On Wed, Dec 01, 2021 at 11:40:10AM +0800, Kuan-Ying Lee wrote: > Remove the paragraph which has nothing to do with the kernel and > add PAC description related to kernel. > > Suggested-by: Mark Rutland <mark.rutland@xxxxxxx> > Signed-off-by: Kuan-Ying Lee <Kuan-Ying.Lee@xxxxxxxxxxxx> This looks good to me. Catalin/Will, did you want to pick this, or do you want Jonathan to do so? Mark. > --- > v1 -> v2: > - Remove compiler option description > - Add PAC description for kernel > > Documentation/arm64/pointer-authentication.rst | 9 ++++----- > 1 file changed, 4 insertions(+), 5 deletions(-) > > diff --git a/Documentation/arm64/pointer-authentication.rst b/Documentation/arm64/pointer-authentication.rst > index f127666ea3a8..e5dad2e40aa8 100644 > --- a/Documentation/arm64/pointer-authentication.rst > +++ b/Documentation/arm64/pointer-authentication.rst > @@ -53,11 +53,10 @@ The number of bits that the PAC occupies in a pointer is 55 minus the > virtual address size configured by the kernel. For example, with a > virtual address size of 48, the PAC is 7 bits wide. > > -Recent versions of GCC can compile code with APIAKey-based return > -address protection when passed the -msign-return-address option. This > -uses instructions in the HINT space (unless -march=armv8.3-a or higher > -is also passed), and such code can run on systems without the pointer > -authentication extension. > +When ARM64_PTR_AUTH_KERNEL is selected, the kernel will be compiled > +with HINT space pointer authentication instructions protecting > +function returns. Kernels built with this option will work on hardware > +with or without pointer authentication support. > > In addition to exec(), keys can also be reinitialized to random values > using the PR_PAC_RESET_KEYS prctl. A bitmask of PR_PAC_APIAKEY, > -- > 2.18.0 >
