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-rw-r--r--arch/mips/include/asm/branch.h5
-rw-r--r--arch/mips/kernel/branch.c128
-rw-r--r--arch/mips/math-emu/cp1emu.c2
3 files changed, 90 insertions, 45 deletions
diff --git a/arch/mips/include/asm/branch.h b/arch/mips/include/asm/branch.h
index 37c6857c8d4a..888766ae1f85 100644
--- a/arch/mips/include/asm/branch.h
+++ b/arch/mips/include/asm/branch.h
@@ -9,6 +9,7 @@
 #define _ASM_BRANCH_H
 
 #include <asm/ptrace.h>
+#include <asm/inst.h>
 
 static inline int delay_slot(struct pt_regs *regs)
 {
@@ -23,7 +24,11 @@ static inline unsigned long exception_epc(struct pt_regs *regs)
 	return regs->cp0_epc + 4;
 }
 
+#define BRANCH_LIKELY_TAKEN 0x0001
+
 extern int __compute_return_epc(struct pt_regs *regs);
+extern int __compute_return_epc_for_insn(struct pt_regs *regs,
+					 union mips_instruction insn);
 
 static inline int compute_return_epc(struct pt_regs *regs)
 {
diff --git a/arch/mips/kernel/branch.c b/arch/mips/kernel/branch.c
index 32103cc2a257..4d735d0e58f5 100644
--- a/arch/mips/kernel/branch.c
+++ b/arch/mips/kernel/branch.c
@@ -9,6 +9,7 @@
 #include <linux/kernel.h>
 #include <linux/sched.h>
 #include <linux/signal.h>
+#include <linux/module.h>
 #include <asm/branch.h>
 #include <asm/cpu.h>
 #include <asm/cpu-features.h>
@@ -17,28 +18,22 @@
 #include <asm/ptrace.h>
 #include <asm/uaccess.h>
 
-/*
- * Compute the return address and do emulate branch simulation, if required.
+/**
+ * __compute_return_epc_for_insn - Computes the return address and do emulate
+ *				    branch simulation, if required.
+ *
+ * @regs:	Pointer to pt_regs
+ * @insn:	branch instruction to decode
+ * @returns:	-EFAULT on error and forces SIGBUS, and on success
+ *		returns 0 or BRANCH_LIKELY_TAKEN as appropriate after
+ *		evaluating the branch.
  */
-int __compute_return_epc(struct pt_regs *regs)
+int __compute_return_epc_for_insn(struct pt_regs *regs,
+				   union mips_instruction insn)
 {
-	unsigned int __user *addr;
 	unsigned int bit, fcr31, dspcontrol;
-	long epc;
-	union mips_instruction insn;
-
-	epc = regs->cp0_epc;
-	if (epc & 3)
-		goto unaligned;
-
-	/*
-	 * Read the instruction
-	 */
-	addr = (unsigned int __user *) epc;
-	if (__get_user(insn.word, addr)) {
-		force_sig(SIGSEGV, current);
-		return -EFAULT;
-	}
+	long epc = regs->cp0_epc;
+	int ret = 0;
 
 	switch (insn.i_format.opcode) {
 	/*
@@ -64,18 +59,22 @@ int __compute_return_epc(struct pt_regs *regs)
 		switch (insn.i_format.rt) {
 	 	case bltz_op:
 		case bltzl_op:
-			if ((long)regs->regs[insn.i_format.rs] < 0)
+			if ((long)regs->regs[insn.i_format.rs] < 0) {
 				epc = epc + 4 + (insn.i_format.simmediate << 2);
-			else
+				if (insn.i_format.rt == bltzl_op)
+					ret = BRANCH_LIKELY_TAKEN;
+			} else
 				epc += 8;
 			regs->cp0_epc = epc;
 			break;
 
