Claudio Carvalho <cclaudio@xxxxxxxxxxxxx> writes: > From: Ram Pai <linuxram@xxxxxxxxxx> > > Add the ucall() function, which can be used to make ultravisor calls > with varied number of in and out arguments. Ultravisor calls can be made > from the host or guests. > > This copies the implementation of plpar_hcall(). .. with quite a few changes? This is one of the things I'd like to see in a Documentation file, so that people can review the implementation vs the specification. > Signed-off-by: Ram Pai <linuxram@xxxxxxxxxx> > [ Change ucall.S to not save CR, rename and move headers, build ucall.S > if CONFIG_PPC_POWERNV set, use R3 for the ucall number and add some > comments in the code ] Why are we not saving CR? See previous comment about Documentation :) > Signed-off-by: Claudio Carvalho <cclaudio@xxxxxxxxxxxxx> > --- > arch/powerpc/include/asm/ultravisor-api.h | 20 +++++++++++++++ > arch/powerpc/include/asm/ultravisor.h | 20 +++++++++++++++ > arch/powerpc/kernel/Makefile | 2 +- > arch/powerpc/kernel/ucall.S | 30 +++++++++++++++++++++++ > arch/powerpc/kernel/ultravisor.c | 4 +++ > 5 files changed, 75 insertions(+), 1 deletion(-) > create mode 100644 arch/powerpc/include/asm/ultravisor-api.h > create mode 100644 arch/powerpc/kernel/ucall.S > > diff --git a/arch/powerpc/include/asm/ultravisor-api.h b/arch/powerpc/include/asm/ultravisor-api.h > new file mode 100644 > index 000000000000..49e766adabc7 > --- /dev/null > +++ b/arch/powerpc/include/asm/ultravisor-api.h > @@ -0,0 +1,20 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* > + * Ultravisor API. > + * > + * Copyright 2019, IBM Corporation. > + * > + */ > +#ifndef _ASM_POWERPC_ULTRAVISOR_API_H > +#define _ASM_POWERPC_ULTRAVISOR_API_H > + > +#include <asm/hvcall.h> > + > +/* Return codes */ > +#define U_NOT_AVAILABLE H_NOT_AVAILABLE > +#define U_SUCCESS H_SUCCESS > +#define U_FUNCTION H_FUNCTION > +#define U_PARAMETER H_PARAMETER Is there any benefit in redefining these? > diff --git a/arch/powerpc/include/asm/ultravisor.h b/arch/powerpc/include/asm/ultravisor.h > index e5009b0d84ea..a78a2dacfd0b 100644 > --- a/arch/powerpc/include/asm/ultravisor.h > +++ b/arch/powerpc/include/asm/ultravisor.h > @@ -8,8 +8,28 @@ > #ifndef _ASM_POWERPC_ULTRAVISOR_H > #define _ASM_POWERPC_ULTRAVISOR_H > > +#include <asm/ultravisor-api.h> > + > +#if !defined(__ASSEMBLY__) Just #ifndef is fine. > /* Internal functions */ How is it internal? > extern int early_init_dt_scan_ultravisor(unsigned long node, const char *uname, > int depth, void *data); > > +/* API functions */ > +#define UCALL_BUFSIZE 4 Please don't copy this design from the hcall code, it has led to bugs in the past. See my (still unmerged) attempt to fix this for the hcall case: https://patchwork.ozlabs.org/patch/683577/ Basically instead of asking callers nicely to define a certain sized buffer, and them forgetting, define a proper type that has the right size. > +/** > + * ucall: Make a powerpc ultravisor call. > + * @opcode: The ultravisor call to make. > + * @retbuf: Buffer to store up to 4 return arguments in. > + * > + * This call supports up to 6 arguments and 4 return arguments. Use > + * UCALL_BUFSIZE to size the return argument buffer. > + */ > +#if defined(CONFIG_PPC_POWERNV) #ifdef > +long ucall(unsigned long opcode, unsigned long *retbuf, ...); > +#endif > + > +#endif /* !__ASSEMBLY__ */ > + > #endif /* _ASM_POWERPC_ULTRAVISOR_H */ > diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile > index f0caa302c8c0..f28baccc0a79 100644 > --- a/arch/powerpc/kernel/Makefile > +++ b/arch/powerpc/kernel/Makefile > @@ -154,7 +154,7 @@ endif > > obj-$(CONFIG_EPAPR_PARAVIRT) += epapr_paravirt.o epapr_hcalls.o > obj-$(CONFIG_KVM_GUEST) += kvm.o kvm_emul.o > -obj-$(CONFIG_PPC_POWERNV) += ultravisor.o > +obj-$(CONFIG_PPC_POWERNV) += ultravisor.o ucall.o Same comment about being platforms/powernv ? > > diff --git a/arch/powerpc/kernel/ucall.S b/arch/powerpc/kernel/ucall.S > new file mode 100644 > index 000000000000..1678f6eb7230 > --- /dev/null > +++ b/arch/powerpc/kernel/ucall.S > @@ -0,0 +1,30 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* > + * Generic code to perform an ultravisor call. > + * > + * Copyright 2019, IBM Corporation. > + * > + */ > +#include <asm/ppc_asm.h> > + > +/* > + * This function is based on the plpar_hcall() I don't think it meaningfully is any more. > + */ > +_GLOBAL_TOC(ucall) You don't need the TOC setup here (unless a later patch does?). > + std r4,STK_PARAM(R4)(r1) /* Save ret buffer */ > + mr r4,r5 > + mr r5,r6 > + mr r6,r7 > + mr r7,r8 > + mr r8,r9 > + mr r9,r10 Below you space the arguments, here you don't. Pick one or the other please. > + > + sc 2 /* Invoke the ultravisor */ > + > + ld r12,STK_PARAM(R4)(r1) > + std r4, 0(r12) > + std r5, 8(r12) > + std r6, 16(r12) > + std r7, 24(r12) > + > + blr /* Return r3 = status */ > diff --git a/arch/powerpc/kernel/ultravisor.c b/arch/powerpc/kernel/ultravisor.c > index dc6021f63c97..02ddf79a9522 100644 > --- a/arch/powerpc/kernel/ultravisor.c > +++ b/arch/powerpc/kernel/ultravisor.c > @@ -8,10 +8,14 @@ > #include <linux/init.h> > #include <linux/printk.h> > #include <linux/string.h> > +#include <linux/export.h> > > #include <asm/ultravisor.h> > #include <asm/firmware.h> > > +/* in ucall.S */ > +EXPORT_SYMBOL_GPL(ucall); This should be in ucall.S cheers
