Merge branch 'riscv-wx-mappings' into for-next

This contains both the short-term fix for the W+X boot mappings and the
larger cleanup.

* riscv-wx-mappings:
  riscv: Map the kernel with correct permissions the first time
  riscv: Introduce set_kernel_memory helper
  riscv: Simplify xip and !xip kernel address conversion macros
  riscv: Remove CONFIG_PHYS_RAM_BASE_FIXED
  riscv: mm: Fix W+X mappings at boot

1 files changed, 49 insertions, 59 deletions

diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 3a5190a09987..12f956b3a674 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -455,6 +455,43 @@ asmlinkage void __init __copy_data(void)
 }
 #endif
 
+#ifdef CONFIG_STRICT_KERNEL_RWX
+static __init pgprot_t pgprot_from_va(uintptr_t va)
+{
+	if (is_va_kernel_text(va))
+		return PAGE_KERNEL_READ_EXEC;
+
+	/*
+	 * In 64-bit kernel, the kernel mapping is outside the linear mapping so
+	 * we must protect its linear mapping alias from being executed and
+	 * written.
+	 * And rodata section is marked readonly in mark_rodata_ro.
+	 */
+	if (IS_ENABLED(CONFIG_64BIT) && is_va_kernel_lm_alias_text(va))
+		return PAGE_KERNEL_READ;
+
+	return PAGE_KERNEL;
+}
+
+void mark_rodata_ro(void)
+{
+	set_kernel_memory(__start_rodata, _data, set_memory_ro);
+	if (IS_ENABLED(CONFIG_64BIT))
+		set_kernel_memory(lm_alias(__start_rodata), lm_alias(_data),
+				  set_memory_ro);
+
+	debug_checkwx();
+}
+#else
+static __init pgprot_t pgprot_from_va(uintptr_t va)
+{
+	if (IS_ENABLED(CONFIG_64BIT) && !is_kernel_mapping(va))
+		return PAGE_KERNEL;
+
+	return PAGE_KERNEL_EXEC;
+}
+#endif /* CONFIG_STRICT_KERNEL_RWX */
+
 /*
  * setup_vm() is called from head.S with MMU-off.
  *
@@ -474,7 +511,7 @@ asmlinkage void __init __copy_data(void)
 #endif
 
 static uintptr_t load_pa __initdata;
-static uintptr_t load_sz __initdata;
+uintptr_t load_sz;
 #ifdef CONFIG_XIP_KERNEL
 #define load_pa        (*((uintptr_t *)XIP_FIXUP(&load_pa)))
 #define load_sz        (*((uintptr_t *)XIP_FIXUP(&load_sz)))
@@ -486,7 +523,8 @@ static uintptr_t xiprom_sz __initdata;
 #define xiprom_sz      (*((uintptr_t *)XIP_FIXUP(&xiprom_sz)))
 #define xiprom         (*((uintptr_t *)XIP_FIXUP(&xiprom)))
 
-static void __init create_kernel_page_table(pgd_t *pgdir, uintptr_t map_size)
+static void __init create_kernel_page_table(pgd_t *pgdir, uintptr_t map_size,
+					    __always_unused bool early)
 {
 	uintptr_t va, end_va;
 
@@ -505,7 +543,8 @@ static void __init create_kernel_page_table(pgd_t *pgdir, uintptr_t map_size)
 				   map_size, PAGE_KERNEL);
 }
 #else
-static void __init create_kernel_page_table(pgd_t *pgdir, uintptr_t map_size)
+static void __init create_kernel_page_table(pgd_t *pgdir, uintptr_t map_size,
+					    bool early)
 {
 	uintptr_t va, end_va;
 
@@ -513,7 +552,9 @@ static void __init create_kernel_page_table(pgd_t *pgdir, uintptr_t map_size)
 	for (va = kernel_virt_addr; va < end_va; va += map_size)
 		create_pgd_mapping(pgdir, va,
 				   load_pa + (va - kernel_virt_addr),
-				   map_size, PAGE_KERNEL_EXEC);
+				   map_size,
+				   early ?
+					PAGE_KERNEL_EXEC : pgprot_from_va(va));
 }
 #endif
 
