On Tue Nov 29, 2022 at 2:43 PM AEST, Rohan McLure wrote: > Include in asm/ppc_asm.h macros to be used in multiple successive > patches to implement zeroising architected registers in interrupt > handlers. Registers will be sanitised in this fashion in future patches > to reduce the speculation influence of user-controlled register values. > These mitigations will be configurable through the > CONFIG_INTERRUPT_SANITIZE_REGISTERS Kconfig option. > > Included are macros for conditionally zeroising registers and restoring > as required with the mitigation enabled. With the mitigation disabled, > non-volatiles must be restored on demand at separate locations to > those required by the mitigation. > > Signed-off-by: Rohan McLure <rmcl...@linux.ibm.com>
Thanks. You might just call them SANITIZE_NVGPRS() etc if it's not functionally important that they're zero. But I don't mind long names too much. Reviewed-by: Nicholas Piggin <npig...@gmail.com> > --- > v4: New patch > --- > arch/powerpc/include/asm/ppc_asm.h | 17 +++++++++++++++++ > 1 file changed, 17 insertions(+) > > diff --git a/arch/powerpc/include/asm/ppc_asm.h > b/arch/powerpc/include/asm/ppc_asm.h > index 753a2757bcd4..272b2795c36a 100644 > --- a/arch/powerpc/include/asm/ppc_asm.h > +++ b/arch/powerpc/include/asm/ppc_asm.h > @@ -74,6 +74,23 @@ > #define SAVE_GPR(n, base) SAVE_GPRS(n, n, base) > #define REST_GPR(n, base) REST_GPRS(n, n, base) > > +/* macros for handling user register sanitisation */ > +#ifdef CONFIG_INTERRUPT_SANITIZE_REGISTERS > +#define SANITIZE_ZEROIZE_SYSCALL_GPRS() ZEROIZE_GPR(0); > \ > + ZEROIZE_GPRS(5, 12); \ > + ZEROIZE_NVGPRS() > +#define SANITIZE_ZEROIZE_INTERRUPT_NVGPRS() ZEROIZE_NVGPRS() > +#define SANITIZE_ZEROIZE_NVGPRS() ZEROIZE_NVGPRS() > +#define SANITIZE_RESTORE_NVGPRS() REST_NVGPRS(r1) > +#define HANDLER_RESTORE_NVGPRS() > +#else > +#define SANITIZE_ZEROIZE_INTERRUPT_NVGPRS() > +#define SANITIZE_ZEROIZE_SYSCALL_GPRS() > +#define SANITIZE_ZEROIZE_NVGPRS() > +#define SANITIZE_RESTORE_NVGPRS() > +#define HANDLER_RESTORE_NVGPRS() REST_NVGPRS(r1) > +#endif /* CONFIG_INTERRUPT_SANITIZE_REGISTERS */ > + > #define SAVE_FPR(n, base) stfd n,8*TS_FPRWIDTH*(n)(base) > #define SAVE_2FPRS(n, base) SAVE_FPR(n, base); SAVE_FPR(n+1, base) > #define SAVE_4FPRS(n, base) SAVE_2FPRS(n, base); SAVE_2FPRS(n+2, base) > -- > 2.37.2
