Unverified Commit 4c3aeb82 authored by Palmer Dabbelt's avatar Palmer Dabbelt
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RISC-V: Avoid using invalid intermediate translations 



This is almost entirely a comment.

Signed-off-by: default avatarPalmer Dabbelt <palmer@sifive.com>
Reviewed-by: default avatarAnup Patel <anup@brainfault.org>
parent 9a6e7af0

arch/riscv/kernel/head.S

+10 −2
Original line number Diff line number Diff line
@@ -96,7 +96,9 @@ relocate: 


	/*

	 * Load trampoline page directory, which will cause us to trap to

	 * stvec if VA != PA, or simply fall through if VA == PA

	 * stvec if VA != PA, or simply fall through if VA == PA.  We need a

	 * full fence here because setup_vm() just wrote these PTEs and we need

	 * to ensure the new translations are in use.

	 */

	la a0, trampoline_pg_dir

	srl a0, a0, PAGE_SHIFT
@@ -115,8 +117,14 @@ relocate: 
	la gp, __global_pointer$

.option pop



	/* Switch to kernel page tables */

	/*

	 * Switch to kernel page tables.  A full fence is necessary in order to

	 * avoid using the trampoline translations, which are only correct for

	 * the first superpage.  Fetching the fence is guarnteed to work

	 * because that first superpage is translated the same way.

	 */

	csrw CSR_SATP, a2

	sfence.vma



	ret