powerpc/watchpoint: Fix quadword instruction handling on p10 predecessors (4759c11e) · Commits · 戴 / test

On p10 predecessors, watchpoint with quadword access is compared at quadword length. If the watch range is doubleword or less than that in a first half of quadword aligned 16 bytes, and if there is any unaligned quadword access which will access only the 2nd half, the handler should consider it as extraneous and emulate/single-step it before continuing. Fixes: ("powerpc/watchpoint: Prepare handler to handle more than one watchpoint") Reported-by:

Pedro Miraglia Franco de Carvalho <pedromfc@linux.ibm.com> Signed-off-by:

Ravi Bangoria <ravi.bangoria@linux.ibm.com> Signed-off-by:

Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200902042945.129369-2-ravi.bangoria@linux.ibm.com

arch/powerpc/include/asm/hw_breakpoint.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -42,6 +42,7 @@ struct arch_hw_breakpoint {
		#else
		#define HW_BREAKPOINT_SIZE 0x8
		#endif
		#define HW_BREAKPOINT_SIZE_QUADWORD 0x10

		#define DABR_MAX_LEN 8
		#define DAWR_MAX_LEN 512

arch/powerpc/kernel/hw_breakpoint.c

+10 −2

Original line number	Diff line number	Diff line
		@@ -520,9 +520,17 @@ static bool ea_hw_range_overlaps(unsigned long ea, int size,
		struct arch_hw_breakpoint *info)
		{
		unsigned long hw_start_addr, hw_end_addr;
		unsigned long align_size = HW_BREAKPOINT_SIZE;

		hw_start_addr = ALIGN_DOWN(info->address, HW_BREAKPOINT_SIZE);
		hw_end_addr = ALIGN(info->address + info->len, HW_BREAKPOINT_SIZE);
		/*
		* On p10 predecessors, quadword is handle differently then
		* other instructions.
		*/
		if (!cpu_has_feature(CPU_FTR_ARCH_31) && size == 16)
		align_size = HW_BREAKPOINT_SIZE_QUADWORD;

		hw_start_addr = ALIGN_DOWN(info->address, align_size);
		hw_end_addr = ALIGN(info->address + info->len, align_size);

		return ((ea < hw_end_addr) && (ea + size > hw_start_addr));
		}

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