From: Ravi Bangoria ravi.bangoria@linux.ibm.com
[ Upstream commit 4759c11ed20454b7b36db4ec15f7d5aa1519af4a ]
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: 74c6881019b7 ("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.co... Signed-off-by: Sasha Levin sashal@kernel.org --- arch/powerpc/include/asm/hw_breakpoint.h | 1 + arch/powerpc/kernel/hw_breakpoint.c | 12 ++++++++++-- 2 files changed, 11 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/include/asm/hw_breakpoint.h b/arch/powerpc/include/asm/hw_breakpoint.h index cb424799da0dc..5a00da670a407 100644 --- a/arch/powerpc/include/asm/hw_breakpoint.h +++ b/arch/powerpc/include/asm/hw_breakpoint.h @@ -40,6 +40,7 @@ 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 diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c index c55e67bab2710..f39e86d751144 100644 --- a/arch/powerpc/kernel/hw_breakpoint.c +++ b/arch/powerpc/kernel/hw_breakpoint.c @@ -519,9 +519,17 @@ 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)); }