Messages in this thread | | | Subject | Re: [PATCH v2 13/16] powerpc/watchpoint: Prepare handler to handle more than one watcnhpoint | From | Christophe Leroy <> | Date | Wed, 1 Apr 2020 08:50:01 +0200 |
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Le 01/04/2020 à 08:13, Ravi Bangoria a écrit : > Currently we assume that we have only one watchpoint supported by hw. > Get rid of that assumption and use dynamic loop instead. This should > make supporting more watchpoints very easy. > > With more than one watchpoint, exception handler need to know which > DAWR caused the exception, and hw currently does not provide it. So > we need sw logic for the same. To figure out which DAWR caused the > exception, check all different combinations of user specified range, > dawr address range, actual access range and dawrx constrains. For ex, > if user specified range and actual access range overlaps but dawrx is > configured for readonly watchpoint and the instruction is store, this > DAWR must not have caused exception. > > Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com> > --- > arch/powerpc/include/asm/processor.h | 2 +- > arch/powerpc/include/asm/sstep.h | 2 + > arch/powerpc/kernel/hw_breakpoint.c | 396 +++++++++++++++++++++------ > arch/powerpc/kernel/process.c | 3 - > 4 files changed, 313 insertions(+), 90 deletions(-) >
[...]
> -static bool > -dar_range_overlaps(unsigned long dar, int size, struct arch_hw_breakpoint *info) > +static bool dar_user_range_overlaps(unsigned long dar, int size, > + struct arch_hw_breakpoint *info) > { > return ((dar <= info->address + info->len - 1) && > (dar + size - 1 >= info->address)); > }
Here and several other places, I think it would be more clear if you could avoid the - 1 :
return ((dar < info->address + info->len) && (dar + size > info->address));
> > +static bool dar_in_hw_range(unsigned long dar, struct arch_hw_breakpoint *info) > +{ > + unsigned long hw_start_addr, hw_end_addr; > + > + hw_start_addr = ALIGN_DOWN(info->address, HW_BREAKPOINT_SIZE); > + hw_end_addr = ALIGN(info->address + info->len, HW_BREAKPOINT_SIZE) - 1; > + > + return ((hw_start_addr <= dar) && (hw_end_addr >= dar)); > +}
hw_end_addr = ALIGN(info->address + info->len, HW_BREAKPOINT_SIZE);
return ((hw_start_addr <= dar) && (hw_end_addr > dar));
Christophe
> + > +static bool dar_hw_range_overlaps(unsigned long dar, int size, > + struct arch_hw_breakpoint *info) > +{ > + unsigned long hw_start_addr, hw_end_addr; > + > + hw_start_addr = ALIGN_DOWN(info->address, HW_BREAKPOINT_SIZE); > + hw_end_addr = ALIGN(info->address + info->len, HW_BREAKPOINT_SIZE) - 1; > + > + return ((dar <= hw_end_addr) && (dar + size - 1 >= hw_start_addr)); > +}
Same
Christophe
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