From mboxrd@z Thu Jan 1 00:00:00 1970 From: paulius.zaleckas@gmail.com (Paulius Zaleckas) Date: Wed, 31 Mar 2010 15:01:12 +0300 Subject: [PATCH v2] MTD: Fix Orion NAND driver compilation with ARM OABI In-Reply-To: References: <20100325152505.17612.40158.stgit@pauliusz> Message-ID: <4BB33988.9070608@gmail.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 03/25/2010 06:26 PM, Nicolas Pitre wrote: > On Thu, 25 Mar 2010, Paulius Zaleckas wrote: > >> We must tell GCC to use even register for variable passed >> to ldrd instruction. Without this patch GCC 4.2.1 puts this >> variable to r2/r3 on EABI and r3/r4 on OABI, so force it to >> r2/r3. This does not change anything when EABI and OABI >> compilation works OK. >> >> Without this patch and with OABI I get: >> CC drivers/mtd/nand/orion_nand.o >> /tmp/ccMkwOCs.s: Assembler messages: >> /tmp/ccMkwOCs.s:63: Error: first destination register must be even -- `ldrd r3,[ip]' >> make[5]: *** [drivers/mtd/nand/orion_nand.o] Error 1 >> >> Signed-off-by: Paulius Zaleckas > > Acked-by: Nicolas Pitre David, Will you take this patch? Or you are waiting till I will add all Cc as Jamie suggested? > >> --- >> >> drivers/mtd/nand/orion_nand.c | 8 +++++++- >> 1 files changed, 7 insertions(+), 1 deletions(-) >> >> diff --git a/drivers/mtd/nand/orion_nand.c b/drivers/mtd/nand/orion_nand.c >> index f59c074..d60fc57 100644 >> --- a/drivers/mtd/nand/orion_nand.c >> +++ b/drivers/mtd/nand/orion_nand.c >> @@ -60,7 +60,13 @@ static void orion_nand_read_buf(struct mtd_info *mtd, uint8_t *buf, int len) >> } >> buf64 = (uint64_t *)buf; >> while (i< len/8) { >> - uint64_t x; >> + /* >> + * Since GCC has no proper constraint (PR 43518) >> + * force x variable to r2/r3 registers as ldrd instruction >> + * requires first register to be even. >> + */ >> + register uint64_t x asm ("r2"); >> + >> asm volatile ("ldrd\t%0, [%1]" : "=&r" (x) : "r" (io_base)); >> buf64[i++] = x; >> } >>