From 98fb754831e1d139f1151e968bdebb6eefb9b581 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Tue, 1 Dec 2015 13:20:40 +0100 Subject: [PATCH 1/2] arm64: update linker script to increased L1_CACHE_BYTES value Bring the linker script in line with the recent increase of L1_CACHE_BYTES to 128. Replace the hardcoded value of 64 with the symbolic constant. Signed-off-by: Ard Biesheuvel Acked-by: Mark Rutland [catalin.marinas@arm.com: fix up RW_DATA_SECTION as well] Signed-off-by: Catalin Marinas --- arch/arm64/kernel/vmlinux.lds.S | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S index 1ee2c3937d4e..71426a78db12 100644 --- a/arch/arm64/kernel/vmlinux.lds.S +++ b/arch/arm64/kernel/vmlinux.lds.S @@ -5,6 +5,7 @@ */ #include +#include #include #include #include @@ -140,7 +141,7 @@ SECTIONS ARM_EXIT_KEEP(EXIT_DATA) } - PERCPU_SECTION(64) + PERCPU_SECTION(L1_CACHE_BYTES) . = ALIGN(PAGE_SIZE); __init_end = .; @@ -158,7 +159,7 @@ SECTIONS . = ALIGN(PAGE_SIZE); _data = .; _sdata = .; - RW_DATA_SECTION(64, PAGE_SIZE, THREAD_SIZE) + RW_DATA_SECTION(L1_CACHE_BYTES, PAGE_SIZE, THREAD_SIZE) PECOFF_EDATA_PADDING _edata = .; From 82d340081b6f71237373d1452e3573a5a122794c Mon Sep 17 00:00:00 2001 From: Catalin Marinas Date: Tue, 8 Dec 2015 17:39:15 +0000 Subject: [PATCH 2/2] arm64: Improve error reporting on set_pte_at() checks Currently the BUG_ON() checks do not give enough information about the PTEs being set. This patch changes BUG_ON to WARN_ONCE and dumps the values of the old and new PTEs. In addition, the checks are only made if the new PTE entry is valid. Signed-off-by: Catalin Marinas Reported-by: Ming Lei Cc: Will Deacon --- arch/arm64/include/asm/pgtable.h | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index 7e074f93f383..63f52b55defe 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -276,10 +276,14 @@ static inline void set_pte_at(struct mm_struct *mm, unsigned long addr, * hardware updates of the pte (ptep_set_access_flags safely changes * valid ptes without going through an invalid entry). */ - if (IS_ENABLED(CONFIG_DEBUG_VM) && IS_ENABLED(CONFIG_ARM64_HW_AFDBM) && - pte_valid(*ptep)) { - BUG_ON(!pte_young(pte)); - BUG_ON(pte_write(*ptep) && !pte_dirty(pte)); + if (IS_ENABLED(CONFIG_ARM64_HW_AFDBM) && + pte_valid(*ptep) && pte_valid(pte)) { + VM_WARN_ONCE(!pte_young(pte), + "%s: racy access flag clearing: 0x%016llx -> 0x%016llx", + __func__, pte_val(*ptep), pte_val(pte)); + VM_WARN_ONCE(pte_write(*ptep) && !pte_dirty(pte), + "%s: racy dirty state clearing: 0x%016llx -> 0x%016llx", + __func__, pte_val(*ptep), pte_val(pte)); } set_pte(ptep, pte);