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Commit 41ca86e8 authored by Ralf Baechle's avatar Ralf Baechle
Browse files

MIPS: Fix branch emulation of branch likely instructions. 



Two issues:

  o For beql_op, beql_op, bne_op, bnel_op, blez_op, blezl_op, bgtz_op and
    bgtzl_op the wrong field was being checked for the instruction opcode.
  o For blez_op / blezl_op and bgtz_op / bgtzl_op the test was testing
    for the wrong opcode.

This bug got introduced by d8d4e3ae [MIPS
Kprobes: Refactor branch emulation].

Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
Acked-by: default avatarLeonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Acked-by: default avatarVictor Kamensky <kamensky@cisco.com>
parent dc93f7b6

arch/mips/kernel/branch.c

+4 −4
Original line number Diff line number Diff line
@@ -317,7 +317,7 @@ int __compute_return_epc_for_insn(struct pt_regs *regs, 
		if (regs->regs[insn.i_format.rs] ==

		    regs->regs[insn.i_format.rt]) {

			epc = epc + 4 + (insn.i_format.simmediate << 2);

			if (insn.i_format.rt == beql_op)

			if (insn.i_format.opcode == beql_op)

				ret = BRANCH_LIKELY_TAKEN;

		} else

			epc += 8;
@@ -329,7 +329,7 @@ int __compute_return_epc_for_insn(struct pt_regs *regs, 
		if (regs->regs[insn.i_format.rs] !=

		    regs->regs[insn.i_format.rt]) {

			epc = epc + 4 + (insn.i_format.simmediate << 2);

			if (insn.i_format.rt == bnel_op)

			if (insn.i_format.opcode == bnel_op)

				ret = BRANCH_LIKELY_TAKEN;

		} else

			epc += 8;
@@ -341,7 +341,7 @@ int __compute_return_epc_for_insn(struct pt_regs *regs, 
		/* rt field assumed to be zero */

		if ((long)regs->regs[insn.i_format.rs] <= 0) {

			epc = epc + 4 + (insn.i_format.simmediate << 2);

			if (insn.i_format.rt == bnel_op)

			if (insn.i_format.opcode == blezl_op)

				ret = BRANCH_LIKELY_TAKEN;

		} else

			epc += 8;
@@ -353,7 +353,7 @@ int __compute_return_epc_for_insn(struct pt_regs *regs, 
		/* rt field assumed to be zero */

		if ((long)regs->regs[insn.i_format.rs] > 0) {

			epc = epc + 4 + (insn.i_format.simmediate << 2);

			if (insn.i_format.rt == bnel_op)

			if (insn.i_format.opcode == bgtzl_op)

				ret = BRANCH_LIKELY_TAKEN;

		} else

			epc += 8;