On Mon, Aug 09, 2021 at 10:10:47AM -0300, Daniel Henrique Barboza wrote: > From: Gustavo Romero <grom...@linux.ibm.com> > > An Event-Based Branch (EBB) allows applications to change the NIA when a > event-based exception occurs. Event-based exceptions are enabled by > setting the Branch Event Status and Control Register (BESCR). If the > event-based exception is enabled when the exception occurs, an EBB > happens. > > The EBB will: > > - set the Global Enable (GE) bit of BESCR to 0; > - set bits 0-61 of the Event-Based Branch Return Register (EBBRR) to the > effective address of the NIA that would have executed if the EBB > didn't happen; > - Instruction fetch and execution will continue in the effective address > contained in the Event-Based Branch Handler Register (EBBHR). > > The EBB Handler will process the event and then execute the Return From > Event-Based Branch (rfebb) instruction. rfebb sets BESCR_GE and then > redirects execution to the address pointed in EBBRR. This process is > described in the PowerISA v3.1, Book II, Chapter 6 [1]. > > This patch implements the rfebb instruction. Descriptions of all > relevant BESCR bits are also added - this patch is only using BESCR_GE, > but next patches will use the remaining bits. > > Note that we're implementing the extended rfebb mnemonic (BESCR_GE is > being always set to 1). The basic rfebb instruction would accept an > operand that would be used to set GE. > > [1] https://wiki.raptorcs.com/w/images/f/f5/PowerISA_public.v3.1.pdf > > CC: Gustavo Romero <gustavo.rom...@linaro.org> > Signed-off-by: Gustavo Romero <grom...@linux.ibm.com> > Signed-off-by: Daniel Henrique Barboza <danielhb...@gmail.com> > --- > target/ppc/cpu.h | 12 ++++++++++++ > target/ppc/translate.c | 21 +++++++++++++++++++++ > 2 files changed, 33 insertions(+) > > diff --git a/target/ppc/cpu.h b/target/ppc/cpu.h > index afd9cd402b..ae431e65be 100644 > --- a/target/ppc/cpu.h > +++ b/target/ppc/cpu.h > @@ -358,6 +358,18 @@ typedef struct ppc_v3_pate_t { > #define MMCR1_PMC3SEL PPC_BITMASK(48, 55) > #define MMCR1_PMC4SEL PPC_BITMASK(56, 63) > > +/* EBB/BESCR bits */ > +/* Global Enable */ > +#define BESCR_GE PPC_BIT(0) > +/* External Event-based Exception Enable */ > +#define BESCR_EE PPC_BIT(30) > +/* Performance Monitor Event-based Exception Enable */ > +#define BESCR_PME PPC_BIT(31) > +/* External Event-based Exception Occurred */ > +#define BESCR_EEO PPC_BIT(62) > +/* Performance Monitor Event-based Exception Occurred */ > +#define BESCR_PMEO PPC_BIT(63) > + > /* LPCR bits */ > #define LPCR_VPM0 PPC_BIT(0) > #define LPCR_VPM1 PPC_BIT(1) > diff --git a/target/ppc/translate.c b/target/ppc/translate.c > index 62356cfadf..afc254a03f 100644 > --- a/target/ppc/translate.c > +++ b/target/ppc/translate.c > @@ -2701,6 +2701,26 @@ static void gen_darn(DisasContext *ctx) > } > } > } > + > +/* rfebb */ > +static void gen_rfebb(DisasContext *ctx)
Oof.. not necessarily a nack, but it would be nice to implement any
new instructions using the disastree path rather than the old ppc
specific decode logic.
> +{
> + TCGv target = tcg_temp_new();
> + TCGv bescr = tcg_temp_new();
> +
> + gen_load_spr(target, SPR_EBBRR);
> + tcg_gen_mov_tl(cpu_nip, target);
> +
> + gen_load_spr(bescr, SPR_BESCR);
> + tcg_gen_ori_tl(bescr, bescr, BESCR_GE);
> + gen_store_spr(SPR_BESCR, bescr);
> +
> + ctx->base.is_jmp = DISAS_EXIT;
> +
> + tcg_temp_free(target);
> + tcg_temp_free(bescr);
> +}
> +
> #endif
>
> /*** Integer rotate
> ***/
> @@ -7724,6 +7744,7 @@ GEN_HANDLER(popcntd, 0x1F, 0x1A, 0x0F, 0x0000F801,
> PPC_POPCNTWD),
> GEN_HANDLER(cntlzd, 0x1F, 0x1A, 0x01, 0x00000000, PPC_64B),
> GEN_HANDLER_E(cnttzd, 0x1F, 0x1A, 0x11, 0x00000000, PPC_NONE, PPC2_ISA300),
> GEN_HANDLER_E(darn, 0x1F, 0x13, 0x17, 0x001CF801, PPC_NONE, PPC2_ISA300),
> +GEN_HANDLER_E(rfebb, 0x13, 0x12, 0x04, 0x03FFF001, PPC_NONE, PPC2_ISA207S),
> GEN_HANDLER_E(prtyd, 0x1F, 0x1A, 0x05, 0x0000F801, PPC_NONE, PPC2_ISA205),
> GEN_HANDLER_E(bpermd, 0x1F, 0x1C, 0x07, 0x00000001, PPC_NONE,
> PPC2_PERM_ISA206),
> #endif
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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