4.4-stable review patch. If anyone has any objections, please let me know.
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From: Paul Burton paul.burton@imgtec.com
[ Upstream commit 08889582b8aa0bbc01a1e5a0033b9f98d2e11caa ]
When building a kernel targeting a microMIPS ISA, recent GNU linkers will fail the link if they cannot determine that the target of a branch or jump is microMIPS code, with errors such as the following:
mips-img-linux-gnu-ld: arch/mips/built-in.o: .text+0x542c: Unsupported jump between ISA modes; consider recompiling with interlinking enabled. mips-img-linux-gnu-ld: final link failed: Bad value
or:
./arch/mips/include/asm/uaccess.h:1017: warning: JALX to a non-word-aligned address
Placing anything other than an instruction at the start of a function written in assembly appears to trigger such errors. In order to prepare for allowing us to follow function prologue macros with an EXPORT_SYMBOL invocation, end the prologue macros (LEAD, NESTED & FEXPORT) with a .insn directive. This ensures that the start of the function is marked as code, which always makes sense for functions & safely prevents us from hitting the link errors described above.
Signed-off-by: Paul Burton paul.burton@imgtec.com Reviewed-by: Maciej W. Rozycki macro@imgtec.com Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/14508/ Signed-off-by: Ralf Baechle ralf@linux-mips.org Signed-off-by: Sasha Levin alexander.levin@verizon.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/mips/include/asm/asm.h | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
--- a/arch/mips/include/asm/asm.h +++ b/arch/mips/include/asm/asm.h @@ -54,7 +54,8 @@ .align 2; \ .type symbol, @function; \ .ent symbol, 0; \ -symbol: .frame sp, 0, ra +symbol: .frame sp, 0, ra; \ + .insn
/* * NESTED - declare nested routine entry point @@ -63,8 +64,9 @@ symbol: .frame sp, 0, ra .globl symbol; \ .align 2; \ .type symbol, @function; \ - .ent symbol, 0; \ -symbol: .frame sp, framesize, rpc + .ent symbol, 0; \ +symbol: .frame sp, framesize, rpc; \ + .insn
/* * END - mark end of function @@ -86,7 +88,7 @@ symbol: #define FEXPORT(symbol) \ .globl symbol; \ .type symbol, @function; \ -symbol: +symbol: .insn
/* * ABS - export absolute symbol