@@ -590,7 +631,7 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
 	 * us to reach paging_init(). We map all memory banks later
 	 * in setup_vm_final() below.
 	 */
-	create_kernel_page_table(early_pg_dir, map_size);
+	create_kernel_page_table(early_pg_dir, map_size, true);
 
 #ifndef __PAGETABLE_PMD_FOLDED
 	/* Setup early PMD for DTB */
@@ -666,22 +707,6 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
 #endif
 }
 
-#if defined(CONFIG_64BIT) && defined(CONFIG_STRICT_KERNEL_RWX)
-void __init protect_kernel_linear_mapping_text_rodata(void)
-{
-	unsigned long text_start = (unsigned long)lm_alias(_start);
-	unsigned long init_text_start = (unsigned long)lm_alias(__init_text_begin);
-	unsigned long rodata_start = (unsigned long)lm_alias(__start_rodata);
-	unsigned long data_start = (unsigned long)lm_alias(_data);
-
-	set_memory_ro(text_start, (init_text_start - text_start) >> PAGE_SHIFT);
-	set_memory_nx(text_start, (init_text_start - text_start) >> PAGE_SHIFT);
-
-	set_memory_ro(rodata_start, (data_start - rodata_start) >> PAGE_SHIFT);
-	set_memory_nx(rodata_start, (data_start - rodata_start) >> PAGE_SHIFT);
-}
-#endif
-
 static void __init setup_vm_final(void)
 {
 	uintptr_t va, map_size;
@@ -714,21 +739,15 @@ static void __init setup_vm_final(void)
 		map_size = best_map_size(start, end - start);
 		for (pa = start; pa < end; pa += map_size) {
 			va = (uintptr_t)__va(pa);
-			create_pgd_mapping(swapper_pg_dir, va, pa,
-					   map_size,
-#ifdef CONFIG_64BIT
-					   PAGE_KERNEL
-#else
-					   PAGE_KERNEL_EXEC
-#endif
-					);
 
+			create_pgd_mapping(swapper_pg_dir, va, pa, map_size,
+					   pgprot_from_va(va));
 		}
 	}
 
 #ifdef CONFIG_64BIT
 	/* Map the kernel */
-	create_kernel_page_table(swapper_pg_dir, PMD_SIZE);
+	create_kernel_page_table(swapper_pg_dir, PMD_SIZE, false);
 #endif
 
 	/* Clear fixmap PTE and PMD mappings */
@@ -759,35 +778,6 @@ static inline void setup_vm_final(void)
 }
 #endif /* CONFIG_MMU */
 
-#ifdef CONFIG_STRICT_KERNEL_RWX
-void __init protect_kernel_text_data(void)
-{
-	unsigned long text_start = (unsigned long)_start;
-	unsigned long init_text_start = (unsigned long)__init_text_begin;
-	unsigned long init_data_start = (unsigned long)__init_data_begin;
-	unsigned long rodata_start = (unsigned long)__start_rodata;
-	unsigned long data_start = (unsigned long)_data;
-	unsigned long max_low = (unsigned long)(__va(PFN_PHYS(max_low_pfn)));
-
-	set_memory_ro(text_start, (init_text_start - text_start) >> PAGE_SHIFT);
-	set_memory_ro(init_text_start, (init_data_start - init_text_start) >> PAGE_SHIFT);
-	set_memory_nx(init_data_start, (rodata_start - init_data_start) >> PAGE_SHIFT);
-	/* rodata section is marked readonly in mark_rodata_ro */
-	set_memory_nx(rodata_start, (data_start - rodata_start) >> PAGE_SHIFT);
-	set_memory_nx(data_start, (max_low - data_start) >> PAGE_SHIFT);
-}
-
-void mark_rodata_ro(void)
-{
-	unsigned long rodata_start = (unsigned long)__start_rodata;
-	unsigned long data_start = (unsigned long)_data;
-
-	set_memory_ro(rodata_start, (data_start - rodata_start) >> PAGE_SHIFT);
-
-	debug_checkwx();
-}
-#endif
-
 #ifdef CONFIG_KEXEC_CORE
 /*
  * reserve_crashkernel() - reserves memory for crash kernel