[PATCH 4.9 55/60] MIPS: Fix bnezc/jialc return address calculation

[PATCH 4.9 55/60] MIPS: Fix bnezc/jialc return address calculation

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Paul Burton <paul.burton@imgtec.com>

commit 1a73d9310e093fc3adffba4d0a67b9fab2ee3f63 upstream.

The code handling the pop76 opcode (ie. bnezc & jialc instructions) in
__compute_return_epc_for_insn() needs to set the value of $31 in the
jialc case, which is encoded with rs = 0. However its check to
differentiate bnezc (rs != 0) from jialc (rs = 0) was unfortunately
backwards, meaning that if we emulate a bnezc instruction we clobber $31
& if we emulate a jialc instruction it actually behaves like a jic
instruction.

Fix this by inverting the check of rs to match the way the instructions
are actually encoded.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Fixes: 28d6f93d201d ("MIPS: Emulate the new MIPS R6 BNEZC and JIALC instructions")
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16178/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/mips/kernel/branch.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/arch/mips/kernel/branch.c
+++ b/arch/mips/kernel/branch.c
@@ -804,8 +804,10 @@ int __compute_return_epc_for_insn(struct
 			break;
 		}
 		/* Compact branch: BNEZC || JIALC */
-		if (insn.i_format.rs)
+		if (!insn.i_format.rs) {
+			/* JIALC: set $31/ra */
 			regs->regs[31] = epc + 4;
+		}
 		regs->cp0_epc += 8;
 		break;
 #endif

[PATCH 4.9 56/60] MIPS: .its targets depend on vmlinux

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Paul Burton <paul.burton@imgtec.com>

commit bcd7c45e0d5a82be9a64b90050f0e09d41a50758 upstream.

The .its targets require information about the kernel binary, such as
its entry point, which is extracted from the vmlinux ELF. We therefore
require that the ELF is built before the .its files are generated.
Declare this requirement in the Makefile such that make will ensure this
is always the case, otherwise in corner cases we can hit issues as the
.its is generated with an incorrect (either invalid or stale) entry
point.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Fixes: cf2a5e0bb4c6 ("MIPS: Support generating Flattened Image Trees (.itb)")
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16179/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/mips/boot/Makefile |   10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

--- a/arch/mips/boot/Makefile
+++ b/arch/mips/boot/Makefile
@@ -128,19 +128,19 @@ quiet_cmd_cpp_its_S = ITS     $@
 			-DADDR_BITS=$(ADDR_BITS) \
 			-DADDR_CELLS=$(itb_addr_cells)
 
-$(obj)/vmlinux.its: $(srctree)/arch/mips/$(PLATFORM)/vmlinux.its.S FORCE
+$(obj)/vmlinux.its: $(srctree)/arch/mips/$(PLATFORM)/vmlinux.its.S $(VMLINUX) FORCE
 	$(call if_changed_dep,cpp_its_S,none,vmlinux.bin)
 
-$(obj)/vmlinux.gz.its: $(srctree)/arch/mips/$(PLATFORM)/vmlinux.its.S FORCE
+$(obj)/vmlinux.gz.its: $(srctree)/arch/mips/$(PLATFORM)/vmlinux.its.S $(VMLINUX) FORCE
 	$(call if_changed_dep,cpp_its_S,gzip,vmlinux.bin.gz)
 
-$(obj)/vmlinux.bz2.its: $(srctree)/arch/mips/$(PLATFORM)/vmlinux.its.S FORCE
+$(obj)/vmlinux.bz2.its: $(srctree)/arch/mips/$(PLATFORM)/vmlinux.its.S $(VMLINUX)  FORCE
 	$(call if_changed_dep,cpp_its_S,bzip2,vmlinux.bin.bz2)
 
-$(obj)/vmlinux.lzma.its: $(srctree)/arch/mips/$(PLATFORM)/vmlinux.its.S FORCE
+$(obj)/vmlinux.lzma.its: $(srctree)/arch/mips/$(PLATFORM)/vmlinux.its.S $(VMLINUX) FORCE
 	$(call if_changed_dep,cpp_its_S,lzma,vmlinux.bin.lzma)
 
-$(obj)/vmlinux.lzo.its: $(srctree)/arch/mips/$(PLATFORM)/vmlinux.its.S FORCE
+$(obj)/vmlinux.lzo.its: $(srctree)/arch/mips/$(PLATFORM)/vmlinux.its.S $(VMLINUX) FORCE
 	$(call if_changed_dep,cpp_its_S,lzo,vmlinux.bin.lzo)
 
 quiet_cmd_itb-image = ITB     $@