From 043cb41a85de1c0e944da61ad7a264960e22c865 Mon Sep 17 00:00:00 2001 From: Zong Li Date: Tue, 10 Mar 2020 00:55:43 +0800 Subject: riscv: introduce interfaces to patch kernel code On strict kernel memory permission, we couldn't patch code without writable permission. Preserve two holes in fixmap area, so we can map the kernel code temporarily to fixmap area, then patch the instructions. We need two pages here because we support the compressed instruction, so the instruction might be align to 2 bytes. When patching the 32-bit length instruction which is 2 bytes alignment, it will across two pages. Introduce two interfaces to patch kernel code: riscv_patch_text_nosync: - patch code without synchronization, it's caller's responsibility to synchronize all CPUs if needed. riscv_patch_text: - patch code and always synchronize with stop_machine() Signed-off-by: Zong Li Signed-off-by: Palmer Dabbelt --- arch/riscv/include/asm/fixmap.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'arch/riscv/include/asm/fixmap.h') diff --git a/arch/riscv/include/asm/fixmap.h b/arch/riscv/include/asm/fixmap.h index 42d2c42f3cc9..2368d49eb4ef 100644 --- a/arch/riscv/include/asm/fixmap.h +++ b/arch/riscv/include/asm/fixmap.h @@ -27,6 +27,8 @@ enum fixed_addresses { FIX_FDT = FIX_FDT_END + FIX_FDT_SIZE / PAGE_SIZE - 1, FIX_PTE, FIX_PMD, + FIX_TEXT_POKE1, + FIX_TEXT_POKE0, FIX_EARLYCON_MEM_BASE, __end_of_fixed_addresses }; -- cgit v1.2.3