Am 15.01.2013 11:47, schrieb Catalin Marinas: > Hi André, > > On 14 January 2013 23:34, André Hentschel <nerv@xxxxxxxxxxx> wrote: >> i'm new to the list (my first kernel mailing list). >> I'd like to request to add a way to distinguish a read from a write pagefault in userspace on arm64(aarch64). >> (That's e.g. in a SIGSEGV handler attached with sigaction and SA_SIGINFO) >> On arm you can use the bit at 0x800 in uc_mcontext.error_code to know which kind it is, but on arm64 i can't find a way. >> (On most other popular architectures you can get that information, too) >> I'd suggest to add a flag to siginfo.si_errno, or to make the esr available to the SIGSEGV handler. > > The problem with exposing ESR directly to user is that it depends on > the MMU configuration (e.g. on Cortex-A15 (32-bit) you have different > formats based on whether you have LPAE enabled or not, though the > 'write' bit happens to be in the same position). > > siginfo for SIGSEGV gives the fault address and type information but, > as you noticed, doesn't say whether it's a read or write. What do you > need this information for? > Thanks for the answer and the confirmation. I'm porting Wine to arm64, some winelib applications may rely on the information in case they handle the exception. -- Best Regards, André Hentschel -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
