From f76c8f6d257cefda60221c83af7f97d9f74cb3ce Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Tue, 19 May 2020 05:49:13 +0000 Subject: powerpc/8xx: Add function to set pinned TLBs Pinned TLBs cannot be modified when the MMU is enabled. Create a function to rewrite the pinned TLB entries with MMU off. To set pinned TLB, we have to turn off MMU, disable pinning, do a TLB flush (Either with tlbie and tlbia) then reprogam the TLB entries, enable pinning and turn on MMU. If using tlbie, it cleared entries in both instruction and data TLB regardless whether pinning is disabled or not. If using tlbia, it clears all entries of the TLB which has disabled pinning. To make it easy, just clear all entries in both TLBs, and reprogram them. The function takes two arguments, the top of the memory to consider and whether data is RO under _sinittext. When DEBUG_PAGEALLOC is set, the top is the end of kernel rodata. Otherwise, that's the top of physical RAM. Everything below _sinittext is set RX, over _sinittext that's RW. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/c17806014bb1c06513ad1e1d510faea31984b177.1589866984.git.christophe.leroy@csgroup.eu --- arch/powerpc/include/asm/nohash/32/mmu-8xx.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'arch/powerpc/include/asm/nohash') diff --git a/arch/powerpc/include/asm/nohash/32/mmu-8xx.h b/arch/powerpc/include/asm/nohash/32/mmu-8xx.h index a092e6434bda..4d3ef3841b00 100644 --- a/arch/powerpc/include/asm/nohash/32/mmu-8xx.h +++ b/arch/powerpc/include/asm/nohash/32/mmu-8xx.h @@ -193,6 +193,8 @@ #include +void mmu_pin_tlb(unsigned long top, bool readonly); + typedef struct { unsigned int id; unsigned int active; -- cgit v1.2.3