[ Upstream commit 93fa5b280761a4dbb14c5330f260380385ab2b49 ] There are situations when memory regions coming from dts may be too big for the platform physical address space. This especially concerns XPA-capable systems. Bootloader may determine more than 4GB memory available and pass it to the kernel over dts memory node, while kernel is built without XPA/64BIT support. In this case the region may either simply be truncated by add_memory_region() method or by u64->phys_addr_t type casting. But in worst case the method can even drop the memory region if it exceeds PHYS_ADDR_MAX size. So lets make sure the retrieved from dts memory regions are valid, and if some of them aren't, just manually truncate them with a warning printed out.
Signed-off-by: Serge Semin <[email protected]> Signed-off-by: Paul Burton <[email protected]> Cc: Ralf Baechle <[email protected]> Cc: James Hogan <[email protected]> Cc: Mike Rapoport <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Michal Hocko <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> Cc: Thomas Bogendoerfer <[email protected]> Cc: Huacai Chen <[email protected]> Cc: Stefan Agner <[email protected]> Cc: Stephen Rothwell <[email protected]> Cc: Alexandre Belloni <[email protected]> Cc: Juergen Gross <[email protected]> Cc: Serge Semin <[email protected]> Cc: [email protected] Cc: [email protected] Signed-off-by: Sasha Levin <[email protected]> --- arch/mips/kernel/prom.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/arch/mips/kernel/prom.c b/arch/mips/kernel/prom.c index 0dbcd152a1a9..90f332f0625f 100644 --- a/arch/mips/kernel/prom.c +++ b/arch/mips/kernel/prom.c @@ -41,7 +41,19 @@ char *mips_get_machine_name(void) #ifdef CONFIG_USE_OF void __init early_init_dt_add_memory_arch(u64 base, u64 size) { - return add_memory_region(base, size, BOOT_MEM_RAM); + if (base >= PHYS_ADDR_MAX) { + pr_warn("Trying to add an invalid memory region, skipped\n"); + return; + } + + /* Truncate the passed memory region instead of type casting */ + if (base + size - 1 >= PHYS_ADDR_MAX || base + size < base) { + pr_warn("Truncate memory region %llx @ %llx to size %llx\n", + size, base, PHYS_ADDR_MAX - base); + size = PHYS_ADDR_MAX - base; + } + + add_memory_region(base, size, BOOT_MEM_RAM); } void * __init early_init_dt_alloc_memory_arch(u64 size, u64 align) -- 2.20.1
