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| author |   Jordan Niethe <jniethe5@gmail.com> | 2019-09-17 10:46:05 +1000 |
|---|---|---|
| committer |   Michael Ellerman <mpe@ellerman.id.au> | 2019-09-21 08:36:53 +1000 |
| commit | 13c7bb3c57dcfe779ea5b4b083f6c47753cc5327 (patch) | |
| tree | b1f09704685bd96151bf3f6882100d5ef0112069 /arch/powerpc/include/asm/reg.h | |
| parent | powerpc: Fix definition of PCR bits to work with old binutils (diff) | |
| download | linux-dev-13c7bb3c57dcfe779ea5b4b083f6c47753cc5327.tar.xz linux-dev-13c7bb3c57dcfe779ea5b4b083f6c47753cc5327.zip | |
powerpc/64s: Set reserved PCR bits
Currently the reserved bits of the Processor Compatibility
Register (PCR) are cleared as per the Programming Note in Section
1.3.3 of version 3.0B of the Power ISA. This causes all new
architecture features to be made available when running on newer
processors with new architecture features added to the PCR as bits
must be set to disable a given feature.
For example to disable new features added as part of Version 2.07 of
the ISA the corresponding bit in the PCR needs to be set.
As new processor features generally require explicit kernel support
they should be disabled until such support is implemented. Therefore
kernels should set all unknown/reserved bits in the PCR such that any
new architecture features which the kernel does not currently know
about get disabled.
An update is planned to the ISA to clarify that the PCR is an
exception to the Programming Note on reserved bits in Section 1.3.3.
Signed-off-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Tested-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190917004605.22471-2-alistair@popple.id.au
Diffstat (limited to 'arch/powerpc/include/asm/reg.h')
| -rw-r--r-- | arch/powerpc/include/asm/reg.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h index 931939af95d1..b3cbb1136bce 100644 --- a/arch/powerpc/include/asm/reg.h +++ b/arch/powerpc/include/asm/reg.h @@ -478,6 +478,7 @@ #define PCR_VEC_DIS (__MASK(63-0)) /* Vec. disable (bit NA since POWER8) */ #define PCR_VSX_DIS (__MASK(63-1)) /* VSX disable (bit NA since POWER8) */ #define PCR_TM_DIS (__MASK(63-2)) /* Trans. memory disable (POWER8) */ +#define PCR_HIGH_BITS (PCR_VEC_DIS | PCR_VSX_DIS | PCR_TM_DIS) /* * These bits are used in the function kvmppc_set_arch_compat() to specify and * determine both the compatibility level which we want to emulate and the @@ -486,6 +487,8 @@ #define PCR_ARCH_207 0x8 /* Architecture 2.07 */ #define PCR_ARCH_206 0x4 /* Architecture 2.06 */ #define PCR_ARCH_205 0x2 /* Architecture 2.05 */ +#define PCR_LOW_BITS (PCR_ARCH_207 | PCR_ARCH_206 | PCR_ARCH_205) +#define PCR_MASK ~(PCR_HIGH_BITS | PCR_LOW_BITS) /* PCR Reserved Bits */ #define SPRN_HEIR 0x153 /* Hypervisor Emulated Instruction Register */ #define SPRN_TLBINDEXR 0x154 /* P7 TLB control register */ #define SPRN_TLBVPNR 0x155 /* P7 TLB control register */ |