linux-kernel - [RFC 1/1 linux-next] tools/lguest: update variables to avoid setreg(eax, eax)

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Message-Id: <1434486430-14003-1-git-send-email-fabf@skynet.be>
Date:	Tue, 16 Jun 2015 22:27:09 +0200
From:	Fabian Frederick <fabf@...net.be>
To:	linux-kernel@...r.kernel.org
Cc:	Julia Lawall <Julia.Lawall@...6.fr>,
	Fabian Frederick <fabf@...net.be>,
	Rusty Russell <rusty@...tcorp.com.au>, lguest@...ts.ozlabs.org
Subject: [RFC 1/1 linux-next] tools/lguest: update variables to avoid setreg(eax, eax)

eax is used for offset calculation but is also a local
variable used to store register value.
Use val for value and defval for default value to remove
this ambiguity.

Thanks to Julia Lawall for Coccinelle scripting support.

Signed-off-by: Fabian Frederick <fabf@...net.be>
---
 tools/lguest/lguest.c | 26 +++++++++++++-------------
 1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/tools/lguest/lguest.c b/tools/lguest/lguest.c
index e440524..d466c79 100644
--- a/tools/lguest/lguest.c
+++ b/tools/lguest/lguest.c
@@ -1611,12 +1611,12 @@ static void emulate_insn(const u8 insn[])
 {
 	unsigned long args[] = { LHREQ_TRAP, 13 };
 	unsigned int insnlen = 0, in = 0, small_operand = 0, byte_access;
-	unsigned int eax, port, mask;
+	unsigned int val, port, mask;
 	/*
 	 * Default is to return all-ones on IO port reads, which traditionally
 	 * means "there's nothing there".
 	 */
-	u32 val = 0xFFFFFFFF;
+	u32 defval = 0xFFFFFFFF;
 
 	/*
 	 * This must be the Guest kernel trying to do something, not userspace!
@@ -1692,29 +1692,29 @@ static void emulate_insn(const u8 insn[])
 	 * If it was an "IN" instruction, they expect the result to be read
 	 * into %eax, so we change %eax.
 	 */
-	eax = getreg(eax);
+	val = getreg(eax);
 
 	if (in) {
 		/* This is the PS/2 keyboard status; 1 means ready for output */
 		if (port == 0x64)
-			val = 1;
+			defval = 1;
 		else if (is_pci_addr_port(port))
-			pci_addr_ioread(port, mask, &val);
+			pci_addr_ioread(port, mask, &defval);
 		else if (is_pci_data_port(port))
-			pci_data_ioread(port, mask, &val);
+			pci_data_ioread(port, mask, &defval);
 
 		/* Clear the bits we're about to read */
-		eax &= ~mask;
-		/* Copy bits in from val. */
-		eax |= val & mask;
+		val &= ~mask;
+		/* Copy bits in from defval. */
+		val |= defval & mask;
 		/* Now update the register. */
-		setreg(eax, eax);
+		setreg(eax, val);
 	} else {
 		if (is_pci_addr_port(port)) {
-			if (!pci_addr_iowrite(port, mask, eax))
+			if (!pci_addr_iowrite(port, mask, val))
 				goto bad_io;
 		} else if (is_pci_data_port(port)) {
-			if (!pci_data_iowrite(port, mask, eax))
+			if (!pci_data_iowrite(port, mask, val))
 				goto bad_io;
 		}
 		/* There are many other ports, eg. CMOS clock, serial
@@ -1722,7 +1722,7 @@ static void emulate_insn(const u8 insn[])
 	}
 
 	verbose("IO %s of %x to %u: %#08x\n",
-		in ? "IN" : "OUT", mask, port, eax);
+		in ? "IN" : "OUT", mask, port, val);
 skip_insn:
 	/* Finally, we've "done" the instruction, so move past it. */
 	setreg(eip, getreg(eip) + insnlen);
-- 
2.4.2

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