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From: Segher Boessenkool <segher@kernel.crashing.org>
To: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: linuxppc-dev@ozlabs.org, linux-kernel@vger.kernel.org, mikey@neuling.org
Subject: Re: [PATCH V2 2/5] powerpc, perf: Add basic assembly code to read BHRB entries on POWER8
Date: Tue, 16 Apr 2013 19:23:19 +0200	[thread overview]
Message-ID: <AAEA07FE-7530-46D3-B2FC-B3FD8EC2C6E2@kernel.crashing.org> (raw)
In-Reply-To: <1366127650-1952-3-git-send-email-khandual@linux.vnet.ibm.com>

> +/* r3 = n  (where n = [0-1023])
> + * The maximum number of BHRB entries supported with PPC_MFBHRBE  
> instruction
> + * is 1024. We have limited number of table entries here as POWER8  
> implements
> + * 32 BHRB entries.
> + */
> +
> +/* .global read_bhrb */
> +_GLOBAL(read_bhrb)
> +	cmpldi	r3,1023

This should be 31, since that is the last entry in the table below.

> +	bgt	1f
> +	ld	r4,bhrb_table@got(r2)
> +	sldi	r3,r3,3
> +	add	r3,r4,r3
> +	mtctr	r3
> +	bctr
> +1:	li	r3,0
> +	blr
> +
> +#define MFBHRB_TABLE1(n) PPC_MFBHRBE(R3,n); blr
> +#define MFBHRB_TABLE2(n) MFBHRB_TABLE1(n); MFBHRB_TABLE1(n+1)
> +#define MFBHRB_TABLE4(n) MFBHRB_TABLE2(n); MFBHRB_TABLE2(n+2)
> +#define MFBHRB_TABLE8(n) MFBHRB_TABLE4(n); MFBHRB_TABLE4(n+4)
> +#define MFBHRB_TABLE16(n) MFBHRB_TABLE8(n); MFBHRB_TABLE8(n+8)
> +#define MFBHRB_TABLE32(n) MFBHRB_TABLE16(n); MFBHRB_TABLE16(n+16)
> +
> +bhrb_table:
> +	MFBHRB_TABLE32(0)


Segher


  reply	other threads:[~2013-04-16 17:22 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-04-16 15:54 [PATCH V2 0/5] powerpc, perf: BHRB based branch stack enablement on POWER8 Anshuman Khandual
2013-04-16 15:54 ` [PATCH V2 1/5] powerpc, perf: Add new BHRB related instructions " Anshuman Khandual
2013-04-16 15:54 ` [PATCH V2 2/5] powerpc, perf: Add basic assembly code to read BHRB entries " Anshuman Khandual
2013-04-16 17:23   ` Segher Boessenkool [this message]
2013-04-17  4:00     ` Anshuman Khandual
2013-04-16 15:54 ` [PATCH V2 3/5] powerpc, perf: Add new BHRB related generic functions, data and flags Anshuman Khandual
2013-04-16 15:54 ` [PATCH V2 4/5] powerpc, perf: Define BHRB generic functions, data and flags for POWER8 Anshuman Khandual
2013-04-16 15:54 ` [PATCH V2 5/5] powerpc, perf: Enable branch stack sampling framework support with BHRB Anshuman Khandual
2013-04-17  7:08   ` Michael Ellerman
2013-04-17 12:07     ` Anshuman Khandual
2013-04-18  2:58       ` Anshuman Khandual

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