| Message ID | 20210713184326.570923-1-maz@kernel.org |
|---|---|
| State | Accepted |
| Commit | 2bab693a608bdf614b9fcd44083c5100f34b9f77 |
| Headers | show |
| Series | [v2] firmware/efi: Tell memblock about EFI iomem reservations | expand |
On Tue, 13 Jul 2021 at 20:43, Marc Zyngier <maz@kernel.org> wrote: > > kexec_load_file() relies on the memblock infrastructure to avoid > stamping over regions of memory that are essential to the survival > of the system. > > However, nobody seems to agree how to flag these regions as reserved, > and (for example) EFI only publishes its reservations in /proc/iomem > for the benefit of the traditional, userspace based kexec tool. > > On arm64 platforms with GICv3, this can result in the payload being > placed at the location of the LPI tables. Shock, horror! > > Let's augment the EFI reservation code with a memblock_reserve() call, > protecting our dear tables from the secondary kernel invasion. > > Reported-by: Moritz Fischer <mdf@kernel.org> > Tested-by: Moritz Fischer <mdf@kernel.org> > Signed-off-by: Marc Zyngier <maz@kernel.org> > Cc: stable@vger.kernel.org > Cc: Ard Biesheuvel <ardb@kernel.org> > Cc: James Morse <james.morse@arm.com> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Will Deacon <will@kernel.org> Thanks, I'll queue this as a fix. > --- > drivers/firmware/efi/efi.c | 13 ++++++++++++- > 1 file changed, 12 insertions(+), 1 deletion(-) > > diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c > index 4b7ee3fa9224..847f33ffc4ae 100644 > --- a/drivers/firmware/efi/efi.c > +++ b/drivers/firmware/efi/efi.c > @@ -896,6 +896,7 @@ static int __init efi_memreserve_map_root(void) > static int efi_mem_reserve_iomem(phys_addr_t addr, u64 size) > { > struct resource *res, *parent; > + int ret; > > res = kzalloc(sizeof(struct resource), GFP_ATOMIC); > if (!res) > @@ -908,7 +909,17 @@ static int efi_mem_reserve_iomem(phys_addr_t addr, u64 size) > > /* we expect a conflict with a 'System RAM' region */ > parent = request_resource_conflict(&iomem_resource, res); > - return parent ? request_resource(parent, res) : 0; > + ret = parent ? request_resource(parent, res) : 0; > + > + /* > + * Given that efi_mem_reserve_iomem() can be called at any > + * time, only call memblock_reserve() if the architecture > + * keeps the infrastructure around. > + */ > + if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK) && !ret) > + memblock_reserve(addr, size); > + > + return ret; > } > > int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size) > -- > 2.30.2 >
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index 4b7ee3fa9224..847f33ffc4ae 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -896,6 +896,7 @@ static int __init efi_memreserve_map_root(void) static int efi_mem_reserve_iomem(phys_addr_t addr, u64 size) { struct resource *res, *parent; + int ret; res = kzalloc(sizeof(struct resource), GFP_ATOMIC); if (!res) @@ -908,7 +909,17 @@ static int efi_mem_reserve_iomem(phys_addr_t addr, u64 size) /* we expect a conflict with a 'System RAM' region */ parent = request_resource_conflict(&iomem_resource, res); - return parent ? request_resource(parent, res) : 0; + ret = parent ? request_resource(parent, res) : 0; + + /* + * Given that efi_mem_reserve_iomem() can be called at any + * time, only call memblock_reserve() if the architecture + * keeps the infrastructure around. + */ + if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK) && !ret) + memblock_reserve(addr, size); + + return ret; } int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size)