[PATCH -fixes 1/2] riscv: Fix module_alloc() that did not reset the linear mapping permissions

[Alexandre Ghiti]

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 at rivosinc.com>
---
 arch/riscv/kernel/module.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c
index aac019ed63b1..862834bb1d64 100644
--- 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
-- 
2.39.2