Re: [PATCH 2/3] powerpc: fix build errors

Hi Anders,

Thanks for these, just a few comments below ...

Anders Roxell anders.roxell@linaro.org writes:

Building tinyconfig with gcc (Debian 11.2.0-16) and assembler (Debian 2.37.90.20220207) the following build error shows up:

{standard input}: Assembler messages: {standard input}:1190: Error: unrecognized opcode: `stbcix' {standard input}:1433: Error: unrecognized opcode: `lwzcix' {standard input}:1453: Error: unrecognized opcode: `stbcix' {standard input}:1460: Error: unrecognized opcode: `stwcix' {standard input}:1596: Error: unrecognized opcode: `stbcix' ...

Rework to add assembler directives [1] around the instruction. Going through the them one by one shows that the changes should be safe. Like __get_user_atomic_128_aligned() is only called in p9_hmi_special_emu(), which according to the name is specific to power9. And __raw_rm_read*() are only called in things that are powernv or book3s_hv specific.

[1] https://sourceware.org/binutils/docs/as/PowerPC_002dPseudo.html#PowerPC_002d...

Cc: stable@vger.kernel.org Co-developed-by: Arnd Bergmann arnd@arndb.de Signed-off-by: Arnd Bergmann arnd@arndb.de Signed-off-by: Anders Roxell anders.roxell@linaro.org

---

arch/powerpc/include/asm/io.h | 46 +++++++++++++++++++++++----- arch/powerpc/include/asm/uaccess.h | 3 ++ arch/powerpc/platforms/powernv/rng.c | 6 +++- 3 files changed, 46 insertions(+), 9 deletions(-)

diff --git a/arch/powerpc/include/asm/io.h b/arch/powerpc/include/asm/io.h index beba4979bff9..5ff6dec489f8 100644 --- a/arch/powerpc/include/asm/io.h +++ b/arch/powerpc/include/asm/io.h @@ -359,25 +359,37 @@ static inline void __raw_writeq_be(unsigned long v, volatile void __iomem *addr) */ static inline void __raw_rm_writeb(u8 val, volatile void __iomem *paddr) {

• __asm__ __volatile__("stbcix %0,0,%1"

• __asm__ __volatile__(".machine "push"\n"

• 	     ".machine \"power6\"\n"
  

• 	     "stbcix %0,0,%1\n"
  

• 	     ".machine \"pop\"\n"
  

  : : "r" (val), "r" (paddr) : "memory");

As Segher said it'd be cleaner without the embedded quotes.

@@ -441,7 +465,10 @@ static inline unsigned int name(unsigned int port) \ unsigned int x; \ __asm__ __volatile__( \ "sync\n" \

• ".machine \"push\"\n"			\
  

• ".machine \"power6\"\n"			\
  

  "0:" op " %0,0,%1\n" \

• ".machine \"pop\"\n"			\
  

  "1: twi 0,%0,0\n" \ "2: isync\n" \ "3: nop\n" \

@@ -465,7 +492,10 @@ static inline void name(unsigned int val, unsigned int port) \ { \ __asm__ __volatile__( \ "sync\n" \

• ".machine \"push\"\n"			\
  

• ".machine \"power6\"\n"			\
  

  "0:" op " %0,0,%1\n" \

• ".machine \"pop\"\n"			\
  

  "1: sync\n" \ "2:\n" \ EX_TABLE(0b, 2b) \

It's not visible from the diff, but the above two are __do_in_asm and __do_out_asm and are inside an ifdef CONFIG_PPC32.

AFAICS they're only used for:

__do_in_asm(_rec_inb, "lbzx") __do_in_asm(_rec_inw, "lhbrx") __do_in_asm(_rec_inl, "lwbrx") __do_out_asm(_rec_outb, "stbx") __do_out_asm(_rec_outw, "sthbrx") __do_out_asm(_rec_outl, "stwbrx")

Which are all old instructions, so I don't think we need the machine power6 for those two macros?

diff --git a/arch/powerpc/platforms/powernv/rng.c b/arch/powerpc/platforms/powernv/rng.c index b4386714494a..5bf30ef6d928 100644 --- a/arch/powerpc/platforms/powernv/rng.c +++ b/arch/powerpc/platforms/powernv/rng.c @@ -43,7 +43,11 @@ static unsigned long rng_whiten(struct powernv_rng *rng, unsigned long val) unsigned long parity; /* Calculate the parity of the value */

• asm ("popcntd %0,%1" : "=r" (parity) : "r" (val));

• asm (".machine "push"\n"

•     ".machine \"power7\"\n"
  

•     "popcntd %0,%1\n"
  

•     ".machine \"pop\"\n"
  

•     : "=r" (parity) : "r" (val));
  

This was actually present in an older CPU, but it doesn't really matter, this is fine.

cheers