From d390e6de89d30402bd06056c40cea72328aec9b1 Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Fri, 29 May 2020 23:27:29 +0200 Subject: [PATCH] x86/hw_breakpoint: Add within_area() to check data breakpoints Add a within_area() helper to checking whether the data breakpoints overlap with cpu_entry_area. It will be used to completely prevent data breakpoints on GDT, IDT, or TSS. Signed-off-by: Lai Jiangshan Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Thomas Gleixner Link: https://lkml.kernel.org/r/20200526014221.2119-2-laijs@linux.alibaba.com Link: https://lkml.kernel.org/r/20200529213320.784524504@infradead.org --- arch/x86/kernel/hw_breakpoint.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/hw_breakpoint.c b/arch/x86/kernel/hw_breakpoint.c index 9ddf441ccaa8..c149c7b29ac3 100644 --- a/arch/x86/kernel/hw_breakpoint.c +++ b/arch/x86/kernel/hw_breakpoint.c @@ -227,14 +227,23 @@ int arch_check_bp_in_kernelspace(struct arch_hw_breakpoint *hw) return (va >= TASK_SIZE_MAX) || ((va + len - 1) >= TASK_SIZE_MAX); } +/* + * Checks whether the range [addr, end], overlaps the area [base, base + size). + */ +static inline bool within_area(unsigned long addr, unsigned long end, + unsigned long base, unsigned long size) +{ + return end >= base && addr < (base + size); +} + /* * Checks whether the range from addr to end, inclusive, overlaps the CPU * entry area range. */ static inline bool within_cpu_entry_area(unsigned long addr, unsigned long end) { - return end >= CPU_ENTRY_AREA_BASE && - addr < (CPU_ENTRY_AREA_BASE + CPU_ENTRY_AREA_TOTAL_SIZE); + return within_area(addr, end, CPU_ENTRY_AREA_BASE, + CPU_ENTRY_AREA_TOTAL_SIZE); } static int arch_build_bp_info(struct perf_event *bp, -- 2.20.1