From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752510AbaEUKE7 (ORCPT ); Wed, 21 May 2014 06:04:59 -0400 Received: from e28smtp05.in.ibm.com ([122.248.162.5]:42680 "EHLO e28smtp05.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751210AbaEUKBw (ORCPT ); Wed, 21 May 2014 06:01:52 -0400 From: Anshuman Khandual To: peterz@infradead.org Cc: linux-kernel@vger.kernel.org, mpe@ellerman.id.au, benh@kernel.crashing.org Subject: [V6 08/11] powerpc, lib: Add new branch analysis support functions Date: Wed, 21 May 2014 15:29:53 +0530 Message-Id: <1400666396-1682-9-git-send-email-khandual@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.11.7 In-Reply-To: <1400666396-1682-1-git-send-email-khandual@linux.vnet.ibm.com> References: <1400666396-1682-1-git-send-email-khandual@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14052110-8256-0000-0000-00000D3D5D3C Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Generic powerpc branch analysis support added in the code patching library which will help the subsequent patch on SW based filtering of branch records in perf. Signed-off-by: Anshuman Khandual --- arch/powerpc/include/asm/code-patching.h | 16 +++++++ arch/powerpc/lib/code-patching.c | 80 ++++++++++++++++++++++++++++++++ 2 files changed, 96 insertions(+) diff --git a/arch/powerpc/include/asm/code-patching.h b/arch/powerpc/include/asm/code-patching.h index 97e02f9..39919d4 100644 --- a/arch/powerpc/include/asm/code-patching.h +++ b/arch/powerpc/include/asm/code-patching.h @@ -22,6 +22,16 @@ #define BRANCH_SET_LINK 0x1 #define BRANCH_ABSOLUTE 0x2 +#define XL_FORM_LR 0x4C000020 +#define XL_FORM_CTR 0x4C000420 +#define XL_FORM_TAR 0x4C000460 + +#define BO_ALWAYS 0x02800000 +#define BO_CTR 0x02000000 +#define BO_CRBI_OFF 0x00800000 +#define BO_CRBI_ON 0x01800000 +#define BO_CRBI_HINT 0x00400000 + unsigned int create_branch(const unsigned int *addr, unsigned long target, int flags); unsigned int create_cond_branch(const unsigned int *addr, @@ -56,4 +66,10 @@ static inline unsigned long ppc_function_entry(void *func) #endif } +/* Perf branch filters */ +bool instr_is_return_branch(unsigned int instr); +bool instr_is_conditional_branch(unsigned int instr); +bool instr_is_func_call(unsigned int instr); +bool instr_is_indirect_func_call(unsigned int instr); + #endif /* _ASM_POWERPC_CODE_PATCHING_H */ diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c index d5edbeb..a06f8b3 100644 --- a/arch/powerpc/lib/code-patching.c +++ b/arch/powerpc/lib/code-patching.c @@ -77,6 +77,7 @@ static unsigned int branch_opcode(unsigned int instr) return (instr >> 26) & 0x3F; } +/* Forms of branch instruction */ static int instr_is_branch_iform(unsigned int instr) { return branch_opcode(instr) == 18; @@ -87,6 +88,85 @@ static int instr_is_branch_bform(unsigned int instr) return branch_opcode(instr) == 16; } +static int instr_is_branch_xlform(unsigned int instr) +{ + return branch_opcode(instr) == 19; +} + +/* Classification of XL-form instruction */ +static int is_xlform_lr(unsigned int instr) +{ + return (instr & XL_FORM_LR) == XL_FORM_LR; +} + +/* BO field analysis (B-form or XL-form) */ +static int is_bo_always(unsigned int instr) +{ + return (instr & BO_ALWAYS) == BO_ALWAYS; +} + +/* Link bit is set */ +static int is_branch_link_set(unsigned int instr) +{ + return (instr & BRANCH_SET_LINK) == BRANCH_SET_LINK; +} + +/* + * Generic software implemented branch filters used + * by perf branch stack sampling when PMU does not + * process them for some reason. + */ + +/* PERF_SAMPLE_BRANCH_ANY_RETURN */ +bool instr_is_return_branch(unsigned int instr) +{ + /* + * Conditional and unconditional branch to LR register + * without seting the link register. + */ + if (is_xlform_lr(instr) && !is_branch_link_set(instr)) + return true; + + return false; +} + +/* PERF_SAMPLE_BRANCH_COND */ +bool instr_is_conditional_branch(unsigned int instr) +{ + /* I-form instruction - excluded */ + if (instr_is_branch_iform(instr)) + return false; + + /* B-form or XL-form instruction */ + if (instr_is_branch_bform(instr) || instr_is_branch_xlform(instr)) { + + /* Not branch always */ + if (!is_bo_always(instr)) + return true; + } + return false; +} + +/* PERF_SAMPLE_BRANCH_ANY_CALL */ +bool instr_is_func_call(unsigned int instr) +{ + /* LR should be set */ + if (is_branch_link_set(instr)) + return true; + + return false; +} + +/* PERF_SAMPLE_BRANCH_IND_CALL */ +bool instr_is_indirect_func_call(unsigned int instr) +{ + /* XL-form instruction with LR set */ + if (instr_is_branch_xlform(instr) && is_branch_link_set(instr)) + return true; + + return false; +} + int instr_is_relative_branch(unsigned int instr) { if (instr & BRANCH_ABSOLUTE) -- 1.7.11.7