On Mon, 2022-07-25 at 16:29 +1000, Rohan McLure wrote: > Macros for restoring and saving registers to and from the stack > exist. > Provide macros with the same interface for clearing a range of gprs > by > setting each register's value in that range to zero. > > The resulting macros are called NULLIFY_GPRS and NULLIFY_NVGPRS, > keeping > with the naming of the accompanying restore and save macros, and > usage > of nullify to describe this operation elsewhere in the kernel. > > Signed-off-by: Rohan McLure <rmcl...@linux.ibm.com> > --- > V1 -> V2: Change 'ZERO' usage in naming to 'NULLIFY', a more obvious > verb
And I see you've addressed my comment re 32 v 64 bit from V1 as well. Reviewed-by: Andrew Donnellan <a...@linux.ibm.com> > --- > arch/powerpc/include/asm/ppc_asm.h | 22 ++++++++++++++++++++++ > 1 file changed, 22 insertions(+) > > diff --git a/arch/powerpc/include/asm/ppc_asm.h > b/arch/powerpc/include/asm/ppc_asm.h > index 83c02f5a7f2a..d6c46082bf7f 100644 > --- a/arch/powerpc/include/asm/ppc_asm.h > +++ b/arch/powerpc/include/asm/ppc_asm.h > @@ -33,6 +33,20 @@ > .endr > .endm > > +/* > + * This expands to a sequence of register clears for regs start to > end > + * inclusive, of the form: > + * > + * li rN, 0 > + */ > +.macro NULLIFY_REGS start, end > + .Lreg=\start > + .rept (\end - \start + 1) > + li .Lreg, 0 > + .Lreg=.Lreg+1 > + .endr > +.endm > + I suppose this could be done using the existing OP_REGS macro, something like OP_REGS li, 0, start, end, 0, 0 - but a load immediate is semantically a bit different from the existing uses of OP_REGS so I don't mind either way > /* > * Macros for storing registers into and loading registers from > * exception frames. > @@ -49,6 +63,14 @@ > #define REST_NVGPRS(base) REST_GPRS(13, 31, base) > #endif > > +#define NULLIFY_GPRS(start, end) NULLIFY_REGS start, > end > +#ifdef __powerpc64__ > +#define NULLIFY_NVGPRS() NULLIFY_GPRS(14, 31) > +#else > +#define NULLIFY_NVGPRS() NULLIFY_GPRS(13, 31) > +#endif > +#define NULLIFY_GPR(n) NULLIFY_GPRS(n, n) > + > #define SAVE_GPR(n, base) SAVE_GPRS(n, n, base) > #define REST_GPR(n, base) REST_GPRS(n, n, base) > -- Andrew Donnellan OzLabs, ADL Canberra a...@linux.ibm.com IBM Australia Limited
