riscv: Fix module_alloc() that did not reset the linear mapping permissions

After unloading a module, we must reset the linear mapping permissions,
see the example below:

Before unloading a module:

0xffffaf809d65d000-0xffffaf809d6dc000    0x000000011d65d000       508K PTE .   ..     ..   D A G . . W R V
0xffffaf809d6dc000-0xffffaf809d6dd000    0x000000011d6dc000         4K PTE .   ..     ..   D A G . . . R V
0xffffaf809d6dd000-0xffffaf809d6e1000    0x000000011d6dd000        16K PTE .   ..     ..   D A G . . W R V
0xffffaf809d6e1000-0xffffaf809d6e7000    0x000000011d6e1000        24K PTE .   ..     ..   D A G . X . R V

After unloading a module:

0xffffaf809d65d000-0xffffaf809d6e1000    0x000000011d65d000       528K PTE .   ..     ..   D A G . . W R V
0xffffaf809d6e1000-0xffffaf809d6e7000    0x000000011d6e1000        24K PTE .   ..     ..   D A G . X W R V

The last mapping is not reset and we end up with WX mappings in the linear
mapping.

So add VM_FLUSH_RESET_PERMS to our module_alloc() definition.

Fixes: 0cff8bff7af8 ("riscv: avoid the PIC offset of static percpu data in module beyond 2G limits")
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20231213134027.155327-2-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c
index aac019ed63b1bdaa766262a5266deb4c8c5a4bdf..862834bb1d64387d161ec0ef6ab0c3debfc9fa1b 100644 (file)
--- a/arch/riscv/kernel/module.c
+++ b/arch/riscv/kernel/module.c
@@ -894,7 +894,8 @@ void *module_alloc(unsigned long size)
 {
        return __vmalloc_node_range(size, 1, MODULES_VADDR,
                                    MODULES_END, GFP_KERNEL,
-                                   PAGE_KERNEL, 0, NUMA_NO_NODE,
+                                   PAGE_KERNEL, VM_FLUSH_RESET_PERMS,
+                                   NUMA_NO_NODE,
                                    __builtin_return_address(0));
 }
 #endif