[PATCH] powerpc: Fix P10 PVR revision in /proc/cpuinfo for SMT4 cores

On POWER10 bit 12 in the PVR indicates if the core is SMT4 or
SMT8. Bit 12 is set for SMT4.

Without this patch, /proc/cpuinfo on a SMT4 DD1 POWER10 looks like
this:
    cpu             : POWER10, altivec supported
    revision        : 17.0 (pvr 0080 1100)

Signed-off-by: Michael Neuling <redacted>
---
 arch/powerpc/kernel/setup-common.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
index b198b0ff25..808ec9fab6 100644
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c

@@ -311,6 +311,7 @@ static int show_cpuinfo(struct seq_file *m, void *v)
 				min = pvr & 0xFF;
 				break;
 			case 0x004e: /* POWER9 bits 12-15 give chip type */
+			case 0x0080: /* POWER10 bit 12 gives SMT8/4 */
 				maj = (pvr >> 8) & 0x0F;
 				min = pvr & 0xFF;
 				break;

-- 
2.26.2

* Michael Neuling [off-list ref] [2020-08-03 13:56:00]:

On POWER10 bit 12 in the PVR indicates if the core is SMT4 or
SMT8. Bit 12 is set for SMT4.

Without this patch, /proc/cpuinfo on a SMT4 DD1 POWER10 looks like
this:
    cpu             : POWER10, altivec supported
    revision        : 17.0 (pvr 0080 1100)

Signed-off-by: Michael Neuling <redacted>

Reviewed-by: Vaidyanathan Srinivasan <redacted>

Correct. P9 and P10 have chip type (smt4 vs smt8 core) encoded in bits
PVR chip type bits 12-15.

Thanks for the fix.

--Vaidy

Michael Neuling [off-list ref] writes:

On POWER10 bit 12 in the PVR indicates if the core is SMT4 or
SMT8. Bit 12 is set for SMT4.

Without this patch, /proc/cpuinfo on a SMT4 DD1 POWER10 looks like
this:
    cpu             : POWER10, altivec supported
    revision        : 17.0 (pvr 0080 1100)

Signed-off-by: Michael Neuling <redacted>
---
 arch/powerpc/kernel/setup-common.c | 1 +
 1 file changed, 1 insertion(+)

This should have a Fixes: pointing at something so it gets backported.

cheers

On Mon, 2020-08-03 at 22:41 +1000, Michael Ellerman wrote:

Michael Neuling [off-list ref] writes:

quoted

On POWER10 bit 12 in the PVR indicates if the core is SMT4 or
SMT8. Bit 12 is set for SMT4.

Without this patch, /proc/cpuinfo on a SMT4 DD1 POWER10 looks like
this:
    cpu             : POWER10, altivec supported
    revision        : 17.0 (pvr 0080 1100)

Signed-off-by: Michael Neuling <redacted>
---
 arch/powerpc/kernel/setup-common.c | 1 +
 1 file changed, 1 insertion(+)

This should have a Fixes: pointing at something so it gets backported.

Yes it should.

Mikey

On Mon, 3 Aug 2020 13:56:00 +1000, Michael Neuling wrote:

On POWER10 bit 12 in the PVR indicates if the core is SMT4 or
SMT8. Bit 12 is set for SMT4.

Without this patch, /proc/cpuinfo on a SMT4 DD1 POWER10 looks like
this:
    cpu             : POWER10, altivec supported
    revision        : 17.0 (pvr 0080 1100)

Applied to powerpc/fixes.

[1/1] powerpc: Fix P10 PVR revision in /proc/cpuinfo for SMT4 cores
      https://git.kernel.org/powerpc/c/030a2c689fb46e1690f7ded8b194bab7678efb28

cheers