Commit 8a5b403d71affa098009cc3dff1b2c45113021ad upstream.

In the irqchip and EFI code, we have what basically amounts to a quirk to work around a peculiarity in the GICv3 architecture, which permits the system memory address of LPI tables to be programmable only once after a CPU reset. This means kexec kernels must use the same memory as the first kernel, and thus ensure that this memory has not been given out for other purposes by the time the ITS init code runs, which is not very early for secondary CPUs.

On systems with many CPUs, these reservations could overflow the memblock reservation table, and this was addressed in commit:

eff896288872 ("efi/arm: Defer persistent reservations until after paging_init()")

However, this turns out to have made things worse, since the allocation of page tables and heap space for the resized memblock reservation table itself may overwrite the regions we are attempting to reserve, which may cause all kinds of corruption, also considering that the ITS will still be poking bits into that memory in response to incoming MSIs.

So instead, let's grow the static memblock reservation table on such systems so it can accommodate these reservations at an earlier time. This will permit us to revert the above commit in a subsequent patch.

[ mingo: Minor cleanups. ]

Signed-off-by: Ard Biesheuvel ard.biesheuvel@linaro.org Acked-by: Mike Rapoport rppt@linux.ibm.com Acked-by: Will Deacon will.deacon@arm.com Acked-by: Marc Zyngier marc.zyngier@arm.com Cc: Andrew Morton akpm@linux-foundation.org Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Peter Zijlstra peterz@infradead.org Cc: Thomas Gleixner tglx@linutronix.de Cc: linux-arm-kernel@lists.infradead.org Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/20190215123333.21209-2-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar mingo@kernel.org [ ardb: Double the size of the slack to account for the lack of an optimization that was introduced in mainline after the release of v4.20. ] Signed-off-by: Ard Biesheuvel ard.biesheuvel@linaro.org --- arch/arm64/include/asm/memory.h | 11 +++++++++++ include/linux/memblock.h | 3 --- mm/memblock.c | 11 +++++++++-- 3 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h index 778af0b7f7fd..c67081301035 100644 --- a/arch/arm64/include/asm/memory.h +++ b/arch/arm64/include/asm/memory.h @@ -303,6 +303,17 @@ static inline void *phys_to_virt(phys_addr_t x) #define virt_addr_valid(kaddr) (_virt_addr_is_linear(kaddr) && \ _virt_addr_valid(kaddr))

+/* + * Given that the GIC architecture permits ITS implementations that can only be + * configured with a LPI table address once, GICv3 systems with many CPUs may + * end up reserving a lot of different regions after a kexec for their LPI + * tables (one per CPU), as we are forced to reuse the same memory after kexec + * (and thus reserve it persistently with EFI beforehand) + */ +#if defined(CONFIG_EFI) && defined(CONFIG_ARM_GIC_V3_ITS) +# define INIT_MEMBLOCK_RESERVED_REGIONS (INIT_MEMBLOCK_REGIONS + 2*(NR_CPUS + 1)) +#endif + #include <asm-generic/memory_model.h>

#endif diff --git a/include/linux/memblock.h b/include/linux/memblock.h index 3ef3086ed52f..ecff64ff365d 100644 --- a/include/linux/memblock.h +++ b/include/linux/memblock.h @@ -29,9 +29,6 @@ extern unsigned long max_pfn; */ extern unsigned long long max_possible_pfn;

-#define INIT_MEMBLOCK_REGIONS 128 -#define INIT_PHYSMEM_REGIONS 4 - /** * enum memblock_flags - definition of memory region attributes * @MEMBLOCK_NONE: no special request diff --git a/mm/memblock.c b/mm/memblock.c index f45a049532fe..74ac4f89018a 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -26,6 +26,13 @@

#include "internal.h"

+#define INIT_MEMBLOCK_REGIONS 128 +#define INIT_PHYSMEM_REGIONS 4 + +#ifndef INIT_MEMBLOCK_RESERVED_REGIONS +# define INIT_MEMBLOCK_RESERVED_REGIONS INIT_MEMBLOCK_REGIONS +#endif + /** * DOC: memblock overview * @@ -92,7 +99,7 @@ unsigned long max_pfn; unsigned long long max_possible_pfn;

static struct memblock_region memblock_memory_init_regions[INIT_MEMBLOCK_REGIONS] __initdata_memblock; -static struct memblock_region memblock_reserved_init_regions[INIT_MEMBLOCK_REGIONS] __initdata_memblock; +static struct memblock_region memblock_reserved_init_regions[INIT_MEMBLOCK_RESERVED_REGIONS] __initdata_memblock; #ifdef CONFIG_HAVE_MEMBLOCK_PHYS_MAP static struct memblock_region memblock_physmem_init_regions[INIT_PHYSMEM_REGIONS] __initdata_memblock; #endif @@ -105,7 +112,7 @@ struct memblock memblock __initdata_memblock = {

.reserved.regions = memblock_reserved_init_regions, .reserved.cnt = 1, /* empty dummy entry */ - .reserved.max = INIT_MEMBLOCK_REGIONS, + .reserved.max = INIT_MEMBLOCK_RESERVED_REGIONS, .reserved.name = "reserved",

#ifdef CONFIG_HAVE_MEMBLOCK_PHYS_MAP