| Message ID | 20220725062906.120088-1-rmclure@linux.ibm.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | powerpc: Syscall wrapper and register clearing | expand |
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 <rmclure@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 <ajd@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) >
Le 08/08/2022 à 09:42, Andrew Donnellan a écrit : > 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 <rmclure@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 <ajd@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 Not sure it would work. You'd get: li .Lreg, 0 + 0 * .Lreg(0) Even if it works that would be odd. > >> /* >> * 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) >> >
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 + /* * 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)
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 <rmclure@linux.ibm.com> --- V1 -> V2: Change 'ZERO' usage in naming to 'NULLIFY', a more obvious verb --- arch/powerpc/include/asm/ppc_asm.h | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+)