linux-kernel - [PATCH v3 16/25] powerpc/ftrace: Use PPC_RAW

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Message-Id: <9292094c9a69cef6d29ee83f435a557b59c45065.1652074503.git.christophe.leroy@csgroup.eu>
Date:   Mon,  9 May 2022 07:36:14 +0200
From:   Christophe Leroy <christophe.leroy@...roup.eu>
To:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        naveen.n.rao@...ux.vnet.ibm.com
Cc:     Christophe Leroy <christophe.leroy@...roup.eu>,
        linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH v3 16/25] powerpc/ftrace: Use PPC_RAW_xxx() macros instead of opencoding.

PPC_RAW_xxx() macros are self explanatory and less error prone
than open coding.

Use them in ftrace.c

Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
v2:
- Replaced PPC_INST_OFFSET24_MASK by PPC_LI_MASK and added PPC_LI().
- Fix ADDI instead of ADDIS
---
 arch/powerpc/include/asm/ppc-opcode.h |  5 +++++
 arch/powerpc/kernel/trace/ftrace.c    | 32 +++++++++------------------
 2 files changed, 16 insertions(+), 21 deletions(-)

diff --git a/arch/powerpc/include/asm/ppc-opcode.h b/arch/powerpc/include/asm/ppc-opcode.h
index 82f1f0041c6f..3e9aa96ae74b 100644
--- a/arch/powerpc/include/asm/ppc-opcode.h
+++ b/arch/powerpc/include/asm/ppc-opcode.h
@@ -352,6 +352,10 @@
 #define PPC_HIGHER(v)	(((v) >> 32) & 0xffff)
 #define PPC_HIGHEST(v)	(((v) >> 48) & 0xffff)
 
+/* LI Field */
+#define PPC_LI_MASK	0x03fffffc
+#define PPC_LI(v)	((v) & PPC_LI_MASK)
+
 /*
  * Only use the larx hint bit on 64bit CPUs. e500v1/v2 based CPUs will treat a
  * larx with EH set as an illegal instruction.
@@ -572,6 +576,7 @@
 #define PPC_RAW_EIEIO()			(0x7c0006ac)
 
 #define PPC_RAW_BRANCH(addr)		(PPC_INST_BRANCH | ((addr) & 0x03fffffc))
+#define PPC_RAW_BL(offset)		(0x48000001 | PPC_LI(offset))
 
 /* Deal with instructions that older assemblers aren't aware of */
 #define	PPC_BCCTR_FLUSH		stringify_in_c(.long PPC_INST_BCCTR_FLUSH)
diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c
index c4a68340a351..ac3f97dd1729 100644
--- a/arch/powerpc/kernel/trace/ftrace.c
+++ b/arch/powerpc/kernel/trace/ftrace.c
@@ -90,19 +90,19 @@ static int test_24bit_addr(unsigned long ip, unsigned long addr)
 
 static int is_bl_op(ppc_inst_t op)
 {
-	return (ppc_inst_val(op) & 0xfc000003) == 0x48000001;
+	return (ppc_inst_val(op) & ~PPC_LI_MASK) == PPC_RAW_BL(0);
 }
 
 static int is_b_op(ppc_inst_t op)
 {
-	return (ppc_inst_val(op) & 0xfc000003) == 0x48000000;
+	return (ppc_inst_val(op) & ~PPC_LI_MASK) == PPC_RAW_BRANCH(0);
 }
 
 static unsigned long find_bl_target(unsigned long ip, ppc_inst_t op)
 {
 	int offset;
 
-	offset = (ppc_inst_val(op) & 0x03fffffc);
+	offset = PPC_LI(ppc_inst_val(op));
 	/* make it signed */
 	if (offset & 0x02000000)
 		offset |= 0xfe000000;
@@ -182,7 +182,7 @@ __ftrace_make_nop(struct module *mod,
 	 * Use a b +8 to jump over the load.
 	 */
 
-	pop = ppc_inst(PPC_INST_BRANCH | 8);	/* b +8 */
+	pop = ppc_inst(PPC_RAW_BRANCH(8));	/* b +8 */
 
 	/*
 	 * Check what is in the next instruction. We can see ld r2,40(r1), but
@@ -394,17 +394,8 @@ int ftrace_make_nop(struct module *mod,
 static int
 expected_nop_sequence(void *ip, ppc_inst_t op0, ppc_inst_t op1)
 {
-	/*
-	 * We expect to see:
-	 *
-	 * b +8
-	 * ld r2,XX(r1)
-	 *
-	 * The load offset is different depending on the ABI. For simplicity
-	 * just mask it out when doing the compare.
-	 */
-	if (!ppc_inst_equal(op0, ppc_inst(0x48000008)) ||
-	    (ppc_inst_val(op1) & 0xffff0000) != 0xe8410000)
+	if (!ppc_inst_equal(op0, ppc_inst(PPC_RAW_BRANCH(8))) ||
+	    !ppc_inst_equal(op1, ppc_inst(PPC_INST_LD_TOC)))
 		return 0;
 	return 1;
 }
@@ -412,7 +403,6 @@ expected_nop_sequence(void *ip, ppc_inst_t op0, ppc_inst_t op1)
 static int
 expected_nop_sequence(void *ip, ppc_inst_t op0, ppc_inst_t op1)
 {
-	/* look for patched "NOP" on ppc64 with -mprofile-kernel or ppc32 */
 	if (!ppc_inst_equal(op0, ppc_inst(PPC_RAW_NOP())))
 		return 0;
 	return 1;
@@ -738,11 +728,11 @@ int __init ftrace_dyn_arch_init(void)
 	int i;
 	unsigned int *tramp[] = { ftrace_tramp_text, ftrace_tramp_init };
 	u32 stub_insns[] = {
-		0xe98d0000 | PACATOC,	/* ld      r12,PACATOC(r13)	*/
-		0x3d8c0000,		/* addis   r12,r12,<high>	*/
-		0x398c0000,		/* addi    r12,r12,<low>	*/
-		0x7d8903a6,		/* mtctr   r12			*/
-		0x4e800420,		/* bctr				*/
+		PPC_RAW_LD(_R12, _R13, PACATOC),
+		PPC_RAW_ADDIS(_R12, _R12, 0),
+		PPC_RAW_ADDI(_R12, _R12, 0),
+		PPC_RAW_MTCTR(_R12),
+		PPC_RAW_BCTR()
 	};
 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 	unsigned long addr = ppc_global_function_entry((void *)ftrace_regs_caller);
-- 
2.35.1