linux-kernel - [PATCH 2/3] powerpc/module32: Use symbolic instructions names.

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Message-Id: <14f88b27ff94f2d5a07a8cbc33ec75e2f8af9cf9.1556534520.git.christophe.leroy@c-s.fr>
Date:   Mon, 29 Apr 2019 10:43:27 +0000 (UTC)
From:   Christophe Leroy <christophe.leroy@....fr>
To:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH 2/3] powerpc/module32: Use symbolic instructions names.

To increase readability/maintainability, replace hard coded
instructions values by symbolic names.

Signed-off-by: Christophe Leroy <christophe.leroy@....fr>
---
 arch/powerpc/kernel/module_32.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/kernel/module_32.c b/arch/powerpc/kernel/module_32.c
index 88d83771f462..c5197f856c75 100644
--- a/arch/powerpc/kernel/module_32.c
+++ b/arch/powerpc/kernel/module_32.c
@@ -170,10 +170,14 @@ int module_frob_arch_sections(Elf32_Ehdr *hdr,
 	return 0;
 }
 
+	/* lis r12,sym@ha */
+#define ENTRY_JMP0(sym)	(PPC_INST_ADDIS | __PPC_RT(R12) | PPC_HA(sym))
+	/* addi r12,r12,sym@l */
+#define ENTRY_JMP1(sym)	(PPC_INST_ADDI | __PPC_RT(R12) | __PPC_RA(R12) | PPC_LO(sym))
+
 static inline int entry_matches(struct ppc_plt_entry *entry, Elf32_Addr val)
 {
-	if (entry->jump[0] == 0x3d800000 + ((val + 0x8000) >> 16)
-	    && entry->jump[1] == 0x398c0000 + (val & 0xffff))
+	if (entry->jump[0] == ENTRY_JMP0(val) && entry->jump[1] == ENTRY_JMP1(val))
 		return 1;
 	return 0;
 }
@@ -200,10 +204,10 @@ static uint32_t do_plt_call(void *location,
 		entry++;
 	}
 
-	entry->jump[0] = 0x3d800000+((val+0x8000)>>16); /* lis r12,sym@ha */
-	entry->jump[1] = 0x398c0000 + (val&0xffff);     /* addi r12,r12,sym@l*/
-	entry->jump[2] = 0x7d8903a6;                    /* mtctr r12 */
-	entry->jump[3] = 0x4e800420;			/* bctr */
+	entry->jump[0] = ENTRY_JMP0(val);
+	entry->jump[1] = ENTRY_JMP1(val);
+	entry->jump[2] = PPC_INST_MTCTR | __PPC_RS(R12);
+	entry->jump[3] = PPC_INST_BCTR;
 
 	pr_debug("Initialized plt for 0x%x at %p\n", val, entry);
 	return (uint32_t)entry;
-- 
2.13.3