Messages in this thread | | | Date | Thu, 08 Jan 2015 23:21:32 +0530 | From | Pratyush Anand <> | Subject | Re: [RFC 6/8] ARM64: Handle TRAP_HWBRKPT for user mode as well |
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On Thursday 08 January 2015 10:31 PM, Will Deacon wrote: > On Fri, Jan 02, 2015 at 06:05:23PM +0000, Oleg Nesterov wrote: >> Let me repeat once again that I know absolutely nothing about arm* ;) >> >> On 12/31, Pratyush Anand wrote: >>> >>> uprobe registers a handler at step_hook. So, single_step_handler now >>> checks for user mode as well if there is a valid hook. >>> >>> Signed-off-by: Pratyush Anand <panand@redhat.com> >>> --- >>> arch/arm64/kernel/debug-monitors.c | 6 +++--- >>> 1 file changed, 3 insertions(+), 3 deletions(-) >>> >>> diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c >>> index b056369fd47d..2676b8655241 100644 >>> --- a/arch/arm64/kernel/debug-monitors.c >>> +++ b/arch/arm64/kernel/debug-monitors.c >>> @@ -236,6 +236,9 @@ static int single_step_handler(unsigned long addr, unsigned int esr, >>> if (!reinstall_suspended_bps(regs)) >>> return 0; >>> >>> + if (call_step_hook(regs, esr) == DBG_HOOK_HANDLED) >>> + return 0; >>> + >>> if (user_mode(regs)) { >>> info.si_signo = SIGTRAP; >>> info.si_errno = 0; >>> @@ -251,9 +254,6 @@ static int single_step_handler(unsigned long addr, unsigned int esr, >>> */ >>> user_rewind_single_step(current); >>> } else { >>> - if (call_step_hook(regs, esr) == DBG_HOOK_HANDLED) >>> - return 0; >>> - >> >> Agreed, we need something like this change... >> >> But did you verify that it can't break other users of register_step_hook() ? >> The current handlers do not check user_mode() == F, they assume that they >> can't be called otherwise. >> >> If this all is correct, please explain why in the changelog. > > I think you're right, and kgdb will need fixing with this change.
OK, I will fix kgdb too when I will send next revision.
~Pratyush
> > Will > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ >
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