riscv: Map the kernel with correct permissions the first time

For 64-bit kernels, we map all the kernel with write and execute
permissions and afterwards remove writability from text and executability
from data.

For 32-bit kernels, the kernel mapping resides in the linear mapping, so we
map all the linear mapping as writable and executable and afterwards we
remove those properties for unused memory and kernel mapping as
described above.

Change this behavior to directly map the kernel with correct permissions
and avoid going through the whole mapping to fix the permissions.

At the same time, this fixes an issue introduced by commit 2bfc6cd81bd1
("riscv: Move kernel mapping outside of linear mapping") as reported
here https://github.com/starfive-tech/linux/issues/17.

Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/arch/riscv/include/asm/sections.h b/arch/riscv/include/asm/sections.h
index 8a303fb1ee3b..32336e8a17cb 100644
--- a/arch/riscv/include/asm/sections.h
+++ b/arch/riscv/include/asm/sections.h
@@ -6,6 +6,7 @@
 #define __ASM_SECTIONS_H
 
 #include <asm-generic/sections.h>
+#include <linux/mm.h>
 
 extern char _start[];
 extern char _start_kernel[];
@@ -13,4 +14,20 @@ extern char __init_data_begin[], __init_data_end[];
 extern char __init_text_begin[], __init_text_end[];
 extern char __alt_start[], __alt_end[];
 
+static inline bool is_va_kernel_text(uintptr_t va)
+{
+	uintptr_t start = (uintptr_t)_start;
+	uintptr_t end = (uintptr_t)__init_data_begin;
+
+	return va >= start && va < end;
+}
+
+static inline bool is_va_kernel_lm_alias_text(uintptr_t va)
+{
+	uintptr_t start = (uintptr_t)lm_alias(_start);
+	uintptr_t end = (uintptr_t)lm_alias(__init_data_begin);
+
+	return va >= start && va < end;
+}
+
 #endif /* __ASM_SECTIONS_H */