Commit d390e6de authored by Lai Jiangshan's avatar Lai Jiangshan Committed by Thomas Gleixner
Browse files

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: default avatarLai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200526014221.2119-2-laijs@linux.alibaba.com
Link: https://lkml.kernel.org/r/20200529213320.784524504@infradead.org
parent 998c2034

arch/x86/kernel/hw_breakpoint.c

+11 −2
Original line number Diff line number Diff line
@@ -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,