powerpc/64s: Remove ICSWX feature from Power9

Power9 does not implement the icswx instruction. This CPU feature is not visible
to userspace and is only used in the CONFIG_PPC_ICSWX code, which is generally
not enabled, and can only be triggered by other code using icswx, which should
not happen on Power9 systems in the first place. So impact should be minimal.

Fixes: c3ab300ea5 ("powerpc: Add POWER9 cputable entry")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/include/asm/cputable.h b/arch/powerpc/include/asm/cputable.h
index ab68d0ee7725861d827d34c4f05ed08001e13274..5869025673b4a8e4e2e7814c2f1bcfcf7417d232 100644 (file)
--- a/arch/powerpc/include/asm/cputable.h
+++ b/arch/powerpc/include/asm/cputable.h
@@ -471,7 +471,7 @@ enum {
            CPU_FTR_PURR | CPU_FTR_SPURR | CPU_FTR_REAL_LE | \
            CPU_FTR_DSCR | CPU_FTR_SAO  | \
            CPU_FTR_STCX_CHECKS_ADDRESS | CPU_FTR_POPCNTB | CPU_FTR_POPCNTD | \
-           CPU_FTR_ICSWX | CPU_FTR_CFAR | CPU_FTR_HVMODE | CPU_FTR_VMX_COPY | \
+           CPU_FTR_CFAR | CPU_FTR_HVMODE | CPU_FTR_VMX_COPY | \
            CPU_FTR_DBELL | CPU_FTR_HAS_PPR | CPU_FTR_DAWR | \
            CPU_FTR_ARCH_207S | CPU_FTR_TM_COMP | CPU_FTR_ARCH_300)
 #define CPU_FTRS_POWER9_DD1 (CPU_FTRS_POWER9 | CPU_FTR_POWER9_DD1)

diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype
index ee87cb37c580a4de59a61f217fff790b354b7385..684e886eaae403e4b2fdf308c1fbf37f548bd263 100644 (file)
--- a/arch/powerpc/platforms/Kconfig.cputype
+++ b/arch/powerpc/platforms/Kconfig.cputype
@@ -279,7 +279,8 @@ config PPC_ICSWX
 
          This option enables kernel support for the PowerPC Initiate
          Coprocessor Store Word (icswx) coprocessor instruction on POWER7
-         or newer processors.
+         and POWER8 processors. POWER9 uses new copy/paste instructions
+         to invoke the coprocessor.
 
          This option is only useful if you have a processor that supports
          the icswx coprocessor instruction. It does not have any effect