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ARCv2: don't assume core 0x54 has dual issue

Bladeren bron 
The first release of core4 (0x54) was dual issue only (HS4x).
Newer releases allow hardware to be configured as single issue (HS3x)
or dual issue.

Prevent accessing a HS4x only aux register in HS3x, which otherwise
leads to illegal instruction exceptions

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
This commit is contained in:
Vineet Gupta
2019-02-21 13:44:49 -08:00
bovenliggende b6835ea777
commit 7b2e932f63
2 gewijzigde bestanden met toevoegingen van 29 en 5 verwijderingen
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26
arch/arc/kernel/setup.c
Bestand weergeven

@@ -199,13 +199,29 @@ static void read_arc_build_cfg_regs(void)
cpu->bpu.ret_stk = 4 << bpu.rse;
if (cpu->core.family >= 0x54) {
unsigned int exec_ctrl;
READ_BCR(AUX_EXEC_CTRL, exec_ctrl);
cpu->extn.dual_enb = !(exec_ctrl & 1);
struct bcr_uarch_build_arcv2 uarch;
/* dual issue always present for this core */
cpu->extn.dual = 1;
/*
* The first 0x54 core (uarch maj:min 0:1 or 0:2) was
* dual issue only (HS4x). But next uarch rev (1:0)
* allows it be configured for single issue (HS3x)
* Ensure we fiddle with dual issue only on HS4x
*/
READ_BCR(ARC_REG_MICRO_ARCH_BCR, uarch);
if (uarch.prod == 4) {
unsigned int exec_ctrl;
/* dual issue hardware always present */
cpu->extn.dual = 1;
READ_BCR(AUX_EXEC_CTRL, exec_ctrl);
/* dual issue hardware enabled ? */
cpu->extn.dual_enb = !(exec_ctrl & 1);
}
}
}