 		case bgez_op:
 		case bgezl_op:
-			if ((long)regs->regs[insn.i_format.rs] >= 0)
+			if ((long)regs->regs[insn.i_format.rs] >= 0) {
 				epc = epc + 4 + (insn.i_format.simmediate << 2);
-			else
+				if (insn.i_format.rt == bgezl_op)
+					ret = BRANCH_LIKELY_TAKEN;
+			} else
 				epc += 8;
 			regs->cp0_epc = epc;
 			break;
@@ -83,9 +82,11 @@ int __compute_return_epc(struct pt_regs *regs)
 		case bltzal_op:
 		case bltzall_op:
 			regs->regs[31] = epc + 8;
-			if ((long)regs->regs[insn.i_format.rs] < 0)
+			if ((long)regs->regs[insn.i_format.rs] < 0) {
 				epc = epc + 4 + (insn.i_format.simmediate << 2);
-			else
+				if (insn.i_format.rt == bltzall_op)
+					ret = BRANCH_LIKELY_TAKEN;
+			} else
 				epc += 8;
 			regs->cp0_epc = epc;
 			break;
@@ -93,12 +94,15 @@ int __compute_return_epc(struct pt_regs *regs)
 		case bgezal_op:
 		case bgezall_op:
 			regs->regs[31] = epc + 8;
-			if ((long)regs->regs[insn.i_format.rs] >= 0)
+			if ((long)regs->regs[insn.i_format.rs] >= 0) {
 				epc = epc + 4 + (insn.i_format.simmediate << 2);
-			else
+				if (insn.i_format.rt == bgezall_op)
+					ret = BRANCH_LIKELY_TAKEN;
+			} else
 				epc += 8;
 			regs->cp0_epc = epc;
 			break;
+
 		case bposge32_op:
 			if (!cpu_has_dsp)
 				goto sigill;
@@ -133,9 +137,11 @@ int __compute_return_epc(struct pt_regs *regs)
 	case beq_op:
 	case beql_op:
 		if (regs->regs[insn.i_format.rs] ==
-		    regs->regs[insn.i_format.rt])
+		    regs->regs[insn.i_format.rt]) {
 			epc = epc + 4 + (insn.i_format.simmediate << 2);
-		else
+			if (insn.i_format.rt == beql_op)
+				ret = BRANCH_LIKELY_TAKEN;
+		} else
 			epc += 8;
 		regs->cp0_epc = epc;
 		break;
@@ -143,9 +149,11 @@ int __compute_return_epc(struct pt_regs *regs)
 	case bne_op:
 	case bnel_op:
 		if (regs->regs[insn.i_format.rs] !=
-		    regs->regs[insn.i_format.rt])
+		    regs->regs[insn.i_format.rt]) {
 			epc = epc + 4 + (insn.i_format.simmediate << 2);
-		else
+			if (insn.i_format.rt == bnel_op)
+				ret = BRANCH_LIKELY_TAKEN;
+		} else
 			epc += 8;
 		regs->cp0_epc = epc;
 		break;
@@ -153,9 +161,11 @@ int __compute_return_epc(struct pt_regs *regs)
 	case blez_op: /* not really i_format */
 	case blezl_op:
 		/* rt field assumed to be zero */
-		if ((long)regs->regs[insn.i_format.rs] <= 0)
+		if ((long)regs->regs[insn.i_format.rs] <= 0) {
 			epc = epc + 4 + (insn.i_format.simmediate << 2);
-		else
+			if (insn.i_format.rt == bnel_op)
+				ret = BRANCH_LIKELY_TAKEN;
+		} else
 			epc += 8;
 		regs->cp0_epc = epc;
 		break;
@@ -163,9 +173,11 @@ int __compute_return_epc(struct pt_regs *regs)
 	case bgtz_op:
 	case bgtzl_op:
 		/* rt field assumed to be zero */
-		if ((long)regs->regs[insn.i_format.rs] > 0)
+		if ((long)regs->regs[insn.i_format.rs] > 0) {
 			epc = epc + 4 + (insn.i_format.simmediate << 2);
-		else
+			if (insn.i_format.rt == bnel_op)
+				ret = BRANCH_LIKELY_TAKEN;
+		} else
 			epc += 8;
 		regs->cp0_epc = epc;
 		break;
@@ -187,18 +199,22 @@ int __compute_return_epc(struct pt_regs *regs)
 		switch (insn.i_format.rt & 3) {
 		case 0:	/* bc1f */
 		case 2:	/* bc1fl */
-			if (~fcr31 & (1 << bit))
+			if (~fcr31 & (1 << bit)) {
 				epc = epc + 4 + (insn.i_format.simmediate << 2);
-			else
+				if (insn.i_format.rt == 2)
+					ret = BRANCH_LIKELY_TAKEN;
+			} else
 				epc += 8;
 			regs->cp0_epc = epc;
 			break;
 
 		case 1:	/* bc1t */
 		case 3:	/* bc1tl */
-			if (fcr31 & (1 << bit))
+			if (fcr31 & (1 << bit)) {
 				epc = epc + 4 + (insn.i_format.simmediate << 2);
-			else
+				if (insn.i_format.rt == 3)
+					ret = BRANCH_LIKELY_TAKEN;
+			} else
 				epc += 8;
 			regs->cp0_epc = epc;
 			break;
@@ -239,15 +255,39 @@ int __compute_return_epc(struct pt_regs *regs)
 #endif
 	}
 
-	return 0;
+	return ret;
 
-unaligned:
-	printk("%s: unaligned epc - sending SIGBUS.\n", current->comm);
+sigill:
+	printk("%s: DSP branch but not DSP ASE - sending SIGBUS.\n", current->comm);
 	force_sig(SIGBUS, current);
 	return -EFAULT;
+}
+EXPORT_SYMBOL_GPL(__compute_return_epc_for_insn);
 
-sigill:
-	printk("%s: DSP branch but not DSP ASE - sending SIGBUS.\n", current->comm);
+int __compute_return_epc(struct pt_regs *regs)
+{
+	unsigned int __user *addr;
+	long epc;
+	union mips_instruction insn;
+
+	epc = regs->cp0_epc;
+	if (epc & 3)
+		goto unaligned;
+
+	/*
+	 * Read the instruction
+	 */
+	addr = (unsigned int __user *) epc;
+	if (__get_user(insn.word, addr)) {
+		force_sig(SIGSEGV, current);
+		return -EFAULT;
+	}
+
+	return __compute_return_epc_for_insn(regs, insn);
+
+unaligned:
+	printk("%s: unaligned epc - sending SIGBUS.\n", current->comm);
 	force_sig(SIGBUS, current);
 	return -EFAULT;
+
 }
diff --git a/arch/mips/math-emu/cp1emu.c b/arch/mips/math-emu/cp1emu.c
index dbf2f93a5091..a03bf00a1a9c 100644
--- a/arch/mips/math-emu/cp1emu.c
+++ b/arch/mips/math-emu/cp1emu.c
@@ -245,7 +245,7 @@ static int cop1Emulate(struct pt_regs *xcp, struct mips_fpu_struct *ctx,
 		 */
 		emulpc = xcp->cp0_epc + 4;	/* Snapshot emulation target */
 
-		if (__compute_return_epc(xcp)) {
+		if (__compute_return_epc(xcp) < 0) {
 #ifdef CP1DBG
 			printk("failed to emulate branch at %p\n",
 				(void *) (xcp->cp0_epc));
generated by cgit-pink 1.4.1 (git 2.36.1) at 2024-10-17 12:40:45 +0000