[ 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 fancer.lancer@gmail.com Signed-off-by: Paul Burton paul.burton@mips.com Cc: Ralf Baechle ralf@linux-mips.org Cc: James Hogan jhogan@kernel.org Cc: Mike Rapoport rppt@linux.ibm.com Cc: Andrew Morton akpm@linux-foundation.org Cc: Michal Hocko mhocko@suse.com Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: Thomas Bogendoerfer tbogendoerfer@suse.de Cc: Huacai Chen chenhc@lemote.com Cc: Stefan Agner stefan@agner.ch Cc: Stephen Rothwell sfr@canb.auug.org.au Cc: Alexandre Belloni alexandre.belloni@bootlin.com Cc: Juergen Gross jgross@suse.com Cc: Serge Semin Sergey.Semin@t-platforms.ru Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 89950b7bf536..bdaf3536241a 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); }
int __init early_init_dt_reserve_memory_arch(phys_addr_t base,