Merge tag 'for-linus-2021-01-24' of git://git.kernel.org/pub/scm/linux/kernel/git...

[linux-2.6-block.git] / arch / riscv / mm / init.c

diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index bf5379135e39b628619de135632876d5338abe9d..7cd4993f4ff21a932b6ef29512f685ea4e947f9a 100644 (file)
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -157,9 +157,10 @@ disable:
 void __init setup_bootmem(void)
 {
        phys_addr_t mem_start = 0;
-       phys_addr_t start, end = 0;
+       phys_addr_t start, dram_end, end = 0;
        phys_addr_t vmlinux_end = __pa_symbol(&_end);
        phys_addr_t vmlinux_start = __pa_symbol(&_start);
+       phys_addr_t max_mapped_addr = __pa(~(ulong)0);
        u64 i;
 
        /* Find the memory region containing the kernel */
@@ -181,7 +182,18 @@ void __init setup_bootmem(void)
        /* Reserve from the start of the kernel to the end of the kernel */
        memblock_reserve(vmlinux_start, vmlinux_end - vmlinux_start);
 
-       max_pfn = PFN_DOWN(memblock_end_of_DRAM());
+       dram_end = memblock_end_of_DRAM();
+
+       /*
+        * memblock allocator is not aware of the fact that last 4K bytes of
+        * the addressable memory can not be mapped because of IS_ERR_VALUE
+        * macro. Make sure that last 4k bytes are not usable by memblock
+        * if end of dram is equal to maximum addressable memory.
+        */
+       if (max_mapped_addr == (dram_end - 1))
+               memblock_set_current_limit(max_mapped_addr - 4096);
+
+       max_pfn = PFN_DOWN(dram_end);
        max_low_pfn = max_pfn;
        dma32_phys_limit = min(4UL * SZ_1G, (unsigned long)PFN_PHYS(max_low_pfn));
        set_max_mapnr(max_low_pfn);