On Tue, Jun 09, 2020 at 01:36:42PM +0200, Michael Kerrisk (man-pages) wrote: > 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 Looks fine, execpt that I think you need to move the .B PR_PAC_RESET_KEYS line here also. Thanks ---Dave > +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)" > [...]
