-- | drivers/firmware/efi/efi.c | 28 |
1 files changed, 26 insertions, 2 deletions
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index d101f072c8f8..b0961950d918 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -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) |