Subject: linux-next: manual merge of the risc-v tree with the origin tree

From: [email-masked]
Date: Fri, 21 Apr 2023 13:15:19 +0100

Hi all,

Today's linux-next merge of the risc-v tree got a conflict in:

  arch/riscv/mm/init.c

between commit:

  ef69d2559fe91 ("riscv: Move early dtb mapping into the fixmap region")

from the origin tree and commits:

  8589e346bbb67 ("riscv: Move the linear mapping creation in its own function")
  3335068f87217 ("riscv: Use PUD/P4D/PGD pages for the linear mapping")
  401e84488800d ("riscv: Move DTB_EARLY_BASE_VA to the kernel address space")
  39b33072941f8 ("riscv: Introduce CONFIG_RELOCATABLE")

from the risc-v tree.

I fixed it up (see below) and can carry the fix as necessary. This
is now fixed as far as linux-next is concerned, but any non trivial
conflicts should be mentioned to your upstream maintainer when your tree
is submitted for merging.  You may also want to consider cooperating
with the maintainer of the conflicting tree to minimise any particularly
complex conflicts.

I suspect something more is needed to handle 401e84488800d ("riscv: Move
DTB_EARLY_BASE_VA to the kernel address space") properly but I have zero
familiarity with this code or ability to test.

diff --cc arch/riscv/mm/init.c
index 0f14f4a8d179a,bce899b180cd2..0000000000000
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@@ -1070,23 -1164,63 +1144,74 @@@ asmlinkage void __init setup_vm(uintptr
  	pt_ops_set_fixmap();
  }
  
- static void __init setup_vm_final(void)
+ static void __init create_linear_mapping_range(phys_addr_t start,
+ 					       phys_addr_t end)
  {
+ 	phys_addr_t pa;
  	uintptr_t va, map_size;
- 	phys_addr_t pa, start, end;
+ 
+ 	for (pa = start; pa < end; pa += map_size) {
+ 		va = (uintptr_t)__va(pa);
+ 		map_size = best_map_size(pa, end - pa);
+ 
+ 		create_pgd_mapping(swapper_pg_dir, va, pa, map_size,
+ 				   pgprot_from_va(va));
+ 	}
+ }
+ 
+ static void __init create_linear_mapping_page_table(void)
+ {
+ 	phys_addr_t start, end;
  	u64 i;
  
+ #ifdef CONFIG_STRICT_KERNEL_RWX
+ 	phys_addr_t ktext_start = __pa_symbol(_start);
+ 	phys_addr_t ktext_size = __init_data_begin - _start;
+ 	phys_addr_t krodata_start = __pa_symbol(__start_rodata);
+ 	phys_addr_t krodata_size = _data - __start_rodata;
+ 
+ 	/* Isolate kernel text and rodata so they don't get mapped with a PUD */
+ 	memblock_mark_nomap(ktext_start,  ktext_size);
+ 	memblock_mark_nomap(krodata_start, krodata_size);
+ #endif
+ 
+ 	/* Map all memory banks in the linear mapping */
+ 	for_each_mem_range(i, &start, &end) {
+ 		if (start >= end)
+ 			break;
+ 		if (start <= __pa(PAGE_OFFSET) &&
+ 		    __pa(PAGE_OFFSET) < end)
+ 			start = __pa(PAGE_OFFSET);
+ 		if (end >= __pa(PAGE_OFFSET) + memory_limit)
+ 			end = __pa(PAGE_OFFSET) + memory_limit;
+ 
+ 		create_linear_mapping_range(start, end);
+ 	}
+ 
+ #ifdef CONFIG_STRICT_KERNEL_RWX
+ 	create_linear_mapping_range(ktext_start, ktext_start + ktext_size);
+ 	create_linear_mapping_range(krodata_start,
+ 				    krodata_start + krodata_size);
+ 
+ 	memblock_clear_nomap(ktext_start,  ktext_size);
+ 	memblock_clear_nomap(krodata_start, krodata_size);
+ #endif
+ }
+ 
+ static void __init setup_vm_final(void)
+ {
  	/* Setup swapper PGD for fixmap */
 +#if !defined(CONFIG_64BIT)
 +	/*
 +	 * In 32-bit, the device tree lies in a pgd entry, so it must be copied
 +	 * directly in swapper_pg_dir in addition to the pgd entry that points
 +	 * to fixmap_pte.
 +	 */
 +	unsigned long idx = pgd_index(__fix_to_virt(FIX_FDT));
 +
 +	set_pgd(&swapper_pg_dir[idx], early_pg_dir[idx]);
 +#endif
++
  	create_pgd_mapping(swapper_pg_dir, FIXADDR_START,
  			   __pa_symbol(fixmap_pgd_next),
  			   PGDIR_SIZE, PAGE_TABLE);