MIPS: math-emu: Fix final emulation phase for certain instructions

Fix final phase of <CLASS|MADDF|MSUBF|MAX|MIN|MAXA|MINA>.<D|S>
emulation. Provide proper generation of SIGFPE signal and updating
debugfs FP exception stats in cases of any exception flags set in
preceding phases of emulation.

CLASS.<D|S> instruction may generate "Unimplemented Operation" FP
exception. <MADDF|MSUBF>.<D|S> instructions may generate "Inexact",
"Unimplemented Operation", "Invalid Operation", "Overflow", and
"Underflow" FP exceptions. <MAX|MIN|MAXA|MINA>.<D|S> instructions
can generate "Unimplemented Operation" and "Invalid Operation" FP
exceptions.

The proper final processing of the cases when any FP exception
flag is set is achieved by replacing "break" statement with "goto
copcsr" statement. With such solution, this patch brings the final
phase of emulation of the above instructions consistent with the
one corresponding to the previously implemented emulation of other
related FPU instructions (ADD, SUB, etc.).

Fixes: 38db37ba069f ("MIPS: math-emu: Add support for the MIPS R6 CLASS FPU instruction")
Fixes: e24c3bec3e8e ("MIPS: math-emu: Add support for the MIPS R6 MADDF FPU instruction")
Fixes: 83d43305a1df ("MIPS: math-emu: Add support for the MIPS R6 MSUBF FPU instruction")
Fixes: a79f5f9ba508 ("MIPS: math-emu: Add support for the MIPS R6 MAX{, A} FPU instruction")
Fixes: 4e9561b20e2f ("MIPS: math-emu: Add support for the MIPS R6 MIN{, A} FPU instruction")
Signed-off-by: Aleksandar Markovic <aleksandar.markovic@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Douglas Leung <douglas.leung@mips.com>
Cc: Goran Ferenc <goran.ferenc@mips.com>
Cc: "Maciej W. Rozycki" <macro@imgtec.com>
Cc: Miodrag Dinic <miodrag.dinic@mips.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Petar Jovanovic <petar.jovanovic@mips.com>
Cc: Raghu Gandham <raghu.gandham@mips.com>
Cc: linux-mips@linux-mips.org
Cc: <stable@vger.kernel.org> # 4.3+
Patchwork: https://patchwork.linux-mips.org/patch/17581/
Signed-off-by: James Hogan <jhogan@kernel.org>

diff --git a/arch/mips/math-emu/cp1emu.c b/arch/mips/math-emu/cp1emu.c
index 192542dbd9724788838a74cb5ed4b8404b0d83fc..d2fcb3084279f17ae1251781c5b6f5be0bf587d9 100644 (file)
--- a/arch/mips/math-emu/cp1emu.c
+++ b/arch/mips/math-emu/cp1emu.c
@@ -1795,7 +1795,7 @@ static int fpu_emu(struct pt_regs *xcp, struct mips_fpu_struct *ctx,
                        SPFROMREG(fs, MIPSInst_FS(ir));
                        SPFROMREG(fd, MIPSInst_FD(ir));
                        rv.s = ieee754sp_maddf(fd, fs, ft);
-                       break;
+                       goto copcsr;
                }
 
                case fmsubf_op: {
@@ -1809,7 +1809,7 @@ static int fpu_emu(struct pt_regs *xcp, struct mips_fpu_struct *ctx,
                        SPFROMREG(fs, MIPSInst_FS(ir));
                        SPFROMREG(fd, MIPSInst_FD(ir));
                        rv.s = ieee754sp_msubf(fd, fs, ft);
-                       break;
+                       goto copcsr;
                }
 
                case frint_op: {
@@ -1834,7 +1834,7 @@ static int fpu_emu(struct pt_regs *xcp, struct mips_fpu_struct *ctx,
                        SPFROMREG(fs, MIPSInst_FS(ir));
                        rv.w = ieee754sp_2008class(fs);
                        rfmt = w_fmt;
-                       break;
+                       goto copcsr;
                }
 
