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[PATCH 09/19] PPC64/TCG: Implement 'rfebb' instruction
From: |
Daniel Henrique Barboza |
Subject: |
[PATCH 09/19] PPC64/TCG: Implement 'rfebb' instruction |
Date: |
Mon, 9 Aug 2021 10:10:47 -0300 |
From: Gustavo Romero <gromero@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.romero@linaro.org>
Signed-off-by: Gustavo Romero <gromero@linux.ibm.com>
Signed-off-by: Daniel Henrique Barboza <danielhb413@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)
+{
+ 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
--
2.31.1
- [PATCH 06/19] target/ppc/pmu_book3s_helper: enable PMC1-PMC4 events, (continued)
[PATCH 07/19] target/ppc/pmu_book3s_helper.c: icount fine tuning, Daniel Henrique Barboza, 2021/08/09
[PATCH 08/19] target/ppc/pmu_book3s_helper.c: do an actual cycles calculation, Daniel Henrique Barboza, 2021/08/09
[PATCH 09/19] PPC64/TCG: Implement 'rfebb' instruction,
Daniel Henrique Barboza <=
Re: [PATCH 09/19] PPC64/TCG: Implement 'rfebb' instruction, Richard Henderson, 2021/08/10
[PATCH 10/19] target/ppc: PMU Event-Based exception support, Daniel Henrique Barboza, 2021/08/09
[PATCH 11/19] target/ppc/excp_helper.c: POWERPC_EXCP_EBB adjustments, Daniel Henrique Barboza, 2021/08/09
[PATCH 12/19] target/ppc/pmu_book3s_helper.c: enable PMC1 counter negative EBB, Daniel Henrique Barboza, 2021/08/09