From f1b0b8c2b7e7f0e6c90ec09696d92b02b81d2307 Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Mon, 12 Oct 2020 08:54:31 +0000 Subject: [PATCH] powerpc/8xx: Always fault when _PAGE_ACCESSED is not set commit 29daf869cbab69088fe1755d9dd224e99ba78b56 upstream. The kernel expects pte_young() to work regardless of CONFIG_SWAP. Make sure a minor fault is taken to set _PAGE_ACCESSED when it is not already set, regardless of the selection of CONFIG_SWAP. This adds at least 3 instructions to the TLB miss exception handlers fast path. Following patch will reduce this overhead. Also update the rotation instruction to the correct number of bits to reflect all changes done to _PAGE_ACCESSED over time. Fixes: d069cb4373fe ("powerpc/8xx: Don't touch ACCESSED when no SWAP.") Fixes: 5f356497c384 ("powerpc/8xx: remove unused _PAGE_WRITETHRU") Fixes: e0a8e0d90a9f ("powerpc/8xx: Handle PAGE_USER via APG bits") Fixes: 5b2753fc3e8a ("powerpc/8xx: Implementation of PAGE_EXEC") Fixes: a891c43b97d3 ("powerpc/8xx: Prepare handlers for _PAGE_HUGE for 512k pages.") Cc: stable@vger.kernel.org Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/af834e8a0f1fa97bfae65664950f0984a70c4750.1602492856.git.christophe.leroy@csgroup.eu Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/kernel/head_8xx.S | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S index 9fd2ff28b8ff2..dc99258f2e8c6 100644 --- a/arch/powerpc/kernel/head_8xx.S +++ b/arch/powerpc/kernel/head_8xx.S @@ -356,11 +356,9 @@ _ENTRY(ITLBMiss_cmp) /* Load the MI_TWC with the attributes for this "segment." */ mtspr SPRN_MI_TWC, r11 /* Set segment attributes */ -#ifdef CONFIG_SWAP - rlwinm r11, r10, 32-5, _PAGE_PRESENT + rlwinm r11, r10, 32-7, _PAGE_PRESENT and r11, r11, r10 rlwimi r10, r11, 0, _PAGE_PRESENT -#endif li r11, RPN_PATTERN | 0x200 /* The Linux PTE won't go exactly into the MMU TLB. * Software indicator bits 20 and 23 must be clear. @@ -482,11 +480,9 @@ _ENTRY(DTLBMiss_jmp) * r11 = ((r10 & PRESENT) & ((r10 & ACCESSED) >> 5)); * r10 = (r10 & ~PRESENT) | r11; */ -#ifdef CONFIG_SWAP - rlwinm r11, r10, 32-5, _PAGE_PRESENT + rlwinm r11, r10, 32-7, _PAGE_PRESENT and r11, r11, r10 rlwimi r10, r11, 0, _PAGE_PRESENT -#endif /* The Linux PTE won't go exactly into the MMU TLB. * Software indicator bits 24, 25, 26, and 27 must be * set. All other Linux PTE bits control the behavior