Hello Dave, I've applied this patch (manually, because 4/6 is not yet applied). I have a question below. On 5/27/20 11:17 PM, Dave Martin wrote: > Add documentation for the PR_PAC_RESET_KEYS ioctl added in Linux > 5.0 for arm64. > > Signed-off-by: Dave Martin <Dave.Martin@xxxxxxx> > Cc: Will Deacon <will@xxxxxxxxxx> > Cc: Catalin Marinas <catalin.marinas@xxxxxxx> > Cc: Amit Daniel Kachhap <amit.kachhap@xxxxxxx> > Cc: Mark Rutland <mark.rutland@xxxxxxx> > > --- > > Since v1: > > * Clarify explicitly that PR_PAC_RESET_KEYS is redundant when combined > with execve(). > > * Move error condition details into the prctl description, to avoid > excessive duplication while keeping keeping related pieces of text > closer together. > > * In lieu of having a separate man page to cross reference for detailed > guidance, cross-reference the kernel documentation. > > * Add safety warning. This is deliberately vague, pending ongoing > discussions with libc folks. > --- > man2/prctl.2 | 80 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 80 insertions(+) > [...] > +.IP > +.B Warning: > +Because the compiler or run-time environment > +may be using some or all of the keys, > +a successful Things got a bit garbled here. I think the next few lines should have been at the end. > +.IP > +For more information, see the kernel source file > +.I Documentation/arm64/pointer\-authentication.rst > +.\"commit b693d0b372afb39432e1c49ad7b3454855bc6bed > +(or > +.I Documentation/arm64/pointer\-authentication.txt > +before Linux 5.3). > +.B PR_PAC_RESET_KEYS > +may crash the calling process. > +The conditions for using it safely are complex and system-dependent. > +Don't use it unless you know what you are doing. I applied the following change after your patch; is it okay? .IP .B Warning: Because the compiler or run-time environment may be using some or all of the keys, a successful +may crash the calling process. +The conditions for using it safely are complex and system-dependent. +Don't use it unless you know what you are doing. .IP For more information, see the kernel source file .I Documentation/arm64/pointer\-authentication.rst @@ -1020,9 +1023,6 @@ For more information, see the kernel source file .I Documentation/arm64/pointer\-authentication.txt before Linux 5.3). .B PR_PAC_RESET_KEYS -may crash the calling process. -The conditions for using it safely are complex and system-dependent. -Don't use it unless you know what you are doing. .\" prctl PR_SET_PDEATHSIG .TP .BR PR_SET_PDEATHSIG " (since Linux 2.1.57)" [...] Thanks, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/