                case fmin_op: {
@@ -1847,7 +1847,7 @@ static int fpu_emu(struct pt_regs *xcp, struct mips_fpu_struct *ctx,
                        SPFROMREG(ft, MIPSInst_FT(ir));
                        SPFROMREG(fs, MIPSInst_FS(ir));
                        rv.s = ieee754sp_fmin(fs, ft);
-                       break;
+                       goto copcsr;
                }
 
                case fmina_op: {
@@ -1860,7 +1860,7 @@ static int fpu_emu(struct pt_regs *xcp, struct mips_fpu_struct *ctx,
                        SPFROMREG(ft, MIPSInst_FT(ir));
                        SPFROMREG(fs, MIPSInst_FS(ir));
                        rv.s = ieee754sp_fmina(fs, ft);
-                       break;
+                       goto copcsr;
                }
 
                case fmax_op: {
@@ -1873,7 +1873,7 @@ static int fpu_emu(struct pt_regs *xcp, struct mips_fpu_struct *ctx,
                        SPFROMREG(ft, MIPSInst_FT(ir));
                        SPFROMREG(fs, MIPSInst_FS(ir));
                        rv.s = ieee754sp_fmax(fs, ft);
-                       break;
+                       goto copcsr;
                }
 
                case fmaxa_op: {
@@ -1886,7 +1886,7 @@ static int fpu_emu(struct pt_regs *xcp, struct mips_fpu_struct *ctx,
                        SPFROMREG(ft, MIPSInst_FT(ir));
                        SPFROMREG(fs, MIPSInst_FS(ir));
                        rv.s = ieee754sp_fmaxa(fs, ft);
-                       break;
+                       goto copcsr;
                }
 
                case fabs_op:
@@ -2165,7 +2165,7 @@ copcsr:
                        DPFROMREG(fs, MIPSInst_FS(ir));
                        DPFROMREG(fd, MIPSInst_FD(ir));
                        rv.d = ieee754dp_maddf(fd, fs, ft);
-                       break;
+                       goto copcsr;
                }
 
                case fmsubf_op: {
@@ -2179,7 +2179,7 @@ copcsr:
                        DPFROMREG(fs, MIPSInst_FS(ir));
                        DPFROMREG(fd, MIPSInst_FD(ir));
                        rv.d = ieee754dp_msubf(fd, fs, ft);
-                       break;
+                       goto copcsr;
                }
 
                case frint_op: {
@@ -2204,7 +2204,7 @@ copcsr:
                        DPFROMREG(fs, MIPSInst_FS(ir));
                        rv.l = ieee754dp_2008class(fs);
                        rfmt = l_fmt;
-                       break;
+                       goto copcsr;
                }
 
                case fmin_op: {
@@ -2217,7 +2217,7 @@ copcsr:
                        DPFROMREG(ft, MIPSInst_FT(ir));
                        DPFROMREG(fs, MIPSInst_FS(ir));
                        rv.d = ieee754dp_fmin(fs, ft);
-                       break;
+                       goto copcsr;
                }
 
                case fmina_op: {
@@ -2230,7 +2230,7 @@ copcsr:
                        DPFROMREG(ft, MIPSInst_FT(ir));
                        DPFROMREG(fs, MIPSInst_FS(ir));
                        rv.d = ieee754dp_fmina(fs, ft);
-                       break;
+                       goto copcsr;
                }
 
                case fmax_op: {
@@ -2243,7 +2243,7 @@ copcsr:
                        DPFROMREG(ft, MIPSInst_FT(ir));
                        DPFROMREG(fs, MIPSInst_FS(ir));
                        rv.d = ieee754dp_fmax(fs, ft);
-                       break;
+                       goto copcsr;
                }
 
                case fmaxa_op: {
@@ -2256,7 +2256,7 @@ copcsr:
                        DPFROMREG(ft, MIPSInst_FT(ir));
                        DPFROMREG(fs, MIPSInst_FS(ir));
                        rv.d = ieee754dp_fmaxa(fs, ft);
-                       break;
+                       goto copcsr;
                }
 
                case fabs_op: